qmikep

Looking for some help with an electrical issue.

I have a 92 w250, that keeps killing batteries. I am gettin about 1 year out of a battery and cannot figure out why.

I figured simple enough I have a parasitic drain I need to find. So I warrantied the last failed battery and put the new one in, I went ahead and made sure all the doors were closed and the key was off, pulled the negative cable off the batter and put a multimeter between the negative battery cable and the negative post on the battery . The meter didn't register any current, I adjusted it from the max setting of 10A to its lowest 200 micro amps , didn't matter, still didn't register anything.

The truck is a 92 and has not had an external voltage regulator installed. While running is seems to be charging at ~14.0v. I've been using a caterpillar group 31 with 1000 cca fwiw.

Anyone have any insight as to why this is killing battery so fast and what else to do to trouble shoot this?

Thanks

nonrev

Fwiw I usually just use a test light, unhook the ground from the battery, hook the test light from the cable to the battery and if it lights up I pull fuses until it goes out ,, make sure you pull your dome light bulb and the first fuse you pull should be for the radio.

NJTman

What are you doing to diagnose the "killing" of the battery ? Are you testing the individual cells with a hydrometer, or assuming the battery is no good and turning it back in? What are you doing to confirm the "dead battery" diagnosis ?

My 92 has consistently charged any battery it has at 13.8 volts give or take. The PCM took over the external regulators in our trucks, vs the older vehicles with the regulator on the wall, so I'm not sure why you've even mentioned the external VR route.

Most of our vehicles have a parasitic draw of one sorts or another. The battery usually doesn't have much of a problem dealing with it. The truck's radio is usually #1 suspect, and simply doing what Vernon (nonrev) said, by disconnecting the negative cable, putting a test lamp between the cable end, and terminal, observing the test lamp being lit, and systematically removing individual fuses, until you find the circuit that's causing the drain. Most likely, the stereo in the truck, unless you have some other device that's the issue.

Are you running clean grounds ? These trucks are notorious for poor ground connections. They should be disconnected, cleaned and replaced once a year (which is what I do), using a bit of dielectric grease at each connection. I also have followed the profound knowledge of Mr. Jim (electric Guru) Lane, and installed extra grounds from the alternator to battery (-), from battery (-) to engine block, and from engine block to frame / body. My alternator, again, is consistent at 13.8 v., leaving my parasitic drain to not cause much effect on the battery at all.

I find it difficult to believe that your truck is "killing" your batteries. Unless the cells are being opened up and contaminated, or you're witnessing significant "boil out" of the cell caps caused by overcharging, your truck may be intermittently not charging while driving, then the parasitic drain finishes it off when you park it.

Try using a professional battery charger (not the truck's alternator) on the battery, testing each cell for variance, and if found good, put a load tester on the battery to see if it's discharging too quickly. If the fully charged battery turns out to be good, clean and add grounds to your ride, and if that doesn't work, a new alternator might be in your future.

qmikep

Ok, I'll try to explain a bit better and dd some more info.

The battery will not even turn , get a tick tick tick from the starter. I attempted to jump the battery and it still wouldn't turn. I took the battery out of the truck and put it on a charger, after it said it was good and fully charged I reinstalled the battery and it still won't crank the truck. I then put it back on the charger, charged it again, reinstalled it in the truck attached the battery leads and measured voltage which appeared to be good(~12.5 don't have the voltage reading as I did not right it down. I then had a helper try and start the truck and measured the voltage while doing so, I hear a tick tick tick tick and itt dropped from ~12.5 to near 0 no crank. Took the battery back to Cat they tested it and gave me a new one all they told me was " it was low". Put the new battery in the truck and it fired right up no hesitation.( this has happened twice over the last 2 years, at least I got my use out of the warranty)

I realize the PCM controls voltage regulation in the later (91.5+) trucks. However since participation on most forums has seamed to stop, I decided to post to a facebook group. If you are not familiar people seam to be unwilling or unable to actually read what is written, so I figured it prudent to add that I had not bypassed the stock system with an external regulator.

I did what nonrev said but with a multi meter.This is how I have found parasitic drains in other vehicles. I even opened a door to double check the meter was working properly, (it was ,with the dome light lit current registered on the meter.) Perhaps I am wrong but its seams to me if a test light would light, I'm pretty sure that's enough current that a multi meter with a range of 10A to 200 micro amps would register a draw too.

You mention the radio, I will say that for a moment (sub 1 second) that when I touch the leads from the negative post to the negative cable it does register some amps then drops to zero immediately. I also hear a "whirring" sound from the radio. I presumed this is the radios memory for the clock. It is not constant though just the immediately after you connect the negative battery cable to the ground or when you bridge the gap with the leads from the meter. Im not sure if there is some spec for the current draw for the radios memory? And as you said I figure with as tiny as that is the system should be more than up to handling it.

On top of this if the truck is going to sit for any about of time I always disconnect the battery and bring it in the garage.

Only thing I can think of is the drain is intermittent, and not sure how I'm gonna find that.

My alternator is 1 year old, I just rebuilt the starter last year . My battery cables are both brand new and have good crimped lugs. My grounds are clean I just finished a complete reseal on the entire engine, and stripped and painted the engine frame and transmission everything went to bare metal all rust removed. (not trying to toot my horn , just saying I don't have the oil ,dirt covered mess that a lot of these trucks got going on in the undercarriage/engine compartment.)

Additional grounds (per Jim lanes write up) to the truck and deleting the fusable links is on the to do list. However, I want to get this battery situation figured out before I do any modifications to the stock electrical system.

NJTman

Good,

I would still do the ground additions, as technically you're not modifying anything. You're just adding clean, New, additional grounds.

I would also purchase a hydrometer, and consider buying a different brand battery if any of the cells turn out to be bad.

BHD

It could just be a bad batch of batteries. My truck would eat a DieHard, every 18 months or so. I switched to a Deka 31 series and haven't had an issue.

I doubt that Cat makes their own batteries, maybe try a different product line.

I think your diagnoses are solid and that you do not have a parasitic drain. But, all of these trucks are old enough to drink, and old electronics do silly things from time to time. Keep us posted on here.

nonrev

I think T-man and BHD are on the money here as a parasitic drain should only ruin the battery if you left sit it all winter and the battery froze.

Angry Johnny

Sounds like crappy batteries to me, the truck isn't doing it in my opinion. If you charge a battery and it still won't turn the engine then the battery is bad. We go through a lot of batteries at work. One of the worst things to do is let them sit and discharge. A battery tender may help your situation.