EEVblog #919 - How To Charge Li-Ion/LiPo Batteries With A Power Supply - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2016, 05:27:41 am
content: How to safely charge Lithium Ion & Lithium Polymer batteries with a bench power supply.

author: PeterL
author_rank: Regular Contributor
timestamp: September 02, 2016, 06:18:23 am
content: At 10:15 you say you can compensate for the voltage drop across the wires by tweaking the max voltage. But I think that is a bad idea.Most charging is done in CC mode, at which point the set voltage doesn't matter. Once it goes in CV mode the current will drop quickly, and so will the voltage drop across the leads. If you had set your PS to 4.230 volt then by the time the cell is full you would in fact have charged it to 4.23V.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 02, 2016, 06:26:29 am
content: Nice and instructive video about charging LiPos.Anyhow, if the max. voltage has to be < 1% of 4.2V, it is no good idea at all to increase the CV setting due to cable voltage drop @ 1.7A in the CC mode.In this case, that would have been about 34mV, which is already 0.8% of 4.2V.As soon as the current drops, going from CC to CV mode, the cable voltage drop also decreases quickly, so the battery would see these 34mV 'overvoltage' sooner or later.Due to this later decrease of the charging current, it also makes no sense at all to give the charging voltage a threshold for this initial voltage drop.Frank

author: Chipguy
author_rank: Unknown
timestamp: September 02, 2016, 06:30:27 am
content: Nice and very helpful advice thereIn 2007 I designed a product that uses this battery:http://shop.lipopower.de/850-mAh-37V-Einzelzelle-1C-38mm-breitThat battery is pretty much what people would have had in their non-smart Nokia phones back then. Like a Nokia BL-5C battery.Before deciding to use them I did some extensive testing on those batteries that also involved an ELV intelligent battery charger:This thing can do charge and discharge cycles and log the data on a PC.So I did cycle some batteries for weeks and found one interesting thing:1) I set it to 1C and 4.200V and left it for 2 weeks, the battery lost x% of it's capacity (can't remember the figures)2) I set it to 1C and 4.100V, also left it for 2 weeks, the battery only lost 1/10 of the capacity it was loosing before.Of course the battery was only charged to about 85-ish% of it's rated capacity, but that was still good enough for me.The test was done with 4 batteries at the same time. They all showed the same aging effect.I am sure the mentioned cutoff voltage given on LiPos is that voltage where they have the highest capacity.So my advice to those who have a less precise power supply would be: Set the cutoff voltage to that value where the tolerance of your power supply would not exceed the 4.200V.As Dave said in the video: You can terminate charging anytime.And to those who want a longer lifetime out of your LiPos: Charge them only up to 4.100V.This is what the product does and about 7 years after release the first and oldest ones started to trickle in for battery replacement. That is very good for Lithium based batteries. Only about 730mAh are used of the 850mAh but the longer lifetimes is worth it.The supplier I use sort of confirmed my findings, they charge the batteries to about 3.95 V.That is supposed to be the ideal voltage to store these batteries, so I have been told.In the meantime there was a design change and the new battery can now be replaced by the customer.I was never really happy with the built in solution but back then availability was not that good as today.

author: lwatts666
author_rank: Unknown
timestamp: September 02, 2016, 06:36:13 am
content: Quote from: EEVblog on September 02, 2016, 05:27:41 amIf you have the monitor option for the DP832, you can set the '<CURR' monitor to sound the buzzer and turn off the output once the charge current drops below the monitor's trigger current. No need for a timer...

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2016, 07:22:50 am
content: Quote from: PeterL on September 02, 2016, 06:18:23 amYes, good point.

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2016, 07:24:00 am
content: Quote from: lwatts666 on September 02, 2016, 06:36:13 amAs mentioned, I deliberately didn't use any programmable capabilities as most people will not have this.

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2016, 07:26:58 am
content: Quote from: Chipguy on September 02, 2016, 06:30:27 amThere is a lot of research out there on this, but it can vary a lot depending upon the type and manufacturer of the cell and their particular process technology.But generally, yes, a lower CV value will give a longer life. Well worth it for lots of apps.

author: Faith
author_rank: Unknown
timestamp: September 02, 2016, 08:06:08 am
content: Video taken down? Can't seem to view it over here and it doesn't appear on the YouTube channel list either >,<"...

author: ez24
author_rank: Super Contributor
timestamp: September 02, 2016, 08:07:11 am
content: Slowly I am switching all my battery uses to 18650s. I have gotten rid of all my C and D cell flashlights and my next item will be a radio that uses 18650s.I got real excited on a previous post because someone wanted to charge 20 of them in parallel. It turned out he wanted to charge 20 batteriesand bought a 6 cell charger. There was a discussion of what "parallel" meant. Did it mean wires or time.After all if 18650s are good enough for Tesla, they are good enough for me and I am glad to see Dave do a video on one of them. Wish there were more videos on them, ie on large packs and chargers.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: September 02, 2016, 08:15:20 am
content: Looks like a big hassle over using a TP4056.

author: Smokey
author_rank: Super Contributor
timestamp: September 02, 2016, 08:24:29 am
content: Quote from: RGB255_0_0 on September 02, 2016, 08:15:20 amIf I can't get it at Digikey (or at least someone on findchips), I'm probably not going to design it in. It would be interesting to see how engineers from different parts of the world think about sourcing parts.And ya, can't watch video. Private.

author: skoven
author_rank: Newbie
timestamp: September 02, 2016, 08:27:54 am
content: what about protection diode when using the Rigol power supply to charge batteries?/s

author: hwj-d
author_rank: Frequent Contributor
timestamp: September 02, 2016, 09:03:14 am
content: Quote from: RGB255_0_0 on September 02, 2016, 08:15:20 amWhy, if you already have a DP832But, yes, got a bunch of these board's and housings cheapest from china warehouse.Input is parallel, battery output goes to each cell separately, +output for sensing 1,45A together. Load curve works fine, doesn't matter which housing got a cell.Works fine for me.

