How To Wire A 12V DC Tankless Water Heater In An RV That Previously Had A 120V Water Heater

Updated 06/02/2025 | Published 02/17/2021

Question:

I currently have a gas electric hot water heater. The electric is 120 volt. The tankless units are gas and 12V DC. Will I need to find or run a 12V DC source from somewhere or should there already be a 12V DC source at the present unit.?

asked by: Michael H

Expert Reply:

For your new tankless water heat that runs on 12V DC, such as Furrion RV Tankless Water Heater - Gas - Automatic Pilot - 60,000 BTU - 16" x 16" Door # FR98SR, you will need to wire this to your RV 12V DC battery and it's not likely there's already any 12 volt wring near your current heater and a 12 volt heater cannot run using 120VAC

I have attached a detailed installation video showing this process.

expert reply by: Andrew N

Ray V.

7/11/2024

Could you send me the video ...need to connect my Figatti RV water heater to my 12v battery

Andrew N.

7/11/2024

@RayV You can see it here https://www.etrailer.com/tv-install-fogatti-rv-tankless-water-heater-2007-starcraft-homestead-lite-fifth-wheel-lsb64fr.aspx

Helpful Links

tv-install-fogatti-rv-tankless-water-heater-2007-starcraft-homestead-lite-fifth-wheel-lsb64fr.aspx

Abby

8/31/2024

@AndrewN Does this video show installing a new 12v power supply for the hot water heater. I currently only have a gas hot water heater and I’m trying to install the tankless and need the 12v power

Lou

3/11/2025

@Abby no it does not, I can’t seem to find anything online about new wiring to a water heater that didn’t have electricity before… let me know if you found something so I can figure it out also, thanks

Bradley

5/30/2025

What do I do if main power is shut off during winter months and then when camping season comes around and power is back on, but battery is so dead for a trickle charger to bring it back to life? To clarify, I permanently installed a trickle charger to battery to keep it charged but didn't count on the fact that main power being off and battery getting dead dead from that.

Andrew N.

6/2/2025

@Bradley Hey there, good question. So that is actually a very common issue during the off season; lots of batteries getting drained or even ruined from being brought to such a low voltage for several months. You really only have 2 options. 1: pull the batteries for winter and keep them in your garage or basement on trickle charger. 2: install an off-grid low wattage solar panel to keep a trickle charge on them. A possible 3rd option is to go over to the batteries a few times during winter with a generator or something to give them some juice during off season.