Right Angle Ring Terminal or what?

Jeff Vaughan · #1 03-22-2010, 06:38 PM

While chasing an oil leak after replacing my ECI recalled cylinders I noticed the silicone boot on the 4 awg connection to the alternator was slightly greyed, it is normally white. It looked alittle toasted. I removed the boot to find that the ring terminal had cracked and had been arcing and had removed a third of the contact post. Probalbe cause: The ring terminal was bent and had a side load on it plus the hole in the ring terminal was oversized for the post. See below:

I plan on replacing the 4 awg wire with a longer wire. I would like to find a right angle ring terminal which will make the connection easier because the 4 awg is hard to bend. Any one know where to find a right angle ring terminal with a 1/4" hole? Any other suggestions are welcome.

Bob Axsom · #2 03-23-2010, 12:14 AM

You need a large service loop in the wires going to the alternator. I had a moderate service loop in mine originally which I thought was more than adequate but my terminal broke during a flight into St. Augustine after a little over a year of flight operations. I replaced the wires with longer ones and routed them forward and up to the alternator area then shaped it into a half circle toward the aircraft centerline and back around outboard so the terminals fell strain free in line with the studs. The wire bundle is a spring and the stress is distributed over a large area. No more problems have been experience in 4+ years. The hard clamp mount in your installation is bound to concentrate the stress in the weak link of the terminal between the stud and the end of the wire. I do not know of right angle terminals other than those bent to suit an installation - obviously inviting breakage.

Bob Axsom

a25afm · #3 03-23-2010, 01:25 AM

Both my flying partner and I had the same failure on our RV-8s. We both replaced the alternator cable with welding cable.

Alan Carroll · #4 03-23-2010, 06:30 AM

I had this terminal break twice. My solution as to replace the ring terminal with a set screw lug (available from McMaster-Carr), which is much stronger. No problem since. I also agree about needing more room for the cable to flex between the support and alternator.

Geo · #5 03-23-2010, 07:04 AM

Please correct me if I'm wrong, but isn't a 4 awg wire a little overkill for the alternator? I thought that size was needed for the starter, but my alternator connection is made with a much smaller wire (not sure what # right now)...

Jeff Vaughan · #6 03-23-2010, 07:58 AM

My alternator is a B & C L-60, 60 amp. 4awg is what is recommended with 60 amp

Just realized I had used Vans wiring kit here and it is or was a 2 awg, P-16 part number.

aerhed · #7 03-23-2010, 07:06 PM

This terminal has broken on at LEAST a million spam cans. A bunch of skyhawks with the big flat front plate have the alt wires coming through right at the alternator. I've replaced that one twice in a day on the same airplane just to get it going again without the hassle of a reroute/approval, etc. Not sure, but I wonder if an adel clamp around the wire on an alternator case bolt keeping the terminal parallel to the alternator case would be cool. Anyone?

MCA · #8 03-23-2010, 08:01 PM

Jeff, a 6 AWG with a 60A alternator will do fine. It can't hurt to go bigger, but a smaller wire may be more flexible.

You should do a load analysis on your electrical devices, and if the total load is <45 A you could use an 8 AWG wire. The alternator only puts out what is needed and won't put out 60A if the max draw is only 40A for example. An exception would be if you needed to charge a drained battery while you are under max electrical load, but that is unlikely.

Ted Johns · #9 03-23-2010, 08:09 PM

Quote:

Originally Posted by Jeff Vaughan

My alternator is a B & C L-60, 60 amp. 4awg is what is recommended with 60 amp

Just realized I had used Vans wiring kit here and it is or was a 2 awg, P-16 part number.

For a 60 amp alternator I'd be comfortable with 8ga. wire (assuming it's tefzel insulated and protected with a fusible link or equiv.), and 6ga. would be "real robust". Just my opinion, but 4ga. is a lot more circular mils than you need.

See: http://www.powerstream.com/Wire_Size.htm

Look at the chassis wiring column, unless you plan to bundle the alternator output wiring with other wires in an enclosed chase.

Jeff Vaughan · #10 03-23-2010, 08:30 PM

Marc and Ted, I got the 4 awg recommendation from a Bob Nuckles article. Noticed he also shows 6 awg on his wiring diagrams. I see the Vans 2 awg was way overkill. Should be alot easier to use a 6 awg.

Thanks Guys