The original poster said he's installing a "ham radio." To me, that conjurs up visions of a little Kenwood or something. In the four day example I cited above, the radio was an Icom IC-3200A - a 1987 vintage 2m/440 rig.

This is a kenwood TM-D700, the specs says 1A or less on receive and a max of ...

All great suggestions to be sure, but if you leave the rig on, it won't run the battery down overnight. I've had different radios in the car and had no problem with a dead battery, except once I left the car for four days. Then it wouldn't start.

You may want to give it a try one night just to see ...

Don't most newer ham radios have auto power off as a feature? My Kenwood TM-V7A is factory-set for 2 hours; my Yaesu FT-8900 is adjustable from 5 minutes to 3 hours.

Even if I leave the mobile on it'll turn itself off after the set time period.

No wires to cut, no fussing around.

Good point, i ...

You can also purchase a "Chargeguard". They can be pre-set from 1 minute to 24 hours before the turn themselves off. We use them quite extensively here in my area with the local PDs. We set them for 2 hours so the cars can run the Vascar system, listen to the radio, etc. without burning fuel or ...

Inadvertantly leaving the radio on would be self-critiquing. You could make an indicator light to let you know that the switch is in the 'constant power' setting. Then there's always the battery-saver sort of method, where the B.S. unit will cut off power to the circuit attached to it when battery ...

Tap the appropriate lines and run them to each side of an SPDT switch then hook the radio hot lead to the center (middle) leg of the switch. One side will select the switched line, the other will select the constant hot.

Ok, thanks. I thought it'd be that easy but i didnt want to fry my new ...

I've got a newbie question for you. I'm installing a ham radio in my car and i want to put a switch so that i can toggle power between coming from the ignition controlled to the constant on. Is it as simple as putting a SPDT switch or would there be issues right when you actually hit the switch ...