author: salviador
author_rank: Regular Contributor
timestamp: September 02, 2016, 09:51:45 am
content: Why

author: b_force
author_rank: Super Contributor
timestamp: September 02, 2016, 11:10:40 am
content: As for a timer, I would use one of these wall plug/mains timer units.They are cheap, and good enough to switch off your power supply.

author: mcinque
author_rank: Unknown
timestamp: September 02, 2016, 11:23:19 am
content: What about the issue that PSUs are two quadrant devices and can't sink current/voltage so connecting a battery to their ouput can damage them? I was always instructed to use a diode and to compensate his loss in voltage. Even Rigol suggest this with a safety note.

author: Brumby
author_rank: Unknown
timestamp: September 02, 2016, 11:29:55 am
content: Quote from: mcinque on September 02, 2016, 11:23:19 amIf the battery voltage is less than the PSU voltage (which is the only logical scenario) then that isn't going to be an issue.

author: crispus
author_rank: Regular Contributor
timestamp: September 02, 2016, 11:38:56 am
content: Quote from: salviador on September 02, 2016, 09:51:45 amFor a couple of hours it was private. I received an email notification in the morning and only at noon was available

author: Zbig
author_rank: Frequent Contributor
timestamp: September 02, 2016, 12:01:07 pm
content: Dave, at 11:24, you meant "switch to constant voltage" but you said "switch to constant current".

author: ja4
author_rank: Newbie
timestamp: September 02, 2016, 12:06:23 pm
content: "How to safely charge Lithium Ion & Lithium Polymer batteries"I would not use the word "safely" without measuring (and taking measures against overheating) the temperature of the battery during charging.

author: Zbig
author_rank: Frequent Contributor
timestamp: September 02, 2016, 12:07:03 pm
content: Quote from: crispus on September 02, 2016, 11:38:56 amI did not notice Dave's remark that you could just dial the PSU voltage up a bit to compensate for the cable voltage drop. It was pointed out here that this reasoning was flawed and Dave agreed. Probably he's pulled the video for a while to edit this bit out.

author: woox2k
author_rank: Regular Contributor
timestamp: September 02, 2016, 12:09:41 pm
content: Video thumbnail has UltraFire 18650 on it but in the video it's not explained that these are deathtraps and should never be used! People might get the wrong idea and start buying those unprotected/sand filled/reused laptop cells 6000mAh 18650's that may blow up at one point.I have personally seen some of them overheat when charging to a point where my charger cut them off. With this bench supply setup there is no temperature monitoring. After taking the labels off those overheated batteries i saw they were just some old trash picked and very rusty unknown laptop cells that had new caps and UltraFire 4000 mAh label stuck onto them.

author: Barny
author_rank: Frequent Contributor
timestamp: September 02, 2016, 12:17:17 pm
content: Its always a good idea to charge lithium cells within a fireproof container.

author: firewalker
author_rank: Super Contributor
timestamp: September 02, 2016, 12:29:25 pm
content: Can you charge it lower C rating? E.g. C/10?Alexander.

author: Zbig
author_rank: Frequent Contributor
timestamp: September 02, 2016, 12:39:23 pm
content: Quote from: firewalker on September 02, 2016, 12:29:25 pmYes, of course. And conversely - some of them you can charge much quicker than C/2 or 1C.

author: dexters_lab
author_rank: Unknown
timestamp: September 02, 2016, 02:16:36 pm
content: @3:20 you say any 3 1/2 inch multimeter will work... but my multimeter is 6 inches tall, will it be ok?

author: R005T3r
author_rank: Frequent Contributor
timestamp: September 02, 2016, 02:19:58 pm
content: Speaking about recharging batteries, I have these Ni Mh here:I have to recharge them, but There's no datasheet so I'm not sure about what to do. However, it's known:1. capacity 5300mAh2. rated 1.2V3. "standard charge" : 530mA 15 h4. "rapid charge": 1500mA 5 hI have a Sony battery charger but refuses to charge them as soon as I plug them in (I still have to figure out why... Everything seems ok according to what's written on the charger datasheet), so I can't recharge them in any way. I do have a Power supply (Agilent U8002A)

author: Zbig
author_rank: Frequent Contributor
timestamp: September 02, 2016, 02:27:14 pm
content: Quote from: R005T3r on September 02, 2016, 02:19:58 pmGiven that they have blatantly lied about their capacity, who knows what else could be wrong with them. There's no way in hell these are 5300 mAh

author: R005T3r
author_rank: Frequent Contributor
timestamp: September 02, 2016, 02:40:08 pm
content: Well, let's charge them... I'm setting up my fire extinguisher and a specific pot to see if they explode during the charging process..

author: Zbig
author_rank: Frequent Contributor
timestamp: September 02, 2016, 03:11:31 pm
content: Quote from: R005T3r on September 02, 2016, 02:40:08 pmBe aware that almost none of what Dave has said regarding Lithium-based chemistry charging process does apply to Ni-Mh. CC/CV method shouldn't be used with Ni-Mh/Ni-Cd and the detection of full charge state is quite tricky with these. The current won't just taper off gracefully to let you know they've had enough. Instead, the "-dV" detection method is most commonly used by the quick chargers and you won't achieve that with a PSU alone. Or you could just trickle charge them very slowly. Keep in mind that the realistic capacity of these could be 2000 mAh or less. If these are real cells at all, that is.

author: R005T3r
author_rank: Frequent Contributor
timestamp: September 02, 2016, 03:31:36 pm
content: Ok, it's better if I make some research before I try to charge them...

author: Rbastler
author_rank: Frequent Contributor
timestamp: September 02, 2016, 04:15:59 pm
content: Where's the video ?

