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Bobil Hybrid & Electric: AC or DC?

Updated: Apr 26, 2022

When travelling on the road, hot water is an essential and thanks to solar and battery technology advancing at a fast pace, its now easy to keep your water hot for free! However, it can be difficult to choose the tank which is right for you, so this blog post will help to guide you through the options.

The Bobil electric tank is available in either 230V or 12v, with the 230v tank having an 800 watt element whereas the 12v tank is fitted with a 200w element. If you intend to spend the majority of time hooked up at campsites, then it makes sense to go for the 230v. This way as soon as you get power the water will start heating, and even if you spend one night away from a camp site the water will stay hot for that evening, then it will start heating when you next plug in.


If you're intending to spend more time off grid, then the choice depends on your electrical system. Heating a tank of water to 75 degrees will take about 60 ah of energy from your battery so if you are using lead acid with no solar, this is best avoided. However, with multiple power inputs, there are plenty of ways to heat your tank. A good solar setup of at least 300 watts should provide enough energy to recharge your batteries and heat your water for most of the summer.



Lithium advantages

If you have lithium batteries with an inverter, then you have a choice of whether to use an inverter to run the 230v system or whether to stay on 12v. There are advantages to both, if you can run at 800 watts with a lithium battery you can switch the water heater on when needed and benefit from the fast heat up times. A 12v heater will take around 3 hours to fully heat the water whereas the 230v heater will only take around 40 minutes from cold. This means you can switch the heater on in the morning for a morning shower, whereas a 12v heater would need to have been left on all night which isn't always possible. 12v systems are ideal for lunchtime/evening showers, whereas 230v gives you more options. You can always put your plug on a timer and have it ready for when you wake up!


Advantages of 230v systems:

  • Faster heat up times

  • Morning showers are possible off grid with no diesel being used

  • 800w element still below camp site power threshold

  • Renogy inverters have transfer switches built in so when hook up is available the power source automaticlly become the EHU.

Disadvantages of 230V system

  • Inverter losses can increase power consumption by 5%

  • Not possible with lead acid batteries- minimum of 150aH of lithium recommended

  • Needs to be manually switched on and off

We hope this helps you with your choice! If you have more questions then get in touch with us at info@bobilvans.co.uk and we'll be happy to help!

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11 Comments


Choosing the right hot water tank for road travel can be tricky. Whether you opt for a 230V or 12V tank depends on your camping style. For installation and system efficiency, consult a qualified HVAC Contractor.

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Miro Manninen
Miro Manninen
Dec 22, 2022

Im testing the 12v heater just with 200ah lithium battery. added starting voltage to be 13.2 and stop to be 12.7. Even when I have full battery heater does not stay on. Is this normal? I think should add the cut time at least 10 to 20 sec so when relay turns it on, it would not directly go off.

I have the pipes to heat water with hot air, but they took so much of space and caused me 2 major leaks in to my trunk so I took all away. Need to do with different pipes and connectors next time.


Any ideas? Thanks!

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Can the hybrid 4kw system heat the van and the water at the same time?


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Bobil Vans
Bobil Vans
Sep 14, 2022
Replying to

Yes, you can set the diverter cable to half way which would direct some hot air to the van and some to heat the water but it makes both less efficient (ie takes longer for the air and water to heat up).

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when you groove out the floor for the copper pipe. Are you grooving the solid insulation or ply board. ie does this need and extra layer of ply to house the pipe. Also, would the heat be better radiated if the groove was foil lined?


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Bobil Vans
Bobil Vans
Sep 14, 2022
Replying to

Yes, we grooved through the solid ply floor, and put another piece of plywood ontop. If you foil lines the grooved holes, this may increase the heat better, but not sure how much difference it would make.

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so would i be right thinking i would not need the heat exchanger which goes on to my diesel heater

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Replying to

so basically would benefit from having both?

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