dry camping

CJ2020MIN wrote:
How to avoid coach batteries being drain while running furnace during dry camping

Since this is a Class C motorhome forum, and since you said "furnace", I assume that you mean a situation where A) the amount of propane for the built-in furnace is not an issue and B), the ability for the main engine alternator to quickly charge the coach batteries exists.

When dry camping during chilly enough weather, we ALWAYS rely on on our safe, relatively quiet, multi-ducted and adjustable ducts hot air outlet system, and the excellent 25,000 BTU built-in furnace to keep us toasty warm -> that's what this system is for.

We close all window shades to create a trapped layer of insulating air between the window glass and the shade, we leave both roof vents open just a very little bit for fresh air ventilation, we cover the cab windshield with an outside cover, we make sure the cab air system has no outside vents left in their open position (by turning the cab air routing knob to OFF before turning off the V10 engine), and we block off the cab area from the coach area with a clip-on curtain so as to somewhat trap a bubble of insulating air within the cab area.

In addition to the above ... we monitor the propane level in our 18 gallon built-in tank carefully and ... we idle the very quiet V10 coach engine every morning for 1 to 1 1/2 hours to allow the big Ford 130 amp alternator to pump 50 to 60 amp-hours of electrical energy back into the coach battery bank. This idling consumes from 0.7 to 1.0 gallons of gasoline each day - and there is no noise to bother any neighbors who might be camping nearby while the engine is idling. BTW, while the V10 engine is idling, the coach furnace can be turned off and insteand the cab heating system can be used to heat the entire coach area - thus saving some propane and permitting even more current from the alternator to be dumped into the coach batteries being charged.

If more battery charging than this is required each day, we can use the built-in coach generator to charge the coach battery bank (which charges the coach batteries slower than the alternator due to the small built-in stock converter and makes more noise but uses less gas than the idling V10) ... OR, we can charge the coach battery bank each day using the small 650 watt ultra-quiet Honda generator we carry along for backup.

We don't use any solar, and we don't have any moisture built-up or safety issues inside the coach while it's being kept warm. However of course, certain other Class C motorhomes with gasoline powered or diesel powered main engines shouldn't be idled much for coach battery charging like the Ford V10 can be.