Using 18V cordless tools on 24V battery bank

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Brlux
Brlux Solar Expert Posts: 73 ✭✭✭
I have several different Ryobi one+ 18V cordless power tools, (Drill, Sawsall, and Circular saw) which I like a lot. I had an old dead battery which would no longer hold a charge so I took the cells out and wired a 16 awg cord to it with a power pole connector on the other end. I took two small 12V 7Ah SLA batteries and wired them in series to get 24V for plugging my new battery creation into. It works great and gives the tools a slight bit more power.

I was thinking this could be great idea for someone off grid. You could get endless work done without having to run an inverter or slow down for battery recharging, amusing the cord limitation would not be to big of a problem.

The 24V is a bit bore than the tools were designed for so it may wear on the tool a bit more but the batteries are around 20V fresh of the charger and you are going to see a bit of voltage drop in your new cables especially with stall currents of around 40A.

I can put the 2 small SLA batteries in a backpack and have probably over 4X the capacity of a fresh tool battery with the added benefit of more power.

I am sure I am not the first to think of this but did not see it mentioned. Any thoughts or experience from others?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,474 admin
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    Re: Using 18V cordless tools on 24V battery bank

    SLA batteries are not real heavy duty--so watch out that you don't over discharge/over charge them... Either can quickly kill them (it always ends up being a price/performance equation--which batteries are cheaper, how long do they last in your application, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Brlux
    Brlux Solar Expert Posts: 73 ✭✭✭
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    Re: Using 18V cordless tools on 24V battery bank

    I am aware of the over charge/discharge considerations of Lead acid cells. I was thinking this could be good for someone with a 24V PV battery bank or perhaps a 12V when they have an additional 12V battery they could put in series to get 24V for operating these tools. My tools also worked decently on 12V, sort of like your battery is near being dead but 24V was much better.

    I realize that the load I am putting on my little batteries with these power tools is quite heavy but for a short durations.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Using 18V cordless tools on 24V battery bank

    buy more of the proper battery packs and have them charging while using a pack in the tool.
  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
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    Re: Using 18V cordless tools on 24V battery bank

    Neils right I have 7 Dewalt 18v XRP batteries and more 18v Dewalt cordless tools than I care to admit (its like shoes with women:blush: according to my wife).I just take advantage of keeping then all charge up when my main batteries are in float or absorb, I havent worked hard enough or long enough to blow through seven in one day. Paying the premium for cordless tools gets defeated if you modify them back to cord.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Using 18V cordless tools on 24V battery bank

    "(its like shoes with women:blush: according to my wife)."

    thanks for that one nigel as that make my day.:D:D
  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
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    Re: Using 18V cordless tools on 24V battery bank

    For stuff with on/off triggers, it will work. Most motors will take a little higher voltage and be fine. For stuff with variable triggers, the trigger will be the weak link. The service company I work at, we go though triggers faster than batteries sometimes.