Battery or Truck problem? Troubleshooting suggestions welcome

Holy crap this turned into a long post.

TLDR: plow truck battery keeps dying. Replaced alternator & battery cables. Auto parts store says battery is fine. A week later trickle charger says possible battery short.

Troubleshooting suggestions? Do I take the battery back for another look?


I have a 1990 F-250 (8 Cylinder 7.5L) truck that I use to plow my driveway here in the mountains of Colorado, originally bought from someone local a few years ago. It’s not in amazing shape
(The color is really more on the “rust” side than “gray”), but for the first year or two it did the job.

But then I started to have issues with the battery losing power, and the truck not starting (or dying when I raise the plow).

Some History
Two years ago I put a new battery in (AutoCraft Gold, 850 CCA @ 0degress, 1000 CCA @ 32degress), which seemed to help for awhile. Later on I had issues with the battery losing power while using the plow, and the battery seeming to not recharge when I stepped on the gas, which led me to replace the alternator (from NAPA, the “exact fit” for my vehicle, rated at 100A). Seemed to perform well after this. I also replaced the negative battery cable at that time due to some corrosion.

But, I still had an occasional low battery after not using the truck for a month. Unsure of where the drain was coming from (and getting tired of disconnecting and reconnecting the battery every time), I attached a trickle charger (NOCO Genius 2D). All was good again.

Fast forward to two weeks ago
After a snowstorm, the truck struggled to start, then died when I attempted to raise the plow. Not enough juice left to crank the engine. Trickle charter reported it was still charging. Brought the battery inside and connected to a full charger, which oscillated between telling me that battery was 100% and 50% charged every few seconds.

This seemed odd, so I took the battery into an auto parts store, who tested the battery and said it was “all good”. Unsure of what to do next, I replaced the positive battery cable (which was also a bit corroded). Truck started without issue.
The next morning, it was dead again. Enough power for the dome light to come on, and to groan at me a bit when I tried to start the engine, but that was it.

I disconnected the plow electrical connector, wondering if something in that could be causing the drain, and let the trickle charger keep working on it.

The next morning, truck fired right up. Plow raised without any issue at all.

This lead me to think there’s something in the plow that’s draining the battery when I leave it connected. So I left it disconnected, and left the trickle charger attached to the battery for good luck.

Another snowstorm! Plow has been disconnected for the past two weeks, but the battery is dead again. Truck doesn’t have enough juice to even crank (again, dome light and little groaning when I try to start it). However, THIS time the trickle charger is giving me an error code: “Possible Battery Short”

I’m at a bit of a loss about what to do next. If there’s really a problem with the battery, will the auto parts store even be able to see it? Two weeks ago one of the stores said the battery was fine, so if there is a “short” (in the battery?), can they detect it?. Other suggestions about what to check?

Also starting to feel like I’m getting close to the point of stopping to invest $$ to fix this vehicle, so that’s something on my mind as well.

The BEST Way TO Perform a Parasitic Draw Test - YouTube

So by your own admission, there is a parasitic draw, and your “solution” was to connect a trickle charger while leaving the battery installed and connected to the truck? While newer vehicles may have computer modules which draw high enough standby current to discharge the battery over time, this type of problem in a 1980’s/1990’s/early 2000’s model is most likely a nicked/damaged/deteriorated wire leaking to ground somewhere. A trickle charger is not the solution for that.

If you are truly unable to diagnose this properly, I would skip the trickle charger, and instead install a battery terminal with integrated disconnect switch. This will prevent the battery from being drained while the truck is not in use.


Completing a parasitic drain test is not that difficult. I would recommend trying to complete this test, if you own a multimeter. I also like the above idea by using a switch. I would recommend buying an RV disconnect. Very simple to use, 2 seconds to disconnect power and reconnect.

Seems like the battery isn’t charging, or the engine isn’t run long enough to let it charge.

Then something is drawing current when it is off.

Measure the battery Voltage with a multimeter first to answer all these questions. Check for Voltage when it is running to make sure it is charging the battery.

Does this truck in fact have 2 batteries?

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