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: September 02, 2016, 04:25:23 pm
content: It got pulled and reuploaded. And then pulled again.

author: Zbig
author_rank: Frequent Contributor
timestamp: September 02, 2016, 04:48:06 pm
content: Quote from: R005T3r on September 02, 2016, 03:31:36 pmhttp://batteryuniversity.comis a good source.

author: tszaboo
author_rank: Super Contributor
timestamp: September 02, 2016, 04:52:38 pm
content: Quote from: R005T3r on September 02, 2016, 03:31:36 pmYou should probably just throw away them at the local recycle bin for batteries. There is no way they are 5300mAh, so they lie, they know they are lying, because NiMh batteries end at around 3400mAh . Maybe it is not secondary battery, they lie about that too.

author: whitevamp
author_rank: Regular Contributor
timestamp: September 02, 2016, 06:00:01 pm
content: Video taken down? Can't seem to view it over here and it doesn't appear on the YouTube channel list either.says privet

author: doobedoobedo
author_rank: Regular Contributor
timestamp: September 02, 2016, 06:04:10 pm
content: Quote from: woox2k on September 02, 2016, 12:09:41 pmNo need to be embarrassed by those Sony, Panasonic, Samsung or LG cells you use any more.Make any battery an UltraFireTM, just think of the capacity gains alone!

author: bxs
author_rank: Regular Contributor
timestamp: September 02, 2016, 06:28:33 pm
content: So Dave, you don't have a charger for 18650... maybe I'm seeing things:For a safe charge at least the temperature also have to be monitored.And the UtraFire 18650, remove that thing from the video or somebody will end up buying that piece of sh*t.

author: ez24
author_rank: Super Contributor
timestamp: September 02, 2016, 07:26:32 pm
content: Quote from: whitevamp on September 02, 2016, 06:00:01 pmMaybe some sort of government secrets were given away? Maybe it is possible to make H bombs with Rigol PS and 18650s, who knows (I do not understand Li ion chemistry). After all CC-CV sounds scary. So I assume only top secret officials can view the video now. Glad I saw it before it went black and I hope the end of life did not start with this videops - I would like someone to explain to me why 18650 batteriescannotbe used for H bombs. After all lithium is used for H bombs.

author: mtdoc
author_rank: Super Contributor
timestamp: September 02, 2016, 07:49:04 pm
content: Quote from: ez24 on September 02, 2016, 07:26:32 pmI'm sure Dave will fix this once he wakes up and see's it. It's 5:45 AM in Sydney now.I'm looking forward to this video.

author: PartialDischarge
author_rank: Super Contributor
timestamp: September 02, 2016, 07:50:02 pm
content: Quote from: ez24 on September 02, 2016, 07:26:32 pmMost electrically powered ordnance uses a technology called "thermal batteries", in which the electrolyte is solid at ambient temperatures but must be in liquid state for electron exchange to happen and thus current to be produced. This is accomplished by interleaving pyrotechnic discs inside the battery that are fired prior to use, when the electrolyte melts it will start generating energy. This will last for seconds to minutes depending on the battery.The reason to use this tech is simple, self discharge is non-existent.

author: Mr.Martin
author_rank: Newbie
timestamp: September 02, 2016, 08:14:21 pm
content: Here is a link to the video.https://www.eevblog.com/podpress_trac/web/8062/0/EEVblog919-Li-IonBatteryPSUcharging-640x360.m4v

author: Involute
author_rank: Contributor
timestamp: September 02, 2016, 08:32:37 pm
content: Why is this video private? I'd like to watch it.

author: ez24
author_rank: Super Contributor
timestamp: September 02, 2016, 08:47:25 pm
content: Quote from: Mr.Martin on September 02, 2016, 08:14:21 pmHoly crap it is getting worse (see pic) OR is it part of the conspiracy? Or is it an alien video (ps my Firefox crashed also thus confirming the alien conspiracy theory)

author: Mr.Martin
author_rank: Newbie
timestamp: September 02, 2016, 09:10:33 pm
content: CQuote from: ez24 on September 02, 2016, 08:47:25 pmI used Chrome to download. And than i can open it with VLC-Player.I found the Link in the Blog-Post under the YT-Video ->https://www.eevblog.com/2016/09/02/eevblog-919-how-to-charge-li-ionlipo-batteries-with-a-power-supply/

author: Involute
author_rank: Contributor
timestamp: September 02, 2016, 10:15:08 pm
content: Thanks. I was able to download and watch, but why was it private to begin with?

author: Fungus
author_rank: Super Contributor
timestamp: September 02, 2016, 10:33:46 pm
content: Quote from: Zbig on September 02, 2016, 12:07:03 pmThe cable voltage drop will be negligible at the end when the charge current drops below 100mA or so.

author: FrankBuss
author_rank: Unknown
timestamp: September 02, 2016, 10:46:21 pm
content: Ok, if you are desperate you can use your power supply to charge a LiPo battery, but I prefer my iMAX lipo balance charger. Costs less than 20 bucks at eBay and has all the features you need, like automatic stop charging after some time or even after some energy, and works perfectly for my 3s and 4s copter batteries as well (these bigger batteries have a big main connector, usually EC3 or XT60, and a smaller XH connector which is connected to each cell for balancing).BTW, what do you think about parallel charging LiPo batteries? I havethis extensionfor my charger and I've used this with up to 4 batteries in parallel. Of course, before start charging I measure all batteries, and I don't connect two batteries in parallel, if the difference is more than a few 10 mV for one cell, to avoid high balancing currents (once I connected the balancing connector backwards and then the main connector and after this I had to solder a new connector to the battery, because the sparks caused some bad black deposits on the contacts). But I've read you should do this with batteries with the same capacity (and age) only, but why this limitation? Once the voltage is the same for all cells of all batteries, it shouldn't matter.

author: ez24
author_rank: Super Contributor
timestamp: September 02, 2016, 11:06:22 pm
content: Quote from: FrankBuss on September 02, 2016, 10:46:21 pmInteresting item - can use three to charge 18 in parallel (wired not timed - private joke) a US link:http://www.ebay.com/itm/YoCoo-2-6S-RC-Lipo-Battery-Charger-Parallel-Balanced-Charging-Plate-Charging-/391526515453?hash=item5b28cc82fd:g:mMgAAOSwIgNXpsa6

