Sprinter Van Battery Problems (1 Viewer)

[aliente_h]

Hello - newbie here.

I’ve got a fully converted 2018 Mercedes Sprinter and I found this thread as my van has died and I’m trying to work out if it’s the alternator or faulty wiring.

The van has been driving fine as it’s been really sunny (400w solar panels) so has kept my solar battery full and hence perhaps been keeping my van battery topped up.

It’s the first overcast day and the van has lost power and will not start showing the signs of a bad alternator - battery metering at 10.8V. Could this indicate that my alternator is the culprit? Until reading this thread, I didn’t realise that my main van battery was being kept topped up by my panels which could explain why I was able to drive last week?

Sorry for the lack of technical detail here. I’m in touch with my electrician and going to speak to a garage on Monday (stuck in Spain so will have to dish out my best Catalan…).

Any thoughts / leading questions welcome.

 

[GeoffnDee]

aliente_h , At 10.8v your starter battery is very flat/knackered , if you could get a jump start , take the voltage reading with your meter at the starter battery , while still running , and this will indicate if your alternator is charging and ok (around 14v )

 

[PDrill]

First thing that comes to my mind is that perhaps the relay connecting/disconnecting the two batteries has failed, the batteries are connected together all the time and any use of electricity drains then both batteries. This is quite easy to confirm, just measure the voltage on both batteries (with a multimeter) and if they are the same (0.0-0.2 volt difference) this might just be the case. Also if you turn on every electric device you have in the living area, the living area battery voltage should drop but the main battery should not be affected. These measurements should be done when it's been a few hours since last drive, as some relays disconnect only when the main battery voltage drops below 12.x volts and that will take some time.