Thread: +12v required behind defender Dash

I'd wire it back to the battery. That way there is no chance of any issues due to the radio.

I always wire + and - back to the battery for the UHF.

Yeah my UHF is back to the battery as well.

so is mine, although its wired back to the second battery

You say that the radio is 25 watt. Is that total current draw, or power output?

A UHF CB would be a 5watt output job, actually drawing in the vicinity of 2 or three amps, fused at 3 or five amps and (for minimal voltage drop) using 10 amp cable.

If you have an ex commercial set converted for CB use then it too should be set to 5watt output. BUT if you have it still on 25watts out, then it would draw around 10-12 amps, be fused at 15amps and use 20 or 30 amp cable.

Radios do not like to be on the end of a power cable that is too light and therefore causing voltage drop when on transmit.

But you never said it was a CB radio. If you have a permit for a non-CB frequency then 25 watts output could be o.k.

In either case, wire it back to the battery, both pos and neg fused identically near the battery.

You could use a relay, triggered off the Ign or Acc circuits if you wish, but drawing the main feed off the battery, if you wish to have key out = all off situation. Mount the relay in the battery box.

Happy chatting,
Rovers4.

Does it have to be on the Dash? There are plenty of cubby box mounting options and the best part is the box is close to the passenger seat and the battery.

Originally Posted by rovers4

You say that the radio is 25 watt. Is that total current draw, or power output?

A UHF CB would be a 5watt output job, actually drawing in the vicinity of 2 or three amps, fused at 3 or five amps and (for minimal voltage drop) using 10 amp cable.

If you have an ex commercial set converted for CB use then it too should be set to 5watt output. BUT if you have it still on 25watts out, then it would draw around 10-12 amps, be fused at 15amps and use 20 or 30 amp cable.

Radios do not like to be on the end of a power cable that is too light and therefore causing voltage drop when on transmit.

But you never said it was a CB radio. If you have a permit for a non-CB frequency then 25 watts output could be o.k.

In either case, wire it back to the battery, both pos and neg fused identically near the battery.

You could use a relay, triggered off the Ign or Acc circuits if you wish, but drawing the main feed off the battery, if you wish to have key out = all off situation. Mount the relay in the battery box.

Happy chatting,
Rovers4.

Thanks Rovers, to clarify, Its an Icom 400 pro and yes is set to 5 watts at the moment. It will only be used at 5w ever unless we ever get stuck and need help where the extra power 'may' be helpful so i will eventually reprogram it to be switchable from 5 to 25w hence me catering for the 25w load.

The way i saw it 25w is only 2.05a at 12v obviously there are overheads on top of that... but the 10a fuse and large cable seemed overkill, not that i mind large cable as the voltage drop you mention is reduced consideably (i went massively overboard on my boat rewire) but i guess Icom are playing it safe and delivering what appears to be a good quality setup.

Originally Posted by rockyroad

Does it have to be on the Dash? There are plenty of cubby box mounting options and the best part is the box is close to the passenger seat and the battery.

Hi Rocky, unfortunately it was either going to be in the dash or an overhead console, and i didnt want to shell out the $475 for a console.. which left me the dash! it actually mounts pretty neatly in there with minimal fuss. All up it took a couple of hours to cut the centre fascia out and mount the radio bracket to the steel plate at the bottom of the dash centre section. LR could easily of catered for double din on that cetre section so i dont know why they didnt... its not like the aircon version of the deefer has acre of real estate to fix things to. Plus i dont like drilling holes in things..

Thanks to those that suggested back to the battery, i have found a +12v permanent on a flying lead connector that hangs around in the fuse box... havent traced it back yet... but its thick and brown so i am assuming some form of accessory connector? and probably back to the under seat fuse box. There are 3 cables in the connector with the other 2 being switched via ignition. Once the dual battery is sorted i will be rewiring to suit and distributing from a blade fuse box. temp fix will do for now..

Anyone have any idea what the connector is tho?

Thanks

Steve