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Replacing a 1.2v with an 18350

  1. Dec 8, 2015 #1
    I have an hair trimmer that the battery has died and i wanted to replace it with an 18350 battery for the extra power i just wanted to ask would i need to put a resistor in series with the motor
    Cheers tia
  2. jcsd
  3. Dec 8, 2015 #2


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    Staff: Mentor

    Welcome to the PF.

    What's an 18350 battery? Why not just replace the original battery with the same type?
  4. Dec 8, 2015 #3
    The 18350 is a lithium ion 3.7 battery that is shorter that the AA size in there and as a hairdresser by trade i wanted the extra power to help cut hair faster
  5. Dec 8, 2015 #4


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    Staff: Mentor

    To replace the 1.2V battery with a 3.7V battery, you would need to include a DC-DC converter to drop the voltage and not waste a lot of power.
  6. Dec 8, 2015 #5


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    that made me laugh :biggrin:
    seriously ... its likely to burn out the motor

    if you really want to use that battery then do as Berkeman suggests in the post above mine

    also consider, you are going to need a new charger as well as the existing charger isn't going to charge up the higher voltage battery

  7. Dec 9, 2015 #6


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    Staff: Mentor

    Looks like the answer is basically no, cannot do.

    But if it uses a standard AA NiMH cell, you might find that the one currently in it is a cheapie and there are higher capacity 1.2V AA's you could drop in as a replacement to give a longer time between recharging. If you can take out the battery to examine it, does it have a number on the side saying how many mAh it is?
  8. Dec 9, 2015 #7
    Thanks for ur help everyone ive just taken it apart again and im just going to see if i can find a new motor rated for3.7v and the recharging will be easy just replace the circuit with one for li ion that uses a usb port and a fone charger
  9. Dec 9, 2015 #8


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    Also be sure that you use a protection circuit. Lithium ion batteries tend to like to burst into flames or explode when abused. This includes over-discharge if connected directly to the motor.

    When shopping for a battery make sure the maximum current is high enough. The lithium-iron-phosphate ones often have high current capability.

  10. Dec 10, 2015 #9
    UYaa thx i use li ion batterys already as i make and use e-cigs but the protection circuit is a good idea iftheres room and as id be using it everyday i'll be puting a voltmeter into the charging stand so that when its plugged in i can check the battery
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