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Topic: Engine Battery Terminal Failure (Read 1011 times) previous topic - next topic

Engine Battery Terminal Failure

Last year in Yellowstone we had a small starting incident. I usually start the generator and let the block heater do it's job for 30 minutes or so when the temps get into the teens. I started the generator but was greeted by an angry German camper pounding on our door. He did not like the noise or smell of the Kubota and let me know it. I decided to just do a normal start but after several seconds the starter quit. Heading back to the engine compartment, I found the ground terminal had partially melted. A pair of vice grips got the job done and I was able to make a pretty good smoke screen for our camping neighbor.

I had replaced the batteries, connectors, etc. on the house side long ago but the engine battery terminals were original. I replaced both top connector terminals and bought STAINLESS hardware for ALL battery connectors. In the photos, you can see the stainless flat washers I installed on both sides of the lug for the cables. In taking a close look, I could see that the lugs were not flat so with a file and about 10 minutes each, they were flattened so they would have maximum contact area with the flat washers. The stainless nylocks and split washers are probably overkill but for a few cents more... Wire wheel used on a bench grinder to clean the battery connecting cables. I also installed an extra ground cable to the frame about 18 inches away (lugs soldered not crimped). Lug installed at 90 degrees as to insure a flat contact area with the lug below.

This area at the very back of the coach gets a lot of water, dirt, what ever is on the road and gets dirty fast. As you can see in the photo, the battery hold down bar (grounded) is only 3 inches or so from the positive terminal on each battery. Mineral deposits and moisture on the top of the batteries can slowly discharge the batteries in the right conditions so good to occasionally clean off the tops. With the cables and hold down off, you can also check each battery with a hydrometer and voltmeter and load tester if you have one.

The whole project took only an hour or so and the hardware cost was $30-35 total. Hope the photos can better describe the "tune-up". The new green and red felt pads not installed yet, forgot to put them on when I finished :(.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Engine Battery Terminal Failure

Reply #1 –
Looks like you did a good job.............. I would have told the "Angry German camper" to mind his own business.
Dub McBride 1996 270

Re: Engine Battery Terminal Failure

Reply #2 –
Pierce, where did you get the new cable ends? I have not seen any that large at the Orielly's where I typically shop.
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: Engine Battery Terminal Failure

Reply #3 –
Kent,

I got them at a NAPA store. Welding shops will also have them. Just under $3 each as copper is expensive now. Would have gone to larger cable but it was a super short run and I already had a length of #1.

I usually drill a hole and feed electrical solder in until lug is full but feeding at the end works just as well. I used the kitchen stove to heat for soldering. Vinegar soak with water cleanup works well for prep on both ends if cable or lug looks oxidized.

With next oil change, I think I will pull the end at the starter and give it the same treatment. I had trouble starting my 4107 bus (8V-71 Detroit) and took the starter in for rebuilding. The guy at the motor electric shop rebuilt it and flattened off all mating surfaces while urging me to do the same on the cables when I installed it. I filed that one away as it spun like a top after he repaired it.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Engine Battery Terminal Failure

Reply #4 –
Pierce,

Very impressive job.
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: Engine Battery Terminal Failure

Reply #5 –
Quote from: dub –
I would have told the "Angry German camper" to mind his own business.
My darling wife would have told him in his own language.  She learned it pretty well while we were stationed in Berlin.  She worked for the U.S. Army's Non Appropriated Fund Office dealing with German vendors who supplied the golf course, rod and gun club and recreational services.  Myself, well I was suppose to keep my mouth shut and ears and eyes open.  But I can impress some of the Amish around here.
1994 U225
build #4514

Re: Engine Battery Terminal Failure

Reply #6 –
Corrosion in the cable will result in increases in resistance and resulting voltage drop as the corrosion is making each wire in the cable smaller in diameter.  Eventually, you will have to replace that cable assembly.  Here  is a good article on this matter.

Battery Cables - Car and Truck Service - Repair

gary (I have lots of advice, just no motorhome. :) )
Gary Spires
Coolants, Cooling Systems, Filtration, Diesel Engines
 

Re: Engine Battery Terminal Failure

Reply #7 –
Quote from: spike45 –
Corrosion in the cable will result in increases in resistance and resulting voltage drop as the corrosion is making each wire in the cable smaller in diameter.  Eventually, you will have to replace that cable assembly.  Here  is a good article on this matter.

Battery Cables - Car and Truck Service - Repair



gary (I have lots of advice, just no motorhome. :) )

Gary,

I have cars out of the 60's and 70's that have had battery cable corrosion and they are still in use today and working fine.  I did not even have to use baking soda on my U300 cable. The failure of the terminal was partially due to the bolts being loose and partially due to a huge extended current draw in the winter through a connector better designed for one battery, not three.

Regarding the condition of the cables, before and after I cleaned the lugs, they will outlast me or my U300.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)