Just installed batteries, but have a problem with SBMS

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Johannes Madsen

Jul 24, 2021, 2:15:23 AMJul 24
to electrodacus
I hve jut installed my batteries but have some problems:

I am not able to turn on EXT3 and EXT4
What ever I try - they are switched of. If I connect the two wires, the external relays works fine

See pic.

How can that be?

2) the cells are fully balanced before installation.
after inatallation and first charge:
cell 1 = 3,3v
cell 2 = 3,5v
cell 3 and 4 = 3,7v

after disconnecting charger (sterling power 12v - 50a)

the cells balanced on 3,3v

What happend while charging?

I have a victron 220A BP, EXT 3 to manage load (shutting of if low voltage).
When I use mu bowthruster, it shutting of (Bowthruster =125A)

How can that be?

If the EXT 3 should manage LOAD on system (Victron 200A BP) then the right setting should be something like:
Type 2
SOC 30%    (Now it is 90%)

If EXT 4 should manage Charging, the settings should be:
Type 1
SOC 90%  (now it is 30%)

Can anyone please help me on this?

Thanks you

Dacian Todea

Jul 24, 2021, 1:24:36 PMJul 24
to electrodacus
1) I see no photo here but from your earlier email you did not connected the EXT IO4 to control the charge source and battery was being overcharge thus the reason both EXT IO3 and IO4 where open circuit as they where trying to stop the charge source and the loads due to severe overcharge.

2) As already mentioned the SBMS0 has no control over charger so it can not stop the charger thus the reason some of you cells are well above 3.55V

3) Again it can be due to over charging so exceeding secondary 3.75V limits or cells are not properly connected to handle 125A meaning under 125A load one of the cells drops below 2.8V

4) Yes EXT IO3 will be type 2 the rest is irrelevant. Same with IO4 managing the charger it will be set as type 1

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