John Drake Services, Inc.
1427 E. 68th Street
Long Beach, CA 90805
Always wear eye protection when working around batteries.
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Charging Batteries - You can't have everything.
How is this for the title of a page?
First off, what will shorten a lead acid battery's life:
Overheating the battery from overcharging and / or keeping the battery in too high of an
Leaving the battery in less than 100% state of charge for long periods of time which can
cause sulfation of the plates - this reduces the battery storage capacity.
Secondly, what will ruin a battery in a short period of time?
A short circuit in either the charging or load side of the battery.
Boiling the electrolyte down below the tops of the lead plates, or just
plain running them dry.
Sure, these conditions seem so obvious that everyone knows them.
Many charging systems are set up so that these conditions are almost guaranteed to happen.
It is not unusual for some battery manufacturers to suggest slightly overcharging their batteries.
What does this mean.
For giggles let's say you have a battery that is rated at 100 amp hours capacity.
You draw it down to 80% state of charge.
In theory you will need to put 20 amp hours back in to bring it back up to 100% state of charge.
When you charge the battery you will lose some power as they heat up as well resistance in the
cables and connections.
A battery manufacturer might say put twenty-five to thirty amp hours back in to make up for the losses -
this would be a five to ten percent overcharge.
That kind of makes sense except for battery over-heating and electrolyte loss (the breaking down of
If the battery had plenty of open space around it to dissipate heat and you kept up on the watering of the
battery this would be a good idea.
How many of us have a battery bank with lots of room around each battery and can force ourselves to
keep them watered as needed?
You can answer that question for yourself.
This can be a problem as some charge controllers, as well as some plug in battery chargers, will pound the
battery(s) during the end of the charging process.
Get to know ALL of the components in your system personally.
This will help you get the most out of the system.
to be continued