Hi Jana.
You have already gotten good responses, the advise about switches
and chargers is on target.
Here are some additional things to consider... [I presume you have
lead-acid type with clean cables].
A lead-acid battery does self-discharge and limits shelf life to
about 6 months.
After 6 months it wont be dead, but will be pretty unusable until
after charging.
Only use between 30 and 50% or 50AH max before recharging for every
100 amp-hrs capacity.
A battery only has so many discharge cycles in it and deep discharge
shortens life.
A dead battery is pretty bad news, you don't get very many full
discharges before failure.
Notice there is no number to hang on cycles, but a well maintained
battery should live many years.
failure? pretty often one cell refuses to take & retain charge.
A simple test is to look for one warm battery amongst a bank of cool
ones after charging.
Sometimes charging doesn't fully complete in one battery and
prevents the others from "filling up".
For lead-acid batteries, there is a de-sulfating procedure that you
might look up some time.
Fully charged good batteries store OK in very cold weather, but dead
batteries ice up and crack the case [very very bad].
Your example of "dead in a month" speaks to some load on the battery
when you think all is OFF.
Refer, hidden light left on, normally some circuit not controlled by
the master switch near the entry consumes energy.
A disconnect switch at the battery bank is good medicine for
unexpected loads.
If the battery itself is bad, usually it registers some voltage [not
dead] while not under load, maybe 10 volts.
But a bad battery will not deliver much current [especially won't
start a diesel engine].
Starting batteries and deep discharge batteries are different --
sometimes not OK for both uses.
Starting batteries are high current and may be quickly charged
[think a couple hours].
Deep cycle batteries are low current and should be charged more
slowly [think many hours].
Don't put both types in one battery bank.
One battery rated for both duties is often a compromise.
Probably the best insurance for long battery life is a "smart"
charger over winter.
One charger for each battery bank.
You probably have a large charger already on board, it might be OK
but not best for all winter use.
A winter charger is better than trusting the 6 month shelf life,
even in warm climates.
And they are very low power & it's easy to find an extension
cord.
OOPS -- too much?
Skip
On 09/21/2011 11:31 AM, Jana Ewart wrote:
Mike would like to know how to "kill the DC" so that it
doesn't drain down the batteries during storage for a
while this winter. (We hope to still get to AZ sometime
this winter.) Our Bird has just been sitting for a month
or so and the batteries are dead; we go and run the
generator and recharge a bit and the next time they are
dead again. Therefore, we can't get the Bird to start
when we want to move her. Any suggestions or tips on how
to avoid this issue would be greatly appreciated. Thanks.
Mike and Jana Ewart
89 PT40WB Royal Conversion
presently in Rapid City SD
--
Blessed are the people whose God is the Lord. (Psalm
144:15)