Price Point of lifepo4 batterys. - Page 1
Forum section: electronics / general

author: mrpackethead
author_rank: Super Contributor
timestamp: May 25, 2018, 11:27:01 pm
content: Hi,I'm wondering if anyone can provide some guidence about the price point of LifePO4 batterys. . I'm investigating some 10kWh battery packs. The pricing being around $3800 USD.Whats the going price for this battery technology

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 26, 2018, 02:12:48 am
content: I paid a little more than $100 or so for 60 32650 cells to make a 12.8V 82Ah pack, but that obviously doesn't include the time needed to assemble the pack.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 26, 2018, 09:47:27 pm
content: Quote from: NiHaoMike on May 26, 2018, 02:12:48 amDid you include battery management hardware?

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 26, 2018, 10:40:19 pm
content: Quote from: ahbushnell on May 26, 2018, 09:47:27 pmThe BMS is about $10 or so. I modded it similar to what Kerry Wong did for his battery pack, but I put LEDs across the resistors to give a visual indication that balancing is active.http://www.kerrywong.com/2017/09/10/modifying-a-4s-100a-lifepo4-bms-module/comment-page-1/

author: mrpackethead
author_rank: Super Contributor
timestamp: May 27, 2018, 09:15:20 am
content: Interesting. At $100 for a 12V 82AH, its nearly 1kwhr. THat would make 10kW, a little mroe than $1000, thats nearly 1/4 of the price of a finshed system.Now makes me wonder

author: mrpackethead
author_rank: Super Contributor
timestamp: May 28, 2018, 02:16:33 am
content: I've been unable to locate LifePO4 batterys at anywhere near this $100/kWh price point NiHaoMike

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 28, 2018, 03:41:28 am
content: I wonder if his video created demand which raised prices.For a pack as large as what you're looking for, a Nissan Leaf pack would probably be good. It might even be possible to reuse the stock BMS. The voltage of around 360V or so is just about right to run common 240V VFDs and PSUs from.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 28, 2018, 09:36:56 am
content: Where did you get your batterys so cheap?

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 28, 2018, 04:19:33 pm
content: Amazon, but they don't see them anymore. Try to find out how much a working Nissan Leaf pack goes for at your local junkyards.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 28, 2018, 08:30:17 pm
content: a leaf battery pack is probably not appropriate for what i need, and i realy dont' want somethign thats got 80% of the life gone already. At the market price of what they are asking for at the moment, the economics dont' make sense for my application.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 28, 2018, 10:27:27 pm
content: Why won't a Leaf pack in good condition work for your application?

author: mrpackethead
author_rank: Super Contributor
timestamp: May 29, 2018, 12:48:59 am
content: Becuase if I did this, i'd want to do it with new materials. ( its going to have to last for a while ). I'm also wanting to do somethign thats repeatable, and doing that with 2nd hand materials that may or may not be avaialble is problematic.Also the form factor and all those other thigns just dont' lend them selves to the problem well.I have variable priced power.. ( we buy power on Spot Market ) which menas on average i pay about 20-25% less than people who are paying on fixed rate contracts. I can get pricing indication 15 minutes before the next 1/2 hour charing period of what the price point is going to be.I need to do some deeper analysis of our usage, and price peaks etc, and work out what the optimal investment in the technology is, in terms of how much to buy to futher reduce the peaks. Putting solar on will optimize this further.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 29, 2018, 01:20:55 am
content: What loads are you running? There might be alternatives to using batteries for at least some of the loads.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 29, 2018, 04:34:54 am
content: Already have so called 'smart appliances' so can ditch some load from peaks.. ( dishwasher, washing machine etc ). Have solar hot water ( with electric backup becuase winter would mean not a lot of water ), but that is already set up for offpeak.Converting from electricity to other energy sources is really not a viable proposition for most of what i use. ( i dont' use electricity for heating, we burn trees! )

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 29, 2018, 05:34:18 am
content: 10kWh seems like overkill for your application. Have you actually done an analysis of the on peak loads and how much each one contributes to the total?

author: mrpackethead
author_rank: Super Contributor
timestamp: May 29, 2018, 08:54:39 am
content: Yes, lots of analysis. The big issue is that when you are buying power on the spot market ( wholesales ) pricing can vary signficantly and in a erratic way. If a power station drops of the grid the spot price can go through the roof really quickly..My average price for power is around 0.08/kWh ( plus fixed transmission costs of around 0.09/kWh ). It has dropped as low as 0.02 and sometimes peaks ( for quite short periods ) over 0.70.I really want to be able to cover myself for 4-5 hours at 2kW. ( essentially i dont' want to make much in the way of lifestyle change ).. so when it does peak out, i can self supply.But right now, at the battery prices is not actually breaking even.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 29, 2018, 08:55:27 am
content: ^^^ putting solar self generation in may sigingicnatly change the picture.

author: Gary.M
author_rank: Regular Contributor
timestamp: May 29, 2018, 10:52:49 am
content: What about the tesla powerwall.?

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 29, 2018, 03:04:57 pm
content: I still think a Nissan Leaf pack would be the way to go. Wait for a deal and get one for substantially less than the $200/kWh individual modules go for.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 30, 2018, 02:55:30 am
content: Thanks but a nissan leaf power pack might met your requiremetns, but it does not met mine.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 30, 2018, 02:56:47 am
content: Quote from: NiHaoMike on May 29, 2018, 03:04:57 pmthanks, but i dont' think it will meet my requriements.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 30, 2018, 02:57:47 am
content: Quote from: Gary.M on May 29, 2018, 10:52:49 amThe idea is great. the problme is at the price, you just can't get get a payback on the investment.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 30, 2018, 03:31:35 pm
content: You can take a look there:http://www.batteryspace.com/96v-lifepo4-battery-packs.aspxYou have to ask for a quote i think.For 10 kWh, it's most likely going to be over $5000.Ouch.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 30, 2018, 06:48:01 pm
content: Quote from: SiliconWizard on May 30, 2018, 03:31:35 pmi can buy 10kW for $3800 without any trouble... Still too high a price point i think.

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 30, 2018, 07:07:44 pm
content: Quote from: mrpackethead on May 29, 2018, 08:54:39 amHad you thought about mechanical generation (LPG/Diesel) as the capital cost may be lower ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 30, 2018, 10:50:39 pm
content: After losses, just breaking even is going to be difficult. Natural gas might be viable if it's cheap enough in the area.Excluding heating/cooling devices (where thermal storage would likely make a lot more sense), I'm having a hard time thinking of a 2kW residential load that would regularly run for at least 5 hours at a time, except for a crypto mining machine.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 31, 2018, 01:33:43 pm
content: Quote from: mrpackethead on May 30, 2018, 06:48:01 pmFor proper LiFePo4 batteries? Where?I'd really suggest not taking any chances and buying from very reputables sources. A 10 kWh battery pack catching on fire or exploding will not be pretty.

author: f4eru
author_rank: Super Contributor
timestamp: May 31, 2018, 08:32:47 pm
content: Thundersky : 0.26 Euro / WhGS : 0.39 Euro / WhThis is for big prismatic cells, so the assembling cost is smaller than for a huge pile of 18650s

author: mrpackethead
author_rank: Super Contributor
timestamp: June 01, 2018, 03:04:21 am
content: Quote from: SiliconWizard on May 31, 2018, 01:33:43 pmLifePO4 is not likely to explode. Different chemistry from lionHave bought many hundreds of smaller packs from this supplier and they are good( solar charge remote small loads )Even at 3800 it’s too spendy without solar

author: splin
author_rank: Frequent Contributor
timestamp: June 02, 2018, 03:22:05 pm
content: Quote from: f4eru on May 31, 2018, 08:32:47 pm0.26 Euro/Wh is approx $0.3/w/h or $1/Ah which is exactly the same price as when I was looking 8 to 10 years ago.It seems odd that we're continually being told that battery prices have been plummeting exponentially, and will continue to do so, for many years.To be fair I assume they are referring to Li-ion cells but even they still seem to quite expensive at around $0.28/Wh (when bought in quantities of 100 or more) but have much poorer cycle life of a few hundred compared to 2 or 3 thousand for LiFePO4. I guess there is simply not enough demand for LiFePO4 cells to stimulate enough competition to drive prices down.$0.3/Wh gives a lifetime cost of $0.19/kWh for the battery alone (given 2000 80% discharge cycles) which is no cheaper than grid electricity.Does anyone know what real-world cycle life expectations are for current LiFePO4 and Li-ion cells are? LiFePO4 cells hadn't been around long enough for the manufacturer's claims to be proven when I last looked a few years ago. Also, most users of these cells were for EV applications which stress the cells much more than in renewable applications, so their cell life experience is not directly applicable.

