Daly BMS problems.

[Happy Camper]

Hey, newbe here with limited battery knowledge please be kind.
So, i had 12 3.2v 100ah lifepo4 (4s4p) with a Daly 4S 250amp BMS set up in my van (12volt) and 3x160 watt solar panels. all working fine but decided to add anothe 4 cells to increase capacity. so i added the other 4 cells, same type as original (4s4p) and conected BMS with everything looking good. Had a 3.2 v increase on each string with 12.6v total. Conected system back up and noticed the 4th cell on the BMS was dropping voltage quickly with only 2amps draw to the point what after 2 hours the BMS shut down with low voltage and differential voltage faults. 4th cell on BMS reading 2.488 on BMS but 3.3 with multi meter?? Also noticed with charger connected (Victron) voltages started to go high on cells 3 & 4 getting to 3.6 while other 2 cells at 3.3. Also i swapped cell packs around (1 with 4) made no difference. allconnections are tight and secure.
Any ideas on what i have done wrong or what problem is??

 

[sunshine_eggo]

You have a very haphazard busbar arrangement. You need to make it look like this:



Each of those breaks result in you BYPASSING a group of 3 cells.

You need to fix your bus bars.

 

[sunshine_eggo]

Trying to put it another way. Please note that even though you want these indicated cells in parallel, the way you have wired them is not in parallel, and each pair will be a different voltage:



I'm not surprised your BMS can't figure out WTF?

 

[Happy Camper]

You have a very haphazard busbar arrangement. You need to make it look like this:

View attachment 205690

Each of those breaks result in you BYPASSING a group of 3 cells.

You need to fix your bus bars.

Yer thanks mate, have fixed busbars now and looks much better. makes sense now i look at it. As a sparky i make a pretty good fitter.

 

[Supervstech]

Yer thanks mate, have fixed busbars now and looks much better. makes sense now i look at it. As a sparky i make a pretty good fitter.

Post up pics. Closeups so we can see if anything else is amis. That much energy, a small mistake can cause a fire.

 

[sunshine_eggo]

Yer thanks mate, have fixed busbars now and looks much better. makes sense now i look at it. As a sparky i make a pretty good fitter.

this shit can make you go cross-eyed... One guy posted up 4 6V lead acid, and it took me 30 minutes to work out that he had 18V instead of 12V...