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Starter and Battery Contactor

Hendoii

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All,
I'm cleaning up my electrical system on my cub and I'm curious about contactor alternatives/recommendations. I have a Cessna S-1579A2 Battery contactor and Cessna S-1991A1 starter contactor. They are both about $150 a piece. Are there any better, more reliable or more affordable options out there that you all would recommend? Thanks!
 
Use most any model that's used in a factory aircraft. If you do a little research you can find the exact relay you need, made by the original company, before it's placed in an 'airplane' box for sale. For example, White-Rogers makes many relays for aircraft installations. Look at the labels on some of the existing Cessna or Piper parts. A google search will help you find the same item under the White-Rogers part number, at a much lower cost. Stay away from automotive types as there are many of them I've stopped installing even on cars because of low quality.

And make sure to install a spike diode on each one!

Web
 
Thanks for the feedback gents. I will continue to research. I'm glad to hear there are more affordable options than $300. While I have your ear. What's the acceptable solution for an under seat battery mod? I have looked at numerous pictures that show both contactors mounted to a plate in front of the battery box under the seat. It looked like a clean solution and I always assumed the one in the pics were Atlee's. I was just about to order the Atlee the other day and realized that it doesn't have a plate on the front of the box to attach the relays. This led me to wonder if people are just building their own box and getting it field approved or if they are buying the Atlee and then putting the contactors on another plate in front of is. Anybody have any ideas?
 
I like the Atlee Dodge tray. There are different ways to wire the relays but this is how I do it.

Mount the tray as per instructions. Mount the master relay to the front edge of the tray. Connect battery positive to relay and battery ground to the side of the boss under the torque tube bracket. Route another 4 ga cable from the master relay, under the floor, up the left side. Mount the starter relay on the cockpit side of the firewall, near the insulated hole in the firewall. Connect that cable to the relay and connect another 4 ga cable from the starer relay and route it to the starter and connect. Bus power comes from a wire connected to the 'hot' side of the starter relay and routed to the bus bar.

This set up allows the least amount of wire and the shortest runs possible, with the battery under the seat. It also lets you connect the master relay and voltage regulator power through separate side of a DPST master switch just like ALL later model aircraft, which gives a safety margin, as all wires go dead whenever the master is switched off (unlike the fused master on originals) and lets you turn off the alternator (at field breaker) and keep the battery on in emergencies. And if your starter relay ever sticks, you can power the starter down by turning off the master. With the original system, you had to ride it out until the battery went dead or the starter motor failed.

Web
 
I have had 3 master contactors fail since I got my experimental cub flying. I did not do the wiring for the cub but paid a guy from Pacific Coast Avionics to do it. I have had another IA look it over twice since then. The first one that failed was one that was in my airplane Bushwacker that had been working properly for 10 years (it was a white rodgers). I replaced it with a Skytec continuous duty master contactor it worked flawlessly for a few weeks and then the same problem started all over again. I would flip the master switch and hear the contactor close but the power that should have been flowing through it was not enough to crank the starter. If I turned the switch on an off a few times it would usually work, this problem continues to get worse over time until flipping the switch on a off does no good. I have since replaced it with another brand new Skytec master contactor and guess what after a few weeks the exact same thing happens. Since I still had the first Skytec I cut the top off and welded ears on that cover so I can take it apart and clean the contact points inside. I took that contactor after cleaning the contact points and put it on the aircraft last week and it works flawlessly right now. Is there any reason any one can see why I have had 3 contactors fail with the same type of slow demise.
 
First off, I'd replace it with another White-Rogers. You did get 10 years out of the last one.

Just to clarify; the master failed, not the starter relay? Was there ever a problem with power to the bus, such as low voltage, or your digital stuff turning off/on randomly? If the only symptom is the starter motor not wanting to turn over, I'd recommend cleaning or replacing the ground strap connections from the engine to the airframe and checking for corroded or crappy terminals on the heavy lead, from the master relay out to the starter motor. Don't forget to check the ground lead at the battery. Surfaces should be shiny and there should be no black/white/green color to the cable inside any terminal crimps.

Web
 
Check out Cole-Hersee solenoids. http://www.littelfuse.com/industrie...tm_medium=redirect&utm_campaign=colehersee-lf

I had trouble with the starter solenoid sticking closed on my 185. It's not fun lifting the cowl while floating across a pond to rap the solenoid with a pair of pliers to get it to release. Then replacing the cowl and starting the engine before piling up on the down wind shore. I replaced it with a Cole-Hersee which is made right here in Boston. No more problem and it has been decades now.
 
