18v power tool to 230v?

Discussion in 'Electricians' Talk' started by dvddvd, Apr 1, 2021.

  1. dvddvd

    dvddvd Well-Known Member

    I have a number of Bosch 18v power tools and 4 ah batteries.

    I recently bought a GWS 18v 10 grinder which is supposed to be the equivalent of 1000 watt corded one.

    The trouble I have with it is it eats batteries and it's the only tool I wished I'd bought the corded version..it uses around 1 ah per min.
    So a 4 ah battery lasts 4 mins.

    So I was thinking could I canablise a Bosch battery and connect it up to a DC power supply?
    I see 18v and up to 40a power supplies on ebay.

    Any views?
     
  2. dvddvd

    dvddvd Well-Known Member

    It appears that the cordless grinders used with the procore batteries can use 80a ...gulp

    May give the idea a miss!
     
  3. quasar9

    quasar9 Screwfix Select

    If it is 1000 watts, at 18v is 55.5 amps. So a 4amp hour battery (4/55.5 * 60) in theory will last you 4.32 minutes, within limits of what you have already found. Assuming you can get power supply that can supply such high levels of current at relatively low voltage, the real challenge is finding cables that can handle the current yet be flexible enough for you to handle the tool comfortably .

    The other problem is that many lithium batteries have a third terminal, usually used by chargers to monitor temperature, but can be used by onboard electronics to ensure the battery is not excessively heating up during discharge. I know some devices sense the voltage of a single cell and shut down before the battery is completely flattened, something you avoid with lithium batteries. You will somehow have to create a voltage to fool the onboard electronics via the third or 4th terminal.
     
  4. dvddvd

    dvddvd Well-Known Member

    Thanks very informative answer...I'll see how it goes.
    I read that if you use the new Procore batteries you get a 25 percent increase in power?
    The normal coolpac batteries will give 40a while the procore give you a boost due to them been able to supply 80a
     
  5. quasar9

    quasar9 Screwfix Select

    I suspect with these procore batteries, they have lowered the internal resistance somehow, as the basic chemistry is the same, giving a higher current drain , a crude comparison would be alkaline batteries vs the older zinc chloride
     
  6. CraigMcK

    CraigMcK Screwfix Select

    Or just buy a mains grinder which will almost certainly be better, safer and cheaper!
     
    malkie129 likes this.

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