12volt vrs 240volt by inverter

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Hi can some one tell me if I for instance I have a 12/240 volt tv would it use less battery power running straight 12volt or with an inverter running 240 volt ,all with say a 100ah battery?
Thanks Dave

[Bros]

Less with 12v

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Thanks Bros
What about a 12/240 volt water heater
specs are
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

[myusernam]

Thanks Bros
What about a 12/240 volt water heater
specs are
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

Wattage does that for you. One is 1000w heater, one is a 300w one. 1000W one will work better.

You can run 240v appliances off an inverter but you will lose out on the efficiency of the inverter - so if it's 80% efficient you will be using roughly 20% more power to run it through an inverter for same wattage output. Modern inverters pretty good, some claim peak 90% efficiency so I guess 80% is a good guide...

P.S. if you want to run a 1000w heater off an inverter then you would need an absolute minimum (and then short life) 1000w continuous inverter (so usually branded at 1200 watt) and you will probably draw 100 amps. I say stick with the 12 volt everything especially if your avatar is the boat you are sticking it on.

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Thanks Myusernam ,I wasn't sure how an inverter worked power wise.
I think I will run on 12 volt when the boat is running and use a generator when on anchor, it only takes 20 mins to get to 75 deg on 240.

[myusernam]

you could also consider a glind system if you have an inboard (use your engine heat)
or one of those nifty gas camping hot water on demand systems. Something as simple as a metal water tank in the engine room near the exhaust / engine can heat up quite nicely

[Bros]

For hot water on the boat I had years ago I had a copper coil wrapped around the engine exhaust with a head tank on the roof.
A generator is the only practical way to power the heater, forget the inverter.