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crinklystarfish

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If I wanted to run a 500W, 230V ac heating element in a boiler of about 25 litres water capacity via an inverter, and my supply voltage to the inverter is a (nominal) 24V dc, what size / rating inverter would I need. (It would only be run whilst the engine was running).

I can do the theoretical sums but am aware that a heating element rated at 500W may actually require more than this to run it, and am also aware some inverters are optimistically rated.

Any of the sparkies out there have a view?

Cheers.

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There's a useful piece on inverters in the Roadpro catalogue (order-able via www.roadpro.co.uk).

 

Regarding your specific question, Roadpro's rule-of-thumb advice is to choose " an inverter with at least the maximum power output that it will require plus a bit more - say 25%". So that's 625W in your case.

 

Seems reasonable to me as there will be inefficiencies in the conversion from 12V to 230V process.

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Interestingly a water heating element will only take a little over 500w on startup as the element heats up so a 600 watt inverter would be sufficient.

 

But you could always purchase a 24 volt kettle from Roadpro.

 

C.

 

 

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Thanks chaps, currently working through the options of a hot water system and one I'm considering is a calorifier hooked up to the vehicle's cooling system but with a 500W element as a back up for use on the rare days where we don't want to move on first thing in the morning, or even rarer days where we don't move at all - and the domestic water in the calorifier has cooled to an uncomfortable point.

Relying on the engine alone on tick over would take way too long to (re) heat the water as the thermostat doesn't even crack for about 15 mins! I figure the engine running + the inverter powering the element would have us up to temperature in a reasonable time. She'd also be able to use a proper hairdryer for the first time ever on the road. I'm not a fan of 230V ac in 'vans but am kind of OK with this compromise. There will be no mains voltage ac hook up point or distribution system at all.

It's just one option, haven't ruled out diesel furnace etc yet though cost and relative complexity put me off. Would prefer not to rely on gas for water heating this time round.

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