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Author Topic: Thermistor for NiCd battery pack.  (Read 1545 times)

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Offline paul8fTopic starter

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Thermistor for NiCd battery pack.
« on: May 03, 2021, 10:20:24 am »
Hi all,

just figured out why this cheap old branch-cutter is failing to charge. The thermal sensor is reading in the k \$\Omega\$ range.
The (8s) NiCd pack will accept a charge when this is bypassed. I'm guessing it's an NTC thermistor???

Any ideas what type it is, and where I could pick up a replacement? Code starts with JJ I think.
(specs & photos attached).
Paul.



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Offline beanflying

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Re: Thermistor for NiCd battery pack.
« Reply #1 on: May 03, 2021, 11:11:02 am »
Depending on how it is wired it will be a NO or NC one of these eBay auction: #132678371472 go with 60C will be safe but allow a good charge rate or even just drop it out of the circuit by opening or bridging as needed.

They were always just a belts and braces with Nicads and all my R/C packs would never have anything like it used or fitted.
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Offline mikerj

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Re: Thermistor for NiCd battery pack.
« Reply #2 on: May 04, 2021, 08:15:43 am »
The JJD-45 thermal switch opens at a nominal 45C.
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Offline beanflying

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Re: Thermistor for NiCd battery pack.
« Reply #3 on: May 04, 2021, 08:45:35 am »
Quote from: mikerj on May 04, 2021, 08:15:43 am
The JJD-45 thermal switch opens at a nominal 45C.

45C would be a likely fail in an Aussie Summer for charging, should be OK for an Irish heatwave  ;)
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Coffee, Food, R/C and electronics nerd in no particular order. Also CNC wannabe, 3D printer and Laser Cutter Junkie and just don't mention my TEA addiction....
 

Offline paul8fTopic starter

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Re: Thermistor for NiCd battery pack.
« Reply #4 on: May 04, 2021, 07:45:53 pm »
Quote from: mikerj on May 04, 2021, 08:15:43 am
The JJD-45 thermal switch opens at a nominal 45C.
That looks about right. Thanks for the post!
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Offline paul8fTopic starter

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Re: Thermistor for NiCd battery pack.
« Reply #5 on: May 04, 2021, 07:49:32 pm »
Quote from: beanflying on May 04, 2021, 08:45:35 am
45C would be a likely fail in an Aussie Summer for charging, should be OK for an Irish heatwave  ;)

Yeah, the best Irish summer will never even come close to a bad summer in Oz!
Thanks for the help.
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