A QUESTION FOR AUTO MECHANICS! Battery keeps going dead, over time, repeatedly.

Master here. Reman alt is the issue. Your welcome

Hmm

ehhh I wouldn't count on that.

If it typically conks out while running you probably have a bad ground or bad alternator or bad voltage regulator.

If it dies while parked overnight you likely have a high impedence short somewhere or a shorted component or a bad battery. Test this with an ammeter (multimeter) in series to see how many mA you are drawing as it sits. Remember that a lead acid battery can't be drained fully more than a couple times or it is pretty much toast! You have to figure out where that amperage is leaking to overnight or you will just be buying battery after battery.

you need to drive at the very minimum once every 2 weeks. For around 15 minutes. The radio flicker shouldn't happen though....

If you park it for more than 2 weeks, take the ground cable off, like someone already said.

Maybe missed it but "over time" wasn't specified?

Batteries lose charge. Even faster in hot climates. That's why trickle chargers exist.

Could die during driving if alternator can't charge the dead battery enough?

Just my two bits, if, north of Portland, Oregon ( whatever Latitude line that is ) you know towards Canada, towards colder climates, yes your battery will get weak in a month, two months or more well,,, just get a trickle charger [1 amp, never hit battery with 100000000000amp booster, yes I exaggerated , booster is hell on a battery, shortens life] and leave it hooked up over the weekend,,, OR put it on Wednesday and try to start it on Saturday when you have the time. Again , this is if you live in cold climate Northern regions otherwise it could be voltage regulator on alternator < today most are junk.

No reply necessary.

Let us know, maybe it was a short in wiring harness, doubtful, once was soaked three times by "electrical specialists" (that did not find problem)
and later I got lucky and found the short myself after three or four weekends.

Again no reply necessary I'm on toy carnival phone toy.

Update: As others have said, pull ground cable, esp!!! if you won't be firing it up every week, and yes it very well could be loose connection on the positive or DIRTY, shine it up good, get those felt , the felt works keeping posts clean.

Last Edited by HOLY CRAP what a forum. on 10/13/2021 01:17 AM

I hate trickle chargers. You want the charge rate to be sufficient to produce bubbles in the electrolyte and hence provide some mixing action.

Trickle chargers are not good. Get a 10 amp or so smart charger that cycles on and off as needed if you want a battery charger/maintainer.

Got same problem on an old motor. Just fit a cutout switch to isolate the battery when you park it up. Cheap and simple solution.

Someone left an OCD2 reader in mine and that was killing the battery over time.

For a spare car or RV a cut off switch is a good idea.
A good sulfanating trickle charger is a blessing for a boat, RV, motorcycle, or spare car battery.

To find the vampire circuit you put an miliamp meter, make sure everything is off,between the ground cable and the negative terminal of the battery. If you get over 8 miliamps start pulling fuses one at a time and when it goes to zero that is the vampire circuit.

My favorite vampire was the light on the makeup mirror built into the visor.

Awesome. But then I bought two remanufactured alternators that BOTH failed in this same way.

Not a problem! I was an ICAR and ASE certified mechanic at Greyson BMW Chevy in Knoxville for nearly 20 years.
With out being there to check it out I can't say for certain what is wrong with it, but I can point you in a few likely directions.
Hope you get it fixed.

By the way, all you auto mechanics,...if your work fires you for not taking the COVID kill shot, then just start your own small business. There are a lot of used cars out there needing fixing due to the COVID complications.

You could make a living just off Craigslist ads, fixing cars.

you have whats called a parasitic draw on the battery possibly somewhere...

bump for later.

I just learned that term tonight! And I'm an industrial electrican. It's a cool term.

I wouldn't find it unusual to get a run of bad alternators. Bad diodes in the alternator will drain the battery.

I had a string of bad alternators, 30 days and they would lock up and smoke the belt. I quit using that company.

The consumer is their quality control.

Good advice on checking for draw and pulling fuses.

it's amazing how smart this place is capable of being when it wants to.

Learned a lot in this thread.

Have to add....

Just because a part is new, doesn't automatically mean it's good.

Took me ten years to begin troubleshooting by testing any new parts. Happens very often, because the consumer is quality control.

Alternators, ignition modules, starters, relays, even spark plug wires. The idea of replacing parts as preventative maintenance is now a roll of the dice.

Is there a coil?

+1. This thread turned into something way bigger than I thought it would.

Clean yer grounds

Starter, the internal motor windings of the starter break down over time and will draw the battery down.

hmm

There truly are MANY things that could be causing this problem!

Try rubbing some mayonnaise on the battery and let it sit over night.

If that does not work, buy a hamster and have him run on the alternator wheel.... that should do the trick!

I had this problem happen to me in the past, I had to buy a new, not a refurb alt to fix it. its worth a try, albeit can be expensive. it can also be some some short, try adjusting the dimmer switch for the dashboard lights if your car has that

A couple things.

1. Pull the 3 wire plug from the back of the alternator and with the key on check all three pins for voltage. Looking at the schematic there should be roughly 12v on all three.

2. Check the drive belt. Serpentine (multi groove) belts are a series of tiny V belts with one cavet: When they wear, they loose traction as the V's no longer grip from the sides and the belt simply slides over the pulley rib tops. The belt may look ok, and feel tight but lacks the traction to turn the component adequately.

3. Fuses. Check/test them all.

4. Battery terminal connectors. Clean them religiously. Replace them if they're in question. The aftermarket universal ones with the pinch bar are horrid and best used in emergencies only. Measure the lengths and get some new cables and battery terminal connectors with a stud and nut. Make sure the ground is clean and secure at the engine/chassis.

Find the fuse for the radio. Pull it. See if problem goes away.

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Sounds like you have a parasitic draw on the system or are Not using it enough to keep the battery charged.

Does the car have an alarm system?

can you install a Battery Maintenance Charger on it.

A lot of cars with Computers will drain the Battery when Not Used for weeks.



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