Is this a Thermistor? and what can I replace it with?

I have been working on a Yamaha Golf cart charger and think this part is causing an issue. I have not been able to find any replacement that matches, but have had a few folks suggest that it is a 2.2k Thermistor.

When this is in circuit the 20A ceramic fuse blows. With it out of circuit the unit turns on and when connected to the cart to charge it engages the charging circuit and then disengages it on a loop.

Any help is greatly appreciated.

Looks like that part marking corresponds to a 3D2-22LC, Inrush Current Limiter.

I’ve closely matched the specs to something we carry:

MF72-003D20 Cantherm | Circuit Protection | DigiKey

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Thanks, That help a bunch.

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Kristof’s component suggestion seems reasonable enough, though the symptoms described suggest faults elsewhere, assuming the ID is correct and it’s indeed being used as an ICL. If the room-temperature resistance is substantially less than the nominal 3 ohms it may be the culprit, but if not I’d look for problems elsewhere.

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Hi Rick, Your comment got me thinking and the info that Kristof provided got me thinking. I think you are right, I just retested the component with the new info. At room temp it reads 3.2 ohms, with a meter connected I heated it with my hot air station and it quickly dropped to 0. I am no suspecting the issue is with the PFC, Unfortunately all the components are coated in epoxy, so i may be out of luck on this one.


Hi @RcRTech ,

It does look like the problem is elsewhere other than the thermistor/in-rush current limiter. As a side note the 2.2k recommendation seems unlikely as seen below, the max resistance we carry is about 1k ohm for that package style.
It sounds like you have blown and replaced the 20A ceramic fuse a time or two. Just wanted to point out that it may require a slow-blow fuse, and that if it was replaced with a medium or fast-blow fuse even at the same current rating that it may not handle the in-rush current requirement causing it to open. I don’t know if this requires a slow-blow fuse, or if you have replaced it with one, but I thought to throw that by you in case.

I’d recommend verifying with the owners manual if the fuses that were replaced have any different ratings then what the manual requires to see if that was a potential issue for the fuse opening.

Although most chargers wouldn’t act like this when attempting to charge a bad battery, it wouldn’t hurt to check the battery and make sure the battery is within the charge parameter limits, as that could be faulting the charger as well.

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Hi Ryan,
Thanks for the extra info. I did end up coming to the conclusion that the 2.2k recommendation was likely incorrect. It is in fact a Semitec 3D2-22 D2 Datasheet and seems to be a functunial component based on my test as mentioned in my comment above.

The fuse was a slow blow and I did replace with the same fuse.

I may keep this around and try to remove the epoxy, as a learning experience, since its just not economical to repair time wise.

Thanks everyone for the input! you have all been very helpful.

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