FS: Single cell LiIon battery management - Page 1
Forum section: electronics / general

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 30, 2017, 11:06:26 am
content: I have been repairing some cameras and the new cells come with a voltage cut off device that has to be removed because the cameras use two cells so it is no good. I have hundreds of these things and rather than stick them in the bin are they of any use to anyone?They are not chargers. You have to give them 4.2 volts and cut off according to the charging rules of your cells. These are to prevent over discharge while using by disconnecting the cell from your device.What I suggest is that if you want some I will stick 10 in an envelope and post them for £1 to cover Paypal, an envelope and stamp. (here's hoping a pound covers it.)UK onlyI am not doing this in order to see them on ebay in a few days. I am doing this so that if you need some you can get some.If you are close enough to Burnley to pick up then come and pick them up gratis. If you need more than 10 then tell me.There is no warranty and no blame if you kill something or burn your house down.

author: Zucca
author_rank: Unknown
timestamp: October 30, 2017, 09:35:40 pm
content: ehm, can you post a better picture so I can read what are the chips used here?Also an image of both side will be very helpful.What about shipping in the EU, Germany?

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 30, 2017, 10:03:31 pm
content: I would have thought posting to Germany would cost more than buying them from China but I haven't looked.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 30, 2017, 10:04:55 pm
content: There is nothing on the other side of the PCB other than tracks and solder pads.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 30, 2017, 10:13:42 pm
content: Hmm, just noticed that the second pictures are different from the first. It seems there may be several different sorts. The Chinese were never good at reputability.Anyway, more pictures. It does look as though maybe this one is for two cells but not fully populated.

author: Zucca
author_rank: Unknown
timestamp: October 30, 2017, 10:33:57 pm
content: DW01A - One Cell Lithium ion/Polymer Battery Protection IChttp://cxem.net/master/files/97_DW01A-DS-11_EN.pdfTXY8205A - Dual N-CHANNEL High Density Trench MOSFEThttp://www.datasheet.es/download.php?id=952031interesting! thanks!

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 30, 2017, 10:49:32 pm
content: Handy looking things.But what to do with bags full of them.From the look of the build quality I wouldn't like to use them for anything serious without at least re-soldering them.

author: ElektroQuark
author_rank: Unknown
timestamp: October 31, 2017, 08:34:24 am
content: I will take some of them if your are willing to send to Spain. I think a simple stamp couldn't be that expensive.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 31, 2017, 09:32:08 am
content: This could get to be hard work.https://www.royalmail.com/germanyhttps://www.royalmail.com/spainIt seems £3.55 is the cheapest, they are not worth sending because it would have to be £4 once Paypal take a slice.Unless you can think of a better way?

author: Mjolinor
author_rank: Frequent Contributor
timestamp: December 01, 2017, 09:50:46 am
content: Does anyone want these batteries? They will have to be picked up from Burnley, UK as no courier that I know of will let you post batteries on their own.bat1.jpg is 500 mAH (some are 600). They have been removed from a camera because they do not last long enough. I have tested some and it is usually just one that has lost some capacity. When new they last about 6 hours but these are replaced if they last 4 hours or less so it should yield 50% OK at least. Some have been knackered by my lack of care while removing, the so get very hot when you cut them in half accidentally.bat3.jpg is 1.4 AH but certainly more than half are knackered. Crap charger in the camera leads to the cells blowing, I reckon the yield of good cells will be as low as 20%.If you want them then I will include single cell management PCBs for them.I have a lot and it seems a waste to throw them away.http://rollingpast.com/john/battery/bat1.jpghttp://rollingpast.com/john/battery/bat3.jpghttp://rollingpast.com/john/battery/bat2.jpg

author: CJay
author_rank: Super Contributor
timestamp: December 01, 2017, 09:56:06 am
content: I don't want the cells but if you still have some of the BMS boards I'd be interested, I'm in Manchester but temporarily transport challenged so they'd need to be posted?

author: Mjolinor
author_rank: Frequent Contributor
timestamp: December 01, 2017, 10:00:22 am
content: How many do you want?Send me a PM with a postal address and an email and I will email you directly.

author: Gyro
author_rank: Super Contributor
timestamp: December 01, 2017, 05:20:14 pm
content: I'd forgotten all about these boards. I'd like to grab a few too if that's ok.PM sent.