Battery Issues?

[Tony Brooks]

2 minutes ago, nb Innisfree said:

I once accidentally left the immersion heater on for several hours which totally flattened our already knackered batts, a full recharge restored them to full working order for several more months. 

 

This is exactly why we need to establish if the problem really is the batteries, a charger fault, or user procedure. I suspect, but don't know, the OP has been under charging the batteries for a long time so a battery fault (sulphated or shorting cells) might be correct, but so could it be a faulty charger supplying insufficient voltage, or user error in not understanding batteries and charging, but if he declines to provide the information asked for we will get nowhere and he might end up spending £300 he did not need to when a few £ on diesel for engine charging could resolve the issue.