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2016, 11:41:57 pm
content: !MAJOR WARNING!What Dave shows here is really dangerous!Never ever connect a battery to a generic power supply without a series diode! If something goes wrong in the power supply excessive currents may flow back into the power supply. Worse, some power supplies have a crow-bar (thyristor) across their output which gets activated in case of an error (overheating for example) and short the battery. I've seen the damage it can do first hand.The voltage across the series diode can be compensated by setting the voltage a bit higher but don't overdo it. There is not much extra charge going into the battery near the maximum charging voltage anyway.Also: when using Lithium batteries always use a UN38 certified pack with an integrated protection circuit against overcharge, undervoltage and current limits.

author: ez24
author_rank: Super Contributor
timestamp: September 03, 2016, 12:10:01 am
content: Quote from: nctnico on September 02, 2016, 11:41:57 pmDon't worry it is a secret video

author: rob77
author_rank: Super Contributor
timestamp: September 03, 2016, 01:42:20 am
content: Quote from: ez24 on September 02, 2016, 07:26:32 pmi assume a specific isotope of lithium is needed for that doomsday deviceand actually there is not much lithium in metallic form in those 18650 batteries, lithium is present there in a form of salt (it's the electrolyte).

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2016, 01:58:44 am
content: Quote from: FrankBuss on September 02, 2016, 10:46:21 pmOf course, I wasn't saying otherwise. The whole point of the video was that I needed to charge an 18650 on the spot and I didn't have a charger.

author: Scottjd
author_rank: Frequent Contributor
timestamp: September 03, 2016, 02:01:02 am
content: Quote from: R005T3r on September 02, 2016, 03:31:36 pmYes, more research is required. NiMh batteries charge differently from what Dave shows.I don't know if I would even trust these. To my knowledge some of the best NiMh batteries are eneloops from Panasonic and the highest capacity is about 2100mA. Since these advertise 5300mA I'm sure that's not true. Even half of this would be 2650 and I don't know any NiMh battery that does real capacity of 2650 for that size battery. So even if they were adding up the two batteries together for marketing on the package it's still probably a lie.If your Sony charger is a NiMh battery charger and denies them, it might be doing that for safety reasons when the charger checks the battery. Some chargers will check the internal resistance of the cell, if it's high then it will not charge them. Or if they are currently over the max voltage it won't charge them. Also if the battery voltage is to low it might not charge them. Since NiMh have a natural storage drain the batteries might be old and have fallen below a safe voltage for a good charger to charge the batteries.

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2016, 02:04:20 am
content: Quote from: Scottjd on September 03, 2016, 02:01:02 am

author: retrolefty
author_rank: Super Contributor
timestamp: September 03, 2016, 02:05:54 am
content: Quote from: nctnico on September 02, 2016, 11:41:57 pmAlways, Never. Typical EU type thinking.

author: tatus1969
author_rank: Super Contributor
timestamp: September 03, 2016, 04:46:24 am
content: Quote from: retrolefty on September 03, 2016, 02:05:54 amIs it typical US type thinking to sort people into boxes? And am I an error because I don't follow these concerns?

author: hedley
author_rank: Contributor
timestamp: September 03, 2016, 05:05:22 am
content: Thanks - your fundamentals Friday and videos like this where you walk through something practical and useful referring to and explaining datasheets are excellent And what got me hooked on eevblog.

author: Chipguy
author_rank: Unknown
timestamp: September 03, 2016, 05:56:34 am
content: Quote from: nctnico on September 02, 2016, 11:41:57 pm!EASY SOLUTION!Hello Major Warning and hello Geneal Purpose,My name is Easy Solution and I would like to offer you one.Yes some power supplies that can also sink current could ruin your day when you don't set them to 4.200V.If they are constructed good then they just blow a fuse or go into overcurrent safety mode. If they are crap they could even blow.Here is an example of a power supply that can not sink current and is safe to use for Lithium-Ion batteries.Here is an example of a power supply that can sink current. It would be a bad idea to set it to anything less than the current battery voltage.That series is called "ZUP", short for "ZERO UP". It definetly can sink current.Very useful for supporting and testing the breaking/recuperation function in BLDC motor controllers as they would charge the battery when spinning down a motor.Solution:Connect a friggin fuse in series to the battery. I used a poyfuse, rated 2.6 Amps and it did fine!

author: FrankBuss
author_rank: Unknown
timestamp: September 03, 2016, 06:17:31 am
content: Quote from: nctnico on September 02, 2016, 11:41:57 pmDo you meanthis test manual? Looks like it describes some testing procedures to ensure that the batteries are safe to be shipped by plane, like low air pressure. Interestingly, I guess nearly all bigger LiPo batteries used for RC hobby will fail, because this happens for a big LiPo if you short it after some seconds (requirement 38.3.4.5 of UN38 says it should survive a short circuit for one hour) :(note: don't try to extinguish a LiPo battery fire with water, better have a bucket of sand available when doing such tests, and when charging)I was thinking such a protection circuit would increase the price a lot, because e.g. for copters you need very high peak currents like 100 A for a fraction of a second. Butthis FEThas half a milliohm Rdson and allows 100 A continuous current (with this low Rdson it would only get slightly warm at this current) and costs 2 dollars. In combination with some other ICs and a more difficult construction, it might increase the price by maybe 30% for a typical 2 Ah / 35C LiPo ("C" is RC-speak and doesn't mean Columb, but the discharge factor, so 70 A continuous current is allowed). I would pay this for the extra safety.

