Wayne.B wrote in
:

Are you saying that all of the charging power is converted into heat?



Eventually, yes. Whether it's the heat of the chemical reaction or the
heat of the internal resistance....it all comes off as heat at some point.

Putting batteries in an unvented, INSULATED box is a big mistake.



Larry
--
Please - Turn OFF cruise control when
you turn on windshield wipers!

On Tue, 02 Oct 2007 19:17:06 -0000, wrote:

Hi:

I cant remember the rule of thumb for sizing an AC shore power charger
to the house bank size. Maybe 10% that is, 40 Ah charger for a 400 Ah
house bank????
Thanks,
Chris

It is frequently recommended that you not charge flooded lead-acid
batteries at more than 20 - 25% of their AH rating - that is, you
shouldn't charge a 400 AH battery bank at more than 80 - 100 amps.

That maximum rate is a consideration when charging from a generator,
where you want to minimise the generator run time. However, when
charging from shore power, you are usually not so concerned about the
charging time, so a much smaller charger may be more appropriate - it
is easier on the batteries to be somewhat gentle with them, and to
charge them at less than the recommended maximum rate.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
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On Wed, 03 Oct 2007 22:04:57 +0000, Larry wrote:

Are you saying that all of the charging power is converted into heat?



Eventually, yes. Whether it's the heat of the chemical reaction or the
heat of the internal resistance....it all comes off as heat at some point.

Putting batteries in an unvented, INSULATED box is a big mistake.

Battery boxes should be vented, no question.

The heat question is something else altogether. If all of the
charging power were converted to heat, there would be no energy left
over for creating a stored charge. Heat represents wasted energy in
the charging process, usually 10 to 20% of the total.