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I have an electric pencil sharpener that has a motor that seem to be intended to run on 6 V (4 x 1.5 V alkaline batteries).

What are my options to make it function with 4 rechargeable NiMH batteries (4 x 1.2 = 4.8 V)? A small conversion IC would be optimal.

ocrdu
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norq
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    First option would be just stick the batteries in and see if they work. It'll run slower, but it may be good enough. Boosting voltage is not a trivial thing for somebody inexperienced to do. Next option is use a rechargable cell that's already at the voltage you want i.e. https://www.amazon.com/Deleepow-Rechargeable-Batteries-3400mWh-Lithium/dp/B09S6BVYGB/ref=sr_1_3_sspa?keywords=aa+lithium+rechargeable+batteries&qid=1669221641&sr=8-3-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1 – Kyle B Nov 23 '22 at 16:41
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    Personally, I wouldn't monkey with it at all. How many pencils are you sharpening??? A set of good AA alkaline probably will last years in that under "normal" use. – Kyle B Nov 23 '22 at 16:42
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    You could always find somewhere to stuff a fifth NiMH cell. But it should be designed to run on lower voltages anyway--alkaline batteries aren't considered "dead" until their voltage hits around 1 or 1.1 volts anyway. – Hearth Nov 23 '22 at 16:47

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Probably no change at all.

The 'end point' for AA batteries is around 1 V, so the sharpener still ought to be producing a reasonable amount of speed and torque at this voltage. The output voltage of AAs will steadily decline from the nominal 1.5 V.

Using NiMHs will give you a more or less constant 1.2 V output. Once the cells dip below 1.1 V, there's little charge left.

If you have the NiMHs, try it and see. If you don't, try it on a lower voltage from a power supply, or three new AAs (1.6 V per cell when brand new, but falls quickly to 1.5 ish).

Neil_UK
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  • I tried just putting the recharables in but it wouldn’t move at all. But after opening it up I noticed some poor connections and after solving those, the thing just seem to work :D – norq Nov 23 '22 at 19:11