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Ron(UK) Ron(UK) is offline
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Default PTC Thermistor for nicad battery pack

A. Kay wrote:
Thanks for the advice. My device looks nothing like the thermal protector
in the pdf. Mine looks similar to an epoxy coated tantalum capacitor. So,
this thermal switch might be a viable replacement. Do you know of a
supplier?

"Ross Herbert" wrote in message
...
On Thu, 06 Mar 2008 06:36:34 GMT, "A. Kay" wrote:

:I am looking for a PTC thermistor, epoxy coated with approximately these
:characteristics:
:6.8k ohm at 45 degrees celsius
:
:I have an old nicad battery pack with a thermistor that failed during
:charging and one of the battery cells split along with the thermistor.
The
:thermistor is inside the battery pack and connected in series with the
:charging circuit. The numbers on the thermistor are 6K8K. After
searching
:the internet I deduced that the numbers meant 6.8K ohm with 10 percent
:tolerance. The 45 degrees celsius was the upper recommended
:charging/operating temperature for the batter pack stated in the manual.
:
:I took the battery pack to a Batteries Plus to rebuild it and their
:suppliers could not find a replacement. I figured that this thermistor
isn't
:that unusual.
:
:Maybe someone can suggest a replacement, at least an electronics store
that
:I can buy only one or two and not a hundred.
:

Most battery packs I have opened don't use a thermistor, they use a
thermal
protector switch.

http://www.sensata.com/files/battery-4mm.pdf

If it looks like the ones in the pdf then it isn't a thermistor. Find a
supplier
for the Klixon/Sensata device and use that.




Sounds like a polyswitch perhaps?

Ron