Help need with batteries not charging???

[Adamsmith243]

Good afternoon all,
Wenhave recently bought a 1993 Hymer B544. When we bought the seller advertised as having 2 new batteries, engine and leisure. We drove home for about 4-5 hours, and when we got back the battery warning light on the control was flashing.
We didn't start the van for about 7-8 days as we had an emergency to deal with, when we tried to start, she wouldn't. Had a friend boost it and all was well. (Leisure battery showing as 10.5v on control panel also). Took for a drive straight away to try and put some charge back. We then went away for a night at a campsite used EHU, following morning she wouldn't start again?
So my question is, does or can the leisure batter draw from the engine battery? And should the leisure battery be fully charged as 4 days later with no use the battery is back 10.5v?
Thank you

 

[mitzimad]

Sounds like the battery is not holding a charge

 

[autorouter]

So my question is, does or can the leisure batter draw from the engine battery? And should the leisure battery be fully charged as 4 days later with no use the battery is back 10.5v?

Normally the leisure battery does not take charge from the starter battery if the engine is not running. If the engine is running, the alternator should be putting charge into both batteries. However if there is a fault somewhere, it can happen.

Two points worth noting. First, flat batteries are often a symptom of a wiring problem or fault, especially if they are newly replaced. Second, a voltage of 10.5V is 5/6 of the normal 12.6V, and is often an indication that one of the six cells in one of the batteries has shorted. If so, it might drag the other battery down to that voltage.

What voltage are you seeing on the batteries when on EHU, and when the engine is running? It should be around 14.5V in both cases. How are you reading the batteries, is it the panel display or a multimeter reading on the battery terminals?

 

[madmick1945]

check that the diode in the vehicle alternator is ok as that may well be the problem

 

[Nedge68]

Have you checked if you checked the battery voltage on EHU and with the engine running? What voltages do you see?
The voltage regulator pack can fail on the alternator causing constant drain or high voltage to the battery.

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