Chad241993
Registered User
Can a Standard Starter/Glow Plug Solenoid be used as an ignition relay for constant duty? It would be my main power supply to run everything.
Standard Solenoid for Constant Duty
- Thread starter Chad241993
- Start date
79jasper
Chickenhawk
No. Neither of which are rated for constant duty.
Sent from my SM-G892A using Tapatalk
Sent from my SM-G892A using Tapatalk
jwalterus
Made in America
I have a constant duty solenoid running my GPs.
Same one's been there since Sept '13
Napa Echlin ST85
80 amp constant duty.
Unfortunately, I just punched it into the Napa website, looks like they are made cheap now
Here's a good one for you:
https://www.amazon.com/dp/B005K2429I/ref=psdc_15731411_t1_B0064MX7US
Same one's been there since Sept '13
Napa Echlin ST85
80 amp constant duty.
Unfortunately, I just punched it into the Napa website, looks like they are made cheap now
Here's a good one for you:
https://www.amazon.com/dp/B005K2429I/ref=psdc_15731411_t1_B0064MX7US
ISPKI
Welding/metallurgical engineer/Metalsmith
I have the same style that jwalterus has. I roasted several of the plastic housing relays before finding that steel barrel type. Most relays are rated for momentary loads, the amp rating for continuous tends to be less than half of the advertised rating but the cheap plastic ones will overheat after a couple months depending on the draw. If you read the descrpt for the one jwalt linked, it has a separate constant load and a much higher surge load. Mine was 28$, 300A surge 150A constant. Been running it better part of a year without issue.
This style has a copper ram rod that is slammed into a plate via a magnet. It has enough force that you can hear it thud from the cab.
This style has a copper ram rod that is slammed into a plate via a magnet. It has enough force that you can hear it thud from the cab.
madpogue
Full Access Member
What do you mean by "run everything"? A relay can't be a "power supply". The "power supply to run everything" is the combination of the batteries and the alternator. A relay is simply a switch. There are plenty of circuits that you do NOT want to switch off, the two most obvious being the hazards and the brake lights.
Chad241993
Registered User
It going to be a rock crawler, I'm not even sure if its going to have brake lights on it. Definitely won't have a hazard switch.
So yeah everything is run from a water proof fuse box in the cab, I have 7 live circuits to run everything including lights. I wanted a HD Relay (100Amp) in front of the fuse box to be a On/Off for the box which in turn runs "everything" including the starter relay/injection pump.
So yeah everything is run from a water proof fuse box in the cab, I have 7 live circuits to run everything including lights. I wanted a HD Relay (100Amp) in front of the fuse box to be a On/Off for the box which in turn runs "everything" including the starter relay/injection pump.
madpogue
Full Access Member
Sounds like you'll be better off with a heavy-duty battery cutoff switch.
Cole hersee make some decent constant duty relays, all the napa ones are being troublesome at my work. Also NO a starter relay wont last an hour constant, and they smell bad while burning up.
Macrobb
Full Access Member
Uh...I did exactly what he's saying on my '88. Everything but the alternator through the continuous-duty relay.
Have it hooked up to a light switch for my master on/off switch... it is nice to be able to switch it off and know *everything* is disconnected... like the hazards and brake lights, cab lights etc. No drain with it off.
Realistically, if you need the hazards on, you can leave the relay on too.
madpogue
Full Access Member
A simple battery cut-off switch (it could still be wired exclusive of the alternator) would be simpler and more reliable. And one less point of failure.
ISPKI
Welding/metallurgical engineer/Metalsmith
I actually disagree. The relay is in fact a switch, it is simply a switch that is actuated by an extremely low amperage current rather than the manual throw of your hand. The difference being that for automotive wiring, you want to keep your high load carrying lines as short as possible with as few areas of potential contact as possible. You can get a Cole Hersee continuous duty solenoid that can handle over 200A continuous for decades without failure. It would be a very bad idea to run that high of a current into a switch in your cab. Not only would that switch be enormous, but it would be a massive safety hazard, hence why car companies dont do that.
I will take a picture of my 150A solenoid setup in my truck tomorrow. It controls power between the large relay on the pass side fender and the cab, effectively controlling power flow to everything in the cab. The 1/0 cable is about 6 inches long, with a 14ga trigger wire running into the factory harness to the cab, very safe and reliable setup. Yes, a battery cutoff breaker would work too, but then he would have to open the hood to start and stop the truck.
madpogue
Full Access Member
The OP never said anything about needing to switch it on and off in the cab. Hopefully no one would consider running the full current of everything in the truck on one wire going through the firewall. Put a master cutoff switch immediately downstream of the battery and call it a day. It doesn't require opening the hood to "start and stop the truck"; you can still use a simple ignition switch on the FSS circuit for that.
ISPKI
Welding/metallurgical engineer/Metalsmith
Well he said he wants the run all of his power through a fuse box and switch power on and off via hd relay, maybe I misunderstood, I just always found those battery cutoff switches to be a pain and these relays are extremely reliable and reasonably cheap. Seems like an quality of life kind of improvement.
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