1st question is how old are the batteries? Under ideal conditions they are probably going to lose about 10% of their capacity within 3 years and 20% by 4 years. (Powersonic DataSheet) I typically replace my batteries every two years but have gone 3 to 4 years depending on how they are performing. Glider usage, could hardly be consider ideal usage for them so less life expectancy isn't uncommon.

Contrary to what seems to be popular opinion, I really don't see a problem with the parallel charging (especially with a low current charger) as long as your trickle charging is holding or bringing the voltage to between 13.5 and 13.8 volts. Use a meter and test this.

I will agree that a bad or weak battery may prevent the other batteries from charging properly, but then again this is really a battery problem not a charger problem.


Brian