1995 F150 302 auto 2WD battery died again. (vehicle, idle, motorcycles, tire)

[vmaxnc]

Had the truck 4 years, then whatever battery was in it died. Someone gave me a Walmart gift card, and there's one close so I picked up their best. 3 year exchange, group 65, 850 CCA. Worked perfectly for two years. The truck could sit for month, and start instantly any time I drove it. Then the battery starts dying after a couple weeks, then overnight. Trickle charged it, and it would always start after that and the subsequent drive. Next day, almost dead. WM swapped it out, saying it had a dead cell. All is good.

Fast forward two years, exact same problem.
Worked perfectly regardless of how long the truck sat, now suddenly it won't stay charged overnight. Just got back from WM, they say it has a dead cell, gave me a new battery.

Is there anything on the truck that could be causing this? Or are these just crappy batteries?

[sunsprit]

You need to check out the alternator for output (which recharges the battery when driving) and for a defective diode (or two or more).

It's entirely possible that the alternator is putting out an adequate charge voltage/current with a defective diode, but you'll have a residual draw upon the battery which is slowly running it down while the truck is parked. Additionally, the bad diode can be causing the batteries to fail due to the A/C component in the charging cycle.

A simple charge test for output will not always reveal a bad diode, so you must have the alternator specifically tested for this. Some shops will have a tester for this, some don't ... I always used an old oscilloscope on the alternator output to see what it was putting out.

[curly5759]

I have a lot of experience with Wal-Mart batteries. As a former Automotive teacher, I had to buy batteries for the school cars (13) and the run- up engines (5). I used Walmart batteries because they were cheap and that helped on the budget end of things, and because Walmart was pretty good about the exchange of defective batteries.

That said, I got about 2 years average on each battery. We abused them pretty hard, constant cranking for starter tests, compression tests, etc, and I kept them on trickle chargers. I got tired of the constant exchange of Batteries and switched to Napa batteries.

They were better, averaging about 3 years or so on 5 year batteries. Of course, they cost more, but Napa would pick up and deliver so that made it worth it to me.

I use Walmart batteries in my own personal cars, and I am getting about 3 years on them. I don't consider that too bad because the Heat down here is hard on batteries. I don't think I have ever had a battery last more than 4 years tops since I started driving. (1973)


Curly

[sunsprit]

Curly's experience with WM batteries is quite different than mine ... and the service cycle of a lot of charge/discharge cycles in the school environment is not typical of private use in a car.

I use WM batteries in our fleet of motor vehicles, everything from my diesel pick-up trucks to diesel cars to our gasoline cars to our older gasoline farm tractors to our riding lawnmowers to my motorcycles ... and typically get 5-8 years service life out of these in every application. It's not uncommon for the batteries to far outlive their pro-rated warranty life. With so many vehicles, it's typical for us that many of them sit during the winter months and aren't even started, so they may have long intervals between starting cycles ... and I haven't seen failures in these batteries.

I've even got a IHC Super A with magneto ignition that doesn't have a generator on it, and the battery gets charged up once or twice a season, as needed, for the starting chore of the motor. That's a pretty severe charge/discharge cycle, and the batteries have each lasted at least 6 years in this application.

Obviously, our climate here in SE Wyoming is a much colder operating environment than the heat of the desert ... but I've been highly satisfied with the WM batteries for a long time.

[Egobop]

Letting the truck sit for long periods can be part of your problem. You should at least start it and let it run for a few minutes at least once each week. It is hard to say without looking at the vehicle, but the fact that it will sometimes start after sitting for a month tells me that a short is highly unlikely. I do not know what kind/quality of battery charger you own but there are some battery chargers that will allow the battery to be over charged. This can kill the battery as well.

[sunsprit]

Originally Posted by Egobop

Letting the truck sit for long periods can be part of your problem. You should at least start it and let it run for a few minutes at least once each week. It is hard to say without looking at the vehicle, but the fact that it will sometimes start after sitting for a month tells me that a short is highly unlikely. I do not know what kind/quality of battery charger you own but there are some battery chargers that will allow the battery to be over charged. This can kill the battery as well.

