Battery Issue

[NDevonGonga22]

I hadn’t used my California for three weeks, but when I went to open it, I found that the starter battery was completely flat and none of the electrics in the van were working.
My car breakdown came out and jump-started the van. He advised me to leave the engine running for about an hour to recharge the battery. After an hour, we switched the engine off and tried to restart it, but there still wasn’t enough charge.
I called them back and asked them to test the battery. After testing, they advised that the starter battery needed replacing, which they did. I was a little disappointed, as the battery was only around 3½ years old.
After the replacement, I noticed that the camper control panel still wasn’t working. I assumed that a three-hour drive would be enough to recharge the leisure batteries, but the control panel remains non-functional and I’m now getting a notification that the second battery is low.
Does anyone have any ideas what might be causing this issue and how to fix it? Could it be that the leisure batteries also need replacing, or is there another fault I should be looking for?

 

[andybeary]

Is it possible that the leisure batteries have been critically low soc for to long and now damaged? You could test the leisure using a meter? I know lead acid agm need to be above i think 12v but if 11.6v then bad. Plug you van into ehu for a day and see if helps bring back to life.

 

[Californication69]