Thread: hot water anyone got one of these?

here is some more info I found:

Duoetto water heater

There are a lot of hot water systems available on the market these days. I would like to introduce you to one that hasn’t been on the market for an extremely long time. It’s the Duoetto water heater.

This Australian made Duoetto water heater is dual 12volt and 240 volt unit with 10 litre storage capacity.

There has been some confusion about the Duoetto water heater in regard to the amount of amps it draws. Before we get into that, ask yourself one question..... How long do you have a shower for when camping? The 10 litre system works on 240 volts at 1000 watts with a current draw of 4.6 amps. On 12 volts the load is 300 watts with a current draw of 25 amps.

You can wire it into your ignition so when you drive it will heat up on the travel so that it doesn’t work your battery super hard. When you get to your destination you will have instant hot water. When you are staying for long periods of time you can work the Dueotto off a toggle switch for showering. The unit needs a 12 volt pump or mains pressure.
The unit if wired correctly by gauging the distance in wiring will use around 22 amps per hour. Remembering this is only a 10 litre unit, and your heating in general is only enough for a shower for a couple of people. Which will take around 25 – 30 minutes in that time it will drag around 9 to 10 amps out of the battery.

If you were to have solar panels running on your camper/vehicle you would maintain that quite easily. For people who don’t have solar installed and would want to use this Duoetto water heater all year round. You would think quite hard about getting solar installed to run this water heater. If you were a camper and always stopping at caravan parks then the idea would be to use it off 240 volt. Remembering that you can also use a generator. On the generator it will take around 15 minutes to get hot enough to have a shower.

When you have the 10 litre Duoetto water heater you would mix the hot water with cold water to have a shower making plenty of water to go round when you’re away your water supply is limited.

There is also a Optima water heater that has 5 litre capacity. It comes in either 12 or 240 volt. Its clever design and mini electrical 5 litre storage makes it ideal for the camper trailer shower. On 240 volts the unit draws 4.6 amps per hour and 1000 watts, on 12 volt it draws 15 amps & 150 watts.

25A isn't too bad given its an electrical heater. A unit with a heat exchanger system will be more efficient but would cost more.

The Colemen unit seem to have a good name. Our Kimberley has a Webasto diesel powered unit (engine block heater in Europe) that uses a heat exchanger. Even so it's a good way to drain the batteries as it still needs a couple of pumps to be running (water & fuel) and so draws (from memory) 10-15A.

Look at one to run on the engine of the vehicle as an option too.

Originally Posted by dm_td5

25A isn't too bad given its an electrical heater. A unit with a heat exchanger system will be more efficient but would cost more.

The Colemen unit seem to have a good name. Our Kimberley has a Webasto diesel powered unit (engine block heater in Europe) that uses a heat exchanger. Even so it's a good way to drain the batteries as it still needs a couple of pumps to be running (water & fuel) and so draws (from memory) 10-15A.

Look at one to run on the engine of the vehicle as an option too.

I dont want to do anything with the engine....and I want it to go on the camper so its not limited to a car.

nothing wrong with the black plastic shower bag $20, power free from the sun

Originally Posted by richard4u2

nothing wrong with the black plastic shower bag $20, power free from the sun

I know i have one used all around kakadu trip however we could only have two short showers with it then we ad to boil water for washing up etc...

the only thing I like with the coleman over this unit is you can have hot water straight away for a cup of tea

and in the fender if you replace the water tank for the wiper spray with a smaller one on the drivers side you can get the 10l solar bag inside the wing. also the math on the second set of their power consumption is out 10 amps out of a 12v battery is only 120watts (lets say 150 and assume that the battery was totally charged and you got some magic watts from the watt faires to make a nice round number) If we believe their former figure (which I do as on the enthalpy charts its close to the power consumption requried)

try this.

put a cup of water into a 600w microwave and set it on medium low or low for a 850w (thats typically about 175W) for one minute and see how hot it gets.

now do it with a liter of water.


to heat 10L of water from 15 degrees to 55 degrees (how much hotter do you want a shower)in 30 minutes takes about (bare with me here) 928.8 watts assuming no losses at 12v thats 77 amps total draw from your battery.

The issue will be the limited 10L capacity.

I used to have a Coromal Rally Camper Trailer, it had 20L gas fired hot water system, it would boil 20l hold it in a tank, then with clod water from the main tanks, mix it to achieve the temp you wanted - even with mixing the hot with the cold water it this would continually run out. Leaving you wait 10-15min for it re-heat.

I have got the Coleman now and it is tops, gas and re-chargeable battery contained on board, heats water on demand, so long as you have got water to put in it, it can be as hot as you want without any waiting.

Prices are comparable too.

Originally Posted by Drover

The issue will be the limited 10L capacity.

I used to have a Coromal Rally Camper Trailer, it had 20L gas fired hot water system, it would boil 20l hold it in a tank, then with clod water from the main tanks, mix it to achieve the temp you wanted - even with mixing the hot with the cold water it this would continually run out. Leaving you wait 10-15min for it re-heat.

I have got the Coleman now and it is tops, gas and re-chargeable battery contained on board, heats water on demand, so long as you have got water to put in it, it can be as hot as you want without any waiting.

Prices are comparable too.

thanks drover...this is really what I was after. someone giving me a pro or a con. I will go the coleman then I think