author: hendorog
author_rank: Super Contributor
timestamp: June 02, 2018, 05:56:11 pm
content: Quote from: mrpackethead on May 29, 2018, 08:54:39 amHehe, I went down this rabbit hole. I am also on spot pricing with Flick. Just couldn't make it economic. I don't think our pricing is as good as yours though.When I first looked at it it seemed as simple as covering the AM and PM peak's with battery power. But since then the pricing has been more consistently high, even overnight, and spiking has become rarer.Having said that the spikes a few days ago cost us $15 - $20, which is significant as the weekly bill is about $40.I think a new battery chemistry is required, one that is cheaper can handle many cycles and high current. Upside is that it doesn't need to be dense and light as Lipo/Lifepo4.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 02, 2018, 06:24:47 pm
content: LiMn (what the Nissan Leaf uses) seems to be "good enough" for a lot of applications that LiFePO4 was thought to be ideal for.

author: hendorog
author_rank: Super Contributor
timestamp: June 02, 2018, 06:28:57 pm
content: Quote from: NiHaoMike on June 02, 2018, 06:24:47 pmIs it cheap enough?

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 02, 2018, 08:57:18 pm
content: Is $200/kWh cheap enough for you? Or less in bulk?

author: hendorog
author_rank: Super Contributor
timestamp: June 02, 2018, 10:11:59 pm
content: Quote from: NiHaoMike on June 02, 2018, 08:57:18 pmYes that would work for me as a DIY, assuming I could get them here close to that price.But that wouldn't be cheap enough for a 'production' product as it wouldn't leave much room for making a profit.I was thinking of 2-4kWh unit, which would just kick in to eliminate draw from the grid during price spikes.

author: metrologist
author_rank: Super Contributor
timestamp: June 02, 2018, 10:14:03 pm
content: Quote from: NiHaoMike on June 02, 2018, 08:57:18 pmThat is interesting, but where are you seeing this? I looked at some used/referb cells and was not confident I'd get enough cycles to break even.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 02, 2018, 10:21:22 pm
content: Quote from: metrologist on June 02, 2018, 10:14:03 pmThat's the going rate for Nissan Leaf battery modules. You can get a better price if you're willing to wait for a deal on a whole pack.

author: hendorog
author_rank: Super Contributor
timestamp: June 02, 2018, 10:33:29 pm
content: Quote from: NiHaoMike on June 02, 2018, 10:21:22 pmNew or used?

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 02, 2018, 10:53:35 pm
content: Quote from: hendorog on June 02, 2018, 10:33:29 pmUsed, but whole packs will state their age and mileage. The individual modules are easy to test. Note that EV use is very demanding on internal resistance so they'll remain useful for lower current applications long after they're no longer useful for an EV.Rinoa Super-Genius has done a few videos on Nissan Leaf batteries, including how to tear down a pack.

author: metrologist
author_rank: Super Contributor
timestamp: June 02, 2018, 11:39:38 pm
content: is there any data on actual remaining capacity and useful cycles, for low current applications? I hesitate because they seem like spent cells. I saw used 7.6V cells for $50US on ebay.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 03, 2018, 12:19:55 am
content: There are a lot of posts on DIY EV sites regarding those.

author: mrpackethead
author_rank: Super Contributor
timestamp: June 03, 2018, 08:21:27 am
content: Quote from: hendorog on June 02, 2018, 05:56:11 pmi'm in Wellington, where are you? REmember my 0.07 is excluding transmission costs. I'm also with flick and i am on the win with them, over any of the fixed price suppliers.. It does seem tough when you get those 80c peaks! Even at $3800 for 10kWhr i can't make it ecomomic at this point. Interestingly however Flick now lets you sell power back into the grid at the spot rate. So, if you had surplus power while the peaks where there, you might be on a win..However on the whole, putting any solar power into batterys right now does'nt stack, unless i was using it to charge an electric car. ( because you have to put the power in there anyway ).I was reading about generating methane, I wonder what the energy losse's in that are. Expect quite high.Quote

author: hendorog
author_rank: Super Contributor
timestamp: June 03, 2018, 08:48:54 am
content: Quote from: mrpackethead on June 03, 2018, 08:21:27 amNorth Shore - i.e. Aucklands bastard childIt was funny watching the council work out all of the things they needed to do after they killed all of the ND contracts when the super city amalgamation happened.Do you mean generate gas using a digester? If so it's basically free so losses don't matter much does It?

author: mrpackethead
author_rank: Super Contributor
timestamp: June 03, 2018, 09:06:06 am
content: No, make methane from surplus electrcicty, and then burning it later...

author: hendorog
author_rank: Super Contributor
timestamp: June 03, 2018, 09:13:44 am
content: Quote from: mrpackethead on June 03, 2018, 09:06:06 amSurely you would just make methane from any old crap, grass clippings, whatever. There is no way to beat that.

author: NorthGuy
author_rank: Super Contributor
timestamp: June 03, 2018, 08:23:53 pm
content: SLA batteries are much cheaper and probably last longer.The efficiency may be a problem. You need to convert AC->DC, then DC->AC, plus battery losses. With LiFePO4 battery losses are small. SLA efficiency is worse. However, Inverter/Charger losses are unavoidable either way. This will only save money if the price difference is really big.

author: hendorog
author_rank: Super Contributor
timestamp: June 03, 2018, 09:38:06 pm
content: Quote from: NorthGuy on June 03, 2018, 08:23:53 pmHmm, I think it is not as cut and dried as that. I just did some quick calcs based on _local_ pricing and even flooded LA loses out to the Leaf modules. I am allowing for a 50% DOD limit for LA which changes the game. Better/worse pricing can no doubt be found, and the Leaf modules are OOS anyway.I agree on the lifetime though. For a small 2 or 3 kWh pack like I want its not a big deal using the second hand cells.However for a large capacity off grid pack I'd be looking for new cells to get a warranty.Nissan leaf module price from here:https://bluecars.nz/shop/battery-module-leaf-gen1-24kwh/48 Ah @ 7.6V = 364.8 Wh$125/364.8Wh = 0.343 $/WhFlooded LA battery price from here:https://www.batteryworx.co.nz/collections/best-deep-cycle-battery/products/crown-6v-220ah-deep-cycle-battery220Ah @ 6V = 1320 Wh$349/1320 = 0.264 $/WhHowever since DoD is 50%, factor of 2 penalty for LA:$349/660 = 0.529 $/WhAlso I would need to consider how many batteries I'd need to parallel up so I can get the power out of it. This would mean I'd need to go for several smaller LA batts instead of a couple of large ones, which will make the pricing worse.Bear in mind this the pricing is in NZD (multiply by 0.7 to get USD), with little effort made to find the best price. They will be doubt be higher than what you are used to seeing as stuff costs more here.

author: NorthGuy
author_rank: Super Contributor
timestamp: June 03, 2018, 10:27:20 pm
content: Quote from: hendorog on June 03, 2018, 09:38:06 pmWhen you buy batteries, you pay for the lifespan. Look, for example, at Trojan T-105 from your store. Why do you think they're more expensive? Because they'll last longer. A battery can store so many kWh through its life. If you look at the datasheets, you can figure how many kWh you can store before the battery wears out (depending on how you use it). If you then re-calculate price per kWh, you'll see that T-105 is actually cheaper.If you buy a used battery, part (most?) of the useful battery life is gone, you only get what remains, possibly next to nothing. That's why your Nissan packs are so cheap. If you go to a local golf-course, I'm sure they'll sell you used SLA batteries for very little, but such batteries will not have much left in them, so they're worth very little.

