Wiring help for trunk mount battery

-
7dart0

7dart0

Well-Known Member
Joined
Apr 20, 2012
Messages
491
Reaction score
104
Location
peabody,ma
I wired everything today using the attached schematic, and when I go from start to run the engine dies.
I'm using the ford starter solenoid instead of the continuous duty relay. Should I have not grounded the ford relay? I mounted it in the engine bay. What gives? Any help is greatly appreciated

Screenshot_20200126-185019_Chrome.jpg
 
This sounds more like key/ ballast problem. What are you using for ignition, and did everything work OK before you went trunk battery?
 
I fixed it. I moved the #14 wire coming from the top of the cutoff switch to the other small terminal on the ford starter relay which is the (s terminal), I also moved my ground to the case of the relay.

Damn relay clicked when I turned the key and started right up and stayed running. I went around to the trunk and hit the cutoff switch and it killed the car. Success!
 
A ford solenoid is not designed to stay energized for long periods of time.
 
Does it fire but shuts off when you let go of the key? Check your ballast resistor. The dual resistors have a coil for start and one for run.
 
toolmanmike said:
Does it fire but shuts off when you let go of the key? Check your ballast resistor. The dual resistors have a coil for start and one for run.
Click to expand...

I changed to GM HEI ignition, so I knew it wasn't the ballast.
 
crackedback said:
A ford solenoid is not designed to stay energized for long periods of time.
Click to expand...

Hey crackedback I have a White/Rodgers relay rated for continuous duty part #70-111224. Would that be a better solution than the ford solenoid?
I just want this to be right.

Thanks
 
Well I justed smoked the ford relay. Car died idling in the driveway and the relay was smoking. Ugh!

I have the 4 pole cutoff switch, cant I just run the (2) 14 gauge wires from the little posts on the switch and cut the blue ignition wire out of the bulk head and attach it to each pole? So when i throw the switch it cuts the ignition?
 
Back when I wired my shut-off, the switch, to be track-legal, had to simultaneously cut both the battery and the alternator output., otherwise the engine can continue to run.
Your way can shut it off, but I don't think it would be track legal.
For the track; the point is not about cutting the ignition;
It's about disconnecting the battery so it can't start a fire after being shorted. But in a Mopar, as long as the vehicle is upright, the engine continues to run on alternator power.... so you have to simultaneously disconnect the alternator........ or rewire the alternator to go to the battery, instead of the ammeter.
 
@7dart0
At least you know the time limit for the load the ford relay was carrying... :lol:
Lots of people make the same assumption. At least it didn't catch fire!

As long as the CD relay is rated for the expected load + some overhead, you should be good! I don't know the catalog or part number. I use Cole Hersee products most of the time.
 
A LONG time a ago (about 72), an aspiring electrical engineer friend of mine had a 70 Chev with factory dual battery, and the interconnect relay was about the size of a horn relay. I mentioned "continuous duty solenoid" and he decided to sub a Ferd solenoid. WENT THROUGH TWO OF THEM before he was convinced I knew WTF I was talking about LOL. He even tried a dropping resistor in the second one to limit coil current. First one lasted about 10 minutes as I recall, I don't remember how long no2 went LOL

Miss that guy. Died in his early 60's of diabetes
 
dart_68 said:
I believe there are ford solenoids rated for continuous duty.
Click to expand...


Never heard of such a thing, at least not a "starter" solenoid. Can you come up with a link, part number, ??

Here is why, generally, that starter solenoids are not continuous duty, and why, generally, continuous duty solenoids are not rated to carry as much current as starter solenoids.

Current carrying capacity of relay/ contactor contacts is a function of their shape, material, size, and PRESSURE AGAINST THE CONTACT. A starter solenoid has a much MUCH stronger electromagnet than does a continuous duty one, which is in fact----the major difference
 
dart_68 said:
I believe there are ford solenoids rated for continuous duty.
Click to expand...

I was referring to the initial post which CLEARLY states a ford starter relay. Excuse me for not saying a "starter" or "that" relay. Sure Ford may have a vehicle that uses a CD relay for some other function, not being discussed here. This is part of the reason many don't choose to post here anymore, nitpicking stuff out of context.

I'm glad the OP's car didn't burn to the ground. :thumbsup:

CH 24143BX is a 200amp CD relay
 
Last edited:
^^^^Yep. And when I say "Ford starter relay" I mean the ones used on Fords. There are lots of different types of solenoid relays, and they all look vaguely similar. There are several different ways they are wired, along with starter vs continuous. One great example of an oddball is the AMC "Ford" one which has an extra terminal for the NSS along with the usual "Ford" terminals. It is NOT a 'grounded base'
 
crackedback said:
I was referring to the initial post which CLEARLY states a ford starter relay. Excuse me for not saying a "starter" or "that" relay. Sure Ford may have a vehicle that uses a CD relay for some other function, not being discussed here. This is part of the reason many don't choose to post here anymore, nitpicking stuff out of context.

I'm glad the OP's car didn't burn to the ground. :thumbsup:

CH 24143BX is a 200amp CD relay
Click to expand...
I actually wasn't trying to be nitpicky but I can see how it would sound like it. Please accept my apologies for the misunderstanding.
 
Hyup; I just put a relay in there between the VR and the Alternator.... but you have to break that circuit separately from the battery, else the alternator output will just run around the circle and keep the relay energized. I don't see how it can be done with an SPST emergency shut-down switch.

I bought the FlamingRiver item; beautiful piece, but just 2 poles. I tried to figure out a different way to make it work. But as long as you keep the ammeter working, it can't be done. Me not smart enough to figure it out.
But if you take the factory output from the alt, and remove that wire that normally goes to the ammeter circuit, and instead run that to B+, at the start relay; then install a new wire from the alt output, back to B+ at the battery in the trunk, then when you shut off the battery, the alternator output has no place to go, and Karumba, the engine quits.
The trick is to route that wire in a safe manner such that it can NEVER EVER short to the body.

I suppose, you could make these circuit changes right at the ammeter, now powering up the ammeter from the start-relay, and re-routing the alternator output that was on the ammeter, out to the trunk. I like it.
 
Last edited:
^^This is what I started out with, but that run of wire back and front may ADD to the voltage drop/ overcharge problem so many of these girls have. That is why I suggest a big relay or continuous duty solenoid to run the car loads

Another concern by many is surge/ spike on disconnect due to the alternator, say, using a "one wire." There exists load protection devices, primarily for marine multi battery use. I have not researched them. "Load dump" and other names
 
You must log in or register to reply here.
-

Back
Top