battery banks
:h this is for the TT group. i have been looking to add an extra battery bank to the tub. when we purchased it. it had already been converted from a single 12 to dual 6. yea i know we haven't even ...
Forum Discussion
Sam Spade wrote:pianotuna wrote:
If it is a lousy converter (wfco) it will take exactly the same time. About 168 hours.
Exactly the same as what exactlty ?
I allow that you might be right but I just don't understand.
Seems to me like the only time this would be true is when the charging source is able to supply WAY more current than a single battery will draw when dead. I don't think that would be true with a 40 amp source.
Allow me to clarify.
The WFCO is well known to charge at 13.6V and not at the claimed 14.4V.
Now, when you apply unlimited Amps to the battery, the battery's Voltage will immediately rise to 13.6V. When this happens, current momentarily stops flowing. Soon the battery will absorb the current and the battery's Voltage will drop allowing current flow again. That is absorption.
If we ignore battery temperature effects, the battery will take 168 hours to charge due to the 13.6V.
Of course we should not ignore battery temperature because that is the limiting factor for current acceptance.
An adjustable charger with a BTS feature will provide an optimal charging current by adjusting Voltage so as to maintain battery temperature within specs at all times.
FYI, Optima AGM batteries have a fast charge spec of unlimited current at 15.6V so long as the battery temperature does not exceed 125F. That is not an optimal charge rate but does give one some idea of what the Optima can accept.
I have been 100% AGM since 2009. Three of my four chargers have BTS; the fourth is a WFCO.
HTH;
John