author: Scottjd
author_rank: Frequent Contributor
timestamp: September 03, 2016, 06:20:04 am
content: Quote from: tatus1969 on September 03, 2016, 04:46:24 amI think it's typical everywhere thinking to classify/group people together for a majority of people.When I was looking into using the bench supply to charge batteries I looked up some documents on rigols website and found this document for the DP800 series and reconditions on charging a battery.http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-02f8/1/-/-/l-befa/l-befa:4b5/DP800%20DP1000%20Active%20Loads.pdf

author: HKJ
author_rank: Super Contributor
timestamp: September 03, 2016, 06:32:31 am
content: Quote from: FrankBuss on September 03, 2016, 06:17:31 amBetter tell the airlines about that, they a taught to use water:Usual it is much easier to get a real LiIon charger instead of using a power supply and they start pretty cheap. For more special applications power supplies are fine.To see charge/discharge curves from many chargers and batteries check here:http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK.htmlPS: Many chargers terminate NiMH charge on voltage, a bit more about NiMH charging here:http://lygte-info.dk/info/batteryChargingNiMH%20UK.html

author: Monittosan
author_rank: Regular Contributor
timestamp: September 03, 2016, 06:56:40 am
content: Thanks dave! Was charging a few 18650 cells not long ago lol.For those of us with a power supply that can sink current can you show us how to make a discharge curve graph? or even just how to record the capacity. I know the BK Precision DC Load can do this but would prefer to use one of the many Agilent supply's lying around.

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2016, 07:13:13 am
content: Quote from: Chipguy on September 03, 2016, 05:56:34 amFor some reason I like the look of that PSU

author: ez24
author_rank: Super Contributor
timestamp: September 03, 2016, 07:53:06 am
content: Quote from: HKJ on September 03, 2016, 06:32:31 amThanks HKJ been waiting for this link

author: Faith
author_rank: Unknown
timestamp: September 03, 2016, 08:04:35 am
content: Quote from: EEVblog on September 03, 2016, 07:13:13 amThere's definitely something to admire about having a minimalist purpose-built applianceI really like how there are arrows between the numbers presumably for easy fine adjustment of the voltage and current.On a power supply especially the less buttons and the cleaner the readouts of values the better.Doing a quick search online doesn't yield many results however. Going to look into this a little further. Have actually been shopping for a new bench-top PSU.

author: HKJ
author_rank: Super Contributor
timestamp: September 03, 2016, 08:10:58 am
content: Quote from: Faith on September 03, 2016, 08:04:35 amI will not agree to that, I prefer to have a numeric keyboard and a rotary encoder, this way I can either key the voltage/current in or use the encoder to adjust it. This makes this close to ideal for me:But the ELV power supply has a good look.

author: Faith
author_rank: Unknown
timestamp: September 03, 2016, 08:16:15 am
content: Quote from: HKJ on September 03, 2016, 08:10:58 amDifferent habits and preferences I guess >,<"... I've always preferred to dial numbers in via a knob. Guess it kinda came along with the classic Agilent E3610A.

author: tatus1969
author_rank: Super Contributor
timestamp: September 03, 2016, 08:32:09 am
content: Quote from: Scottjd on September 03, 2016, 06:20:04 amSure, but I wanted to show the mirror here. And it doesn't make it right because many do it.

author: Chipguy
author_rank: Unknown
timestamp: September 03, 2016, 08:34:20 am
content: Quote from: Faith on September 03, 2016, 08:04:35 amThat is an obsolete model.I got one on the bench at work. When I bought it many years ago I also went by the looks and practicality of it.And it is really precise, that display is not for shows.However the quality of some parts is not very good, the rotary encoder is failing for the second time now (ALPS).The electrical design is partially bad. When it comes from the factory it only has a built-in two wire mains cable.Since it uses a pretty good toroidial transformer the capacitive coupling between mains and secondary is very high, resulting in a high leakage current. That is just bad design. It blew up some CMOS stuff because when I was touching it with the ESD strip on I mananged to get some 80V AC on a MOSFET gate. Even with 1M (me connected to the strip) enough to blow it up.So I had to modify it. I put an IEC320 socket into the backplate and connected the internal GND to earth using a X2 capacitor.Eversince the leakage current is mostly going trough that capacitor, only some <5V remain when measured with 1M Ohm impedance.That's not the first time ELV made bad power supplies.The model before that had another design failure:There are electrolytic capacitors for the power supply part and one for the control part.If the one for the control part starts loosing capacity due to aging the power supply would supply >30V to your circuit when you switch it off, because the cap for the inerts discharges faster than the ones for the PSU part.

author: Fungus
author_rank: Super Contributor
timestamp: September 03, 2016, 08:57:35 am
content: Quote from: rob77 on September 03, 2016, 01:42:20 amIf you want some lithium metal you can buy an ordinary lithium battery. There's a roll of lithium foil inside.(And yes, youcanbuy them in airport shops after you pass security)

author: vlad777
author_rank: Frequent Contributor
timestamp: September 03, 2016, 11:17:02 am
content: Hi, Dave's video reminded me of a gadget to tear down.I took this battery , but I dont know if the circuit is protection or charging circuit ?The small SOT23-5 says 2420 , it could be LM3620 charger.The larger package says S8209 and seems to be just a pair of mosfets.What could be the green wire?

author: Fungus
author_rank: Super Contributor
timestamp: September 03, 2016, 12:03:03 pm
content: Quote from: vlad777 on September 03, 2016, 11:17:02 amBattery charger circuits have inputsandoutputs. I suspect that's an output wire (where you connect the load).

author: kalleboo
author_rank: Regular Contributor
timestamp: September 03, 2016, 12:09:05 pm
content: Quote from: doobedoobedo on September 02, 2016, 06:04:10 pmThere's never been a more suitable brand name

