Electrical Mini-Starter Wiring

[RekeHavoc]

Hey guys,
I know how to wire the mini-starter, but I have a couple of questions about things that probably I am the only one concerned about LOL.

All of the kits have you move the large starter cable to the same post of the starter relay as the BATT +. The moment you do this, this cable is now always hot and unfused. But the starter pulls so many amps during startup that I don't know how you could fuse this cable. Has anyone tried?

Re: the starter solenoid trigger wire, it is also unfused, but would only be carrying current while cranking. I was told the starter solenoid on the mini-starter can pull up to 45-50A. All of the kits I've seen come with 12 AWG for the trigger wire. I guess it can withstand that kind of current in short bursts. Has anyone fused this circuit?

What am I missing?

 

[AeroCoupe]

To my knowledge it’s not fused on any of the OEM cars so why bother? The inrush will increase with compression. My guess is these will inrush in the 200-300 amps and draw around 40-50 amps when just cranking.

 

[Mustang5L5]

I have no data to back this up, but the reasons I was told if that the ignition switch cannot directly trigger the relay on the starter. Too much load for the smaller gauge wire. Now, the 12G wire is sufficient for that load, but the ignition uses something smaller. 18G perhaps. So what Ford was was keep the ignition wire triggering the original starter relay just as it has for 10+ years prior to that point. The OG starter relay then triggers the starter mounted relay on the new style mini starter.

It's a good opportunity to "delete" the original starter solenoid and convert to a Bosch style relay. You can simply replace the original solenoid with a distribution block. You can then mount a Bosch style relay (I used a Bosch 75A relay) anywhere and then use the original ignition trigger wire to activate the relay, sending power down to the starter to trigger that.

 

[RekeHavoc]

It's a good opportunity to "delete" the original starter solenoid and convert to a Bosch style relay. You can simply replace the original solenoid with a distribution block. You can then mount a Bosch style relay (I used a Bosch 75A relay) anywhere and then use the original ignition trigger wire to activate the relay, sending power down to the starter to trigger that.

This is precisely what I have done. Do you have the 12 AWG trigger wire fused at all? I found a diagram on another thread where the guy fused this with a 20A fuse. I'm just not sure if that will be reliable or not. Or if it's even necessary.

 

[Mustang5L5]

This is precisely what I have done. Do you have the 12 AWG trigger wire fused at all? I found a diagram on another thread where the guy fused this with a 20A fuse. I'm just not sure if that will be reliable or not. Or if it's even necessary.

No fuse. In my mind it's not necessary for the trigger wire or the main feed wire down to the starter.

 

[RekeHavoc]

...main feed fire down to the starter.

This is what I'm trying to avoid.

 

[Mustang5L5]

Lol. wire i meant.

I'd do a fusible link over a fuse in this case. 12G wire, run a 14G link. If anything overloads that will burn. Problem is i'd hate to burn one up accidentally.

I'd have to put a clamp meter on and see what the inrush is on that wire. The factor config has both the main power feed and trigger wire unfused so that's how mine is.

 

[AeroCoupe]

I have had the mini starter in my Coupe and the T-Bird for at minimum of 20 years now and have never had a fuse on the 10 gauge wire or the 4 gauge wire. I do not know a single person that has wired one that way. Not saying it isn't something you cannot do I'm just questioning why a person would want to do it if even the cars that come with them from the factory don't have it.

 

[ZephyrEFI]

I'm ashamed to admit, but I wired up the ministarter yeeeeeeeaaarrrrssss ago using what I'm guessing could only be the original (and later found to be VERY corroded) starter cable always hot. Never had a fire, haha. It's been replaced now.

 

[Bullitt347]

GM fuses their main battery power cable going to the starter.
It is a 450 amp fuse at the battery.
We have seen some blow.
Usually when the starter seizes up.

 

[Mustang5L5]

What size wire does GM use?