author: hendorog
author_rank: Super Contributor
timestamp: June 03, 2018, 10:42:57 pm
content: Quote from: NorthGuy on June 03, 2018, 10:27:20 pmYes of course - and that is the 'risk' part of the equation. With the top end battery you get a warranty. With the warranty most decent manufacturers are incentivised to make them go the distance.Of course they put many limitations around the warranty. Ensuring compliance with the warranty conditions all of the time may be difficult in an experimental type setup like the one being discussed.I'm just saying that on a small scale it might be worth the risk. I'd need some way of working out the health of the modules.

author: mrpackethead
author_rank: Super Contributor
timestamp: June 04, 2018, 01:27:49 am
content: Rough is this fesible math.Heres the 1/2 hour spot market price sorted into price bins of sorts..At USD $400/kwH for batterys, lets assume 3000 cycles to 80%, we can get 20,000kWh out of a 10kWh battery pack over its life. . Thats goign to cost me $NZD 0.10c per unit for the battery.There is no savings to be made by using the battery to provide power until the unit cost of power is > average + 0.10c or in our case; 16.7c units. We should never charge the batterys if power is greater than average cost;The average cost of 'peak priced power ) is 24.8cThere were 974 hours over the dataset that exceeded that ( 1489 days ).. or 2.7% of the time. 87% of the peaks that are greater than 16.7c are less than 2 hours wide. My household use does tend to use power in line with the peaks, and i use 1.4kWhr/hrs on average during the peak. ( i already ditch non essential loads ). 5kWh of storage probably will suffice, which will cost me about $2000USD ( $2800 NZD )My potnetial savings over a year, are 236hours * 1.4kW ( 24.8 - 6.7c ) = $59.80!!!! Factor in the 'cost' of the battery.. its just $26.76 per year im ahead. If i factor in cost of money at say 4.9%,, ( 2800 * 4.95 ) = $138 / year. I'm down $110 a year for the hassle.Conclusion: putting a battery in byitself to round off the peak power prices, has negetive economic benefit.The next scenerio to consider is see what impact putting a sensible sized solar system in is along with the Batteries. Power generated locally is going to have an 9.8c advantage over anything that is imported as it wont' attract any distribution fees. I can also 'sell' surplus power back into the grid at the same rate as i buy it for ( the spot rate ).I use about 1200kW per month on average. We only increase useage slighly during winter. The bulk of useage will fall outside of the peak solar production hours.

author: hendorog
author_rank: Super Contributor
timestamp: June 04, 2018, 03:48:17 am
content: Is your spot price list for your network node? I think that is important as I think the price for each node can go up due to local effects as well as regional and national effects.So if its just a regional price then you might be missing some spikes.I'm no power expert though.

author: mrpackethead
author_rank: Super Contributor
timestamp: June 04, 2018, 06:33:04 am
content: Its the actual price paid at my location.

author: NorthGuy
author_rank: Super Contributor
timestamp: June 05, 2018, 12:17:45 am
content: Quote from: mrpackethead on June 04, 2018, 01:27:49 amAnd you haven't even factored in Inverter/Charger losses.

author: mrpackethead
author_rank: Super Contributor
timestamp: June 05, 2018, 02:53:30 am
content: I had included them in the life time of the battery, but had'nt added the energy cost for the 'lost' energy. Its almost a moot point, becuase there is'tn much of a way of paying for it.As a bit of an exercise i wondered what would happen if i moved the point at which i cut over to batterys higher, so i only chopped off the more expensive peaks. As you can see from teh histogram those just get less and less, and even though you need a smaller battery, the payback doe'snt get any better.I need to remodel this with solar, which i expect will actually change the game plan. Since i have my actual historical data of useage and the actual pricing, i probably can model this quite well. My gut feeling is that with solar i might be slightly up, but not so much that it would be worth the effort to do.

author: hendorog
author_rank: Super Contributor
timestamp: June 05, 2018, 06:26:56 am
content: Quote from: mrpackethead on June 04, 2018, 01:27:49 amI'm not convinced the logic is correct. I think you need to work out the cost of each peak and sum them up. The average won't work. I have had massive peaks which have cost $20 or more on their own just for an hour or two of power. I am pretty sure that your maths will not account for those peaks, and those are the ones which will pay for the system if they are frequent enough. AFAIK there is no price cap on a spike so the system is also cheap insurance against a crazy bill.Also consider that you will only be using 330 odd kWh of 'battery life' in a year. So your battery will last for 60 years at that rate.Also $400/20000kWh = USD 2c per unit, which is NZD 3c not 10c, and 80% of 3000*10kWh is 24000kWh not 20000.

author: Mr.B
author_rank: Unknown
timestamp: June 05, 2018, 06:57:49 pm
content: Following.

author: mrpackethead
author_rank: Super Contributor
timestamp: June 05, 2018, 09:14:36 pm
content: Quote from: hendorog on June 05, 2018, 06:26:56 am$4000 for 20,000kW But my math was wrong as well. Its much more than 10c! ( the 20,000 factored in some loss at the inverter and converio )Add up the peaks, and sum them.. sounds like an average. :-)

author: NorthGuy
author_rank: Super Contributor
timestamp: June 05, 2018, 11:19:52 pm
content: Quote from: mrpackethead on June 05, 2018, 02:53:30 amYou just calculate that you need to buy more energy to recharge the battery.With solar there are also different pathways, with different losses, such as:Solar->Inverter->House - requires 1.10kWh per kWh usedSolar->Charger->Battery->Inverter->House - 1.35kWhGenerator->House - 1.0kWhGenerator->Charger->Battery->Inverter->House - 1.45 kWhSo, you can choose your pathways by timing loads. If the sun is shining or the generator is working, using energy is much cheaper because it doesn't go through batteries. It also saves battery life. That's how I save energy.Also, you can wait with recharging your battery until the price is really low. This will increase your savings - buy low sell high.

author: hendorog
author_rank: Super Contributor
timestamp: June 06, 2018, 12:30:19 am
content: Quote from: mrpackethead on June 05, 2018, 09:14:36 pmAh of course, I screwed up the total price.However I still think the average method is wrong. You are averaging all of the peaks and then averaging all of the usage, and then multiplying those together to get the final answer.However I think you need to work out the cost of each peak (usage x price) and then sum those to get a correct answer.Consider if in one hour you used 2kW of power at a very high rate of $50/kWh. The cost of that hour could be $100, but you are only multiplying the average usage (1.4kW) by the average peak price for the entire year - of say 20c - so that hour looks like it something like 28c.Where did you get the spot pricing data from? I will download mine and try and have a work out. The Flick website has gone to crap for historical data older than about a year, so I can't scrape much data from them.

author: a59d1
author_rank: Regular Contributor
timestamp: July 21, 2018, 08:31:39 am
content: Some people in this thread are being way too picky about using secondhand lithium cells. You will certainly lose some of the capacity with a used cell, but "most of the usable capacity"? No. The worst degradation ever seen on a Leaf pack is something like 65% after 7 years, meaning you've lost 35% of the capacity. Most likely you'll be getting 75-90% of the original capacity at a cartoonish discount. If your BMS is properly designed, this should never be a problem.And if you're annoyed about having to use someone's old cells, get real. Stationary storage is not (and won't be for the foreseeable future) a primary consumer of new cells due to the fact that energy mass and volumetric density doesn't matter as much when your battery is sitting in a basement or warehouse vs. strapped to the bottom of a moving car.If you're almost willing to pay $380/kWh to your current supplier for 10kWh, and you can get Leaf cells for less than $200/kWh, you're making money if the cells have anything more than 53% of their original capacity left.And for the record, it is literally impossible to buy new cells or packs for less than $100/kWh. There are rumors that Tesla may have beaten that number internally, but they're sure as shit not selling their batteries at cost to anybody.Even better: if you hold on and wait a year or two, you'll start to see the supply of recovered (undamaged, mind you) batteries from crashed electric vehicles grow dramatically, and prices will drop proportionately. Right now, there is simply way more demand than supply.As an addendum, note that this was written from a US-centric perspective, as was NiHaoMike's. Having batteries shipped to Australia from the US, especially 10 kWh of them (!) is an absolute nightmare when they're not already installed in a vehicle.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 21, 2018, 04:38:49 pm
content: The question still unanswered is what residential load is using 2kW for at least 5 hours on a regular basis? There's probably a better solution like thermal storage rather than using batteries.

