How to Trigger In-Cab Relay?
11-07-2021, 08:09 PM
#1
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How to Trigger In-Cab Relay?
Hey all I have a novice question looking for an expert answer. I have some experience working on wiring in my rig, but only slight confidence in my schematics.
Big picture, I'm trying to set up an additional cigarette outlet in the back of the JK as a "dedicated" portable battery charger when driving around. I would like this new outlet to be hot only when the engine is ON so that I don't accidentally drain the car battery when parked. I want to avoid the switched-power-from-the-fuse-box method as I have a bus bar in the cab that needs to be always hot (separate topic).
My plan is to set up in the back of the jeep, a relay with the trigger tapping into the 12v cig lighter HOT wire in the dash, and then grounding the relay into a stud on the body. FYI, my dash cig lighter is only hot when the engine is on. This new relay (12 AWG 30A) would be wired in "after" the bus bar so that my other accessories would be always on.
The question is...Will the hot wire from the dash cig lighter work to trigger the relay? Would it be too much power for a trigger on the relay?
Thanks in advance.
Big picture, I'm trying to set up an additional cigarette outlet in the back of the JK as a "dedicated" portable battery charger when driving around. I would like this new outlet to be hot only when the engine is ON so that I don't accidentally drain the car battery when parked. I want to avoid the switched-power-from-the-fuse-box method as I have a bus bar in the cab that needs to be always hot (separate topic).
My plan is to set up in the back of the jeep, a relay with the trigger tapping into the 12v cig lighter HOT wire in the dash, and then grounding the relay into a stud on the body. FYI, my dash cig lighter is only hot when the engine is on. This new relay (12 AWG 30A) would be wired in "after" the bus bar so that my other accessories would be always on.
The question is...Will the hot wire from the dash cig lighter work to trigger the relay? Would it be too much power for a trigger on the relay?
Thanks in advance.
11-07-2021, 10:59 PM
#2
JK Newbie
It should be fine if it is only the trigger for the relay. The trigger only draws a few milliamps to trip the relay. I did the same thing to power half of a 16 circuit distribution box.
11-08-2021, 06:39 AM
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Thanks for the response! What was your setup? Did you daisy chain your relays? Or are all your circus run off of one relay?
11-08-2021, 09:57 AM
#4
JK Newbie
Here is what I did. The power for the relays come from the 40 amp fuses and go to the power side of the relay. The power port inside the Jeep is powered on with the key just like yours.
When the key is turned on the power point energizes the trigger circuit of the 2 40 amp relays letting power go through the relay from the fuse box to the 2 power inlets on the distribution box
and I have key on power to half of the box. The other half of the box is always powered on by the 80 amp fuses in the fuse box. I have since found some 75 amp relays that I plan on replacing
the 40 amp relays.
Here is a picture of my engine bay electrical mods just for giggles.