Yes it is the master contactor. The light for alternator and electronics international gage are my first indication that it is doing it again, i.e. no lights on instrument panel. I have all new ground wires, that is where we started.
I have a ground going to a stud on torque tube tower from the battery, one going from the engine case to the engine mount. One going from the battery to the engine case. Way overkill but wanted to rule that out

This is a brand new airplane everything is new and shinny.. sent starter back and skytec sent a brand new one to me a month ago.
 
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Yes it is the master contactor. The light for alternator and electronics international gage are my first indication that it is doing it again, i.e. no lights on instrument panel. I have all new ground wires, that is where we started.
I have a ground going to a stud on torque tube tower from the battery, one going from the engine case to the engine mount. One going from the battery to the engine case. Way overkill but wanted to rule that out

This is a brand new airplane everything is new and shinny.. sent starter back and skytec sent a brand new one to me a month ago.

the starter solenoid should be hook to the same battery post as master, thats how piper did it... not in series with master.. eliminates one set of contacts...

the root cause of your failure is the big bolts have square heads on them INSIDE solenoid and are getting "rotated" slightly when you attached the cables to them and tighten and is only making contact on one of the square corners, and burning... cut the top off a dead one to see what i mean
 
Excellent info.

So if Piper has a direct path from battery to starter through the starter solenoid, if that solenoid hangs up in the closed position, there is no cure other than letting the battery or starter "lunch" itself?

Is there such a thing as a mechanical quick disconnect that can handle the starter current? My ground cable is by my foot, and I would be happy with a way to isolate the battery at that point in an emergency.
 
An RV battery isolate switch is about the closest thing that I've come across to fit that description. Otherwise a wing nut on the ground stud maybe?

Web
 
the starter solenoid should be hook to the same battery post as master, thats how piper did it... not in series with master.. eliminates one set of contacts...

the root cause of your failure is the big bolts have square heads on them INSIDE solenoid and are getting "rotated" slightly when you attached the cables to them and tighten and is only making contact on one of the square corners, and burning... cut the top off a dead one to see what i mean

also the master switch itself could have burnt contacts... easy to jumper past it to verify... seen that many times with starter switches without the diode installed..
 
Yes it is the master contactor. The light for alternator and electronics international gage are my first indication that it is doing it again, i.e. no lights on instrument panel. I have all new ground wires, that is where we started.
I have a ground going to a stud on torque tube tower from the battery, one going from the engine case to the engine mount. One going from the battery to the engine case. Way overkill but wanted to rule that out

This is a brand new airplane everything is new and shinny.. sent starter back and skytec sent a brand new one to me a month ago.

This is the problem I had a year or two ago. I had what i thought was a bad battery so I replaced it with new. Then new starter and battery contactors and cables. Still wouldn't start good, always acting dead. I lived with it for probably 4 or 5 years. Then, out of the blue, it dawned on me and we started looking. No ground from engine to anything. A couple new ground straps and this 0-360 spins over and starts like never before.
I thought this could be your problem, but you have that covered. Let us know what you find, Im always interested.
 
Since I still had the first Skytec I cut the top off and welded ears on that cover so I can take it apart and clean the contact points inside. I took that contactor after cleaning the contact points and put it on the aircraft last week and it works flawlessly right now. Is there any reason any one can see why I have had 3 contactors fail with the same type of slow demise.

Mike, I actually already looked inside as you can see from my first post. I am a machinist and put it up on my surface plate to check the contact points and they indicated within a few thousandths parallel to the contact washer that makes the circuit. I also have always backed the jam nut with a wrench to keep that stud from rotation. It's got to be something or I have just been unlucky with the Skytec contactor.

It is interesting to note that the IA that sold me both contactors (friend of mine) just texted me today to tell me he has had a fairly new one also fail on a Cessna 150 that he is in charge of maintenance on. I think I will buy another brand if the one with my removable top fails again.
 
Skytec is having lots of trouble with their master solenoids, I have had 3 sent to me for free from factory after buying the original from ACS. The explanation I got was that as they heat up, they are giving off some kind of gas that is corroding the plunger or contacts inside. They also assured me that my skytec starter solenoid would not have the same problems. All 4 of the master solenoids I had on my plane started to work intermittently after about a month and then not work at all. I finally got sick of them and just replaced both my skytec master and starter solenoids with Lamar units. Skytec starter seems to be well built, but they missed on the solenoids. What does the inside of one of these look like when not working?
 
a.crane that sounds like the problem I am having. I only cut the first one open but it looked very corroded where the copper washer/plunger makes contact. The contact points where also corroded. Maybe since the one I cut open is not sealed air tight anymore I won't have a problem with it but I am going to by another well liked brand if it even hints at not working again.
 
HA, if I did that then you would not have all the information! Then you would just be guessing on my problem and all the things I have already tried. Which you did and you were wrong
 
Got a recommendation about what diode to use for the master and starter relays? I'm starting my wiring, and I never learned how to speak diode.
 
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