We use Polyfuses on our power supply.

When we first got samples to play with we connected them directly across
a car battery to see what would happen. It was remarkably unspectacular.


Regards,


Mike Watson

In message  <34C5D398.4B33E1AC@magna.com.au> PICLIST@MITVMA.MIT.EDU writes:
> Hi,
>
> May I draw on the eternal wisdom of the list?  I have a problem with
> battery protection.
>
> Our product uses a 12V 3AHr NiMh battery pack (and 3 PIC's).  The
> battery pack is designed for use in rough environments, and for this and
> other reasons, the terminals have been left relatively well exposed.
> This is a problem if the battery is short circuited.  The batteries are
> a small but expensive part of the unit.
>
> Can anyone suggest a way of short circuit proofing the batteries?  The
> method has to :
>
> 1. Be user-resettable after a short circuit, or self-resetting.
>
> 2. Respond very quickly after the current limit is exceeded (batteries
> are quickly damaged).  Ideally the current limit will hardly be exceeded
> at all, even for an instant.
>
> 3. Draw very little or preferably no quiescent current (NiMH
> self-discharge automatically :-).
>
> Some "resettable" fuses that we've tried are way too slow.  The current
> limit by the way is 9A.
>
> Any ideas?
>
>
> Thanks.
> David Lions
> bjlions@magna.com.au.NOSPAM
>

--
Denison Mayes Group