Tom,
The rated charging voltage of those batteries is probably pretty close,and actually
MUST be identical because you have only one source, and they're essentiallyparalleled
while charging. It is not a problem to parallel different batteriesas long as the rated
charging voltage is the same. Note that you cannot place mismatchedbatteries in SERIES
(such as 6-volt golf cart batteries), even to the point of having themdiffer
significantly in age.
The forklift battery connector that I mentioned is a 2 pole, heavy plasticjob, with a
big handle to pull it apart. The contacts are huge, plated, spring-loaded,and "wipe" as
the connector is engaged/disengaged. Depending on size, they'll handlehandle a couple
of hundred amps for lengthy periods of time; forklifts often have #4cable going to
these connectors. This connector wouldn't replace the Bargman, butsupplement it.
The whole thing might be moot anyway: a fancy hookup to the vehiclewould be needed only
if you are normally running off battery power and are moving oftenenough to charge it
up. Plus, using a lot of battery, and driving for only a few hours.I'd think that
extensive boondocking would warrant solar panels or perhaps a smallDC genset. (in case
anyone is interested, there's lots more to them than simply beltingup an old car
alternator to a lawnmower engine!)
Did you say that you have one of those "E-meter" gadgets? Can you elaborateon how it
works and what it does for you?
Tom H. wrote:
> Jim Dunmyer wrote:
>
> > I'm not too sure I'd worry a lot about isolating the trailer andvan batteries
> > because of a "mismatch". They're charged by the same source anyway,aren't they?
> > And why would you NOT want the extra AHs of the van auxilary batteryavailable to
> > the trailer?
> >
> >
>
> Jim,
>
> My thinking in the mismatch is that the trailer batteries are two4D Lifeline AGM
> (absorbed glass mat, which I'll describe later) batteries while thevan auxiliary
> battery is the Optima AGM deep cycle Group 34 battery. This meansthat if I connect
> the trailer batteries to the auxiliary battery terminal on the isolator(with a
> heavy duty spade connector which should handle the current) thatI will essentially
> be charging three batteries in parallel on that one terminal side,the three would
> be the two trailer batteries and the van auxiliary battery. Sincethe an auxiliary
> battery is a different size and type, it will charge at a differentrate. It is my
> understanding that a battery bank consisting of mismatched batteriescan ruin an
> alternator and/or batteries due to variances in the individual batteryinternal
> resistances and charging rates, etc. Whether this will happen I donot know ut each
> of these batteries was quite expensive and I hate the idea of riskingthis without
> having a better feeling about the consequences. It still seems ome that I am going
> to have to use a three battery isolator.
>
> I just wrote an article about AGM batteries for the next issue ofthe Vintage
> Advantage (presently at the printers). An excellent primer and sourcefor this
> technology is available at http:///www.dcbattery.com/lifeline2.html.
>
> Now as far as running #4 wire to the trailer connector, I figuredI would splice in
> the largest physical size I could at the connector. Although thiswill result in
> some current carrying capability, the mere transport of the larger4 gauge cable
> directly from a battery source and to the back of the tow vehicleshould result in
> minimal voltage drop which is often a limiting factor for the chargeline.
>
> Would like to know more about the fork-lift style connector, is thisa connector for
> between the tow vehicle and trailer in place of the Bargman? I havenever seen this
> used.
>
> Tom H.
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