Tom, I will say that I have learned a few things about living off ofbattery power. I'm sure
that noe that you've ditched the electric hot water you will have muchmore 12 Volt resourses
to do other things. I kind of agree with Jim that paralleing the baterieswont do much as long
as they are at the same state of charge when hooked together thereshouldn't be any problem
however I guess you use them separately so now there is a new ballgame. A quiet generator
comes to mind but with the hot water heater gone you might ot needto add mor weight. I only
wish I knew about the instant hot water heater before I bought the6 gallon suburban that I
installed last fall.. Dave

"Tom H." wrote:

> Jim,
>
> The rated charging voltages is pretty close but the internal resistancesand capacity are
> not. However, perhaps my concern is overly cautious although I havealways understood that
> mixing different battery types and sizes is not a good idea.
>
> As far a being a moot point, in fact the situation of normally runningoff of batteries and
> moving often is a situation that I often find myself in. Since Iwork full time, our trips
> are typically logistically planned so that we cover a lot of milesin the beginning and
> often stay at boondock sites since we are only stopping for sleep.I have been in
> situations several times over the past couple of years where we diddelete the batteries
> and were only able to recoup small recharging from the tow vehicle.However the major
> reason for this deletion was that my previous hot water heater waselectric only, which we
> used through an inverter, and thus this would rapidly run us down.Just this week I
> finished final installation of the PrecisionTemp 500 LP continuous/instantaneouswater
> heater. Everything appears to be working well and we'll be testingit next week on a 10
> day trip to FL (our first trip since November '98).
>
> The E-meter that I have discussed was actually purchased at http://www.rvsolarelectric.com/
> although I have since seen this same meter at West Marine and atJade Mountain. It is
> described on the Jade Mountain web site (http://www.jademountain.com/metr.html)as:
>
> E-Meter: New reading as a % of charge with digital precision. A breakthroughin
> versatility, information and cost. Complete, accurate (99.95%) dataon your battery bank.
> Displays amp hours, volts, amps, kilowatt-hours, state of charge,consumption rate, and
> more. Also acts as a digital ammeter, letting you know how much powereach DC load draws.
> Optional RS-232 computer output. 0-50V, requires 500 amp shunt. Excellentall around meter:
> highly recommended!
>
> I am very impressed with this meter as I can program it for instantaneousreadouts of A-hrs
> as well as remaining A-hrs in the battery bank. As you surmised,it uses a shunt to
> measure the current while the battery bank data was input by me asdenoted in the battery
> information. I am not using the RS-232 output because I am satisfiedwith the information
> I can presently get from the meter as it is.
>
> Tom H.
>
> Jim Dunmyer wrote:
>
> > Tom,
> > The rated charging voltage of those batteries is probably prettyclose, and actually
> > MUST be identical because you have only one source, and they'reessentially paralleled
> > 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 havingthem differ
> > significantly in age.
> >
> > The forklift battery connector that I mentioned is a 2 pole, heavyplastic job, 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'llhandle handle a couple
> > of hundred amps for lengthy periods of time; forklifts often have#4 cable going to
> > these connectors. This connector wouldn't replace the Bargman,but supplement 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 youelaborate on how it
> > works and what it does for you?