Victron Blue Smart IP65 reports short circuit

Q&A and troubleshooting
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1

Hi,

I wanted to charge the two AGM 23V batteries in my car with the Victron Blue Smart IP65 12/7 charger. One is for starting the car, the other one is for supplying camping equipment.
The second battery could be charged properly, but the Blue Smart is reporting short circuit errors for the first one (main car battery) all the time. I measured all connections, the batteries voltage, etc. No short circuits, everything looks fine when measured separately. But when connecting the Blue Smart it’s complaining about the short circuit all the time.
If I switch the charger back to the second battery, it’s charging perfectly fine.

The first battery itself is working fine in the car, I measure 12.5V and it’s supplying the car with energy properly.

Any idea on what I’m doing wrong?

2

If the battery is in the car then the charger may be confused by whatever loads are running on the car, it is only a 7A output so quite limited.

3

Yes I figured this might be a thing but then I disconnected the battery from the car and got the same result. :frowning:

4

No idea why one battery would do this and not the other unless the starter battery has something wrong with it giving it a low resistance which the charger is detecting.