Tool battery packs

Discussion in 'Power - Site Power/Batteries/Generators/Solar' started by l33tDad, Jul 31, 2019.

  1. l33tDad

    l33tDad New Member

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    Okay, I'm still in the planning phase for a complete tear down and rebuild of a gifted PUP ('85 Palomino Pony) and am thinking about electric. I'm an avid DIYer in construction and have a bunch of Dewalt 20v portable tools and 5AH battery packs. Our camper isn't going to have anything that needs 120v and I don't think that I'm even going to install that option and as such, everything inside will run on 12v (LED lighting, maybe a 12v pump for the little sink and a ceiling vent fan). My thought is, if it's possible, to use my tool batteries as a power source, but I can't find anything online that would be of any help. Any thoughts?
     
  2. eoleson1

    eoleson1 Well-Known Member

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    I would be afraid that the excess voltage would damage some of the devices; the pump in particular.
     
  3. l33tDad

    l33tDad New Member

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    Right ... I guess my question is that if anyone knows of an adapter or something to get 12v out of the pack. I know that Dewalt has an adapter for USB (5v) so I can charge/power a USB device from a 20v battery pack, but I can't find anything for 12v. I understand how to make a simple voltage divider, but am looking for more of a "turn key" solution I can buy.
     
  4. NMroamer

    NMroamer Active Member

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    Voltage converters are really not very efficient.
    You will lose a lot of power in the form of heat generated by the conversion.
     
  5. SteveP

    SteveP Well-Known Member

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    Since you're in the planning stage look at 12/24 volt options.
     
  6. SteveP

    SteveP Well-Known Member

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    I realize you're trying to use what you have but:

    20v x 5ah = 100 watt hours
    12v x 35ah = 420 watt hours

    Assuming 90% conversion efficiency, which is very good, it will take 420wh/(100wh*.90) = 4.66 fully discharged 20 volt batteries to equal the output of a single g24 deep cycle battery at less than 50% discharge.

    Compare the cost of conversion vs the cost of a single g24 battery, at about $100 + the cost of a plastic battery box, about $10.
     
  7. roybraddy

    roybraddy Well-Known Member

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    Don't know if your trailer has requirement for electric brakes... If so it is really hard to beat having a regular 12V automotive type battery for that requirement...

    My neighbor here just picked up one of those JOB SITE FM radio's that runs from a tool battery pack... Kinda neat haha...

    I took my weed wacker 20V battery over to his place to see if worked his radio and it didn't... Would not fit the slide... It seems there are a bunch of different styles of 20V Battery packs haha...

    Roy Ken
    [​IMG]
     
  8. l33tDad

    l33tDad New Member

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    No electric brakes, it has dry weight of 920 lbs.

    I agree with everyone that a deep cycle battery would be more efficient and I'm all a go on it as the power converter that's actually in the PUP works fine, but I'm not looking to power any more than 3 or so LED lights and maybe a 12v pump for the sink and/or a little roof vent fan. Nothing more. I have 6 of the 5AH packs, 3 of the 3AH packs and 3 of the 1.5AH packs. As stated, I'm just trying to use what I have is all. (I also have one of those job site Dewalt radio's and it is awesome lol)

    Maybe I'm overthinking the whole thing and for the few times that I would need battery, just get a 12v deep cell and hook it into the converter. The thing I don't like is that according to the manual I found for it, it doesn't charge the battery :\
     
  9. xvz12

    xvz12 Well-Known Member

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    I bought an adapter from FleaPay that my works with my DeWalt battery packs, dc-dc regulator that reduces the voltage to 12 volts, actually you can set it anywhere from 10-20v. They came in various amp ratings, maybe something like this would work for you?
     
  10. tombiasi

    tombiasi Well-Known Member

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    It’s just the wrong battery for this application. There is a time and place for MacGyver, this isn’t it.
     
  11. NavarWynn

    NavarWynn New Member

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    Any appropriate Dc - DC step down buck converter is going to work, but the smaller ones have an output limit of a few amps - though these tend to be more efficient for low draw devices. If you were to build a rack to hold like 5-6 of your batteries, and plumb them all into a parallel 'pool' to feed several smaller converters (say one for each circuit - matching the convertor power output to the device draw), and switching power from the battery pool to each converter on demand, that'd likely be the most efficient way to do it. However, in the end, it's likely far less cost efficient than simply buying a proper deep cycle and feeding the draws directly. While possible, it seems like a lot of work, effort, and cost to do something you could do cheaper, easier, and faster - even given that you already have several $$$ worth of batts.

    If your primary concern is that the converter doesn't charge the 12V battery when hooked up to shore power, then just get a smart charger with a reasonable peak output, and plug it into the 120VAC output. Even the cost of that plus the deep cycle battery would likely be cheaper....
     
  12. lostboy

    lostboy Active Member

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    Did you ever try this and get it to work or did you just opt to buy a 12v battery?
     

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