Has anyone used the 12v electric (electric only) on demand water heaters, they draw a few amps but it's only for a few minutes and I have 400 A/H of Lithium batteries, let me know, thanks in advance.
Easy enough to calculate. Look on the bottom of your home kettle for wattage. Put exactly a litre in your kettle. Time how long it take to boil. Then you can calculate the watt hours required. Add another 10% for inverter inefficiencies.
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Havent used one but there are too many variables to determine the power usage. Firstly water temperature into the heater and the amount of water you use are two major factors.
Not sure what size unit you have 6l or 10l but using the Duoetto 10l unit it takes 2hr 15 mins to heat the water from 15C to 70C using 25A @ 12v therefore 56.75Ah. If you use 5l of that water then you will use approximately another 28.4Ah or 5.675Ah for every litre of hot water that you use. There is of course cycle heating of the hot water but given the efficiencies of the heater insulation that will be minimal. This of course does not include inefficiencies of the system so allow another 10%. If you have a 6l unit then look at 60% of those figures.
Your 400Ah of LiFePO4 batteries will handle the hot water system with no issues. The trick is being able to replace the power that you use.
the 12v instantaneous water heaters are on the internet, they install inline just under the sink or shower, space wise & cost they look great but they draw 2-3000w so that pretty much eliminates them as I only have a 3000w inverter, the Duoetto 10L heater takes a long time to heat up what is only a small amount of water, I don't want gas are there any other water heaters on the market that you can recommend. I have very little space as I am building a slide on camper for my ute.
Have you looked at Marine Calorifiers? We have one in our car, the second vehicle we have had one in & love it. It is basically a heat exchanger inside an insulated tank. Water is heated by waste heat from your vehicle's motor. Costs nothing to run, always have hot water when you arrive somewhere, never have to think about it, water stays hot for up to 3 days. Has an adjustable tempering valve so you can select temperature at the turn of a knob. This automatically adds cold water as it is dispensed at the temperature you choose. Tanks are from around 10 litres upwards. Ours is a 22 litre. Most also have a 240v heating element so if you are on a powered site/have lots of solar or a generator you can just plug it in instead of driving. If we are staying in one place for more than 3 days we either boil a billy or go for a drive. 20 minutes drive heats water enough for a shower. Longer drives heats your water up to engine coolant temps. With the cold water being added automatically water it makes the 90 degree water go much further. We have ours inside the canopy on our ute.
Another alternative is a diesel water heater. Some people use their calorifier in conjunction with a diesel water heater, so if out bush & not wishing to drive the diesel heater can pump heated glycol through a second coil inside the tank to heat the water.
-- Edited by Cuppa on Saturday 29th of April 2023 08:57:54 PM
-- Edited by Cuppa on Saturday 29th of April 2023 09:01:17 PM
Thanks Cuppa, must say I never considered one but certainly worth a look, my slide on is made to be removed from the ute easily and regularly so I can go off 4 x 4 ing with just the ute but as they say where there is a will there is a way. This would have been great in my last campervan.
Thanks Cuppa, must say I never considered one but certainly worth a look, my slide on is made to be removed from the ute easily and regularly so I can go off 4 x 4 ing with just the ute but as they say where there is a will there is a way. This would have been great in my last campervan.
I know of someone who recently fitted one to their slide-on using some QD fittings which apparently close on disconnection - so no loss of fluid.
