GL: Battery Charging

[Bob Kunath]

Hi,

I posted looking for recommendations on AGM batteries a few weeks ago,
and received a few positive reviews for DEKA (aka West Marine)
batteries, made by East Penn.  I bought them even though I think
Lifeline are built better mainly because Lifeline are very difficult
and expensive to get in the Mid-West, but you can pick up West Marine
at any WM store, and they were on sale.  Three 4D's cost about $1150,
they were on sale.  Thanks for the comments!

Now for a secondary question on the same topic.
When leaving the boat for a few days, we always leave the
inverter/charger on, theory being that if the bilge pumps were needed
they would get all the power they need.
Now that the Loop is finished, that means that for about 20 weeks per
year (we need to spend more time on the boat), the house batteries are
on the trickle mode for about 4-5 days per week.  At rest, the
batteries measure 12.8 volts.  On the charger, 13.4 volts.
The house bank replacement we just did was the second in 8 years. Both
times I blamed the house battery failure on external events, not age.
Now I have second thoughts.

The starter battery is only charged when the engines are running.  I
just replaced that battery after 8 years not because it failed, but as
PM because it was 8 years old and I was doing the others anyway. The
generator AGM battery is also 8 years old, and it only gets charged
when the generator is running.  Again, these are AGM's. so no
maintenance is required or even possible.

The pivotal question here:  Is it better to keep the house bank on
trickle (13.4v) when we leave the boat or shut off the charger?  Does
that continous 13.4 charging rate do a slow burn on the batteries that
shortens their useful life ?
-- 
Bob Kunath
Sans Souci
Pacific Seacraft 38T
bobkunath@gmail.com
(847) 540-8175
cell:  (847) 921-8175