Dead Batteries After 8 Months? Surely Not!

[stevensuf]

So, my super dooper - piece of excrement batteries died after only 8 months of use, never taken below 50% charge bar the last week or so, and only because the whole 500amp hours were only lasting 2-3 hours and i did not have enough fuel to waste running the engine all night on an Atlantic crossing.

My question is, the shore power charger is 3 stage and fine, the solar charger 3 stage and fine, the alternator is a dumb regulator sits at 14.2v and gives the batteries whatever they will absorb at this voltage and holds them there, now i knew this could have been a long term problem on long motoring journeys, but when the batteries were charged it showed only 10-15 amps at 14.2v surely this should not have fried (ie degassed the batteries so quickly) ???

(bear in mind the boat was probably consuming 10 of those amps, ie the alternator was only pumping 5 amps into 500 amp hours of batteries for longer periods once they were charged)

I am thinking the batteries have been below par since the day i got them.

Answers on a postcard please..