author: woodchips
author_rank: Frequent Contributor
timestamp: July 22, 2018, 05:07:34 pm
content: As has been mentioned, surely a diesel generator is much the cheapest way to generate electricity?Can buy a 10-15kVA 3ph 400V genny for about £3k, $4k.These are probably 80% efficient, and if you can use the cooling water as well then that is over 90%. Diesel costs about £0.70 litre, $0.90, and you get 10kW litre.To store electricity then fork lift batteries are the best choice. Could even make the batteries yourself out of lead sheet formed into a Vee shape either side to maximise area. A static system has no real limits on size or weight, so the Lithium advantages are null and void. Need a large container, lots of battery grade acid, and significant energy to form the battery, a one off job.It has been pointed out, Matsch - Capacitor, Magnetic Circuits & Transformers, that the energy stored in 1lb, 454g, coal is about the same as a flywheel 9' in diameter, weighing 1 ton and rotating at 3,600rpm. And the flywheel would need to be in a vacuum. Similarly a 6V 100 Ah battery (this is 1964 so LA) gives 600Wh or 2,180,000J or about 14% of 1lb coal. Oil, hydrocarbons, are about 11.5/8 kWh per kg.I too have had zero luck in finding these wonderful cheap lithium batteries, and this is just s few to replace the Ni-Cds in my drill.

author: splin
author_rank: Frequent Contributor
timestamp: July 27, 2018, 11:51:24 pm
content: Quote from: woodchips on July 22, 2018, 05:07:34 pmThe massive two stroke diesels used in large container ships can reach 56% efficiency or more. Car engines can achieve around 42% but a cheap diesel generator probably won't do much better than 30 to 35% average, especially given that it probably won't be running at peak efficiency much of the time.Older Lister diesels, much loved by many UK off-gridders, whilst very simple and reliable probably only run around 20 to 25% efficient.If you can use the heat then the overall efficiency could approach 90% but it is usually very difficult to match the heat and electrical loads over the course of a year so the average seasonal efficiency will be much lower.QuoteI'm pretty sure they don't exist in the retail market. LiFePO4 don't seem to have come down in price at all in the last 10 years, and whilst Li-on cells may have reduced in price over the years, they are still expensive for retail customers and lead acid are still the most economical for most.

author: tytower
author_rank: Contributor
timestamp: July 28, 2018, 09:04:56 am
content: I just read briefly through this thread and all i can say is there is a load of BS in there posted by people sitting in chairs that know very little about Lithium Iron Phosphate . LFP or LiFePo4.Firstly.. this is not Lithium Ion technologySecond... LiFePo4 does not explode or burn .Third ..You can expect to use these batteries from full charge down to 20% of charge left or less every day.Fourth... You are likely to be able to do this on the same set of batteries 5000 times or better.Fifth ..100 amp hour cells can be had for USD $ 90 atm approx from China ..Check the weight though.Sixth.. LiFePo4 cells sit at 3.2V for most of their cycle and only fall below 2.5 volts at the very end of their capacity.Seventh..LiFePo4 cells jump quickly to 3.55Volts which my manufacturer says is full.Eigth....A BMS (Battery Management System is essential to stay inside these limits.Ninth..They have aluminium cases these days andTenth.. Lead acid AGM etc only last 3 or so years and that only if you don't discharge them below 50% of their capacity. If you get better than than that great for you but don't try to convince me.That said can you see the value in going LFP now ?10 Years you will get out of them and you only need a third of the capacity you are using now ....and you dont have all the fiddling with 18650 little battery systems and the like.You need a controller for solar that just feeds in current at a reasonable voltage for a reasonable time to recharge.Here is a good site to start learninghttps://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

author: a59d1
author_rank: Regular Contributor
timestamp: July 28, 2018, 01:04:53 pm
content: Quote from: tytower on July 28, 2018, 09:04:56 am$900/kWh is not particularly competitive. LiFePO4 fires are also not unknown, but they are much less common than lithium ion fires.

author: splin
author_rank: Frequent Contributor
timestamp: July 28, 2018, 02:18:26 pm
content: Quote from: a59d1 on July 28, 2018, 01:04:53 pmThat's $900 for 1000Ah which is 3.2kWh or $281/kWh. Still expensive though and, unlike Li-ion, they have barely come down in price - 10 years ago they were around $100 for a 100Ah cell.

author: mtdoc
author_rank: Super Contributor
timestamp: July 28, 2018, 04:00:41 pm
content: Quote from: tytower on July 28, 2018, 09:04:56 amNo. If you know what you’re doing, bottom balancing and no BMS (but proper charge controller settings, LVCO, etc) is a better, safer option. Otherwise, then sure, a good BMS would be a ood idea.QuoteSome do, some don’t.QuoteUtter nonsense. As long as you don’t do something stupid, quality deep cycle FLA will last 10- 15 years (large traction batteries longer) and AGM 8-10 years in daily cycling applications.Yes, LFP make good sense and are financially competitive with LA when one considers lifetime costs. But don’t oversell them, they are not always the best option.

author: mrpackethead
author_rank: Super Contributor
timestamp: July 29, 2018, 08:11:59 am
content: Best thing i can do to chop off the peaks, is to install a Natural Gas Powered gen set. Can buy natural gas at about 5c/kwH. Conversion to electricty is about 25% efficent. so, give or take it costs 20c/kWh.

author: Eka
author_rank: Regular Contributor
timestamp: September 24, 2018, 12:31:46 am
content: So, how do the numbers come out when you make the system 5X the size you need and sell back some of it when prices are high?

author: mrpackethead
author_rank: Super Contributor
timestamp: September 24, 2018, 01:05:28 am
content: They would say you would loose money.

author: tautech
author_rank: Super Contributor
timestamp: November 04, 2018, 11:40:25 pm
content: Quote from: mrpackethead on May 30, 2018, 06:48:01 pmHave a look at what these guys have to offer:http://en.winston-battery.com/index.php/products/power-batteryWith a bit of a hunt you can find suppliers.Guy I know has banks of them for his off the grid house giving him 22 KWh of storage.EDITLink updated

author: f4eru
author_rank: Super Contributor
timestamp: November 05, 2018, 11:00:06 am
content: Quote from: mtdoc on July 28, 2018, 04:00:41 pmWhat do you mean by " bottom balancing" ? Manually controlling the individual cell voltages when discharged ? That kind of "human BMS" sounds like fun and completely error free

