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Truck Battery Runs Down When Parked

toxcrusadr

toxcrusadr

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Starting to think my vehicle has a tiny slow current drain somewhere, anyone dealt with this before?

I thought my battery was going bad this winter - bought Dec 2010 but it's at least a 60 or 72 month battery, Interstate (not cheap) and my last one went 7 years. '95 4WD Ford Ranger that usually sits days between uses, sometimes longer. Began having trouble starting it after days of non use last fall. Since batteries go bad when it gets cold, I expected it to get worse, but it hasn't. I charge it and start up the truck and run it, it's fine - until it sits for a long time. Happened again last week when I was gone for a whole week. Totally dead. Jump started it, and when I got where I was going, I put a 10A charger w/ a meter on it and it said about 50% charged. After a couple hours it was close to 90% on the meter.

The only thing I can correlate this to is how long it sits between uses, and since it isn't getting worse and will hold a charge, it does not seem to be the battery itself.

Could it have a small current drain that eventually runs it down? Haven't put an amp meter on it yet, thought I might try that. I do have trouble with the door switches - sometimes the dome light does not go off, but the truck knows and shuts it off after a couple mins after I drive away. Think maybe it comes on randomly when parked? I never notice it in the dark but it would not be visible in daylight just walking by unless you looked. Actually the Ranger has all kinds of bad switches - door lock switch doesn't work on one side, cruise control quit, radio power switch doesn't work, etc. My only complaint about it - I love this truck.

Any thoughts?
 
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No such thing as turning it all off anymore. I'd suspect either the radio or security system if you have one. Then again, four years ain't all that bad for anything but the best of batteries anymore.

PS ... love them little toy trucks! I'll show you mine, you show me yours!

93ranger-topper-done.jpg


Dang tailgater! BACK OFF! I'm peddling as fast as I can!! <G>

PS ... you also need a bunch more cranking amps in cold weather. If it starts easier and more consistently after the weather warms up, it's definitely the battery. First thing to check is the cable connections are clean (both ends), and next a deep cycle test at the local auto parts.
 
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Five years on a battery is pushing it, doesn't really matter what the warranty is, that just costs you extra, it really hasn't got much to do with the quality of the battery.

Most newer vehicles have some parsitic drain on the battery, you can hook a Digital meter up in series with the battery to monitor it, should be well under 100 mA in most cases.

Best thing to do is have the battery load tested to see how much it's really capable of, it should be good for 300 amps without dropping below 9.6 volts or so, depending on the amp rating of the battery itself of course.
1/2 the cold cranking amps is the usual test load.
 
What Eric said.

First, measure the current drain and go from there. Find your fuse panel(s) and start pulling fuses until you find the big draw, if any. That will kinda narrow it down.

Or, just get a new battery. :) Charge it up after it's installed as there's no telling how long the battery has been sitting around.



Murray
 
I know that modern highly electronicized (and very expensive) automobiles need to be run (and/or have batteries recharged) quite frequently, or all of the vampire electronics (more like zombie electronics) will suck the battery's life out of it.

Plus, as (also) already said, wintertime is hard on batteries, 'specially aging ones.

My little Toyota Taco is just about at the point of needing a new one, in fact...
 
skippy_ps said:
What Eric said.

First, measure the current drain and go from there. Find your fuse panel(s) and start pulling fuses until you find the big draw, if any. That will kinda narrow it down.

Murray
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I did this on an old beater Camry years ago, after I found the big draw (something in the fuel injection circuit) I rewired the fuse with a switch after the fuse . when you start it you have to turn on the switch and leave it on while driving, turn it off when parked.
but you should probably just get a battery.
 
Modern cars have become extremely battery-dependent. Four years is the point when many start fading in the stretch. Batteries don`t like to remain in a state of discharge for very long....it effects their ability to take & hold a charge for any significant period of time.
Something like a Battery Tender Plus is a good thing to use on a car that sees infrequent use.
There are a few good DIY videos on Youtube which walk you through the process of checking for parasitic electrical drains in your car....check `em out.
 
