Can my walky-talkie take 5 volts?

I have a set of walky-talkies, and they have horrible battery life, so I was planing to use them as intercoms, one getting power from my usb port, one getting power from an mutilated cellphone charger (both 5 volts). my Walky-talkies are meant to use 3 AAA batteries. (4.5 volts). is this setup possible, or will it ruin my walky-talkies?

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verence6 years ago
The 5V from USB should be fine for a 3AAA powered device as batteries are only rated as 1.5V. In real life they change the voltage depending on their charge level from slightly higher than 1.5V down to 1V and even lower if the load will still work with such low voltages.

If you want to play it safe, just add a standard silicon diode. A 1N4148 will probably not be able to handle the current but a 1N4001(1N4002, ... 1N4007) or similar will be fine. Anode of the diode to the plus output from USB, cathode (the side with the ring) to the plus input of your device.

Speaking about current, if a device drains batteries fast, that means it draw a not negligible current. A walkie-talkie will use a lot of current when transmitting. So now my standard comment, if anyone tries to use a USB as a universal power supply: A USB port that is not initialized (by a connected micro controller device and a matching driver in the operating system) is only guaranteed to deliver 100mA, 500mA when initialized and power budget of the USB hub allows. It should not be damaged by overcurrent or shortage, but well, written standards are one thing, real life is another, so it might.

And my standard advice for the USB-as-U5VP (universal 5V power supply) user: Use a wall wart. Anything between 3.5V to 5V DC (the latter possibly with the diode as above) should be fine.

Or just attach a bigger battery pack. Like 3x AA if you use primary cells or even 4xAA if you want to use accumulators (NiMH, NiCd). As the accumulators are only rated with 1.2V the 4x1.2V=4.8V should be fine. With the bigger batteries, you still would be mobile.
wmiller45 years ago
it will work dandy good - im running a 3 AAA fm transmitter from a USB hub - its been powered continuously for over 6 mos . no temp diff and it passed the sniff test after 1 week lol
ARJOON6 years ago
go ahead. it won't affect.
76543216 years ago
I've heard most electronics can handle +/- 0.7 volts, so I think you're good.
Vyger6 years ago
I don't think it will be a problem. Most battery powered stuff has a plus and minus window since not all battery's are the same. You should fit within that. If its to much voltage it will get warm/hot but should not burn out. Run it and see if it gets warm. If it does then you might need to put a resister in the line to drop the voltage.
However if it does go pop, I'm sorry, but it really shouldn't.
One caution, be very careful not to get the polarity reversed as that could burn things out, possibly even the USB on your motherboard. I had a USB keyboard that shorted out and destroyed the on board USB.
CameronSS Vyger6 years ago
+1. Unless you have a tremendously ghetto walkie it likely has an internal voltage regulator of some sort anyway. That tiny overvoltage is highly unlikely to burn anything out.
Re-design Vyger6 years ago
I agree.