I'm awful needy these days, hope I can get to the bottom of this. Truck in my signature had weak batts all of a sudden, they're not new but I've kept my eyes on them and they're still good enough. When I disconnected them to charge I got larger than usual spark on final battery disconnect. Charged batteries and got same spark on reconnect. Checked with my tester, which goes to 250 ma and it pegs the needle. It was always high, like 125 but nothing like this. I checked my relays (starter, glow plug and plow) and they all seem to be functioning as intended. GPR and starter relay (on fender) both tested some ohms across the large lugs, the same (.85 I think but it depends on what setting the ohm meter is on and I'm not too knowledgeable there). No ohms across large lugs on plow relay. Pulled each and every fuse in cab and under hood, unhooked alternator. Did not crawl under and check starter but squatting down I can tell that it is still tight in place. Any ideas, help and insight would be appreciated.

Thanks,
Mark

 

Mark what's your read on each batt after 2 minutes running??

Curious

 

Do you mean start it and check the voltage on each battery after it's run for 2 minutes?

 

Yes sir, just make sure you allow for GP timeout and see what the voltage is at each battery using just the terminals, no ground on engine. That will tell us if your alt is pushing too much and if too little it leads us down another path.

What is the exact age of the batts and what brand if I may be so forward.

Denny

 

12 volt DC should be your DMV setting btw. If you think it's a parasite (I plow too, make sure your control head is shut off and disconnect the pos post on your plow motor if it's older. If it's completely detachable like my western we'll look at that after this.

Denny

 

Batteries came with the truck (to me), they're Walmart 850 CCA dated something like 12/13. I know they're getting older but I keep an eye on them and they're maintaining about 12.6 when unhooked. That other parasitic drain will suck them down in a week or two on me if I don't use it or disconnect them batteries. Not sure about age of plow but it's a Meyer EZ Mount and is disconnected. Relay sits next to passenger's side battery and it clicks when I play with the joy stick. I also have disconnected the plow light relays and they're not it either.

 

Mark,
I would have your batteries load tested, individually of course. I had the same issue when I bought my truck, NAPA tested everything (in) the truck and said everything was good! I had gut feeling, pulled both and had Sears load test them. One dropped to 4% with only 10% load, the other they said was fine but wouldn't charge past 70%. Swapped both, problem gone.

 

Kinda thinkin it's time.

Load test them but the plow tears em down in a hurry.

Mine are 3 and I'm feeling the strain so I'm renewing. I don't winch much and I do have a high idle kick but the plow really tears them down.

JS

 

Just did a re-read. Start with fresh batteries and see what we see. Batteries can hold a note as long as the band plays but for what your looking at and what you use it for and as little as you use it for. I say yes, it's that time.

Sorry

 

The two major parasitic drains I've found are 1) Bad alternator, and 2) Starter/relay

You can disconnect one at a time and let it sit overnight and then check it.

 

Time for new batteries it might be but that won't cause a parasitic drain. The only think that I can think of that I haven't checked is down on the starter but I'm thinking that the electricity has to go through the relay on the fender before it gets to the starter. Even when disconnecting the alternator et al I get my needle pegged on the tester. This is not a battery problem, it's either a short somewhere or a stuck relay and I have yet to find where it's at.

 

But if your batteries are not charging then what you think is a PD could actually be a charging issue. Just thinking out loud here.

 

Aaaaa, got that, I have a meter that I stick in the cigarette lighter, it's putting out 13.9V +-

 

Hmm, I was hoping for easy.

 

All fuses are out... in both boxes? Relays too? Make sure they're labeled or you take a picture before moving things around.