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2016, 12:22:54 pm
content: Quote from: retrolefty on September 03, 2016, 02:05:54 amWell one of my ongoing projects involves lithium battery packs so I have seen a thing or two which can go horribly wrong. The certification lab which tests the battery packs used to have the battery testing lab inside the building. They thought it would be good enough to use a heavy duty fire proof cabinet. They where wrong! As a result of a big fire (due to operator error BTW) they moved battery testing to outside units with some distance to the main building.Also, lets put some numbers in place. A generic 18650 Li-ion cell has an internal DC resistance of about 25 milli-Ohm. At 4V this means it can push 160A into a dead short. In that case the amount of power involved is 640W which is dissipated somewhere. Multiply that 640W with the number of cells in a pack. The problem is that 18650 cells look like oversized C Alkaline cells which are pretty harmless. Li-ion cells however contain a boat load of energy and can release that quickly. In general you really have to be carefull with devices which can hold a lot of energy. Think about something simple like the coil spring in the suspension of you car. When something goes wrong during dissassembly it will snap your arm right off if your arm happens to be in the way.Also don't assume a high quality power supply can't go wrong. These are typically fitted with a crow bar in order to protect the load against the PSU going bad but when charging a battery you really don't want that. Again, I've seen this go wrong!

author: Kleinstein
author_rank: Super Contributor
timestamp: September 03, 2016, 04:23:54 pm
content: Good power supplies often have a crowbar, but they should also have a fuse (or something that acts like it at the output, so the crow bar current will be limited. Still this could end up with a deep discharged cell.With a series diode, it gets tricky to set the maximum voltage right. Even with an R+D parallel combination the charging will turn to reduced current quite early and take longer.I would at least add a fuse. With a possibly explosive device it's good to have a fuse. Even old bombs had one.

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2016, 06:01:26 pm
content: A fuse at the output of a PSU is a bad idea because it increases the PSU's output impedance which may be bad for other purposes.

author: Barny
author_rank: Frequent Contributor
timestamp: September 03, 2016, 10:07:02 pm
content: Quote from: Kleinstein on September 03, 2016, 04:23:54 pmWith an 4-Terminal measurement of the cell, a diode should not be a problem

author: Someone
author_rank: Super Contributor
timestamp: September 03, 2016, 11:02:47 pm
content: Quote from: Barny on September 03, 2016, 10:07:02 pmMany power supplies (and other 4 wire measurement devices) have limits on the differential voltage, its not a perfect fix.

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2016, 11:20:23 pm
content: Quote from: nctnico on September 03, 2016, 06:01:26 pmErr, just put it in series with the battery. No need to permanently modify your supply.

author: ez24
author_rank: Super Contributor
timestamp: September 04, 2016, 03:58:42 am
content: chez never would have thought charging one battery would be so controversial. Dave get the shit flying - charge two batteries(I liked the photo of the guy who had hundreds)

author: Chipguy
author_rank: Unknown
timestamp: September 04, 2016, 05:43:29 am
content: Quote from: EEVblog on September 03, 2016, 11:20:23 pmThat's exactly what I proposed. Do not build a fuse into the PSU, connect it in series to the battery. Outside the PSU of course.And for the higher impedance: All that the higher impedance is going to result in is that the switch-off point will take a bit longer to reach and that the battery will have not quite 4.200V but a few mV less (the voltage drop at switch-off time).

author: Chipguy
author_rank: Unknown
timestamp: September 04, 2016, 05:50:07 am
content: Quote from: ez24 on September 04, 2016, 03:58:42 amYeah I can see now why Dave re-uploaded it. (Twice even?)Especially that impedance thing would become a never ending story haunting both, forum and YT comments for eternity<- just had to use that "new" emoticon for the sake of it

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2016, 07:37:27 am
content: Quote from: EEVblog on September 03, 2016, 11:20:23 pmThat is not what Chipguy and Kleinstein suggested in their earlier posts!The picture from the bench filled with -appearantly- Li-ion cells and heaps of lose wires just makes me cringe. But maybe I'm too old and no longer thrilled by the idea that something I do could set the house on fire and kill the inhabitants. Think about someone who enters the room and somehow causes a short circuit (bumping the table while cleaning, knocking something over, pulling a wire, etc).

author: samgab
author_rank: Frequent Contributor
timestamp: September 04, 2016, 07:58:35 am
content: Yeah, that was my thinking too: Just a simple 2 or 3A fuse in line with the wire to the battery holder would be a good safety measure to fend off paranoia in case of an inferior PSU... Then if something goes wrong with the PSU causing a short condition, the fuse would blow, no harm done.

author: EEVblog
author_rank: Unknown
timestamp: September 04, 2016, 08:27:32 am
content: Quote from: Chipguy on September 04, 2016, 05:50:07 amI've noticed this on my previous battery videos (and I have a lot of them). I still get email from 5 year old videos.i don't know what it is about batteries...

author: ez24
author_rank: Super Contributor
timestamp: September 04, 2016, 08:35:13 am
content: Quote from: EEVblog on September 04, 2016, 08:27:32 ambatteries, religion, and politics - what can you doI know - lets talk about religious politician's cell phones batteries.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2016, 08:50:11 am
content: Quote from: EEVblog on September 04, 2016, 08:27:32 amThey are a key component for anything which needs power where there is no mains outlet. Add all the different chemistries, sub-chemistries, charge/discharge rate versus endurance and some foolklore to the mix and suddenly you have an interesting subject.

author: tatus1969
author_rank: Super Contributor
timestamp: September 04, 2016, 10:52:45 am
content: Quote from: ez24 on September 04, 2016, 08:35:13 amclose enough?

author: tatus1969
author_rank: Super Contributor
timestamp: September 04, 2016, 11:01:42 am
content: Quote from: EEVblog on September 04, 2016, 08:27:32 amits not about batteries, its about Lipo/LiIon. From my RC hobby, I already had two Lipos on fire personally, one of them almost burning up my house (ehmmm, should I mention not to charge them unattended...). Teslas on fire, burning iPhones and other gear hurting people, Segways in flames, airplane's possibly going down. A known of mine is selling Lipos, and he told me that he had a brand new Kokam in his stock, never touched or charged it, and it just caught fire in the shelf. Probably manufacturing defect.

