"Larry W4CSC" wrote in message
...
Kelton wrote in
:

Unless you're all using submarine 6250AH cells, I doubt you'll ever see
100A coming out of a 100A charger,


I suppose that the amp meter on the remote panel of my Heart inverter might
be lying, but it at least claims that it pumps out 100 amps into my 450
amp-hour battery bank.

especially these new computerized-charge models.

It would be only the "smart" chargers that would drive that kind of current
into a battery bank that a recreational boat is likely to have for more than
a minute or so.

If the battery is THAT dead, there's no sense charging it.

Why?

Run
the batteries down to what you normally do, then watch the charging
current
curve on that 100A charger.

If it is a "smart" charger and rated at 100 amps it should drive the full
100 amps until the end of the "Bulk" phase, which is when the battery
voltage reaches 14.4 volts. If you have a simple "taper" charger then the
current will start to drop off as the battery voltage increases.


1200 watts will simply boil the electrolyte in
a lead acid battery that cannot dissapate that much heat (the batteries in
these boats).

If you charge at high rates you certainly need to monitor the electrolyte
level in the battery closely. To maximize the service life of the batteries
it is advisable to limit the charge current to no more than 20% of the
capacity; if you have a 100 amp-hour battery don't charge it at a rate
greater than 20 amps.

Rod