Off Grid Home Forums Technical Discussion Hi need expertise on off-grid electric in France Re: Hi need expertise on off-grid electric in France


shaun- a couple of places to start.

first maybe convert your power usage from watts to amps. since this is the battery rating. look on the tags of each motor and get the amps. multiply amps x the amount of hours you will run the appliance.

i.e fridge. good ones are about 6 amp then there are 12 amp and then 15 amp. lets say you have a 15 amp fridge.

15 amp x 24 hours is 360 amp hours. of course actual use may be less but always pad you figures so you don’t under build your system.

another example. i use x-mas lights. 50 led in a strand cost about 8 u.s. dollar the day after x-mas.

power is .036 amp. lets say you have 3 strands plugged in and on for 4 hours at night. .036 amp x 12 = .432 amp.

so lighting isn’t an issue refrigeration will be. 360 amp hours would be 8 L16 batteries using 50 % per day.

on the inverter decision. i would not recommend less then 4000 watt inverter. this will allow you to grow with your needs and wants. a hand skill saw will not run on a 2500.

a typical u.s family home 3br 2 ba washer/dryer electric hot water uses about 1000 kilo watt hours a month(100,000 watts). 50 % of this is the electric h20 heater and fridge. on a good solar day with a 500 watt solar array you may capture about a 3 kWh or about 100 amp hr ( about 25 % of a 4 battery bank) just like padding your amp calculations i would not build a system to use 50 % of your storage daily. i think the 25 % is good. compensating for clouds or higher usage.

another thing to keep in mind is not to have more battery storage then you energy sources can maintain. if your reasouce can not produce enough recharge on a regular basis you will harm you batteries or have to run a generator often.

hope this helps.