author: electrodacus
author_rank: Super Contributor
timestamp: November 06, 2018, 05:23:52 pm
content: I have huge experience with energy storage as this is my hobby for the past 6 to 7 years and I currently live in an offgrid net zero energy house powered 100% by solar that means electricity and heating and it is the most cost effective solution possible.My small house energy requirements are as follows peak month January requires 1000kWh for heating and 120kWh as electricity for appliances most of that electric cooking the 120kWh is included in the 1000kWh heating as any energy you use inside the house ends up as heat.Heating season here in Saskatchewan Canada is about 7 months per year so total energy needed for heating is around 5000kWh to 6000kWh (depends on how cold it is in a particular year) and average of 120kWh/month as electricity that is about 1400kWh/year thus total energy requirement 5000kWh + 1400kWh = 6400kWhMy system is made out of a 10kWp PV array (can produce in a year about 14000kWh) so less than half of available energy is used but this makes sense as it is designed to use almost all available energy in winter and there is up to 90% unused energy in summer that makes perfect economic sense and will explain later.There is a large thermal storage 158kWh capacity made of 97kWh 14m^3 concrete floor and a water storage tank 1500liter 61kWh capacity then for electricty I use a 5kWh LiFePO4 battery just enough for 24h autonomy as the huge PV array can produce worst case the minimum energy required about 4kWh in worst overcast day.Total cost of the system $15K and expected life of the system at least 30 year thus $15000/30years/12month = $42/month total energy bill for heating and electricity.Put this in another way $500/year / 6400kWh = 7.8cent/kWh but is not quite a fair representation as the energy used for heating is at around 5cent/kWh while the one used for appliances is around 18 cent/kWhThus heating with PV solar is the most effective heating option even cheaper than the next option natural gas.Now with this out of the way I want to give you some numbers for perspective very relevant to this treadCost amortization for different elements sort of best casePV panels cost amortization 2 cent/kWhThermal storage as low as 1 cent/kWhLiFePO4 around 15 to 20 cent/kWh (best option but still not a good solution for grid energy storage so do not add a battery to your grid connected house just have a grid connected PV array if you care about costs and is valid anywhere in the world).Tesla PowerWall or similar storage devices at least 40 cent/kWh very bad investment if you care about savings and not just want an UPS and do not care about costs.Lead Acid 60 cent/kWh up to over $1/kWh depending on battery used and in what conditions still very bad for energy storage applications.Car alternator or small gasoline or diesel generator at least $1/kWh so extremely bad idea in most cases.This is a bit of advertising but for details about my open source devices making my house solution possible see the documentation in myKickstarter campaigndescription.

author: hendorog
author_rank: Super Contributor
timestamp: November 06, 2018, 06:17:49 pm
content: Quote from: electrodacus on November 06, 2018, 05:23:52 pmNot to mention you have probably added at least that to the value of your house.Many would happily spend $15K on a new bathroom with earns nothing, but complain that a solar system because it is not profitable enough.

author: tytower
author_rank: Contributor
timestamp: July 13, 2019, 10:57:59 pm
content: Quote from: mtdoc on July 28, 2018, 04:00:41 pmHave a look on utube or search DIY Will Prowse. Look for his video comparing lead acid cost to LFP. His statement about Lead acid " if you get better than 3 years then you are not using them" rings strong with me . After all thats whhat lead acid batteries were designed originally for . Quick discharge for a short time and then immediate recharge for auto use . Storage batteries in lead don't work that well in that situation as you well know.

author: tytower
author_rank: Contributor
timestamp: July 13, 2019, 11:05:26 pm
content: Quote from: f4eru on November 05, 2018, 11:00:06 amBottom balancing at say under 3 volts means getting all the cells down to an equal voltage point before recharging.By joining each cell in parallel current flows from the high to the low cells and eventually settles down to very little current flowing .Then the cells can be reconstructed into a series string and recharged until one cell reaches 3.55V or so and the pack is fully charged and balanced.Notice in the pic the loops which allow you to get a current meter on each to check the flow.LFP , LiFePo4 cells spend most of their life at about 3.2Volts.

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 04:35:48 pm
content: I would only consider lead, LFP or LTO for the safety aspect if the installation is anywhere near my living space,Delivered cost from a trusted supplier with local warranty return will vary enormously by location.North American distribution channels are very immature and risky if buying on price, not advisable IMO.LFP longevity is many thousands of cycles and at least a few decades calendar life, if properly cared for.Variables include temperature, depth of discharge, charge & discharge C-rates, tweaking voltages and stop-charge setpoints on charge profiles, balancing & float policies, redundancy layers in protection circuitries etc.Very easy to overspend unnecessarily, but then again, a single failure event can render the whole bank instant scrap.Personally I'd look at old-school cheap but good FLA. In NA, the best battery value by far is Duracell (actually Deka/East Penn) deep cycle golf cart batteries,but around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.Even with lower usable-capacity ratio, comes to ~10¢ per kWh of storage, and may well go 6-8 years if cycled not too deeply on average say 2-3 times a week.

author: electrodacus
author_rank: Super Contributor
timestamp: July 19, 2019, 05:41:24 pm
content: Quote from: john61ct on July 19, 2019, 04:35:48 pm~10¢ per kWh ? How did you got this number ?Do you have a link to datasheet for that battery?

author: Nauris
author_rank: Regular Contributor
timestamp: July 19, 2019, 07:07:05 pm
content: Quote from: electrodacus on July 19, 2019, 05:41:24 pmFor example, if you take that battery:https://www.solaris-shop.com/trojan-sind-06-1225-solar-industrial-flooded-6v-1225ah-battery/Capacity: 1225Ah/6V 7.35 kWhWeight: 190 kgPrice: 1222 USDCycle life: 3600@50% DoDThen1222 USD/(7.35 kWh x 0.5 x 3600)=0.092 cents per kWhLooks suprisingly competitive actually if you dont't mind the weight and why would you if it is just sitting there somewhere stationary.But does anybody have any information on the Sunica.plus flooded NiCd batteries Saft advertises for solar use? Too exotic and too expensive I guess?

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 07:22:44 pm
content: Quote from: electrodacus on July 19, 2019, 05:41:24 pmBest to just call their support dept for tech detailsHere's an overview from Maine Sailhttp://www.cruisersforum.com/forums/f14/duracell-gc2-charging-specs-163920.html#post2092450and a basic list of modelshttp://www.eastpennmanufacturing.com/wp-content/uploads/Deka-Pro-Master-Golf-Car-Flyer-0248.pdfAs for the math, say 215Ah per pair, 12-13V call it 2.5kWh. Last set I bought cost $220 shop was a 20min drive away, so call it $250 per pair delivered?Sometimes Trojan can be found cheaper, but rarely.Other good FLA brands in NA are Superior, US Battery and Crown.Rolls / Surrette are at a whole 'nother level and priced accordingly, but it is common for them to last 14+ years even cycled daily.I think quality lead pricing being so low here is one of the factors holding back development of LFP and LTO distribution channels, as opposed to Europe and down under, where lesser quality and more expensive AGM are the norm.

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 07:25:42 pm
content: Quote from: Nauris on July 19, 2019, 07:07:05 pmGotta factor delivery costs in, for a small bank would add a lot to the final cost.Not to mention breaking your back anytime they need moving.

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 07:35:21 pm
content: Will Prowse is not exactly an authority on the technical aspects of DC electrics.Not bad for a YouTube "influencer" but that's a pretty low bar.Drop-ins really are for convenience, people that don't want to get up to speed on the details.I am very skeptical they will have longevity like a properly engineered system based on top quality cells, there's hundreds of makers out there, under a dozen known good.

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 07:42:14 pm
content: Quote from: f4eru on November 05, 2018, 11:00:06 amYou really need to do more research if you don't know the difference between bottom and top balancing.A BMS is really just a collection of protective functions, how you implement it is up to you.There are many methods for maintaining balance at the per-cell level, and in some use cases just checking manually every so often is just fine, good cells treated well just don't need more.There are very few "all in one" BMS solutions I would consider. I wish fully open hardware and FOSS firmware were more common (shout out to Dacian, just realized who I was talking to 8-)

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 07:47:11 pm
content: Quote from: mtdoc on July 28, 2018, 04:00:41 pmWell stated.In both cases, top-quality cells and the infrastructure+knowledge to care for them properly are required to make the investment pay off.Only noobs go all fanboy for one particular solution, there are too many variables involved in each use case.

