"Capt. Neal®" wrote in message
...

"Gary Schafer" wrote in message
...
On Sat, 16 Apr 2005 10:12:46 GMT, "Pete Styles"
wrote:


"James Hahn" wrote in message
news "Meindert Sprang" wrote in message
...
snip


The other possibility is that due to a deeper discharge of one
battery, it
takes longer for the total voltage to reach the point where the
charger goes
from bulk to float. So while for the more empty battery the charge is
still
ok (bulk), the other one still gets the full bulk current too while it
should receive a float charge.
Deeper discharge of some cells in the string will not, of itself, mean
that the charge takes longer. The _difference_ doesn't matter. The
amount of charge required controls the charge time. Whether OP is
running his radio off one battery or both makes no difference to the ah
used, and therfore no difference to the charge time (except, of course,
that if he uses a converter he will be consuming more ah for a given
usage than if he uses just one battery).

Go and read my last post again. The charge doesn't magically share itself
according to need between the two batteries connected in series. Instead,
the charging current supplies equal charge to both batteries. If one
becomes fully charged before the other, then the only way that the
partially charged battery can get more charge is by overcharging the
other. That overcharge is "energy" which cannot be stored in the battery,
but has to go somewhere, and that somewhere is either/or elctrolysing the
battery water to oxygen and hydrogen, and heat. If the discrepancy is
small, it probably doesn't matter, but if not, then it certainly does.

Pete is right on the mark. Reread his prior post. Also go back and
read Bruce's post on the subject. It is bad news to tap a battery
bank.

You can get away with it for a time but it will shorten battery life
because the two batteries do not get charged equally.
As Pete says, "in order to get the battery that is used the most
charged fully you must overcharge the other". There is no way around
that.

Overcharging a battery not only cause water loss but it can warp the
plates in the battery among other things.

Overcharging is the biggest killer of batteries.
Just ask anyone that still uses a feroresonant charger. They will tell
you batteries last only a couple of years.

Do it properly and use the inverter.

regards
Gary

I disagree. Two 12v batteries in series to make a 24v battery will
self-level
with respect to charge.

They will self level even if one is tapped to run a VHF. No harm will come
to either battery. Voltage can be likened to pressure.
I hope this helps.

CN


Capt. Neal thinks I'm wrong.
I rest my case!
:-)
P.