author: retrolefty
author_rank: Super Contributor
timestamp: September 04, 2016, 11:57:36 am
content: Quote from: nctnico on September 04, 2016, 07:37:27 amLets face it, different people have different attitudes about their personal risk aversions with the actions they take with the hobbies and work they do. I know that probably driving is the biggest personal risk I face but I accept the randomness of the universe I find myself in.

author: tatus1969
author_rank: Super Contributor
timestamp: September 04, 2016, 12:16:58 pm
content: Quote from: retrolefty on September 04, 2016, 11:57:36 amAs long as we are talking about hobbyist things done at home I agree. But as soon as we are spreading this information, like us posting and Dave blogging, we implicitly take a certain responsibility.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2016, 12:48:20 pm
content: Quote from: retrolefty on September 04, 2016, 11:57:36 amI had a feeling someone would come up with this comparison but it doesn't hold up because (in most countries) you need a license to operate a car (or any motorised vehicle) in order to become aware of the dangers and (re)act accordingly.

author: Scottjd
author_rank: Frequent Contributor
timestamp: September 04, 2016, 01:37:25 pm
content: Quote from: tatus1969 on September 04, 2016, 11:01:42 amAnd let's not forget the timing of Daves most recent video just a couple days before the new Samsung galaxy Note getting recalled world wide being a hot (no pum intended) topic in the media now. Good timing DaveThe media spreads the news, and miss information for drama effectabout these recalls on devices people have in their homes and carry in their pockets. A lot of people that don't understand or even do electronics as a hobby.Then questions come up like: if the phones are made with different manufactured batteries,then why recall them all.mWhy not only recall the ones with that one manufactured battery? Samsung said it was the battery, not the charging circuit. If it's just battery then the company should have a list of serial numbers affected and not have to recall every phone.Or is Samsung and other companies not telling us the truth? Don't they care about the safety of the customers? What if this happens with all cell phones? Don't batteries get tested and certified for safety?And then people start to worry and thing about all the devices in the home that has a Li-Ion battery in the house and panic and think the worst because the media makes it look like that, and it feeds fuel to the fire.

author: Scottjd
author_rank: Frequent Contributor
timestamp: September 04, 2016, 01:45:31 pm
content: Quote from: nctnico on September 04, 2016, 12:48:20 pmInteresting thought, but in the US the drivers licenses with most states don't teach anything about the dangers of gas being flammable to get a license. You can buy an electric car not knowing anything about the battery that powers the car. Consumers assume it's safe, the DOT (department of transportation) allowed it so it must be ok. So if the government allows it, the it must have been tested. OR the legal disclaimers in small print in the manual (that no one reads) covers the companies @$$ so they are not responsible the the consumer assumes all risk. So what does the license teach about dangers of driving in your country? Does it cover different gas mixes like ethanol and battery dangers?

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2016, 02:30:06 pm
content: Well over here you learn things like not hitting other cars, take a turn slow enough, how far a load may extend at the front & rear of a car, put a net over a load in a trailer and that sort of stuff which make driving safer for you and others.

author: Fungus
author_rank: Super Contributor
timestamp: September 04, 2016, 02:35:40 pm
content: Quote from: Scottjd on September 04, 2016, 01:37:25 pmDo they have a list of names and addresses of people who bought those particular phones?(And they're probably doing some ass-covering as well, just in case. You know how the press loves these stories)

author: Scottjd
author_rank: Frequent Contributor
timestamp: September 04, 2016, 03:37:59 pm
content: Quote from: Fungus on September 04, 2016, 02:35:40 pmTrue, I think Samsung mobile sit started to turn a profit again and now this.I did notice some countries had the Panasonic cell, and then they changed it to some other cell for other country releases. I guess it wasn't tested enough. I also noticed the top charge voltage was 4.4V and not 4.2V, and the nominal voltage was 3.85V and not 3.6V. I guess companies are under pressure to provide the most battery life because that as what people want. They want something to run all day and not have to charge it. I've only seen one like this were they are trying to push the capacity further in Li-Ion cells. You can see this on the iFixit tear down.It brings up a separate topic also about how tech companies these days are so much in a rush to be the first to release the latest tech that the consumer becomes the beta tester. They figure these days they can fix the bugs later with software updates and firmware and people accept this as OK. Not when I was growing up, maybe because companies couldn't push firmware updates like they can today?I'm slowly still waiting for the MS surface pro 4 to get all the bugs worked out that I've owned for a few months now.It's anoying, and probably for another topic but I just had to rant, but does kind of have to do with the recall also because I wonder if Samsung wasn't in such a rush to beat apples new cell phone release date then maybe this would have never made it into the hand of people buying them.

author: Fungus
author_rank: Super Contributor
timestamp: September 04, 2016, 04:47:12 pm
content: Quote from: Scottjd on September 04, 2016, 03:37:59 pmI'd prefer a choice of charging options in the phone config menu:1) Charge to 4.2V - get maximum time between charges2) Charge to 4.1V - get maximum battery longevityeg. My phone used to run for 10+ days when it was new. Two years later and it's down to 5 days.(Yeah, I'm not one of those people who checks his Facebook page every ten seconds {or whatever it is all those people are doing all day long on their phones}, my vice is EEVBLOG forums between compiles).

