"Wayne.B" wrote in message
...
On Sun, 15 Jun 2008 15:20:55 -0700 (PDT), "
wrote:

His service life
numbers suggest that some AGMs will be expected to last 10 years.
AGMs have only been popular in marine use for less than a decade so it
may be hard to get real numbers. My experience has been fantastic.

I have heard the same from others whom I respect. I will probably
convert one of my house banks to AGMs in the future.

While I cannot comment on AGM batteries, my experience with gel batteries
may be of interest.
In 2005 I imported a boat from Florida to Norway. The survey was carried out
in mid March and the batteries were Ok and powered up all auxiliaries
properly.
Three months later she arrived in Norway and the batteries were flat
because, as recommended by the makers, the refrigerator was connected
directly to the batteries rather than going through the panel and nobody had
thought to disconnect it.
I tried to charge the batteries with a powerful charger and it could get no
current at all to pass through the batteries-they blocked the current
completely..
I found that very surprising although I had half expected them to accept,
but not retain, a charge.