Frank Dinger wrote:
One thing to keep in mind is that battery voltage changes with
temperature, and any float or trickle charger that doesn't take this
into account can shorten a battery's life considerably. So if you want
to get the longest life from your battery, you should make sure the
charger is properly temperature compensated.

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Roy , If the lead acid battery charging current is limited to 0.1C ,(example
a 15Ah sealed battery is charged at max 13.8 V with a current not exceeding
1.5A) is temperature compensation then still a necessity to optimise the
battery's (usable) life ?
And if it is, in which temperature range ? I have not found this info
through Web based tutorials.
I am very interested in this topic since I charge a number of batteries
(some non- sealed some sealed) by means of a (150 W max)wind generator and
2 pcs 64Wpeak solar panel.

TIA for any advice

Frank GM0CSZ / KN6WH

I'm sorry, but I don't have an answer to your question. Actually, I'm
not sure there is a simple answer. There are a number of quite different
types of lead-acid battery, with different plate compositions,
construction, and electrolyte form (e.g., liquid and "starved" -- as far
as I can tell, gelled electrolyte is no longer used or is at least very
rare, in spite of the fondness hams have for dubbing every sealed cell a
"gel cell"). Each has its own characteristics, advantages, and
shortcomings. I heartily recommend a careful reading of the
manufacturer's recommendations for the particular battery you'll be using.

In more general terms, I don't think any lead acid battery manufacturer
recommends constant current charging at any level. Charging to maintain
a cell at full charge (float charging) is, in my experience, invariably
recommended to be constant voltage, not constant current, with the
voltage being temprature compensated (lower voltage at higher
temperature). The amount of current is then whatever the battery
requires to maintain full charge.

I did a quick google search of

lead-acid battery float charging "temperature compensation"

and came up with quite a few hits including some basic tutorials, a
couple of which were http://www.powerstream.com/SLA.htm and
http://www.emrg.ca/ideas&info/gel_cell/battery_care.htm. There are many
more available. But again, batteries can differ quite a great deal, so
you should really get information specific to the particular battery, or
at the very least, to the general class of battery, that you'll be using.

Roy Lewallen, W7EL