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 04, 2016, 06:45:49 pm
content: Quote from: retrolefty on September 04, 2016, 11:57:36 amYep, and in the EU, most houses are built much more rigid than those U.S. energy-wasting, thin-walled houses, made from wood, which also burn down by igniting LiPos much easier than especially here in GER.And the traffic in GER is also much more dangerous than in U.S. because everybody is speeding like crazy.Sorry, couldn't resist to add a few more prejudices.Frank

author: hwj-d
author_rank: Frequent Contributor
timestamp: September 04, 2016, 08:31:53 pm
content: So, should i send one or two of my selfmade (#13) 18650 chargers to Dave?

author: Zbig
author_rank: Frequent Contributor
timestamp: September 04, 2016, 09:15:53 pm
content: Quote from: Fungus on September 04, 2016, 04:47:12 pmNewest Sony Xperias reportedly have a mode where they "learn" your charging habits and, when connected for the overnight charge in the evening, will charge their battery quickly up to 90% , then sit and wait until morning, and only then top it up to 100%, just before you're awake. Smart.

author: fubar.gr
author_rank: Unknown
timestamp: September 04, 2016, 10:49:10 pm
content: Quote from: EEVblog on September 04, 2016, 08:27:32 amBattery related topics seem to attract the free energy/overunity crowd like honey attracts bees.I think this is the reason there's so much bad info on batteries that has persisted for so long, such as desulfation or the "memory effect".

author: tatus1969
author_rank: Super Contributor
timestamp: September 05, 2016, 05:43:24 am
content: Quote from: fubar.gr on September 04, 2016, 10:49:10 pmNiCd memory effect is not bad info, it was like that at the time (15 yrs ago (?)).

author: fubar.gr
author_rank: Unknown
timestamp: September 05, 2016, 05:56:43 am
content: Quote from: tatus1969 on September 05, 2016, 05:43:24 amThe memory effect would emerge only after a set of several, very specific conditions were met.It was very hard to reproduce in a lab and practically impossible to arise on a consumer device.What people would atribute to the memory effect was in fact the normal battery degradation due to exceeding maximum charge cycles or otherwise mishandling the battery.

author: retrolefty
author_rank: Super Contributor
timestamp: September 05, 2016, 01:47:43 pm
content: Quote from: fubar.gr on September 05, 2016, 05:56:43 amI believe NASA discovered this problem in early Nicads in some early satellite battery failures. Some kind of whisker growth that would limit battery capacity. Solved by a manufacture process correction many decades ago but the myth of continued 'memory effect' seems to always live on.

author: b_force
author_rank: Super Contributor
timestamp: September 05, 2016, 01:50:38 pm
content: Well, i guess certain people forget Ohms law with power losses. But you can better have a fuse in front of the mains than in front of your battery. Assuming the fuse has the same resistance P=I^2*R.The current on the mains side is much lower, therefore the losses are much lower.This is the same reason why working on a 115Vac mains voltage is resulting in much more losses (or thicker copper wires).Overall, relatively speaking for just the battery power supply, it's a little far fetched. Maybe you safe 1-2% at most. Really something that keeps you awake all night.

author: Fungus
author_rank: Super Contributor
timestamp: September 05, 2016, 05:53:55 pm
content: Quote from: b_force on September 05, 2016, 01:50:38 pmA fuse on the output won't make much difference to a battery charger.For most of the charge cycle you're in constant current mode so the fuse is mostly irrelevant. When you switch to constant voltage mode the current drops very rapidly towards zero. Small current means very little voltage loss.

author: nctnico
author_rank: Super Contributor
timestamp: September 05, 2016, 09:15:03 pm
content: Quote from: b_force on September 05, 2016, 01:50:38 pmThe mains fuse doesn't prevent a battery to set the secundary side of a PSU on fire. What fuses do is prevent fire by offering a defined, safe and controlled weak spot. They don't prevent electronic parts (especially semiconductors) from breaking because fuses are slow. So yes you'd need either a diode (preferred; see Rigol's document) or at least a fuse when charging a battery from a PSU. BTW chances are a PSU will activate it's crow bar or active load circuit when it sees more voltage across the terminals than expected so just use a diode.

author: b_force
author_rank: Super Contributor
timestamp: September 06, 2016, 11:27:18 am
content: Obviously. But why are we talking about fuses anyway?I never said it would be a good solution to 'protect' your circuit?If you want fast response, there are better ways.It's also not hard to compensate for any voltage drops in these low voltage circuits.

author: drussell
author_rank: Super Contributor
timestamp: September 06, 2016, 10:45:58 pm
content: Quote from: b_force on September 06, 2016, 11:27:18 amWhat?!!They were talking about putting a fuse between the battery and the power supply (which is a darn good idea!)You'rethe one who went off on a silly tangent about putting a fuse in the primary side of the PSU...That's not going to protect the battery from exploding if the PSU does something dumb for any reason, like essentially short out the battery due to an overvolt crobar circuit, etc... A diode and fuse is always a good idea.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 07, 2016, 05:29:11 pm
content: The right place for the fuse would be directly at the battery holder or contact, as this would also safe you from a short in the more or less free flying cables. Just don't add unsafe cabling to tweak in a fuse.Depending on the design of the supply, it could be possible to have one inside. The important part would be to have it in the current path only, with voltage sensing after the fuse and the fuse between the terminal and reverse protection diode and if present the crow bar. Some better supplies already have a fuse at that position.

author: thm_w
author_rank: Super Contributor
timestamp: September 07, 2016, 09:22:21 pm
content: The usb charge modules were already posted, but heres a ready made solution:https://www.fasttech.com/products/0/10001919/5310300-miller-ml-101-v6-0-smart-18650-li-ion-batteryCompact, simple, cheap. You can also get a powerbank style that provides 5V usb output.

author: doobedoobedo
author_rank: Regular Contributor
timestamp: September 07, 2016, 09:36:41 pm
content: Quote from: thm_w on September 07, 2016, 09:22:21 pmIf we're going fasttech, why not just get a battery with a built in chargerhttps://www.fasttech.com/products/1/10026239/5744205-authentic-znter-3-7v-1500mah-usb-rechargeablethey even do AAs with a 1.5V buck regulator along with the chargerhttps://www.fasttech.com/products/1/10026239/5744207-authentic-znter-s15-1-5v-1250mah-usb-rechargeable

author: Flipflop
author_rank: Contributor
timestamp: September 15, 2016, 10:15:02 pm
content: QuoteI remember reading in Practical Electronics magazine about LiIon battery technology (long before they were in domestic devices) and the article said they would never be in domestic use due to the fire risk of them. There seems to have been quite a few incidents recently with devices catching fire. Recently in the east of England a womans mobile phone caught fire in her hand and it wasn't being charged at the time either.