BMS

Using Arduino General Electronics
1

Hi.

I have just built a Lion battery pack.It`s a 5p10s (36 volt).My problem is that the BMS turns off
power at discharge already at 34 volt (3,4 volt each cell).That is too early as the specification says
2,5 volt.I have 3 different BMS brand.They do them thing all 3.Charging is no problem,They charge up to
4,2 volt before the BMS turns off.Has anybody some ides what wrong?

Regards
Jan

2

Has anybody some ides what wrong?

Yes.

You did not read the "How to use this forum" post, and failed to supply information required to answer your questions.

3

This is a question for the documentation of the BMS...

That said, the discharge curve for LiPo is very flat until around 3.5v, then it rapidly falls off; you lose less capacity than you think by stopping that early, and it's better for the batteries (in terms of service life) to not discharge them as far.

4

Thanks for your answer.I see what you mean.It`s better not to discharge the battery too low.However I think I could discarge down to 3 volt without shorten the lifetime of the cells that much.Naybe there is nothing wrong with the BMS but instead there is one or more cells in the pack that are bad and make the BMS turn off discharging earlier than expected.Maybe.Thanks again!

Jan

5

Hi,
Can you post a link to data/spec of the BMS please.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks.. Tom.. :slight_smile:

6

I tried to attach pictures but I did not manage.Sorry!

7

Hi,
Keep you pictures about 1Mbor less, if they are to big, rescale them with PAINT or some other graphics application.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Thanks.. Tom.. :slight_smile: