I'm ready to add a 12 volt hook up to my stead but have a few questions to those that have already traveled this route. I understand the "stock" way of connecting some 20 Amp cable in from the 12 volt socket to the battery with a 20 Amp fuse in line. I'm just a little concerned that there may be some risk of discharging the battery totally if an appliance is left connected for too long with the engine off. What I would ideally like to do is add a switch in line to isolate the socket. Is it as simple as it sounds? Do I just splice the switch in between the fuse and the switch.

Also, do I have to run the earth from the socket back to the battery (means I have to fit a switch to isolate power to the 12 volt socket,) or could I run the earth into the earth coming from the horn switch thus negating the need for an inline switch as the power to the 12 volt socket will be isolated when the ignition switch is turned off.

That would be the ideal solution. I would like to fit a 12 volt socket that is powered when the ignition switch is on and isolated from power when the igntion switch is off.

Any thoughts??
The socket will be used primarily for my new Etrex GPS but on occasion will be used with a small compressor.

 

OK here it goes: buy a automotve relay for fog lights or similar. preferably one with 4 terminals. run 20 amp ground from batt directly to negative of socket. Run 20 amp positive wire from batt to terminal 87 of relay and from terminal 30 of relay to positive of socket. next run smaller wire (same size as horn ground)from horn gound or similar to terminal 85 of relay. finally run another smaller wire from an ignition key on positive wire to terminal 86 of relay. cant use headlight wire because there are two-hi and lo beam. your best bet would be to locate this wire feeding power to beam switch. relay is basically a power activated switch. terminals 85- and 86+ is the swiching part which uses little power. when relay is energized, terminal 87 connects with terminal 30. finding somewhere to mount the relay may be the hardest part. Clear as mud !?!

 

Sounds like a lot of work.. Just remember to unplug stuff from the bike, its worked for me for 2 years with no problems.

 

Gotcha! But do I have to use a relay? I theory, if I locate the +ve feed to the headlight (before the dimmer switch) I can slice into that and have the socket earthed. I'm sure the main and dip beams have a common earth and the handlebar switch is hot, this appears to be the ideal place to splice in.(+ve feed prior to the handlebar switch.)

Are there really going to be any problems slicing into the OE wiring or should I just go external and fit a socket that is HOT all the time.

 

Personally, I'd leave it hot all the time. chances of u leaving compressor on are slim im guessing. only other thing is gps. considering 2 AA will run unit for 24 hours i dont think it will drain the bike battery very quickly. Plus youd be to eager to post up your tracks for all us to see after each ride anyhow to be leaving it plugged in! LOL!

 

They are relatively low powered devices.
I don't think you will need to use a relay.
I picked up v+ from the ignition switch when connecting the GPS.

If you intend to run high powered stuff, then a relay will help.

 

I suggested relay for use of compressor. dunno, might be too much for smaller wiring. myself im gonna get one of those CO2 powered inflators. nice and small and great for the trail kit.

 

I would use a fuse...tis better to blow a fuse on the trail then to melt a wire whip and the bike won't get you home!!!

 

Reduce the fuse to say 10 amps to be safe but I think you will have no problems.
If you were drawing more than that, you better have the motor running

 

very true. dont use 30 amp tho! lol. or tinfoil!