My Dremel 800 multi-tool went phut this morning! There was a short spark inside somewhere. I took it apart and tested the speed controller with my multi-meter. There is no output voltage so it would appear that the speed controller circuit has blown somewhere. However, I also noticed that the 10.8v lithium-ion battery is producing an output voltage of 12.2 volts. How can this be? I tested the multi-meter on my car battery and it reads 12.5v so there is nothing wrong with the meter. Is the battety suspect and could this be the cause of the problem? Any suggestions are welcome because I would hate to replace the speed controller and then blow it again.
My Dremel 800 has gone phut! Over-voltage?
- Thread starter jerryoncairnhill
- Start date
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Nominal voltage and peak voltage are two different things. Li-ion cells have a nominal voltage of 3.6V or 3.7V (usually, there are quite a few different chemistries), but their peak can easily exceed 4V, up to about 4.2V. 10.8V/3 = 3.6V, 12.2V/3 = 4.07V.
That's not exactly a calibrated voltage source, now is it?
No. The battery is fine.
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