I want to make a solar charger for tool batteries. I’m thinking plug a standard AC dual 5 amp 20v battery charger into an inverter charged via a solar battery bank. Enough to charge four batteries during the day. That’s not in the budget so I’m going to start small with just one battery at a time (600watts?). Maybe two batteries a day if I can afford it.

Who here has built such a battery bank? What advice do you have? What handy online calculators do you recommend? Is there a spreadsheet available that is better than a calculator? In the past I would have looked for those myself but search engines are totally useless now. Would you rather have one big battery hooked up to the inverter or a bank of smaller batteries in series or parallel?

  • FauxPseudo OP
    1•2 days ago

    The problems I have with that:

    1. most power tools do not have 12v chargers
    2. that limits the ability to charge multiple types of tool batteries without having a dedicated 12v charger for each brand of batteries. I want to be able to plug in a Makita, Hercules or DeWalt charger into the inverter so that I’m not brand locked.
    3. if the 12v too battery charger dies the whole system is useless. By plugging a standard AC charger into the inverter you can pull a backup charger you pick up at a pawn shop and just plug it in.