author: electrodacus
author_rank: Super Contributor
timestamp: July 19, 2019, 07:51:09 pm
content: Quote from: Nauris on July 19, 2019, 07:07:05 pmThat seems to be at half MSRP in therms of cost but fair enough as it is available at that price.The 3600 cycles at 50% DOD means using it that way every day for 10 years and then you ignored the calendar aging that can be very significant in solar energy storage application's where battery most of the time is less than fully charged.Also that capacity is for 100h discharge rate but if you want to assume a 50% DOD every day then best case charge and discharge need to happen in less than 10h each.If you then look at 10h capacity it is just 835Ah significantly less than at 100hThen if you also consider calendar aging and also the fact that you need a significantly oversized battery capacity for your application compared to LiFePO4 and also the much lower charge discharge efficiency.They mention a service life of 17 years based on IEC61427 and if you check what that means herehttps://www.trojanbattery.com/pdf/RE_IEC_61427_Standard.pdfthey consider that 50 + 100 shallow cycles are equivalent with 1 year of service life.The first 50 cycles are 30% DOD and the 100 cycles at 25% DOD with very low discharge rates just 0.1C (10h discharge rate).For simplicity I will be generous and say 150 cycles at 30% DOD x 17 years as the max possible life for the battery again excluding most of the calendar aging as that is not considered in this tests that only take a few months.$1222 / 150 x 0.3 x 17 x 5kWh = $0.32/kWh way to optimistic as calendar aging is not considered in the IEC61427Now if you do the same for LiFePO4 and ignore calendar aging you get300 to $400/kWh cost and 3000 to 6000 cycles at 100% DOD but I will take a Winston cell that is just 5000 cycles at 80% DOD so$400 / 5000 cycles x 0.8 = $0.1/kWh again if you include calendar aging the realistic number I always use is $0.2/kWh.My battery is made with A123 cells (I fully offgrid) and I use the battery heavily at an average 47% equivalent DOD every day and after first year measured degradation was 0.9% from that around 0.3% is from cycling and 0.6% is from calendar aging. This cells are rated 5400 cycles at 100% DOD.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 19, 2019, 08:03:36 pm
content: Quote from: john61ct on July 19, 2019, 04:35:48 pmI did some modeling for different batteries as applied to my particular system about 7-8 yeras, and FLA Deka (8L16) came at $0.35/kWh, which was second from the last, which was Deka gel (8G4D) at $0.54/kWh. The first place - Surrette 12CS11PS came at $0.14/kWh. I only considered LA batteries back then.

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 08:50:30 pm
content: Of historical interest I suppose. Well L16s aren't GCs, and maybe they weren't flogging the "Duracell" label through consumer retail nationwide back then.Deka's GEL aren't quite as good as Sonnenschein from whom they licensed the tech.But can last a **very** long time, just a bit finicky on the charge profile requirements, easy to damage overcharging.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 19, 2019, 09:34:50 pm
content: Quote from: john61ct on July 19, 2019, 08:50:30 pmI don't think the prices have changed much. Surrettes actually went down a bit in US dollars. They were $1300, now they're $999:https://www.solar-electric.com/su12357ampho.htmlThey're still about the same in CAD

author: john61ct
author_rank: Regular Contributor
timestamp: July 19, 2019, 09:49:19 pm
content: I meant the Deka GCs being so much cheaper now

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 21, 2019, 01:54:17 pm
content: I was curious and found these on Amazon:https://www.amazon.ca/RUIXU-LiFePO4-Battery-Off-Grid-Applications/dp/B07SZ6LR83Among others.Problem with Amazon though is you really don't know what you're getting, it's basically a fancier ebay. So it's still a lot of money and you don't know if it's just going to fail in a year or explode and kill all your family. You get 90 day return policy to whatever it is, and that's it. If it fails then you're on your own and there's no contact or company behind it or anything.Too bad it seems so hard to find reliable sources for this stuff though. I want to start experimenting with lifepo4 and regular lithium ion and eventually maybe even convert over my lead acid systems but without reliable sources I will stick to lead acid for stationary battery plants.

author: john61ct
author_rank: Regular Contributor
timestamp: July 21, 2019, 03:13:25 pm
content: I think it is likely that vendor Ruixu is indeed selling genuine Sinopoly cells, a well respected maker.However there's no way to tell in advance whether or not they are QA rejects, or sold out the back door by the night shift, etc.They also sell through Ali and eBay, which have decent buyer guarantee policies.If you are ready to go with thorough capacity testing, checking IR matching, voltage sag, self-dischargethen I think odds are pretty good of being able to judge the cell quality within a week or two.Of course a seller able to accept returns on the same continent as you would be better.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 21, 2019, 04:40:13 pm
content: Quote from: Red Squirrel on July 21, 2019, 01:54:17 pmOr directly from China at much cheaper cost, such as:https://www.alibaba.com/product-detail/Hot-Sales-Lithium-Ion-Lifepo4-48V_955841194.htmlEither way, there's no way to find out if the batteries are going to last.

author: john61ct
author_rank: Regular Contributor
timestamp: July 21, 2019, 08:24:42 pm
content: Quote from: NorthGuy on July 21, 2019, 04:40:13 pmThat is a completely different seller. Here is Riuxuhttps://m.aliexpress.com/store/v3/home.html?shopId=5015059&sellerId=238482081This is them on eBayhttps://www.ebay.com/sch/i.html?sid=bulbman702Of course contacting a known good manufacturer and buying direct is the best way, but certainly costs a lot more than through the riskier sellers.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 21, 2019, 11:09:34 pm
content: Quote from: john61ct on July 21, 2019, 08:24:42 pmMost sellers sell the same. They pack little batteries into big packs and optionally add BMS. Your luck only depends on how good were the little batteris they used. These may be premium new batteries, or some used junk at the end of their life. Who knows ...

author: tytower
author_rank: Contributor
timestamp: July 21, 2019, 11:31:09 pm
content: Man thats a big price above .To get a good sized house bank of say 48 volts wound be $8000 plus delivery, and that's still only 400 Ah.Hope anyone using them has the good sense to compress the sides slightly to stop expansion.With a normal BMS these days each board uses a chosen chip with the needed cut off points for each function being monitored.What your board monitors is defined by the chip specs so its up to you or your manufacturers recommendation.They are usually back to back Mosets on the board used for switching so both must be on for current to flow. They are always on the negative line.If a Mosfet is turned off , the whole battery pack is turned off.Its my conviction that anyone who says run LFP without a BMS has not really used their battery pack and are stuck in the old lead acid era when you start to worry at 80% SOC. hard to get out of but get out of it you must and use your LFP's to full advantage.The world is catching on.

author: john61ct
author_rank: Regular Contributor
timestamp: July 21, 2019, 11:57:31 pm
content: Quote from: NorthGuy on July 21, 2019, 11:09:34 pmYes, but in this case we were discussing sourcing quality LFP from known-good factories - Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly and A123 (now Lithium Werks / Valence / Super B).> They pack little batteries into big packs and optionally add BMS.I did not see anyone talking about those, very rare for the above.In this case, large hard-case prismatics, where 60Ah cells are small, go up to thousands of Ah per cell.And specifically, the units under current discussion are made by Sinopoly, that's the only reason that specific seller Ruixu is being discussed.Hence my pointing out that your suggesting some random Ali seller flogging completely different cells as an alternative is not helpful.Or are you actually specifically recommending that seller, if so then for what, and why?

author: john61ct
author_rank: Regular Contributor
timestamp: July 22, 2019, 12:06:25 am
content: Quote from: tytower on July 21, 2019, 11:31:09 pmYes, we're looking for top-notch quality LFP, so if you know of more reasonably priced sources suitable for NA please link to them.Even for a much smaller bank, the delivery cost alone is usually $600+Keep in mind they're Hazmat, and Trumps's tariffs may have an impact any day now._____Depending on the use case and your care protocols for checking / monitoring, there are many choices how to implement "BMS" functionality.Sure LVC / HVC and temp failsafes can be critical, adjustability is key,but thousands of banks built from new quality cells don't need any re-balancing at all cared for properly, zero capacity loss over thousands of daily cycles, some hitting a decade now.Yes compression plates are standard.

author: john61ct
author_rank: Regular Contributor
timestamp: July 22, 2019, 02:12:48 am
content: I don't think trying to include cycle life across different chemistries yields a clearer picture.Vendor lab results have hardly **any** relationship to reality.A 100Ah 12V drop-in Battle Born can't realisticall be compared to 1000+ Ah bare cells from CALB or Winston, or baby 2500mAh cylindricals from K2.The variation by usage patterns between say propulsion vs solar storage could be 500 cycles vs 6000.And that's just within LFP!

