Broken mosfet?

[wilko129]

Have a NanoAB mosfet installed in my EBR and all worked great until I tried using a 11.1v battery in the rifle which blew the fuse (only 20amp). When I replaced the fuse with a higher current one I found that the mosfet is not working as a switch any more and is constantly open as soon as I attach the battery. It even works without the switch wire attached so obviously the mosfet is allowing current through without it.

I have taken it apart and made sure no wires are touching anything they are not meant to and that's all fine so am I right in thinking my mosfet is broken? I find this very hard to believe/upsetting because the mosfet is meant to be a pretty good one so I never thought it would break from a 20amp surge.

Any thoughts would be really appreciated.

[wilko129]

Re: Broken mosfet?

Any ideas guys?

Just been running my new armalite on 11.1v all day without mosfet with no problem?

[Genista]

Re: Broken mosfet?

I guess it depends on what caused the fault in the first place.

MOSFET's (as in the component) are easily damaged by overvoltage on the switch leg, which could conceivably have happened.

The reality of most traditional mosfet designs, is that they offer little or no protection over themselves.

The component is probably replaceable if you have the skills, and assuming that it's not covered by warranty.

[wilko129]

Re: Broken mosfet?

Okay so the switch leg is the probable broken part right? To replace it I need to identify which model it is and de-solder it, to then re-solder a new one in or is just a case of cleaning up some solder which has spread over it?

Appreciate the help BTW.

[Genista]

Re: Broken mosfet?

You'd have to replace the whole mosfet, which means finding the right part in the right case.

You could try the manufacturer, but it may not be worth repairing, given the time.

Miniaturisation and high current aren't great bedfellows without a high cost too.

[wilko129]

Re: Broken mosfet?

Ok thanks mate, would this mosfet be okay for current spikes from a 7.4v lipo cause I don't want to keep going through mosfets really but need one or my rifle will just keep breaking?

[Genista]

Re: Broken mosfet?

I don't know the spec for the nano but it's likely that a 7.4v lipo would be fine (depending on the power of the Lipo). It may be capable of running an 11.1v lipo and you may have just been unlucky.

As the nano is just a miniaturised version of the original, DIY design. For my money, I'd always go for a proper controller by BTC etc.

[wilko129]

Re: Broken mosfet?

Thanks for the help mate.

[Scotty Dog]

Re: Broken mosfet?

Gate offer a 1 year warranty on their mosfets, I've had 2 replaced by them no problem. Either fill in the warranty form on their website or contact whoever you purchased it from for a replacement.