On 11/26/2014 10:19 AM, RobertMacy wrote:



...snip...

good point about indoors vs outdoors. I had a battery explode INSIDE my
car's engine compartment. I stupidly left the contacts loose and enough
gas enough spark and the battery became non-existant with acid washing
the interior of the engine compartment!

Why not on a really small trickle charge say 100mA, or 10mA, or 1mA, or
whatever it takes to sustain the voltage? ignoring temperature.



The problem with a trickle charger is that it simply puts out a small
but unregulated amount of current. In the probable event that it's
output would be slightly higher than the battery's idle discharge rate,
the voltage could go above the battery gassing point. Not only will this
use up water, it will be putting out hydrogen.

Plus, if the battery was discharged, a trickle charger would take
"forever" to recharge the battery.


Most chargers are regulated to prevent excess gassing and some are even
adjustable.


Except for all the batteries that I have in UPS's I never keep any of my
extra batteries on charge. They are kept in a cool location and some are
only "topped off" twice a year.

I have a couple of rarely used 6V gel cells that are over 20 years old.
One is low capacity but usable but the other still has decent capacity.

Had the batteries been kept on float charge they would not have lasted
more than 4 or 5 years.