UHF radio power. Switched or always live?

[MalcomM Senior Member Find all posts View Profile Close MalcomM]

Just wondering what people think of have the UHF radio wired so thats it always has power available or switched via the ignition?

Switched means no battery flattening but if the driver falls off a cliff with the keys then no one can call for help as you can't turn it on.

Whats the consensus?

[D4D Addicted PP Member Find all posts View Profile Close D4D]

My Icom is wired direct to the aux as it has a auto-shutoff feature.

[Davros Advanced Member Find all posts View Profile Close Davros]

I prefer to have it direct wired and not on the accesories circuit.
2 reasons...

1. I was taught to do it this way from way back when I was a kid. I was told then that sourcing power direct from the battery, and earthing back to same, was the best way to do it. This advice was from my next door neighbour when I was a kid. He was an auto electrician and his words were gospel to me then. I am not sure if the advice holds true today, but that is how I still do it anyway.

2. To me, a UHF radio is potentially an emergency rescue device. It shouldn't need a key to get it to work.

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

I have mine directly wired so it is live all the time.... I doubt very much that a UHF will flatten a battery, as I have left mine on over night many times when camping, and the current draw is very minimal

[wes Senior Member Find all posts View Profile Close wes]

I have also wired mine to the main battery and on continuous power.As previously stated i also treat it as a safety device and am happy for anyone to acces my vehicle to use at any time
it will only draw higher current when transmttting.

[Jeff and Cel 120 Member Find all posts View Profile Close Jeff and Cel 120]

We have wired ours to accessory power for the time being. We will probably change this once a 2nd battery is installed

Jeff

[K & M McF Senior Member Find all posts View Profile Close K & M McF]

Wired direct. I have left it on many times overnight and it makes no impact. It is not like a car radio that is using power to make noise.

[samo Addicted PP Member Find all posts View Profile Close samo]

mines wired directly in as well, uses bugger all power, its off the aux battery as well. cheers samo

[Hpycmpr Junior Member Find all posts View Profile Close Hpycmpr]

Direct to the aux batt too. More so that I can leave it on and not have to worry about starting in the morning. Although I doubt it would draw much.

[Richoson Avid PP Poster! Find all posts View Profile Close Richoson]

Same as Samo


Sent from Richos iPhone using Tapatalk

[wsp Member Find all posts View Profile Close wsp]

Hi I'm with the majority hard wired to the second battery as stated above don't need keys
Cheers Wayne

[MalcomM Senior Member Find all posts View Profile Close MalcomM]

Thanks for the comments guys.

[Boyesy Lurker Find all posts View Profile Close Boyesy]

Also the same as Samo Cheers Boysey

[LiveFreeAndRoam Avid PP Poster! Find all posts View Profile Close LiveFreeAndRoam]

Wow, quite a few replies here, and I didn't want to be left out

Mine is connected to ....

... main battery and always live.

When I considered this, I figured the aux is designed to go flat from time to time (e.g. after running a fridge for days) and will recharge only after the main reaches the appropriate charge. I prefer to not have the UHF on the second-rate power grid .

This does raise concerns about the likelihood of flattening your main battery, in the event you inadvertently left the UHF powered all night.

Check your UHF specs, but for the GME TX3440, it states:

• Transmit = 1.5 Amps
• Receive muted < 0.190 Amps
• Recieve at max AF output = 0.600 Amps

Assuming you don't transmit very much (typical when sleeping ) and there is little receive traffic, then for a 100Ah battery being drained at 0.190 Amps, you would get about 250 hrs of use, or around 10 whole days! [I'm assuming you can get 50Ah from a 100Ah battery before the voltage drops to an unusable value].

Just for interest sake, compare this with an ERPS that draws less than 0.020 Amps, or about 100 days of continual use before the battery is dead.

Oh and I'm sure I don't need to ask for someone to check my maths and my logic .

Cheers,
LFaR.

[Justo77 Senior Member Find all posts View Profile Close Justo77]

Mine is connected straight to the main battery. I've left it on a few times overnight and never had an issue with battery drain.