66% or better

Resurrecting an electric razor

[Salvatore Ventura] likes a close shave from an electric razor, and nothing shaves closer than a new set of blades. After shelling out for some sharp ones, the rechargeable batteries died so he set out to replace them with a couple of double A’s (not the ones pictured above as those are alkaline).

This fix actually increased the original battery life of the razor by about 30%. That’s thanks to a larger capacity than the battery that had come with the razor. But [Salvatore] didn’t get to enjoy the windfall for very long. One morning the charge light was blinking on the razor and it wouldn’t spin up at all. After testing the batteries with a multimeter he found that they had a full charge and figured it was the main board that had gone out.

The real question is, what is that board actually doing? A bit of study led him to the conclusion that it is just a charging circuit, and an on/off switch. He kissed the board goodbye, wired up the AA battery holders directly. Now he jams a paper clip into the recharging jack, shorting the pins to complete the circuit. He could even keep using rechargeables with an external charger if he was careful not to run them too low.

Build your own hub motor

Hub motors put the power inside of the wheel. [Teamtestbot] goes deep into the hows and whys of building these motors, from parts, to windings, to the math behind the power ratios. The working example puts an electric motor inside the rear wheel of a Razor scooter. Past projects used belts to transfer the work of the motor to the wheel of the scooter. By integrating the motor and the wheel you end up with a much cleaner looking product. Check out the motor testing and the scooter test drive after the break.

For more tips on building your own electric motors take a peek at the Fly Electric page we covered back in November.

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