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temp controller Answered

hi
dont know is anybody can help

replacing the batteris in my drill pack and found that it has what looks like a thermistior??? to control chaging temp.  unfortunatly when dismantling I shorted it out to + and i believe blew it. i need to renew it as it lookslike it feeds relay in charger to switch  when fully charged (its a 1 hour fast charge)  how ever dont know what it is . it appear tobe connected in series with a resistor ???(again not sure can up load a photo if it helps)
the thermistor is 2 wire and marked M20 tp118/c 02c if that helps, the resistor 05u-045G
peter

Discussions

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rickharris

6 years ago

The thermistor measures the temperature of the battery pack - A feature of Nicad batteries is that when fully charged their temperature rises. the charger uses this to reduce the charging rate to a trickle to avoid over charging.

Thermistors are fairly standard devices.

As you will see on this page

http://www.rapidonline.com/SearchResults.aspx?kw=thermistor

there is a large range and you will need to try to find some information from the one you have so you can select another.

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peter354rickharris

Answer 6 years ago

posibly found what it might be???
going to buy and replace.as it makessense. the metal componet is possibly thernal switch backed up with themal fuse.
let you know how i get on
peter

M064691P01WL.jpg
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peter354rickharris

Answer 6 years ago

the problem is I’m not sure it is a themistor, the second metal component looks like a thermal fuse .The first has 118/c printed on it and has a cold res of about 1 meg, it’s this i think i fried as the battery shows fully charged even when discharged,
The problem is with the thermistors sugestion is they are temp/res sensitive and i have no idea what current i need to switch the, I assume, relay

The cells I am using come from a battery pack that has just the 2 connections,

Looking at the charger, that won’t come apart easily i have decided not to adapt as it has a transistor and without mapping out circuit not sure what is connected to what. Can anybody see any reason not just remove the fried circuit and replace with wire and charge as any other battery?
peter

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mpilchfamily

6 years ago

Try retaking the picture. Move the item away from the camera and use the zoom if you have one. You'll need to keep it about 3 feet away if you want the camera to focus on the item and not the background. Then in a picture editor crop the image so you get nothing but the item your trying to take a picture of and you'll have a much better closeup of it.

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canucksgirlpeter354

Answer 6 years ago

You'll get a much better photo if you put the object onto a flat surface with a solid color background, like a white sheet of paper. Then re-take the photo as close as you can, and in focus.

(I hope that helps).

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peter354canucksgirl

Answer 6 years ago

That’s about as good as it gets, as taken with a mobile phone. With a variable focus camera, or SLR all thing are possible
any idea what it might be ,as i say its connects to the - pole of battery, and is defiantly a heat sensor, though why two components as i would have thought the relay coil should have been enough to limit current as it fried well when i accidently shorted it to +

Going to modify charger so it switches on rather than work out what the components are , then switch on , and watch out for smoke