Mobile radio power voltage

[MadisonMod]

Hello everyone. Does anyone know if it's possible to up the voltage in a vehicle for a mobile radio? I know vehicles are considered 12 volt and amp hr depends on size of battery, but I would like to up the voltage similar to using a power supply. Maybe its possible to design something with digital selection capabil 14 or 15 volts . Has anyone done experiments or have any ideas?

 

[dave457]

Most vehicles run at 14v while running, what problems do you have running it at 12/13 v.?

 

[FlatlandBusa]

Most vehicles charge @ 13.8 - 14.8 volts and this will drop as temperature increases. Many newer vehicles have battery management that drops the charge voltage to 12.9 when the computer thinks the battery is charged.

To hold the voltage as high as possible use large gauge power cables and consider a super cap if you are running power.

 

[nomadradio]

MFJ sold, or may still sell a gadget for this. More or less. Some radios have internal voltage regulators that fall down when running from the vehicle's battery alone, especially when it falls below 12.0 Volts. Some RCI sideband mobiles will begin to 'warble', or drift frequency transmitting sideband in step with your modulation if the vehicle's engine is not running.

Turns out there are two, the 4416 and 4418. Here's one of them:
https://mfjenterprises.com/products/mfj-4416c

It boosts the battery-only voltage up to what the alternator will supply when the motor is running. Never asked how high the output voltage can be adjusted. It's meant to keep the radio's performance the same whether the engine and alternator are running or not.

This is the only commercial product I have stumbled across that does this job.

73

 

[BJ radionut]

N8XJK Super Booster - West Mountain Radio

12V to 13.8V DC/DC converters regulator from 100 to 700 Watts in stock at PowerStream.

24 volt to 12 volt DC-DC converters suitable for automobile electronics.

www.powerstream.com

 

[MadisonMod]

Most vehicles run at 14v while running, what problems do you have running it at 12/13 v.?

No problem with regular charging system. I contacted my radio straight to the battery and the voltage is 12.6 .the radio would perform better at 14.5 to 15 volts.

 

[MadisonMod]

No problem with regular charging system. I contacted my radio straight to the battery and the voltage is 12.6 .the radio would perform better at 14.5 to 15 volts.

Sorry connected

 

[MadisonMod]

MFJ sold, or may still sell a gadget for this. More or less. Some radios have internal voltage regulators that fall down when running from the vehicle's battery alone, especially when it falls below 12.0 Volts. Some RCI sideband mobiles will begin to 'warble', or drift frequency transmitting sideband in step with your modulation if the vehicle's engine is not running.

Turns out there are two, the 4416 and 4418. Here's one of them:
https://mfjenterprises.com/products/mfj-4416c

It boosts the battery-only voltage up to what the alternator will supply when the motor is running. Never asked how high the output voltage can be adjusted. It's meant to keep the radio's performance the same whether the engine and alternator are running or not.

This is the only commercial product I have stumbled across that does this job.

73

Thanks. I'm checking them out. I appreciate it

 

[loosecannon]

No problem with regular charging system. I contacted my radio straight to the battery and the voltage is 12.6 .the radio would perform better at 14.5 to 15 volts.

it actually would not.
pretty much all the circuits in your radios are run off of voltage regulators that take in a larger voltage and regulate it down to a lower voltage.
these devices do not change the lower voltage output just because the input voltage dropped by a volt or so.
they are designed to work with a range of input voltages and still only put out exactly the voltage they are designed to.

yes, the collectors of the final and driver transistors in SSB mode will have the input voltage on them, so technically the output would go up if the input voltage went up, but you are talking about like 1/2 a watt of improvement unless you goosed the voltage up to 18vdc+ and at that point you would start blowing voltage regulators and let the smoke out of the radio.

remember that in order to gain 1 S-unit in someone's receiver, you will need to quadruple your power output.
if you key up with 4 watts and hit them with an S-5, to get to an S-6 you'll have to key up with 16 watts.
this is true regardless of the amount of power you start with.
LC