Looking for 12-volt tankless hot wter heater

[dngoodchild]

Anyone know of a source. Google seems to only find 120 and 240 volt ones!

All the best,

David N.

[rbgarr]

Not sure a 12 volt system could generate enough heat transfer fast enough to keep up with the demands of a tankless system.

[paladin]

Good grief...it takes forever to make water hot enough for coffee or tea in just a 4 cup pot at 12 volts....

[willmarsh3]

If you draw 150 amps from a 12 volt battery bank (about what a diesel starter might draw) you get 1800 watts. That assumes that the battery voltage stays at 12 volts while drawing that much current. If the battery bank is big enough maybe.

To heat up 8 oz (228 grams) of water to shower temperature - say from 68 degrees sitting in the tank to 104 for the shower or 20 degrees celsius rise would take about 20,000 joules of energy.

A supply of 1800 watts will heat that water up in about 10.5 seconds. 2000 watts will heat up a gallon in just over a minute.

You'll then have to run the engine for a bit to recharge the battery.

I don't know of any commercial units like this so you might have to design and build your own.

[S/V Laura Ellen]

Why not just run the engine and use the cooling water and a heat exchanger to make the hot water?

You will need to run the engine to recharge the batteries with a 12V system, why not cut out the middle man.

[willmarsh3]

My new engine has a fitting specifically for a "domestic hot water" option - which is usually how its done. I'm told that one can have hot water after running the engine for 20 minutes or so.