2nd battery on jumper cables

[ieracer]

Going out for a three day dry camping 30 miles from highway in my Tioga Class C. Have Optima coach and main and in the past the furnace draws all of the coach battery by 3 a.m. and at 18 -20 deg F it gets really cold. Have had to get up, start up the coach to get the gen running to run the furnace.

I have a second Optima fully charged and was going put it on the ground in front of the RV to hook it up parallel with jumper cables to hopefully run the furnace all night (typically at 65 cause we like it warm).

Anyone had any issues or done this before? I am bringing a stand alone battery charger also, the inverter/gen doesn't charge the coach battery very fast at all.

There is very little room in the F350 engine comp and a dual battery here is not possible.

Thanks!

 

[Lou Schneider]

It'll work, but not perfectly.  The extra resistance in the jumper cables and clamps will restrict the power going in and out of the second battery.  Doing this for a few nights won't hurt anything, but long term you'll develop an imbalance between the two batteries.

Make sure your portable charger is rated for AGM batteries.  They can be damaged if a dumb charger applies too much voltage or doesn't shut down once the battery is full.

 

[JW of Opechee Shores]

I think you are really pushing it even with a second battery: how about a small generator to run the heater now and then. I wouldn't want to find out that both batteries were so weak I couldn't start the motor home

 

[Just Lou]

I would make sure all batteries were fully charged prior to leaving, and then I would just hook up the second battery (via the jumper cables) at the beginning of my stay, and go from there.  Just don't get over confident and let both batteries discharge too far before you start the gen to recharge.

 

[Gary RV_Wizard]

Should work fine if its a halfway decent set of jumper cables. Some of the el cheapo ones have relatively small gauge wire and crappy clips on the ends, but they still have plenty of capacity vs the modest amount a furnace draws (5-8 amps).

 

[Scott-0168]

Talked to the RV techs here in Florida and they said bad or weak house battery's can damage your inverter on any RV!

Scott 

 

[Just Lou]

Talked to the RV techs here in Florida and they said bad or weak house battery's can damage your inverter on any RV!Scott 

This is, no doubt, a true statement when the terms "bad" and "weak" are understood to mean shorted cells, grossly sulphated plates, diluted or contaminated electrolyte, run dry, etc...

Batteries that simply have low AH capacity, by design (or even age), should not cause the converter/charger any great distress.  They simply will not perform to expectations and will require more frequent recharge cycles and time.

 

[dave61]

Talked to the RV techs here in Florida and they said bad or weak house battery's can damage your inverter on any RV!

Scott 

Scott, I assumed the OP meant converter rather than inverter, could be wrong though.

 

[PJ Stough]

Talked to the RV techs here in Florida and they said bad or weak house battery's can damage your inverter on any RV!

Scott 

Off topic perhaps, but dont always believe everything an RV tech says.  The first time I took our RV to a dealership for some repair, the tech told me I could run down my house batteries to nothing, and they would be ok.  I am glad I had been reading this forum and others to know that what he said is not true.

Paul