What is an inverter
An inverter takes 12V power from the battery bank and converts it to 230V to run mains appliances from that 12V battery bank.
How many watts is your appliance
Most appliances have a Watts rating printed on them. This watts rating will relate directly to the size inverter you need. If you have a 350Watt appliance you'll need an inverter of AT LEAST 350 watts and likely larger.
The ratings of some appliances are at the maximum watts and others are at the average watts. Its worth looking more closely at the specifications to find out which yours is. Microwaves are an example of an appliance which may be rated at 800Watts but can surge to twice that during use.
Some appliances have an Amps or MilliAmps rating instead of a Watts rating. If the rating is 1 Amp at 230V it will be around 230Watts.
How does this relate to my 12V battery bank
Dont think that a mains appliance rated at 1Amp will therefore consume 1 Amp in your motorhome.
If an appliance is rated at 1 Amp at 230V it will be about 230Watts (Amps x Volts = Watts).
To find out how much power this will consume at 12V, divide 230Watts by 12V (the voltage of your battery bank) and you'll find it consumes around 20Amps or 20Amp hours per our of use (Watts / Volts = Amps).
All inverters are not rated equally
A good quality inverter will generally run constantly at the watts level it's rated to and surge to around twice that for say 30 seconds. So, it will literally run a 350Watt appliance for a long period of time.
A cheap inverter rated as 350Watts will likely only be able to surge to that level for a period of time and it will run at a lesser level constantly. Typically you wont find this in the specifications, you'll only find this out when you go to run something.
Some really good Inverter advice
We've lost count of how many customers have arrived with a low cost inverter only to throw it out because of how disappointing its been in:
We and they definitely recommend you purchase a reasonable quality inverter right from the start and avoid the disappointment.
- wasted money
- wasted power
- unnecessary noise
- unable to run the loads required of it