author: NorthGuy
author_rank: Super Contributor
timestamp: July 22, 2019, 04:03:51 am
content: Quote from: john61ct on July 21, 2019, 11:57:31 pmNo. I am not recommending any sellers. Moreover, I believe that buying any of these batteries is a huge risk, and I would strongly recommend against that.

author: john61ct
author_rank: Regular Contributor
timestamp: July 22, 2019, 04:15:22 am
content: Then it seems you have no interest in the actual topic, won't have anything constructive to add to the thread and I suggest it best you just ignore it.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 22, 2019, 04:23:27 am
content: Quote from: john61ct on July 22, 2019, 02:12:48 amCycle life is the most important thing. That's what you're paying for. The battery which would last 3000 cycles in your application is 3 times more valuable than the battery which lasts 1000 cycles. The chemistry is secondary. That's why big FLA batteries beat GC by huge margin. That's why buying Chinese LiFePO4 with generally unknown/unpredictable cycle life is a bad idea.

author: john61ct
author_rank: Regular Contributor
timestamp: July 22, 2019, 04:36:54 am
content: Bad idea for yourself, according to your priorities & prejudices, aversion to risk, level of knowledge and experience, attachment to money or joy in discovery.We each have our differences in those and many other areas.

author: mrpackethead
author_rank: Super Contributor
timestamp: July 22, 2019, 04:43:39 am
content: Quote from: john61ct on July 22, 2019, 04:36:54 amAs a sub-100 poster, you need to earn some creditability before we'll take you seriously as well.

author: john61ct
author_rank: Regular Contributor
timestamp: July 22, 2019, 04:49:22 am
content: I'm just here to learn and to help if I can.No interest in any damn pecking order.

author: f4eru
author_rank: Super Contributor
timestamp: July 22, 2019, 07:06:14 am
content: Pb FLA with 3000 cycles ?That´s quite unlikely, and even if perhaps atteinable under ideal conditions, it will need regular maintenance, which is then a bigger cost than the battery itself.-> reasonnable quality (chinese) LiFePo4 beat this setup economically.They last the same 3000 cycles, but with less risk of not making those, and with zero maintenance.

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 22, 2019, 12:47:51 pm
content: FLA maintenance is fairly cheap just need distilled water. If you have a lot of em then it even pays to get a water ionizer/distiller to make your own distilled water. That's what they do here at work for CO batteries. There's also VRLA and AGM which are maintenance free but not a fan of those as they tend to not last very long and are 3x the price. You get maybe 1-2 deep discharges from them and they're toast. May as well try to source out lithium based at that price point. (whether it's lithium ion or lifepo4). lifepo4 is probably best bet for stationary but as discussed it's sourcing them that's hard but same goes for lithium ion. There's vape shops I guess but don't think they do any kind of bulk orders. Would be nice if places like Digikey sold them but they don't seem to have much.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 22, 2019, 01:25:45 pm
content: Quote from: f4eru on July 22, 2019, 07:06:14 amThe bigger the battery, the longer it lasts. This is because thicker plates take longer to corrode.The only maintenance I do is measure SG and add water twice a year. The whole procedure takes 1/2 hour, so it's 1 hour per year.

author: f4eru
author_rank: Super Contributor
timestamp: July 24, 2019, 12:10:47 pm
content: Nice if it works out for you.Also, factor in cost of training, because if the guy doing it makes mistakes, it may cost a few tenths of thousands in downtime and replacements.Not a risk with LiFePo4.

author: john61ct
author_rank: Regular Contributor
timestamp: July 24, 2019, 03:42:19 pm
content: It is **much** easier to murder an LFP bank if you don't have the correct gear and knowledge to care for them properly, build the failsafe protection systems at bothe the cell and pack levels,, constantly monitor, periodically test and balance the cells etc.If all goes well depending on the use case, especially temperatures and C-rates, yes LFP can last a **very** long time - 3000 cycles barely broken in, and maybe end up cheaper than lead.But the up-front investment in not just top quality cells but all that infrastructure, maybe 5-10x the cost of a good FLA bank - depends on your local market conditionsmakes getting that ROI very risky financially.The most compelling reason to pay so much more are use cases where the much higher C-rates, both in and out, are required, aka power density.Or where half the weight and volume - energy density - adds a lot of value, e.g. racing yacht, small camping van. . .

author: f4eru
author_rank: Super Contributor
timestamp: July 24, 2019, 08:37:31 pm
content: Quote from: john61ct on July 24, 2019, 03:42:19 pmI don't think that ratio of 5-10x is correct.Perhaps you have only BMS available with heavy gold plating, costing 10x the price of hte battery, but in the real wold, for any commercial application, automating away battery maintenance to a good and cheap BMS makes the most sense.

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 24, 2019, 08:52:31 pm
content: Quote from: f4eru on July 24, 2019, 12:10:47 pmWhy would you hire someone for that? It only really needs to be done once or twice a year. Even if it had to be done more often it makes no sense to hire someone for that.

author: tytower
author_rank: Contributor
timestamp: July 24, 2019, 09:54:57 pm
content: It seems to be human nature to interfere in things that they just don't know sufficiently about. A little knowledge can be a dangerous thing.I frequently get people telling me that LiFePo4 can be charged to 4.2v which of course they cannot. They must not go above 3.6V. Different technology to Lithium Ion but people get on and start flaming the thread before they accept they are wrong and fade away without retracting the silly stuff.The difficulty seems to me to be caused by people with a little knowledge not reading the posts properly first.Don't have a suggestion on how to avoid that except perhaps " Read Well".Now on suppliers I have not taken the risk to buy any larger cells from china. It seems that there is a seller on every street corner selling these now and when you talk to them they are the big main manufacturing plant. There seems to be no way , short of going to china, to ensure you are dealing with an honourable truthful factory, They all claim to be that.I took the chance and got 8 Lifepo4 cells of 50Ah to test about 2 years ago now from Shenzen OHC factory supposedly and they have been going well to date with a $30 BMS and a $20 Cellog8 and recently an active cell balancer for $17. They cost about $550 AUD landed at my door.I decided to fein a battery cell breakdown and see if their promised warranty of 6 years had any backing. After many ,many emails to almost anyone who seemed likely to listen including Ali Express with all its security claims and promises , I have not been able to get even one reply ! Just completely ignored and without recourse.So I guess before I buy the bigger capacity cells that I need and want now, I will have to wait until an Australian reseller appears that offers a warranty , and that means they will be expensive. I see that Amazon in the states is giving some good prices to the yanks but have not seen any on australian amazon and they will not ship from the states to here.

author: tytower
author_rank: Contributor
timestamp: July 24, 2019, 10:23:44 pm
content: Quote from: john61ct on July 22, 2019, 12:06:25 am

author: john61ct
author_rank: Regular Contributor
timestamp: July 24, 2019, 10:40:14 pm
content: BMS does not "automate maintenance", but yes good ones are relatively expensive for a small pack (under 200Ah @48V nominal or say 10kWh).That size would be under $900 for deep cycle Pb, EPM/Deka FLA delivered. And no need for new charging gear, protective hardware etc.Compare to LFP.These are the only packaged systems I'd consider: OPE-Li3 (Lithionics/Ocean Planet), Victron, MasterVoltFor bare cells: ​Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly and A123 (now Lithium Werks / Valence / Super B)Delivered cost in the US, with ability to warranty return domestically, is very very high compared to lead. Much higher price ratio than elsewhere, and people there often would go with inferior AGM as well, and often of meh quality as well.So as with most things "it depends".PS any links to decent BMS lines, e.g. that allow user adjustability of setpoints and are considered reliable would be appreciated.

