Aftermarket "remote" start switch

[supermanotorious]

So you're building a kart from scratch or throwing a new (to you) motor with electric start in an existing kart without any switches up front to start the engine and wondering how you can start it from the driver's seat. Check out the solution I came up with the same issue in a different application.

Running heavy enough wires to the front to bridge the starter relay terminals "safely" just isn't cost effective or smart. You'd need a heavy gauge wire to and fro and you'd have 12v+ up there which just isn't all that safe.

Here's where automotive relays save the day!

In this configuration, terminals 85 and 86 receive the "input" signal (power and ground for activation). 12v+ comes from the main battery post to post 85 (white wire) and negative will come from my negative momentary switch up front in to post 86 (black wire).

Post 30 (blue wire) also connects to the main battery post for bridging the terminals. Post 87 (yellow wire) goes to the other terminal on the main starter relay.

When the black wire on post 86 is grounded, the relay bridges the terminals and starts the engine!

PS: don't drool on your keyboard while eyeballing that 40 series drive unit

https://www.youtube.com/watch?v=p6hh1-VpcN4

 

[supermanotorious]

here I've mounted the relay socket to the engine case

 

[ML-TOYS]

Cool idea but dont you still have to put the switch to the run position anyways.

 

[supermanotorious]

I believe so otherwise the coil is grounded, that's not an issue for this build, there is also a remote kill switch I'll post soon

there are no lights or aux items on the electrical system so leaving the engine in the "run" position is not a problem

 

[mr gunby]

Interesting! You added a relay to activate a relay. I fail to see the need.

 

[supermanotorious]

this relay BYPASSES the existing relay and connects the 2 terminals independently, now- I could simply activate that relay by turning on it's 12v signal but that would require another relay unless I ran the 12v+ wire to the switch which is something I want to avoid

 

[tazmannusa]

It doesn't take much power for the start relay so running small wire up front to push button or key switch and back is no big deal

 

[supermanotorious]

I hope you mean the "input" wires, not to the bridged connection

 

[tazmannusa]

I hope you mean the "input" wires, not to the bridged connection

There is only one start relay wire on the original starter it's the spade connector, It only takes an amp or two to activate the relay so around 16 gauge wire would work fine , as long as you fuse the start relay circuit coming from battery going forward it would be just as safe as anything else .
Just a bit confused as to why you would need large wires and it would be unsafe ?

 

[supermanotorious]

that method you're describing is correct and acceptable, it's not what I want however, I mean large gauge wires for running a wire from the post to the switch up front, back to the opposite post

 

[tazmannusa]

OK I see running the main battery and starter wires up front would not be a good idea.
So your just wanting your start relay circuit going forward to ground only with no + going forward?

 

[supermanotorious]

correct, no positive wires up front, so those who say this is useless, go ahead and show me how to have a negative only wire switch up front...

 

[tazmannusa]

My thinking is it's a tossup, granted you don't have + power up front but if that one wire shorts it will engage the starter where the other method with a short, blows the fuse, circuit is dead and no damage .
I will be wiring my 420 for starting from drivers seat but I need the + up there for lights.
what would be neat would be to go with wireless remote, start , stop , and choke

 

[supermanotorious]

agreed again

my friend designed wireless start, throttle, and kill for his winches, seems he's willing to share the design with me but has yet to do so......

he uses a multi function controller you would typically see on r/c cars, he uses strong servos, a receiver, and a custom made steel box to hold it all together

if he shows me how, I'll see how he feels about me sharing on the forum