Inverter

[Andy_5065210]

Hi all,

I purchased a Durite 1500watt inverter last year for my boat, never used it through, and have lost the instructions.

My querie is what could I run off this unit,what would be the ideal size battery,is ther a calculation to work out its power consumption etc?

I've just bought my first caravan, and I thought I could use the inverter in it. any comments would be gratefully recieved

 

[ProfJohnL]

Hello Andy,

Basically if you look at the current consumption of the 230V ac appliance you want to use (in Amps) and multiply by 21, That will give you the approximate current the 12V dc battery will need to be able to deliver. If you are seriously looking at pulling 1500Watts (1.5KkW) then the calculation will be 1500/230 = 6.52A now multiply by 21 = 137A at 12Vdc!

Of course if you only use part of the capacity, then the 12Vdc currant needs also drop.

What size of battery? - the biggest possible.

 

[PaulA3]

John L I dont know where you got your equation from

Ohms law

Watts = Volts x amps

so amps = watts divided by volts

1500/12 = 125 amps

howerver there will be losses when using an inverter which will push the amps up (may be this is john L equation )but it will bepend on the quality of the converter how big these losses are.

 

[ProfJohnL]

John L I dont know where you got your equation from

Ohms law

Watts = Volts x amps

so amps = watts divided by volts

1500/12 = 125 amps

howerver there will be losses when using an inverter which will push the amps up (may be this is john L equation )but it will bepend on the quality of the converter how big these losses are.

Hello Paul

You are quite right VA does = W

And Yes, I did allow for losses by using a current conversion of 21 rather than 19.1 In practice that usually works fairly close to real life.

The other alternative is to use your 1500/12 = 125A + 10% = 137A

It all depends on how you want to do it!

Cheers