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I have battery-powered hair clippers that charge with a 2.4V 2000mA AC adapter. I'm looking for the best possible way to lighten or eliminate the adapter, as the one that was included is huge and very heavy. Ideas:

  1. Ideal would be if I could use a 2400mA USB charger (i.e. http://amzn.to/2dRxKAz), and somehow make a small converter/plug to step the voltage down from 5V to ~2.4V. That would eliminate the need to travel with a 2nd adapter entirely. Is there a way to do this safely?

  2. A less ideal approach could be to use a universal AC adapter capable of 3V / 1000ma (i.e. http://thd.co/2donCwf). As I understand it rounding up to 3V should be ok, and since it's just charging - not running - supplying 1000ma instead of 2000 would only mean it charges more slowly (which is fine).

Thoughts would be greatly appreciated.

Edit:

As per a very helpful comment, I believe #1 can be done with a buck converter (i.e. http://ebay.to/2eb2mg9) set to output 2.4V. To its input I would attach a micro usb port (http://ebay.to/2eg52oZ), and to its output I would attach the clippers' charge plug.

I've also read that to make the charger identify the port as a higher-amp 'charge port' (aka to tell it to supply more than 500mA), I should short the 2 data pins together in the micro USB port (reference: http://bit.ly/2dCbGEM). Does all this sound like it would work?

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Something like this LM2596S based DC-DC convertor would work really well. I have had good experience buying on eBay. Then you need a micro-B USB receptacle and a DC power plug but you have to check the dimension of the hair clipper power plug. Plug the receptacle into whatever USB charger you already have to check the voltage. Wire up the convertor and adjust it to get the output voltage matching the clipper power adapter you are replacing. Then wire up the power plug and try it out. If the USB charger doesn't have enough power it won't work but it won't catch on fire. In that case you will have to upgrade the USB charger, but that will be good for charging your other stuff too.

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  • \$\begingroup\$ Yup, pretty much exactly what I ended up doing (as described in the "Edit" of my OP above) :) \$\endgroup\$ – Metal450 May 1 at 16:23
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Your #1 idea is the better one. Get a USB charger that supplies a decent current, more is better with chargers.

Then you just need a cable with a USB plug on one end, some voltage regulation/conversion and the correct D/C plug for your clippers on the other end.

That just leaves choosing what you want to use to control the voltage. Changing voltages is a pretty common task so there are a lot of options on how you want to do it. An electrical engineer is going to immediately want to buck. They are like chickens, going around all: 'buck, buck, buck'.

But any DC-DC convertor or even regulator (maybe? I don't think the heat would be too bad) should be fine. They just need to be spec'd to handle the current and of course deliver the voltage you want.

You don't need to do anything weird with the cable, your clippers aren't smart enough to know to draw different currents from a USB source.

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