author: Psi
author_rank: Super Contributor
timestamp: July 24, 2019, 10:44:20 pm
content: Anyone got recommendations for storing 8kWh over a 1 hour period?I want to dump 35A at mains voltage (220V) into a battery for 8kWh of storage and only have 1 hour to do it.You see, I get 1 hour of free power every day from my power company

author: john61ct
author_rank: Regular Contributor
timestamp: July 24, 2019, 10:55:21 pm
content: Great that Australia, the Lucky Country, doesn't require Hazmat, also much closer to and tighter economic integration with China.The US does require Hazmat, with very high fines for trying to cheat. Much higher shipping, and big tariffs coming RSN I'd bet.And self-importing makes effective warranty moot, roll of the dice, with thousands at stake I'd want a trusted domestic seller myself. US distribution channels for quality cells are **very** under-developed.Tort law liability risks along with the much cheaper availability of quality deep cycling lead are the two biggest factors IMO.And yes quality matched cells in many use cases do not need "a BMS" as such, as long as all the required functionality is there.Crappy BMSs have killed many banks, can give the owner a false sense of security.To stand a chance of getting a decade or more you need to start with top notch quality and also know what you're doing.And if you don't think they'll last that long why go that way?Quality FLA routinely goes much longer, cheaper up front - at least in NA - and lots less stress.Does Rolls / Surrette sell down under?

author: john61ct
author_rank: Regular Contributor
timestamp: July 24, 2019, 10:59:07 pm
content: Quote from: Psi on July 24, 2019, 10:44:20 pmGet a very big bank.Going over 0.3C will reduce longevity. Over 1C even more so.High charge/discharge rates are why life cycles are quoted so low, EV and other propulsion use cases being the norm more than low-rate House bank usage.

author: tytower
author_rank: Contributor
timestamp: July 24, 2019, 11:04:36 pm
content: User adjustability on BMS is not something I have come across. Generally what I have seen is the use of a chosen values chip.There is no reason you could not engineer a suitable chip onto a board or even search and obtain a pre-made board that has your chip on it.I'll post a chip datasheet when I find it to demonstrate that.(Might take a while,not on my desktop)The problem area though is amps through it and I have not seen many cheap ones that go above 60 amps continuous. They can be paralleled but it gets messy then doesn't it. Mine run at 24 volts Nom so 60 Amps at say 27 Volts is 1620 watts with peaks of about 3000 watts for short bursts.I don't pull but about 5 amps continuous right now through a 1000 watt inverter so I don't know if those tops stack up.Probably the best device I have added is the active balancer to "automate" my pack. It is keeping each cell within 30 mv very effectively atm and I have had problems with cells going really badly out of balance.On a much larger capacity system those variations would not be as noticeable but on a 50 Ah bank they sure are a problem . I've been watching it for a fortnight or so now and have had the best looking Cellog8 balance readings I have ever had. If I had a bad cell then the loss of voltage from that cell would be fed from higher cells maintaining overall stability and the loss of pack capacity barely affects me as solar pulls them all up next day.

author: tytower
author_rank: Contributor
timestamp: July 24, 2019, 11:07:15 pm
content: Oh I see now . Silly me You are still flogging Lead acid . Its a dead horse mate .

author: john61ct
author_rank: Regular Contributor
timestamp: July 24, 2019, 11:51:57 pm
content: I'm not flogging anything.Just saying there is no "one correct choice" across the board. Fanboyism is counter-productive.The scales outside the NA market favor LFP in a higher % of use cases.

author: electrodacus
author_rank: Super Contributor
timestamp: July 25, 2019, 12:06:40 am
content: Quote from: Psi on July 24, 2019, 10:44:20 pmHow much is the cost of energy outside of that 1h when is "free" if it is less than 25 to 30 cent/kWh then it will not be economical to add a battery to store that "free" energy.Even so you will need 15 to 20 years of free energy storage to break even and is unlikely this 1h of free energy will last that long.There is no place in my opinion for grid connected storage at this time if you care about economics.

author: tytower
author_rank: Contributor
timestamp: July 25, 2019, 12:22:02 am
content: Quote from: john61ct on July 24, 2019, 10:59:07 pmThis thinking pervades present day use of batteries and seems to be a hangover of lead acid which is made for auto use of a quick discharge to starter with an immediate recharge to 100 % SOC . Use in Solar systems try not to discharge below 50% and you find the guys claiming more than 3 years life simply are not using them.Contrast that with what is said and what I'm finding with LFP is that discharge even down to 20% SOC is uneventful. They come back up and hold capacity normally despite repeated incursions into this territory.Most manufacturers suggest 1C discharge rates and I have seen some at 5C.(The problem here being lithium metal plating of the electrode) I'll stick to 1C and see .I expect to get 8000 cycles at least at that rate should last 22 years if discharged daily and still be at 80% capacity even then . Time will tell.(You can buy bags of Lithium Iron mix online if you want to play)Boating users that I am familiar with can only claim 4 or 5 years that I have seen so its early days but believe me USE your LFP pack to get full advantage of its capabilities. That's why the cost comparisons with lead acid just leave those in the dust.If you get half your present L/A capacity in LFP you will still have twice the available useable power so factor that in along with their lifespan and it should be obvious where the future is going with LFP.There are big things coming with LFP too getting up to 3 times more from much the same chemical composition and cheaper cost.For just a general example of charge and discharge rates that are generally acceptable see here but there are many examples out there.For a comparison of price with L/A see here

author: Psi
author_rank: Super Contributor
timestamp: July 25, 2019, 12:49:20 am
content: Quote from: electrodacus on July 25, 2019, 12:06:40 amYep, that's the main reason i've not build it yet.But if i ever run into a huge box of free 2nd hand 18650 cells i'll consider giving it a try.The main issue is i would need a massive number of cells to be able to store 8kW that quickly. Probably like 20-30kW of capacity.Setting up your electric car to only charge within that hour each day might be a good use of the hour. Get a 30A 230V fast charger installed in ya garage.

author: tytower
author_rank: Contributor
timestamp: July 25, 2019, 12:54:23 am
content: Make sure everything that runs gets switched on at that time.

author: john61ct
author_rank: Regular Contributor
timestamp: July 25, 2019, 01:12:27 am
content: Quote from: tytower on July 25, 2019, 12:22:02 amYes, following the vendor specs is not optimal for longevity.They are absolute maximum "stress ratings", the limits to which the devices can be stressed without causing immediate damage. These limits are not recommended for normal operating.Operating frequently at those limits will produce reduced reliability/lifetime.Of course the owner may truly **need** to fast charge, and if 8000 cycles is expected otherwise, not be interested in trying for more.Same sort of curve between average DoD% and total lifecycles with LFP as with lead, BTW.Your rig your choice, just know what the trade-offs are.

author: john61ct
author_rank: Regular Contributor
timestamp: July 25, 2019, 01:16:03 am
content: Quote from: tytower on July 25, 2019, 12:22:02 amWill Prowse is not by any stretch a technical expert.Professional social media influencer, a year ago hardly had a clue, got schooled hard spouting off all kinds of misconceptions.Great orientation for noobs on a budget though, and he is pretty cute.

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 25, 2019, 02:05:33 am
content: Quote from: tytower on July 25, 2019, 12:54:23 amCan also store energy thermally. Ex: during that hour have a bunch of electric heaters go on in winter, since the power is free just get it as warm as you can handle in the house for that hour. Then when the hour is over your regular heat, whether it's electric or gas, won't have to run for a bit. Could get smart with a hot water based system too to store even more heat.Anything like fridge, freezer etc could also be turned off automatically say, an hour before, then turn on during the free hour. Anything that's on UPS could also be set to run on battery right before the power is free. I suppose every little bit could help and it would essentially be free to do this.Crossed my mind to get battery storage though to store power off peak and then run off batteries on peak. But reality is, the usage is not really the expensive part of the hydro bill, it's all the fixed fees. So reducing usage in one way or the other hardly does anything.

author: NorthGuy
author_rank: Super Contributor
timestamp: July 25, 2019, 02:28:26 pm
content: Quote from: Psi on July 24, 2019, 10:44:20 pmAfter you get the batteries, add solar panels and enjoy 24 free hours every day