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What 13.8 volt amperage is available to run a radio?
Posted: Fri Sep 25, 2020 10:04 am
by emmett518
We're thinking of taking PCX150s on a back roads, cross country trip from California to Massachusetts. Since I have a ham radio license, I'd like to install a 50 watt, UHF / VHF FM transceiver on the PCX.
Does anyone know how much 13.8 volt capacity can be provided by the alternator to run such a radio? Can the PCX support a radio that draws 15 amps on transmit?
Thanks
Re: What 13.8 volt amperage is available to run a radio?
Posted: Fri Sep 25, 2020 11:12 am
by Conelite
You are better off using a handheld. 15amps on the small scooter battery might be much. BaoFeng it lol
Re: What 13.8 volt amperage is available to run a radio?
Posted: Sat Sep 26, 2020 6:29 am
by Coasting
It can supply a maximum of around 24 amps, but quite a few of those are already spoken for (eg lighting). Personally I wouldn't do it.
Re: What 13.8 volt amperage is available to run a radio?
Posted: Sat Sep 26, 2020 4:34 pm
by you you
Buy a cellphone?
Re: What 13.8 volt amperage is available to run a radio?
Posted: Sun Oct 04, 2020 6:05 pm
by OldGuywhoTinkers
My own 2013 PCX150 has an AC generator (not an alternator) that rectifies power from three phase AC to 12 volts DC. The book rates it at 308 watts. Lets call it 300.
By my calculations of Ohm's law (feel free to correct me) Using the Power known is equal to current times voltage or dividing actual current into power or dividing voltage into power, I read the AC generator as capable of 22 - 23 amperes if the engine is running at above 1,000 rpms, (my estimate)
So in theory, you can transmit while driving because the engine will be above 1,000 rpm. But that doesn't mean you have 15 amps available from the AC generator idling at a traffic light. The extra power would have to come from the battery. I think it could work, but you would need or might want to change to a higher capacity Lithium Ion battery to make up for transmit power. Using the transmitter much with engine off could lead to a dead battery.
Re: What 13.8 volt amperage is available to run a radio?
Posted: Mon Oct 05, 2020 6:35 am
by iceman
Usually the 12V outlet has a 5A fuse, which is to protect wiring not equipment (that should have it's own fuse).
So, you would need to lay in extra wiring direct to the battery and go easy as the batteries are rated approx 6AH, so very little time to talk.
Not really practical at all.