Adding tank heaters for winter use.

SDcampowneroperator wrote:
I have to comment again, concerning tank heaters. 12v wont do, as the amperage they draw is 10 times 120volt. 3 heaters, @ 250watts ea., is 6 amps at 120v, 60 amps at 12volts! Your battery would be dead in minutes, as well your converter would be maxed out trying to power only the tank heaters not to mention the rest of the house.

I have installed tank heat on 2 of my units, with one a 1997 HR 32WFS , I used old waterbed heaters with their thermostats set at 45f ( 8c) then ran the power cables to where I could plug them into my inverter when on the road or dry camped ( with the truck running or when power went out ) or into an outlet when hooked up to power( hydro to us dual US and Canucks ) Worked great to temps below -40 c or f
On the first one, a 1987 Award Columbia which had all exposed tanks I used 5 watt/ ft. heat cable glued to the underside of the tanks around the pump and dump valves, then spray foamed the entire underbelly tanks and all. That worked OK also but required proactive attention as it was not automatic thermostatic so I had to pay attention the temps outside.
In either case the trick is to dump only when the waste tanks are full or if not heated then use copious water, sinks full, flush full bowl 3 times amounts of water to carry the wastewater to the drain. , be certain your waste hose is graded if not heated. Most of all, vent and dehumidify the house or all your attempts at keeping warm will backfire because the moisture WILL condense in your walls rotting and ruining all your attempts leaving you with a rotten unheatable,unliveable hulk.
Seen that, a new Airstream interior destroyed in one winter in Coronach, Saskatchewan, Canada

What you say is only true if 12V tank heaters are the same wattage as 120V tanks heaters ... which they may not be. Is there an Internet link to the specs of 12V/120V tank heaters showning how many watts each model consumes?

I've been down under my tanks looking at it's 12V heaters on the bottoms of the GW and BW tanks. The wires to these 12V tank heaters don't appear to be anywhere near high enough gauge to carry the currents that you're mentioning.

Regarding battery amp hours consumed to power 12V tank heaters ... tank heaters cycle On and Off as they're opperating, depending upon how much water is in the tanks and the air temperatures ... so their current draw from the batteries is not constant.

I prefer 12V tank heaters for emergency drycamping insurance. When hookup camping, I assume that they wouldn't be offered if common RV converters couldn't keep up with their power needs.