Inverter Output
I am going to install an inverter. According to the Kill A Volt meter,the refrigerator draws 88 watts AC. How much would it draw at 12 volts?
Forum Discussion
88W at 120V is .73A
Typically converting from 12V to 120V is a factor of ten so that would be 7.3A at 12V BUT that does not include inverter LOSSES.
Typically inverters large enough to handle the inductive load surges a compressor style fridge will present you can easily add an extra 2A at 12V.
So your fridge will be drawing close to 9.3A at 12V so for simplicity round it to 10A at 12V.
Now hopefully you have not bought an inverter as of yet..
When attempting to run a home fridge from an inverter you NEED to account for the STARTUP SURGE. Inductive motor loads have a very large startup surge, this surge MUST be considered in order to successfully start the fridge.
Typically the startup surge is 9 - 10 times the run current.
So in your case .73A at 120V will see a surge of 7.3A at 120V
So your 88W run will be 876W, the typical urge is to use a 700W inverter with 1400W surge. RESIST this urge.
Instead consider at a minimum a 1000W inverter with 2000W surge. The reason for this is most elcheapo inverters have too little of surge time and typically result in unpredictable results.
By the way that startup surge will result in the inverter drawing at least 75A-90A at 12V so make sure your 12V wire to the inverter is heavy and as short as possible.
For my setup I used 1/0 and only 3ft each (pos and neg) long to the batteries.
Make sure you FUSE the 12V wire...
Typically converting from 12V to 120V is a factor of ten so that would be 7.3A at 12V BUT that does not include inverter LOSSES.
Typically inverters large enough to handle the inductive load surges a compressor style fridge will present you can easily add an extra 2A at 12V.
So your fridge will be drawing close to 9.3A at 12V so for simplicity round it to 10A at 12V.
Now hopefully you have not bought an inverter as of yet..
When attempting to run a home fridge from an inverter you NEED to account for the STARTUP SURGE. Inductive motor loads have a very large startup surge, this surge MUST be considered in order to successfully start the fridge.
Typically the startup surge is 9 - 10 times the run current.
So in your case .73A at 120V will see a surge of 7.3A at 120V
So your 88W run will be 876W, the typical urge is to use a 700W inverter with 1400W surge. RESIST this urge.
Instead consider at a minimum a 1000W inverter with 2000W surge. The reason for this is most elcheapo inverters have too little of surge time and typically result in unpredictable results.
By the way that startup surge will result in the inverter drawing at least 75A-90A at 12V so make sure your 12V wire to the inverter is heavy and as short as possible.
For my setup I used 1/0 and only 3ft each (pos and neg) long to the batteries.
Make sure you FUSE the 12V wire...
