I thought if you were off the Electric Grid you had to have the Charger (Wind or Solar) charge into a bank of Batteries and they invert to AC for use in your Home.

The Bank of Batteries is expensive and eventually needs to be replaced.

I read a brief article on a Solar Powered Shed and the Authors of the article were surprised the Batteries only lasted about 1/2 of the projected life.

What they found out is that if the Batteries are discharged below a specific Voltage (sorry I can't remember) it cut the life of the Batteries.

They re-did the project with more Battiest so that the Battery Voltage did not drop below the amount that caused decreased life and got close to the max Battery life.

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84 300D, 82 Volvo 244Gl Diesel