Run GMRS HT on USB

[CMG1012]

I ordered a KG-UV9G and the Wouxun ELO-004 V2 BTE-9 12V Battery Eliminator Cigarette Lighter Plug. Has anyone successfully converted the cigarette lighter plug to USB? I would like to run this radio plugged into my car full time. There is a USB plug readily available next to where I would mount radio.

[FrostyFruits]

You can try this adapter to make sure it'll run the radio before cutting the cable. You could also splice into this if needed.

https://www.amazon.com/Cigarette-Lighter-Socket-Female-Converter/dp/B07DDKD7Y7?th=1

[BoxCar]

USB voltage is 5VDC while the radio runs on 7.4VDC so the USB will not directly charge the radio or run it.

[Lscott]

15 hours ago, CMG1012 said:

I ordered a KG-UV9G and the Wouxun ELO-004 V2 BTE-9 12V Battery Eliminator Cigarette Lighter Plug. Has anyone successfully converted the cigarette lighter plug to USB? I would like to run this radio plugged into my car full time. There is a USB plug readily available next to where I would mount radio.

As pointed out already USB is only 5 VDC. You can get a DC to DC converter however there is a second problem. Most USB adapters/plugs can only supply 1 amp max. A 5 watt radio will likely draw up to 2 amps at the battery terminals on transmit. The total power drain on the low voltage side of the DC to DC converter will be higher due to the lower input voltage, power in = power out + converter losses, which will exceed the rating for the USB outlet.

[CMG1012]

Thank you all, lots to learn!

[Screech]

Even if it had enough power, odds are there would be lots of noise on the power input.

 

[Lscott]

23 hours ago, Screech said:

Even if it had enough power, odds are there would be lots of noise on the power input.

 

 Very true. Those USB power adapters likely use some type of switching power supply, which is a huge noise generator, with very little filtering on the output.

This is another point too. Most of your 120VAC to 13.8VDC power supplies are also using a switching type design. The ones used for powering mobile radios are specifically designed with more shielding and noise filtering. Some people have purchased cheap ones only to discover later the noise generated wipes out the signals they are trying to receive. There is a reason why the ones designed for two way radios likely cost more so a cheaply priced one may not be the best deal.

[BoxCar]

13 hours ago, Lscott said:

 This is another point too. Most of your 120VAC to 13.8VDC power supplies are also using a switching type design. The ones used for powering mobile radios are specifically designed with more shielding and noise filtering. Some people have purchased cheap ones only to discover later the noise generated wipes out the signals they are trying to receive. There is a reason why the ones designed for two way radios likely cost more so a cheaply priced one may not be the best deal.

Switching power supplies have to meet FCC requirements for noise so the blanket statement that switching power supplies are major noise generators is mostly false. The early switching supplies did not have to be designed with the filtering now required so they were a problem but more in the frequency ranges below those used for GMRS frequencies. You have a better than 99% chance that any switching supply having an FCC label will power your radios with no noise.

[Lscott]

5 hours ago, BoxCar said:

Switching power supplies have to meet FCC requirements for noise so the blanket statement that switching power supplies are major noise generators is mostly false. The early switching supplies did not have to be designed with the filtering now required so they were a problem but more in the frequency ranges below those used for GMRS frequencies. You have a better than 99% chance that any switching supply having an FCC label will power your radios with no noise.

They do cause interference. I design high frequency high power switching power supplies for a living. Trying to shield those things is far harder than you think. There are various ways noise can escape from them each requiring their own technique to correct it. That costs money the manufacturer won’t spend on the cheap models, which might be OK for consumer grade use around broadcast radios. However communications grade radios are a lot more sensitive and not all switching power supplies are suitable to use around them. I have a few on the shelf at home I can’t use around my radios for that reason. I don’t care what FCC labels are on them.