800w / 12v DC Water Pre-Heater???

800 watts will heat water substantially. It will also draw 70 amps or so. How many batteries are you carrying?

Wow - 80amps at 12V...... how big are the cables connecting
everything? and can your batteries supply that kind of current?

G

In my Truck Camper the hot water tank is 12" from the faucet so I have no use for it. Just passing it on for someone with a motor home or large TT. Would imagine you would only turn it on for a few seconds until the hot water from the tank reaches the faucet. Would save a bunch of water if it heated fast enough.

Folks use booster water heaters in houses all the time to conserve water.

Think about this 800 watts/12 volts = 66.66666666666666666666666 amps

That a devilish amount of current.

Pre heater, would go before the water heater not after
Heading the water between the WH and the faucet, would not do much good, it would have to be right under the faucet, and use big cables going to the battery bank
Would be better off using one of those 120v instant hot water for coffee or tea things mounted on the kitchen counter

Where this might help , is "pre heating" water going into WH for camping in cold weather

It's real use is as a block warmer, for truck engines by heating water/coolant, an aux pump is also used to help circulate the warm coolant thru the no block and radiator
But that heavy amp draw, is going to be a killer unless you have a big converter our the engine is running

there are a variety of 12v and 120v heaters that replace the plug/ rod on your water heater. They could assist in getting the water up to temp faster.

But not to your faucet any faster. The whole point is to heat the water at the faucet so you do not have to run it and wastewater.

Rbertalotto wrote:
But not to your faucet any faster. The whole point is to heat the water at the faucet so you do not have to run it and wastewater.

Then install a 'recirc' pump on hot lines back to WH cold inlet line

Yes... But
If your in campground with water, why worry
If your an experienced boon docker you already have water saving procedures in place,
And that is a very heavy power draw..a power expensive way.. To save a little water.. Power that has to be replaced
My batteries are farther from my water pump than yours..and for TT its even further as their batteries are usually up front