Lithium battery charger - Page 1
Forum section: electronics / beginners

author: Mule
author_rank: Contributor
timestamp: June 02, 2017, 09:28:49 am
content: Hello,So I have bought this 15A 4S chargerhttp://www.ebay.co.uk/itm/162190890145?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITAnd I have wired the board up to my 4S 18650 battery bank, and have plugged it into my DC Power Suppy. The volatage of my 4S batteries at the moment is very low at 13.8V.Now a couple of questions:Why is my power supply not suppling a current? Power supply voltage reads 16.8V and current is 0A?How do I go about charging my 4S batteries with this?Cheers,

author: Habropoda
author_rank: Regular Contributor
timestamp: June 03, 2017, 04:45:58 am
content: That board is not a charger, it is a battery protector.If your battery pack already has protection you probably don't need it.Try limiting the current on your power supply to one amp. The protection board might be tripping with too much charging power from it.

author: ebastler
author_rank: Super Contributor
timestamp: June 04, 2017, 06:25:34 pm
content: Please, do yourself a favor. If you don't have the expertise -- as witnessed by your trying to charge the batteries without an actual charger circuit that defines the voltage & current -- please leave those Lithium batteries alone!This can get dangerous. Battery chargers will typically be operated unsupervised, and improper operation of Li batteries can create a fire hazerd.

author: Mule
author_rank: Contributor
timestamp: June 04, 2017, 07:10:41 pm
content: Point taken! I will get a 4S charger instead.On a side note though, how does a charger work compared to a power supply?

author: ebastler
author_rank: Super Contributor
timestamp: June 04, 2017, 07:32:20 pm
content: Quote from: Mule on June 04, 2017, 07:10:41 pmThat must have been Habropoda's point, not mine...QuotePlease -- do some reading, on the fundamentals of rechargeable batteris and the hazards of Li batteries. Then decide whether you want to proceed with a homebrew charger, and if so, make informed decisions how to build it. Asking to be spoon-fed partial information, and then embarking on this project with very incomplete knowledge, is not a good idea.I realize that this is the Beginner's forum, and I don't mean to be harsh or discourage you. But this is not a great beginner's project. Power supplies -- be they based on mains supply or Li batteries -- can be dangerous. Dangerous voltages in mains supplies, fire hazards in both types.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: June 04, 2017, 07:37:57 pm
content: Any power supply with CC/CV mode can be used to charge the 18650's. A dedicated LILO charger has the over voltage, over current protection circuits built into the controller so you don't blow up the battery you are trying to charge. If you have an adjustable bench top power supply, you can set the max voltage and max current and charge the battery pack safely, but more than likely, 15A is not going to be a safe current.Please take a few minutes and do some research before you start plugging your battery into anything. Go onto YouTube and watch a few videos or spend a few hours reading up on the topic. TheQuote from: Mule on June 04, 2017, 07:10:41 pm

author: ebclr
author_rank: Super Contributor
timestamp: June 04, 2017, 08:01:20 pm
content: This information is the basishttp://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

author: Inverted18650
author_rank: Frequent Contributor
timestamp: June 04, 2017, 08:06:44 pm
content: This is a little setup I used when I 1st started to charge salvaged laptop cells.I bought a cheap little CC/CV power supply from eBay. This one is a MingHe D3806 (Vmax 38, Amax 6). It can also display capacity as you are charging the pack. (this will not monitor individual cell voltages and I only use it to charge loose cells.)The tray will hold four 18650's. I wired this one up to charge them in series. Make sure you label the positive end so you don't insert the battery in the wrong way around - that is BAD!The bag protects you incase the batteries explode. An often over looked safety feature but please spend the $10 and get one.

author: debininja
author_rank: Contributor
timestamp: June 04, 2017, 08:57:37 pm
content: QuoteThat's honestly areallybad idea (unless you have balancing wires to individual cells). I know for sure many of the laptop cells go bad at different rates.(I salvaged many of them from laptops myself. It always feels like disarming a bomb...)Some cells might have an internal resistance of 60mOhm, but others might be at 150mOhm. There will be differences in voltage drops through different cells. So even though you might set a voltage limit (4.2V * 4 = 16.8V) and a current limit (say 2.5Amps, close to 1C), some will be getting more stressed or less stressed due to their internal resistances. A better idea is to put them all in parallel, that way, the voltage is the same for all, and cells that are weak (internal resistance wise) will decide the current rate.EDIT: never mind, it seems you have balance wires. Carry on, citizen!

author: Inverted18650
author_rank: Frequent Contributor
timestamp: June 04, 2017, 11:35:47 pm
content: I have balance leads for all of them, just didn't capture the entire wiring harness in the pic. I use the Turnigy Reaktor Quadcore Charger ( I have four of them that are hardwired directly to 300W solar panels) for the testing now. But I charged thousands of the 18650's with the D3806 setup prior to buying a real charger. Just set the V(outmax) to 16.8 with just 1A out and it works great. You can watch the amps fall as the supply hits its CV stage and when the amp draw hits .100mah (varies depending on the battery manufacture specs) stop the charge. I also have a hand-held, external, temp sensor that alarms me if any cell gets warmer than the others.I've been building LILO packs for a few years now and have never had a cell explode. I make and sell 24V, 600-1000Ah banks for DIY solar. I use new PKCell branded 3000mah batteries now for my builds, but started it all with just a box of old laptop packs. The first bank I built is still running strong on a 2400W PV system.

author: edavid
author_rank: Super Contributor
timestamp: June 05, 2017, 01:55:16 am
content: Quote from: Inverted18650 on June 04, 2017, 11:35:47 pmBut for loose cells, why not just buy an Lii-500 charger? It costs less than the D3806.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: June 05, 2017, 04:14:06 am
content: Quote from: edavid on June 05, 2017, 01:55:16 amDidn't know the li-500 exsisted really. Looks like a many of the other 4 cell, dedicated battery chargers in the same price range. Probably works well and is way cheaper than the Reaktor, but I like the D3806 ( only $13.00) because I can use it for other projects too. You can also connect a dummy load to the output, put the battery bank on the input, and use it as a discharge tester. The D3806 is a handy little multi-purpose adjustable, bench power supply. It has several cool like features that I really like.

author: Mule
author_rank: Contributor
timestamp: June 05, 2017, 08:35:47 am
content: Misunderstanding.I was saying that I will buy a charger, instead of embarking on the potentially dangerous road of charging the batteries myself. But thanks for the super vigilant warnings!Quote from: ebastler on June 04, 2017, 07:32:20 pm

author: ebastler
author_rank: Super Contributor
timestamp: June 05, 2017, 09:03:39 am
content: Quote from: Mule on June 05, 2017, 08:35:47 am

author: debininja
author_rank: Contributor
timestamp: June 05, 2017, 04:17:32 pm
content: I'd recommend any of the following chargers that are compatible with the cheali aftermarket firmware, which adds a whole bunch of neat features.https://github.com/stawel/cheali-charger/blob/master/README.md#hardwareI have a Turnigy Accucel 6 80W, but it has some really old CPU that doesn't support the firmware. I paid $25 for it, so I guess it's alright.