|
|
From: (no name) (no email)
Date: Thu Sep 02 2004 - 18:09:54 EDT
In a message dated 8/21/2004 5:54:29 PM Eastern Daylight Time,
writes:
I believe it is exactly that repetitive cycling of your expensive main
bank(s) you mention, between just about fixed points - full charge 100% and
1 refrigerator run say 96% - that does the damage. The battery never gets
below that 96% point and gets "lazy" through leaving the remainder of the
capacity stagnant. I know that wasn't a very scientific description but it
represents what I've seen happen. I think it applies to sealed batteries
more than lead-acid but the same applies to some extent. It seems like if
your batteries are good for 1000 cycles, you are using up those cycles
unnecessarily under the float conditions even though they may only be 4%
cycles. You are wearing out that spot on the plates.
The above is very interesting.
"Forever" I have read that the less (less often and less deeply) the battery
is discharged and recharged the longer it will last. Most of this info is
from Home Power magazine.
Until one day years ago on this list when a Navy submarine crewman mentioned
that they routinely and periodically discharge and recharge the submarine's
propulsion batteries as per the manufacturer's instructions.
>>>> Andina -- The wearing out can be imagined as metal being plated back
and forth acrossthe electrolyte. That metal starts out as a nice flat machined
surface.
Every time you plate some off, then plate it back it never goes exactly back
in the spot where it came from so your nice flat plate ends up with bumps
and hollows. With age those bumps and hollows get bad enough to cause
shorts or opens. So if this is happening in the same few fractions of a
millimeter on the surface all the time, it will get spongy or crusty and
disfigured. By periodically cycling the batteries to a deeper and not a
consistent level as you do when cruising, you break up the crusty top and
bury it with fresh metal.
Norm - But the plates on a lead acid battery are not machined surfaces.
They are pockets in sheet metal that are filled with a lead paste, the active
material.
Norm
S/V Bandersnatch
Lying Gloucester MA
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
|