I replaced the 14 year old Optima red top in my '93 GMC K1500 4x4 last fall not because it was failing but because I left my key on for 4 days and was sure that would kill it. I think I got my $$$ worth out of it. I replaced it with the same but the new ones are Henco In Mexico so I doubt it will last as long.

I usually put a trickle charger on my batteries over night a couple times a year to make sure they have a good charge.

To find your parasitic draw....Disconnect the ground from the battery. Wire a small 12 volt bulb(like a tail light bulb) between the ground cable and ground post. The bulb should go bright for only a moment, then should go out if all is well.
If it stays bright, go to the fuse panel and remove and replace one fuse at a time until you see the bulb go dim. When you see the bulb go out, you will have identified what circuit is drawing down the battery. Then you just have to find what on that circuit is causing your problem. Very easy and quick.

The last time I had a problem like this, it drove me crazy for a couple months. Turned out to be a glove box light. An ice scraper was interfering with the switch and the bulb stayed on constantly.

Good luck.
 
jbrainey said:
I replaced the 14 year old Optima red top in my '93 GMC K1500 4x4 last fall not because it was failing but because I left my key on for 4 days and was sure that would kill it. I think I got my $$$ worth out of it. I replaced it with the same but the new ones are Henco In Mexico so I doubt it will last as long.

Good luck.
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Nope, won't last as long. I bought Optima's for my off-road trucks (read: abuse) for years and had great luck. Loved them.

I think Johnson bought them, moved them to Mexico and I had a string of bad ones. 6 months to a couple of years, that's all.

I stopped buying them and just get generic deep-cycle gels now. Oh well.
 
When I read the title I thought 'Ford'. When I read the ad, bingo.

My primary advice would be: turn off everything, park it, disconnect the battery and put in an ammeter that can take 10 amps. wait. come out in the morning and read (an old swing needle meter works best)

The diode pack in those year alternators fail such that they allow a reverse current leak that can hit 5 amps (or sometimes more) it starts small, they heat, it gets larger.

Seen it many many a time over the last few decades. otherwise, the constant power for the radio and EECIV will tally around 100ma or so

now if it were GM TBI Id say look at the oil pressure sender (long story but seriously)
 
Here in the desert, about 3 years is max for an under the hood battery. Walmart = quick exchange for a couple of twenty dollar bills.

Murray
 
AHA, a Ford-specific problem may be the cause. I'll look into it.

I still think the battery is not crapping out, it got no worse all winter as I expected it to. I've seen plenty of them die and this one did not follow the progression of that disease. I still think it's a parasitic current somewhere. If it's not the alternator I'll find it by checking current draw at the fuses.

Did I mention this is a '95 and does not have all those fancy electronics?

Thanks jbrainey and quaddriver. Raspberries to everyone with poor reading comprehension. :lmao:
 
sKiZo: Nice truck, mine's forest green, extended cab, no cap. I don't have a pic on me but I'll try to find one later. 4.0L V6 - the 'biggest small truck' I could find. Hauled a lot of stuff with it and it's held up pretty well.
 
It is the alternator. I have run into just this issue with both Ford Windstar company vans that I owned. I replaced both alternator and battery after about the third time this happened. When one gets weak, it takes the other out unless you catch it early in failure.
 
Dennis Gardner said:
It is the alternator. I have run into just this issue with both Ford Windstar company vans that I owned. I replaced both alternator and battery after about the third time this happened. When one gets weak, it takes the other out unless you catch it early in failure.
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Many newer cars have the voltage regulator built inside the alternator. It`s often the regulator that goes bad, and you can save a good amount of money by just replacing that, rather than the entire alternator....
 
The way jbrainey states with the 12V test light in between the ground cable and ground post, is how I start with a battery draw, or being suspect of one. In other words remove the neg cable and put test light in the path. Make sure there are not any doors open (dome light on) and/or pull the bulb out of the underhood light if there is one. If the test light lights up, there is a draw. Also do a quick check of obvious things like a glovebox light that could be sticking.
 
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