Which inverter to use for rate shifting?

I am a DIY guy and I would tackle the problem a bit different.

First off, they make battery chargers that turn off when the charge is full and also some of them turn on automatically when the battery get low on on charge. I even seen chargers that can be programmed to come on at a specific time.

Me, I would get a charger for it and a time relay that tells the charger to come on and off at a specific time. This would turn your charger on after midnight  and off at 6AM.

If you should get solar power at a later time just hook the solar power in parallel to the charger unto the battery, the solar charge controller will start to charge and stop the charge as needed.
Midnight til 6 the grid is charging your batteries and then the sun takes over and continue to charge the battery throughout the day.

If the battery voltage is too low the inverter will shut down so in that area there will be no damage done to the battery.


Another thing is.....you can not get 15 kw out of a 15 kw battery unless you discharge the battery voltage and amps down to zero/nothing at all, that is where Peukert's law come in. In reality it is more like around 80% of that. You only can take 80% of power max from those batteries without killing the battery early and you have to check the max charging and discharging amps those batteries can handle. Go over those specs and you shorten the life of the battery.

Chargers and batteries have losses. Lets say you took 10kw out of the battery, it may take 14 KW or more to put it back because of heat losses and losses when the chemical change takes place while charging takes place.

6 hours may not be enough to charge those batteries, because in order to keep batteries alive you should not go over the charging amps that is listed on the battery.