Li-Ion 4P Balance Pinout - Page 1
Forum section: electronics / general

author: metrologist
author_rank: Super Contributor
timestamp: January 20, 2019, 02:35:41 pm
content: I'd like to put in service a pack but do not know the pinout. Some detail starts on page 7 of this document and a picture on page 19.https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/57436/160124.pdfI measure 0 volts between all pins and I suspect there is a circuit cutting the voltage. The wires areredredwhiteblackblackblackAny help thanks

author: Nusa
author_rank: Super Contributor
timestamp: January 20, 2019, 04:59:22 pm
content: Balance charging only works on serial packs, not parallel packs. If you wanted to charge the cells separately, you'd have to electrically disconnect them from each other first.As for the pinout, the most likely is red = +, black = -, and white = thermistor (try measuring resistance between white and black). I suspect the same color wires are the same terminal doubled up for current and/or utility. Easily confirmed by measuring resistance.That document only talks about testing. Only useful info for you is probably the stated capacity and charging currents mentioned early on. The fact you measure 0V is not a good sign, but until you try charging it you won't know for sure.

author: station240
author_rank: Unknown
timestamp: January 20, 2019, 06:05:40 pm
content: In several places, including one of the photos of the module, it's clearly a single lithium cell.The casing has 3.8V printed on the stainless steel casing.The document also mentions there is a switch to cut all power in/out of the battery.Do some resistance tests, see if the two red wires are connected internally, do the same for the two black wires.At a guess, I'd say bridging between the white and black, might be the way to turn it on.Entirely possible the cell has discharged to 0V, and that is why there is no voltage.

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 20, 2019, 10:03:41 pm
content: If the wires are the same colour, they do the same thing. If its 1 cell or a few cells in parallel, you don't need to balance them, the downfall is that if 1 fails the rest will be unusable also.

author: station240
author_rank: Unknown
timestamp: January 21, 2019, 08:01:09 am
content: Quote from: nsrmagazin on January 20, 2019, 10:03:41 pmHahaha, you haven't seen chinese wiring looms then.The BMS balance cable sets are things likeA) 1 Red wire, rest are black wires, no matter how many cells are involved.B) Several Red wires, rest are black wires, again same issues.C) Random colour wire order; Black, Red, White, Yellow, Orange, Green, Blue, Purple. So Black is positive, Purple is negative, the other wires are between cells.There is a reason I don't assume wires are actually what they appear, certain sloppy people will use whatever colour wire they have left in stock.

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 21, 2019, 10:44:46 am
content: Even from the chinese sellers I have not see a this bad device. Its true that they don't follow the colour standards, but what you are refering to is too much.

author: aargee
author_rank: Frequent Contributor
timestamp: January 21, 2019, 11:44:37 am
content: I agree with Station240, Chinese cables should not be relied upon for colour coding, I’ve seen everything from red + multiple black wires to random rainbow wiring for BMS connections.One 13S pack I have for my E-Bike has a BMS with the random rainbow wiring.The pack in this case may be dead flat, showing nothing on the balance connector as suggested.

author: metrologist
author_rank: Super Contributor
timestamp: January 21, 2019, 03:36:18 pm
content: The cell might be dead. It looks like 4 flat cells and there is a PCB, but I have not broken the shrink wrap yet. Maybe I will apply some volts across each end of the plug (red/black).

author: metrologist
author_rank: Super Contributor
timestamp: January 23, 2019, 04:20:53 am
content: Oh, it's not a balance circuit - it just cuts the output when the voltage gets low to prevent over discharge. Just needed a charge. Nice 10.4AH pack.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 23, 2019, 04:44:57 am
content: A lot of BMS chips have a "shipping mode" that requires connecting a charger to get out of.