Lew Hodgett wrote in news:1QTpi.12042$zA4.313
@newsread3.news.pas.earthlink.net:

To replace 375 AH you will require 375/115 = 3.3 hours of engine time.



A pipe dream of battery chemistry. 375AH requires 5 hours (from 50%
discharge, not zero) at 38A, not 115. Batteries charge at 10% of AH
rating, not 30, if you want to convert the electrolyte, giving it time
for circulation.

The two batteries will recharge from 50% very nicely at moderate
temperature at 75A for 5 hours on the new 90A alternator. NO battery
will charge at 115A for very long before the interplate electrolyte has
been converted faster than it can be replaced by convection in the
electrolyte. This is why you see the current drop in the first
place....NOT because it has become charged. After the initial current
blast has reconverted lead sulphate into acid, that acid must move out of
the way to be replaced by more lead sulphate ions convecting in from
below by the heat of charging. There's quite a circulation. Charging
too fast, say at 115A trying to force it fast, only results in the
conversion of H2O into hydrogen gas and lead oxide, that violent gas
bubbling it's doing at high charger currents, once the initial lead
sulphate to sulfuric acid conversion has wained on the initial blast.

I suppose we could build a magnetic drive circulator pump into the bottom
of the cells under the plates and you could charge the hell out of it,
then....

Larry
--
Charging takes time.....the more time, the better.