Sorry, but this is some of the worst advice you can give to a vehicle owner ....

1) Start and run for a few minutes at least once a week is a great way to create more moisture and acids in the oil/engine than it solves. All you've done is heat up the coolant a little bit, and the metal of the motor ... so it can cool down and condense moisture inside. If you're going to run the motor, run it at least long enough to get the motor up to operating temperature and keep it there for 30 minutes or so, to drive out the moisture. BTW, normal operating temperature is not when the water temp reaches normal temp, but when the OIL reaches normal temp. If you don't have an oil temp gauge, then it's better to figure on at least 30-45 minutes of driving the car to achieve the moisture removal. Idling it, even at a fast idle, for awhile ... won't do the moisture removal.

2) You don't apparently understand low amperage draws ... as opposed to a direct high amperage "short" which can discharge a battery very quickly. A small portion of an amp draw, such as one might encounter with a bad diode, or a clock and some parasitic electronics draw (think aftermarket radio system), can drain a battery slowly ... over a period of weeks. An amperage draw is an amperage draw is an amperage draw, which drains a limited power source down in time.

3) Yes, you can overcharge a battery with certain battery chargers. But typically, these are larger shop rapid chargers as opposed to the small units (under 10 amps) that are sold to the retail consumer. If this was the case, then it's not the battery's fault for the failure, however. That's customer abuse.

[Wilson513]

Usually this is caused by a small electrical short. The insulation on a wire becomes worn and it short out. Not enough current to start smoking or light up the alternator light, but enough to kill the battery. The crappiest battery will keep its charge, not matter how weak, over a good amount of time. So you need to stop worrying about the battery and start looking for the real cause. Want to test this? Charge the battery, then disconnect the positive terminal battery cable and let her sit for a couple of days and hook the cable back up and see if it starts.

This is particularly common on pickup trucks because the shake around so much that the wires running through the body get worn after 15 years.

I've had this show up in trailer wiring, inside courtesy lights, even on a makeup mirror in my K2500 Burb.

[M3 Mitch]

Or take the battery terminal off (either one will work) and put a test light between terminal and cable. Light on = current is being drawn somewhere. If the light is not on, you can try an ammeter, best of all would be to use a clamp-around type on the test lamp or for that matter if you have a good clamp-around you don't need to take the clamp off the terminal, just clamp around either battery cable and read the current draw with the truck turned off.

A first step towards troubleshooting would be to pull (and then replace) each fuse in the fuse box one at a time. When the light goes out, (or ammeter reads "0") this is the circuit with the problem.

Depending on what that circuit is, removing the fuse can be a temporary repair as well.

Slightly off topic but only slightly - a new battery really should be "initialized" by charging it fully before it's put in service. Tire store nitwits will of course deny this, claiming what they sell you is "ready to go" and of course the battery *will* start your car as it comes off the shelf, but depending on how long it's been sitting on that shelf it's probably at about 80% of a full charge. You can initialize manually by charging and measuring electrolyte density, but that's certainly the hard way. Any decent "smart" charger will do the job for you.

Battery Tender is my personal favorite, you can get a plug to go in the cig. lighter socket and "backfeed" to charge the battery, avoiding the need to leave your hood open or unlatched. If you put the charger box in the driver's seat you will have to work at it to drive up while still plugged in.

This, too, can be a temporary work-around for the OP's truck, the BT will make up for drains and keep the battery fully charged, provided the drains are less than an amp or so.

Sunsprit as usual makes a good point about the diodes in your alternator sometimes going out and allowing the battery to discharge. Sometimes if this is happening you can just barely see the alternator warning light glowing faintly if you put the car in a very dark place, engine off. Knucklehead jump starting techniques (particularly using more than 12 volts to "geterdun") will fubar these diodes in some vehicles.