BOSH Charger with faulty mosfet. Suitable replacement

Discussion in 'General Electronics Chat' started by roadey_carl, Aug 30, 2010.

  1. roadey_carl

    Thread Starter Senior Member

    Jun 5, 2009
    Hello everybody,

    I have a bosh drill charger that goes "BANG" every time its plugged in. I’ve tested almost everything and found that a 100uF capacitor and a mosfet is faulty. the transformer and coils are functioning correctly. I have replaced the capacitor but I’m having difficulty finding the mosfet I need. The mosfet I have is a P4NA80 found here

    the mosfet I think would be a suitable replacement is here

    could anyone spare a few minutes to see if I’m going along the right lines?

    Thanks alot
  2. Jaguarjoe

    Active Member

    Apr 7, 2010
    The unit you selected is only rated at 600 V. The original is 800. That's a big difference. Although I can't see 600 V in a simple battery charger much less 800, there must (or at least should) be a reason why Bosch went with 800V. They have a stirling reputation and it would be hard to challenge them. There is a slight difference in gate threshold voltage too but I don't know if that's enough to worry about though. Without the schematic, we're flying blind.
    If the 800V jobbie is still being made, why not just buy it and be done with it? If the 600V one is all you have to work with, you could take a gamble and try it. Worst that will happen is you'll kill it.
  3. roadey_carl

    Thread Starter Senior Member

    Jun 5, 2009
    Cheers for your reply Jaguarjoe,

    I can't get hold of the original mosfet, I think Il try and find an 800v one just incase. Like you said they must have chosen that mosfet for a reason!

    I have no idea where I would get hold of a schematic for the charger unit.... but I understand it makes it alot harder to say without you seeing it!
    Thanks for your help!