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Discussion Starter #1 (Edited)
Hi, got battery and BMS for my microcar but it is not working! I am mechanic and electician and built up everything except battery. I got 5 batteries from VW car with 14,8 Volt and 105 Ah.
I cannot reach the guy who sold me battery and BMS...
But BMS isn’t „starting“ battery. I see 4 cells are on almost 5 volts instead of 3.7 volts.
Anybody can help?
Thanks
Kind regards
ger
 

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Manually measure the cells that the BMS says are 5v. If they read normal you have a problem with the wiring between the BMS and the batteries.

Did you install the BMS or did it come with the batteries pre-installed?
 

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Discussion Starter #3 (Edited)
Hi, originally I didn’t install BMS. But when I went home I was re- installing the BMS wiring (shorten the wires to fit). But I just take one wire off shortening and then put on to the cell and so on. I think this method should not caused wiring faults by me....
How to measure the cell voltage? Do i measure from the pins where the wires go to BMS and Battery + ?
Attached the installation.
Thanks for helping!!!!!!
 

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There should be 20 cells in your BMS display but you only show 18.

i can't make any sense of your wiring since there are duplicate labels--take some time to re-do your labels and check your wiring.
 

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Discussion Starter #5
Sorry, don’t understand. I have cell 1-18 on the 1st Display site and cell 19-20 On the second display site.
Cell 21-32 are not available so voltage is 0.
Why you say cus 18 cells?
 

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sorry i didn't see the other display with CELLS 19 and 20.

there is something really wrong to be reading ~5V for a CELL (3p block).

It might help if you label the cells by their BMS number instead of having duplicate labels as seen in the photos. e.g. there should only be 1 cell labelled as "1".

Also can't clearly see the jumpers that connect the modules.
 

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Discussion Starter #7 (Edited)
How to find out the right label for the cell.
Can I screw off one BMS wire from cell and see on display voltage changes to 0Volt?
There is also an addition wire from (I guess) cell nr. 1 and cell nr. 20 Going to BMS...
And from cell nr 1 a black wire to BMS Display (is the „minus“ part of power supply).
 
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