Split charger

I have been having issues with the batteries charging correctly. It all started with my batteries being being replaced. They were passed their sell by date. The new batteries don't seem to be functioning well. The leisure battery does not hold enough charge to power the inverter and the main battery is sluggish in starting the engine when linked. At first I thought it was the alternator but after a bit of testing it seems to be the split charger.

I have had a look at the amp hours on the batteries and they are significantly different. After reading up a bit on the net this is apparently not a good thing. I'll be taking the batteries back this weekend to get two with the same amp hours rating. Hopefully this will do the trick. Will keep you posted.