A relay for Natasha's heated grips

This cold snap that's finally leaving us behind here in Colorado highlighted to me the need to install a relay on my heated grips to prevent the accidental "leaving them turned on" when parking the motorcycle.

Background: On Natasha, my 1996 Ural Sportsman Sidecar Rig, my alternator failed and caused me much grief. More details on that here: LINK.

To get around the fact that I was leery of putting in the same model alternator that had failed so disastrously, and the additional fact that upgraded alternators were back ordered for the foreseeable future, I installed a Total Loss Electrical System to power the electric needs of my Ural: LINK.

For cold weather riding, I installed some heated grips I got on Ebay directly inline with my Ural's OEM battery, a small motorcycle battery. Regular usage shows that a day's commute of 25 miles/1 hr uses up about .8 volts so hooking it up to the trickle charger at night is somewhat akin to keeping it charged the regular way with an onboard alternator.

Trouble is, the lazy way I had initially hooked it up, if you left the heated grip control switch in the ON position, it was draining the battery, whether you were enjoying the benefits of the heat or not! I thought I was smart enough to turn it off when parking the motorcycle but this past Monday proved me wrong. I left the switch on, drained the spare battery, had no heat for the ride home. That experience was not a lot of fun since it was below freezing!

Tonight, I got a 30 amp relay from the auto parts store and after blowing several fuses because I thought I could figure it out on my own; found instructions in the form of a diagram off the offroaders.com website. Once I wired things up correctly, I then had heated grips that were only powered when the motorcycle's ignition is on.

Source: www.offroaders.com

I used a wire to connect to Natasha's rear tailight circuit to act as the "switched power" source that connects to connector 86 above. Connector 85 I hooked up to Natasha's main battery ground wire. Connector 87 went to the heated grips' control switch and finally connector 30 was hooked inline with a 5 amp fuse(that came with the wires for the heated grips) to the positive terminal on my spare battery. I get heat with the ignition on, no more blown fuses, and no more inadvertent draining of my spare battery because of carelessness on my part.