Best type of UPS battery? - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 09, 2018, 10:33:45 am
content: I have finally decided to ditch my generator backup power subscription as it is costly and the voltage fluctuates so much my room looks like a Christmas tree light with blinking lights.Will be getting a sine wave ups instead however I am not sure what type of battery would be best suited for my needs.Looking for 4x200 AH batteries to be connected in series as the UPS is a 48V model.There are two options in the market: Flooded and sealed lead acid batteries.Flooded is more expensive and requires bi-monthly checking of water levels but is supposed to be better for deep cycle applications like in my case and should last 3-5 years.I prefer the sealed ones as they are about 100$ cheaper each and should last 2 years or so with 0 maintenance.Still unsure which ones to go for what do you recommend?

author: Benta
author_rank: Super Contributor
timestamp: October 09, 2018, 12:22:49 pm
content: Sealed. Don't underestimate what the acid fumes do to the surroundings.Most important thing is to buy batteries specified for deep discharge. Car starter batteries are not suited.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 09, 2018, 12:40:12 pm
content: If you expect it to be used more than once in a while, look into lithium packs, most notably Nissan Leaf modules.The sealed batteries being so cheap and only warrantied for 2 years is quite suspect. They're normally considerably more expensive than regular lead acid.

author: wraper
author_rank: Unknown
timestamp: October 09, 2018, 12:46:15 pm
content: Quote from: NiHaoMike on October 09, 2018, 12:40:12 pmYou also need to charge them properly. I won't leave lithium packs unattended, especially when they are charged without tight charge control and robust protection.

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 09, 2018, 04:59:03 pm
content: It depends on how you need to draw power (cycles and time)Even thousands cycles lead acid batteries are now available (if you want recyclable solution)Or things like LiFePo are fairly robust and available in hundreds Ah cells/batteriesOr for short periods of time are suitable supercaps

author: Jeroen3
author_rank: Super Contributor
timestamp: October 10, 2018, 11:07:13 am
content: Quote from: drummerdimitri on October 09, 2018, 10:33:45 amDo you have highly variable loads?

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 10, 2018, 11:23:25 am
content: Quote from: Jeroen3 on October 10, 2018, 11:07:13 amNo, the generator power quality coming from outside is of terrible quality.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 10, 2018, 11:29:08 am
content: Quote from: Miyuki on October 09, 2018, 04:59:03 pmWell the power goes out every day for a total of 6H or so.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 10, 2018, 11:29:59 am
content: Quote from: NiHaoMike on October 09, 2018, 12:40:12 pmWe don't have those in Lebanon. Also, they are prohibitively expensive.

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 10, 2018, 12:55:52 pm
content: For this use is suitable for example forklift batteries even can be used by cell so easy repair if one cell is dead just continue with little lower voltageOn most places can be found cheap used ones and have long durabilityI plan to use some of them for solar system, used ones cost here about 80-100$ per kWh and last thousands deep cycles and have buyback at like one third of price so owning cost is really low at end

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 10, 2018, 01:24:25 pm
content: Quote from: drummerdimitri on October 10, 2018, 11:29:08 amDuring the day or at night? Have you considered an off grid solar setup or building your own CHP generator? (I'm not sure if there's much heating demand in your area.)

author: IDEngineer
author_rank: Super Contributor
timestamp: October 10, 2018, 01:32:37 pm
content: Quote from: wraper on October 09, 2018, 12:46:15 pmAgreed, and careful charging isn't limited to lithium cells. In a former life I was responsible for multiple, geographically diverse processing clusters in various colocation facilities spread across the US. The number one maintenance item was replacing batteries in UPS's due to absolutely horrible charging circuitry in UPS's made by APC, supposedly a (the?) leading brand at the time. The batteries would swell so badly from mistreatment that they could not be slid out of their enclosures and we'd have to completely diassemble the unit to remove the batteries. This would happen within six months of fresh battery installation. Happened across multiple UPS sizes, models, etc. The one common denominator was that the brand was APC. I won't buy APC andaggressivelyrecommend against them to everyone I talk to due to the endless manhours lost to this nightmare.Moral of the story: Make sure you are properly charging your batteries, regardless of their chemistry, if you don't want to be spending a lot of money replacing them all the time.

author: rstofer
author_rank: Super Contributor
timestamp: October 10, 2018, 02:12:28 pm
content: The bestbatteryfor deep cycle operation is the flooded type. True, they need maintenance, but at least maintenance is possible. With SLA batteries, you have no idea what is happening with the battery and it is never good.Particularly for cycling applications, you really want flooded cells.But then there is a problem! Flooded batteries are somewhat messy and the fumes given off during recharging are corrosive.In the power industry, the circuit breaker trip mechanisms often run on 48VDC (or 120VDC) and the power will be provided by flooded lead acid batteries. In the nuclear industry, the batteries have a glass housing so visual inspection for sulfation is possible.In the janitorial market, there are floor buffers that use flooded lead acid batteries. The Trojan series seems quite common:https://www.trojanbattery.com/markets/fm/6v/These flooded batteries are fully cycled every day and last for years.Alas, I have no idea what might be available in Lebanon.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 10, 2018, 02:26:05 pm
content: Quote from: NiHaoMike on October 10, 2018, 01:24:25 pmThis is a temporary solution for my vacation house so not interested in pouring too much money into it for now.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: October 10, 2018, 02:31:04 pm
content: Quote from: rstofer on October 10, 2018, 02:12:28 pmWe do have flooded trojan batteries but they're 420$ a pop which is quite expensive unless of course they will last me at least 3 years then it's a worthwhile investment.Not sure if I should get those vs the similar made in Indian ones which cost 330$ each.What do you think? Is trojan worth the price difference?

author: Siwastaja
author_rank: Super Contributor
timestamp: October 10, 2018, 02:39:29 pm
content: Battery "subtype" (there are much more to this than just flooded/gel/AGM) and the actual manufacturer and the specific model are extremely important.Trojan is an absolute classic widely used in deep discharge cycling applications (all kinds of electric vehicles) - it's some kind of "known-good reference". It may last 10 times longer than your proposed no-name equivalent. Or, the cheaper alternative might be just as good or even better! It's impossible to know without actual experience on the actual specific product.I'd pick the Trojan if you can handle the fumes and adding water (distilled!). At least it won't be too far away from the optimum.Li-ion conversion is of course, technically, the best bet on almost all aspects, has been for a few years already, but it's still kinda theoretical. Even in 2018, I'm still not aware of proper conversion kits/products, so you need to be a fairly experienced design specialist on both li-ion chemistry and power conversion / battery management electronics to do it. So while I would consider doing it, I can't just recommend it to almost anyone.