Powering Scamp furnace with auxiliary 12 volt supply.

[zack sc]

I have a newish Scamp 13 with a back up camera that will drain about five amp hours overnight. There is an on-off switch for the entire 12 V system, so I can turn that off when boondocking and not waste any power. The problem is, sometimes I would want to use the built-in Scamp furnace at night and that requires 12 V power to run the fan. So I was wondering about setting things up to allow the use of a different power source for the furnace fan, for example, a Jackery lithium ion battery that I keep inside the Scamp. I was thinking that I could wire in some Anderson connectors and switches so that I could supply power only to the furnace? Does that seem like an OK idea? It is kind of nice to be able to turn off the 12 V system at night. It gets rid of extraneous lights like the voltage indicator and little blue lights on the 12 V chargers. I use headlamps at night anyway. The only 12 V thing I really want to be able to use is the furnace fan. I would love to get advice on this, the perils and potential pitfalls etc.

[AC0GV]

Originally Posted by zack sc

I have a newish Scamp 13 with a back up camera that will drain about five amp hours overnight. There is an on-off switch for the entire 12 V system, so I can turn that off when boondocking and not waste any power. The problem is, sometimes I would want to use the built-in Scamp furnace at night and that requires 12 V power to run the fan. So I was wondering about setting things up to allow the use of a different power source for the furnace fan, for example, a Jackery lithium ion battery that I keep inside the Scamp. I was thinking that I could wire in some Anderson connectors and switches so that I could supply power only to the furnace? Does that seem like an OK idea? It is kind of nice to be able to turn off the 12 V system at night. It gets rid of extraneous lights like the voltage indicator and little blue lights on the 12 V chargers. I use headlamps at night anyway. The only 12 V thing I really want to be able to use is the furnace fan. I would love to get advice on this, the perils and potential pitfalls etc.

and run the backup camera on another supply or turn it off. Turning off the power to the trailer kills the LP gas/CO detector, the vent fan, lights and the water pump. I'd run the backup camera on the backup light power from the tow vehicle.

[Jon Vermilye]

You might consider changing the power source for the back up camera to the running lights (taillights) of the trailer. That way you can power them by the tow vehicle.

[Wayne Collins]

Forget about the furnace, Get a warmer sleeping bag, wear you long woolies. socks and stocking cap to bed.

[gordon2]

Originally Posted by Wayne Collins

Forget about the furnace, Get a warmer sleeping bag, wear you long woolies. socks and stocking cap to bed.

That might be good advice but keep in mind that this is same guy who wants to run his furnace while doing a 10 minute drive so the camper stays warm.

See: https://www.fiberglassrv.com/forums/...tml#post812042

[thrifty bill]

+1 Connect to running lights or add a $5 switch. No way I would spend $500 or more for the Jackery just to power the furnace, and as noted by others, you will need 12V DC for a lot of stuff, not just the furnace Propane alarm and lights are two that come to mind.

Buying a Jackery is basically the most expensive approach.

[Civilguy]

Originally Posted by zack sc

I was wondering about setting things up to allow the use of a different power source for the furnace fan, for example, a Jackery lithium ion battery that I keep inside the Scamp.

Most importantly, running any arrangement without active propane, smoke and CO detectors could ultimately be a fatal flaw in the literal sense of the word.

My recollection is that the furnace fans draw about 2 to 4 amps, depending on what model you have. Per a listing on Amazon, the "Jackery Explorer 240 is equipped with a 240 watt-hour (16.8Ah, 14.4V) lithium ion battery pack".

So, if the furnace is running intermittently, it sounds like this arrangement might just about do the job - ? I'm not clear on how far the LI battery in the Jackery can be drawn down.

You would need a double-pole three-position switch to swap the positive and negative leads between the trailer battery and the Jackery. Something like this:

https://www.amazon.com/Switch-double.../dp/B01CRI7V7M

Whatever you do, you will ultimately have to restore the consumed-power to the trailer battery or the Jackery.

As folks have suggested, you could swap the circuitry around to avoid parasitic loads on the trailer battery. It sounds like this would be a good thing to do regardless. The blue LED's electrical power consumption is so minimal, you might consider just applying some tape to block the light if they bother you at night.

[Darwin Maring]

Dont forget the CO detector. Running a heater that creates CO and runs on Gas you need several detectors. CO, Gas, Fire.

Put a switch on the camera.

[Civilguy]

Originally Posted by Darwin Maring

Dont forget the CO detector. Running a heater that creates CO and runs on Gas you need several detectors. CO, Gas, Fire.

Thanks, I edited my post to add the CO and smoke detectors.