240v water heater on 120v

[DAVEHOLMAN]

I need an electrical wizard to fact check this. I read that if you connect a 240v water heater element on 120v, you draw 1/4 the rated watts.

My goal would be to minimize invertersize. I can't find 120v water heaters with less that 1400watt elements. I'm thinking of a 3000watt, 240v. That should only draw 750watts from the inverter.

I understand my recycle time will increase, but are there any other negatives? Strain on the inverter or batteries, etc?

My alternative is turning everything else off when I want hot water.

[Jolly Roger bus 223]

uh what?
regardless of your source ?
you will still only get 120 and never a true 230?
but i aint a sparky so i will shut up now.
just bumping this thread so the more knowledge able people will pick up the phone and help out

[DeMac]

Most 240v WH draw power from two 120v conductors and no grounded conductor. Just a ground. Where do you intend connect the 120v neutral?

Check the manufacturers voltage ratings on the elements & thermostats, might be fine.

Great if your water is already prewarmed or solar heated.

[joeblack5]

Yes that will work fine.
For a 3000 watt /240 volt element will dissipate 750 watt at 110 volt.. recovery time will be about 4 times as long.

Still takes the same energy to heat a mass of water.
But you can get away with a smaller inverter and use it 4 times as long.

Normally the 240 vac is black and red . So at 120 volt you will now connect your white ( neutral) and black ( 120 vac line of your inverter to the black and red of the water heater.
Safety ground stays the same.

Good luck.

Johan

[DAVEHOLMAN]

Originally Posted by joeblack5

Yes that will work fine.
For a 3000 watt /240 volt element will dissipate 750 watt at 110 volt.. recovery time will be about 4 times as long.

Still takes the same energy to heat a mass of water.
But you can get away with a smaller inverter and use it 4 times as long.

Normally the 240 vac is black and red . So at 120 volt you will now connect your white ( neutral) and black ( 120 vac line of your inverter to the black and red of the water heater.
Safety ground stays the same.

Good luck.

Johan

Excellent. And other than the inverter being used longer, which I assume will marginally shorten its life, no danger (so long as it's wired correctly)...

Thank You!