I'm rewiring the electric hoist in the rear bed corner of my Ranger. Doing it right this time. The hoist came with a 20 amp thermal limiter and a good 10 feet of 12 AWG wire from the battery back to the hoist. That makes sense to me with DC current. Now I want to turn on/off power with a relay. I have a couple of new 20 and 40 amp relays but the leads are 16 AWG at best. Is that adequate for 40 amps? Seems like that ought to be 12 AWG wire.
In general the On/Off in a relay is very small AWG as it is the switch not the conductor, the conductor on the IN and OUT of the relay should be full AWG to handle 40 amps w/ a CB or fusible link back to the power source. Could be wrong, probably not the first time today........ Cheers, Doc
I would use the electrical gear made for bumper winches, including remote controls. They make the power control relay necessary for a high-torque (read: high amperage draw) 12 volt motor.
Clark, remember the starter solenoid on the inner fender of most Fords ? Those are the go-to relay used in most heavy draw DC winch apps. They are also used in pump motor switching on RV leveling jacks. Simple to wire in and definitely can stand the load you will use them for.
Are the Ford starter relays something I could use to control my electric radiator fan? I am less than impressed with what is available.
Ford starter solenoid relays are usually rated intermittent duty, you need a continuous duty rated relay for an electric fan relay. Using the Ford solenoid relay as continuous duty will usually cause the coil inside to overheat/burn. I have had great service from using 70 amp cube relays(using them on my electric fans for over 6 years without an issue), here is a pic showing the difference between a 70 (L) & 30/40 amp (R) relays . Hope this helps.
Thanks AQL. I like the sound of the 70 amp as I think I am at the edge of 40 amps and it seemed like if I got a 30/40 it would be toast pretty soon. Any idea where the 70 came from?
You can get them off Ebay, I pick them up at my local Pick-a-part for pennies on the dollar. Last time I was at one, I ask the counter guy how much for fuses and/or relays that would fit in a 1 gallon freezer bag, he said $10(I had a big shit eatin grin). I bet I got over $200 worth of fuses/relays in that bag and boy was he surprised. On a side note they are used parts(relays) but I have yet to have one fail on me be it a 70 or 30/40 amp relay and being a Ford part they are probably built more robust than a cheap Ebay offering. I know the Lincoln Mark VIII's have the 70 amp relays, IIRC the mid 90's T-bird/Cougars with 2 speed electric fan do as well. I have used the 70 amp relays on my Windstar cooling fans and Mark VIII fan motors(I have tested a few with a DC clamp meter and these have a 60-69 amp spike at start-up and about 30 amps running on high speed-'94-'96 Mark VIII motors are 2 speed, the '97/'98 models are single speed with it's fan speed varied by the PCM). Again, hope this helps.
AQL (Professor) are these the relays that reside inside the fuze boxes in the engine bay (on more modern cars) or are they mounted some where near the fans etc. Cheers, Doc
They are usually mounted inside a separate relay box, on the passenger side fender(Lincolns). It has been a while since my last relay huntin' trip though. IIRC, A '94-'97 Chrysler Concorde has these 70 or 75 amp relays. New, these are $78 each, I picked them for a $1 each(yep, I'm cheep sometimes). They are located on the driver's side fuse/relay panel near front core support/battery mounting area. I actually like these better due to the copper spade terminals.
Thanks for the intel. I am using a CrownVic fan so maybe I need to return to the scene of the crime. Am wanting to put relays on the headlights too and this would make for a nice tidy upgrade that I could get parts for if needed. That was my logic with the CV fan as they are cheap in the boneyard or at the local Parts-o-rama. Thanks Clark for putting up with the highjack on your thread.
I have a small relay that is triggered by the temp sensor. It in turn triggers the constant use solenoid I bought on Amazon for about $30 that supplies the fan. But I am running a Lincoln Mk VIII fan and those pull a lot of current. Plus I am a fan of overkill. Russ
I guess I have a similar setup and am concerned the little relay supplied with my controller will be good for about an hour. We will see what my next hunting expedition at the bone yard shows.
I'll just mention in passing -- if you find a '89 Ford Taurus in a yard, it has 3 of those relays in a box mounted under a brace in the engine compartment. Not sure about the current but they look the same as what has been shown. I used one to operate a radiator fan.
That's the CCRM--constant control relay module. It has the PCM, fuel pump and fan relays, so if you want to do up EFI in a smaller Chero, that would likely be better than the bigger fuse/relay boxes.
