How do I get this battery to work? - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 09:31:05 am
content: Firstly, here are some pictures to help you understand how each cell is connected to the PCB. (excuse the rushed editing)Here is a close up of a cell.Main ICThis is a battery from a laptop that broke a few months ago. I shut down the laptop one day and it didn't turn back on again. The status lights on the sides didn't light up either. I took it apart but was unable to pin the cause of the failure on a single area or component. One thing that left me confused was the fact that the battery wasn't outputting any voltage on the + and - pins. (I also tried plugging it into the motherboard and then measuring, but still no luck)I looked around for some information about this, I wanted to use the battery for a power bank, or something similar. I had this sitting on my shelf for a few months, today I decided to take it apart. When I measured the voltage of the battery cells, all four of them were working fine, and were outputting 4.1V each.Here are my questions: Why isn't the battery pack outputting 15.2V (as is mentioned on the pack)? How do I get the pack to work? If the controller board is actually broken, then how can I safely use the cells (what voltages for charging, etc)? Could this battery, and the possibly faulty controller board, be the cause of my laptop's death?

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 09:39:33 am
content: Could you recommend a board for me? Also, what voltage would I charge it at?

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 09:48:55 am
content: Ahh okay thanks for that, I was searching for 4s.

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 09:54:29 am
content: Would something like this work? (https://tinyurl.com/yctwcszk) The 1s 3.7v 10A Version. So when I charge it, I connect it to the P+ and P-? For the charging, do I just connect the power supply to the P+ and P- pins, and just leave it for a few hours? Does the protection board stop charging once it's full?

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 10:05:00 am
content: Woah! Calm down.I was just searching up what you told me to, and found one that seemed to match your description... I searched for TP4056, but it comes up with Lipo charging modules, And the maximum current output is 1A, which is not enough for a power bank (at least a good one). I am assuming the USB port on a module like this (https://tinyurl.com/y7tonnpk) is for charging, so how do you draw power from the battery?Edit: Ok, I found out that you need a separate module to draw power, so would that module I mentioned earlier (https://tinyurl.com/yctwcszk) work as the output of the battery? I also found out that the 1A is for charging the battery... Is that adequate?

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 12:17:02 pm
content: Would something like this work?

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 17, 2018, 03:20:20 pm
content: Quote from: skillz21 on February 17, 2018, 09:31:05 ammaybe nothing is broken, maybe the main chip battery management controller went into protect/fault mode due to some unexpected condition when you turned off the laptop. maybe searching the controller datasheet is a good idea and see how to reset it to get the pack back to life? there are many laptop battery repair guide/hack in the net you can search for your model or management chip... maybe this can get you started?http://www.ti.com/lit/ds/symlink/bq40z50.pdfymmv.

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 09:51:46 pm
content: Quote from: Mechatrommer on February 17, 2018, 03:20:20 pmThanks for that info, but honestly, I think that something in the motherboard is toast, I tried to connect 16v from the battery cells directly to the laptop motherboard and.... a wire on my connection shorted, that was pretty stupid of me, but i think that connecting the battery back to the laptop isn't really a smart idea... Thanks for that info anyway, I'll give it a try. I have one of these lying around from an old power bank (https://tinyurl.com/y9row5yl), If I connect it directly to the four cells in parallel, would it work safely?

author: skillz21
author_rank: Frequent Contributor
timestamp: February 17, 2018, 10:29:05 pm
content: Quote from: Mechatrommer on February 17, 2018, 03:20:20 pmActually, do you know how I could reset the board? I tried briefly short-circuiting the connectors 2 and 5, which has 16v on it, but the protection is still on... why? How do I reset it?

author: Jwillis
author_rank: Super Contributor
timestamp: February 18, 2018, 12:52:13 am
content: How old is the battery pack.Even lithium batteries wear out.Even new ones can can fail prematurely if not kept charged to at least 70% before storing .No battery likes to be left uncharged for extended periods of time .New packs should be properly cycled for extended battery life.Even if one cell is failing the board will sense that and won't charge.It's a safety feature.You can replace the cells but in most cases it's much cheaper just to trash it a get a new one. Is that wire broken in pic 3?That's the temp sense.

author: skillz21
author_rank: Frequent Contributor
timestamp: February 18, 2018, 04:27:27 am
content: Quote from: Jwillis on February 18, 2018, 12:52:13 amThe pack is a few months old, and it was charged to over 70% when the laptop died. The wire slightly broke when I tore open the covering, but the pack was not functioning before I opened it. Anyway, I desoldered the cells and scrapped the PCB, I want to use the cells in parallel for a power bank.

author: soubitos
author_rank: Frequent Contributor
timestamp: February 18, 2018, 11:48:05 am
content: You do not need a BMS module with a protected TP4056 moduleCan you measure the dimensions of the batteries?

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 18, 2018, 12:52:33 pm
content: Quote from: skillz21 on February 17, 2018, 10:29:05 pmiirc on other BMS chip, there is a reset pin you connect to +V briefly. another option is googling "how to repair/reset <insert your laptop model> battery pack". but since i can see you want to re purpose the batteries, i dont see much point to it anymore.

author: Jwillis
author_rank: Super Contributor
timestamp: February 18, 2018, 05:42:54 pm
content: I think they're 3.8volt 3080mAh.Charge limit would be 4.35volts

author: soubitos
author_rank: Frequent Contributor
timestamp: February 18, 2018, 05:45:20 pm
content: Quote from: Jwillis on February 18, 2018, 05:42:54 pmAll the better charging them up to 4.2V