Community Forums

HR Imperial · 01-15-2014, 09:51 AM

We are dry camping in desert and seems like all my battery's drain down (coach and house) I thought the were separate. My coach battery is a single 12 battery an 8D though. To start a 8.3 cummins think I need 3 12 volts? I did load test all battery's and they are good

Ed-Sommers · 01-15-2014, 10:19 AM

You said "seems like". A little testing and logging is what's needed, so you know what you need.

Ed

BFlinn181 · 01-15-2014, 10:51 AM

You should be able to start an 8.3 on one good 12v battery, although many use 2 six volt bats. in series to create 12v with more amperage. If you have a battery isolation switch on your chassis battery, parked boondocking for a period of time, you could switch it off. Your chassis system has phantom loads like engine and transmission ECU, radio/clock memory, etc. The house and chassis should not usually be cross connected except by a solenoid that connects for emergency boost and charging. You could test by checking voltages of each battery system with everything off, then check again after starting generator. Both should show increased voltage when charging. Then shut off generator and start engine and again see if both systems show increased voltage due to alternator charging.

While camped in the desert, you could maintain batteries with a solar charging system.

HR Imperial · 01-16-2014, 10:26 AM

This morning all coach and house battery's at 11 volts all I have is a battery dead man switch to shut off coach battery

BFlinn181 · 01-16-2014, 11:22 AM

If your batteries are at 11 v, that means they are about 85% discharged. It will take many hours of generator running to bring them up if you can. Repeatedly discharging to 12 v will kill your batteries, believe it or not.

deandec · 01-16-2014, 11:38 AM

Most DP rigs have a chassis battery shut off switch and house battery shut off switch. They are not dead man switches, but require positive action to turn them off or on. The only dead man battery switch on my rig is the house battery boost to help start the engine.

It sounds like all your batteries are broken or you have a heavy drain on one battery bank that is drawing down all the batteries.

If the latter case, a battery isolator may also have failed.

You might be able to jump start the generator by trying to jump your auto battery to the house battery. Let the car run a bit before trying to start the generator.

Your generator however, may not charge your chassis battery.

You should have a boost switch on your dash that will combine the house battery with the chassis battery to start the engine once the generator has recharged the house battery (allow at least two hours of generator run time).

How many amp hours of storage do you have in your house battery bank?

We typically drop from @ 12.6v to 12.2v overnight with tv, furnace, and limited lights running. Our bank is 440 AH from four golf cart batteries 6vdc. At 12.2 v is time to recharge.

BFlinn181 · 01-16-2014, 11:59 AM

Your 'dead man switch' (more commonly known as a battery shut off or isolation switch) probably doesn't 100% stop battery use. Typically engine ECU, radio memory, safety monitors/alarms are wired around BIS and over time can cause battery discharge. The only true 'dead man' switches I've ever seen are on RR locomotives, forklifts, outboard motors, and terrorist bombers.

wa8yxm · 01-16-2014, 04:39 PM

AN 8-D is like 260 amp hours or there about (Roughly a pair of GC-2) when it comes to power... The chassis will slowly drain from parasitic loads and self discharge.. Best suggestion is to re-charge them.. If your rig does not have a bi-directional isolator add a Trick-L-Start to it. (This provides the reverse direction) and run the Generator for a few hours before you are ready to leave.

ohhwell · 01-17-2014, 08:59 AM

Quote:

Originally Posted by wa8yxm

AN 8-D is like 260 amp hours or there about (Roughly a pair of GC-2) when it comes to power... The chassis will slowly drain from parasitic loads and self discharge.. Best suggestion is to re-charge them.. If your rig does not have a bi-directional isolator add a Trick-L-Start to it. (This provides the reverse direction) and run the Generator for a few hours before you are ready to leave.

To bring an 8d down to 11v overnight (from what I could tell on the OP's follow-up) would be way more than a parasitic load. Either the coach battery is no good and needs to be replaced, or something is pulling WAY too much power from it. The coach battery is not supposed to be used for powering any house systems.