# Dead Battery? Dead Alternator? Both? Something else?



## Steve2444 (Sep 28, 2020)

You may have multiple issues, but the fact that the tow truck guy got it to jump right up, to me means the connections are compromised as your battery reading is 12.7v.
However the batt could be bad as well even with 12.7v. Take it out and have it tested, auto parts stores will usually do it free.
Now the terminals may be loose or corroded, he most likely connected to the cables bypassing the battery.


----------



## joed (Mar 13, 2005)

What is the battery voltage when you try to crank it?
If you get it to start what is the voltage at the battery?
How old is the battery. If more than 5 years, change it.


----------



## runagate (6 mo ago)

Lets investigate:

Do you have a short somewhere that is draining battery ?

To test, turn everything off, even the cabin light, unscrew one battery pole, and carefully remove an put back on and look for spark. More scientific, put the multimeter to Amps, and check between removed battery plug and battery.


----------



## runagate (6 mo ago)

Test 2:

Battery charge capacity.

Turn on the lights and try to start.

Do the lights dim all the way ?


----------



## chandler48 (Jun 5, 2017)

After you clean all the connections and are able to start it, what is the reading with a volt meter. It should be somewhere around 14+ volts. If it is, then you possibly have a dead battery. The PO knew it when he sold it to you and had it charged right before you got there.


----------



## Luvapottamus (6 mo ago)

It's the battery.

Your ignition system would have drained it to stalling on a 60 mile drive....had it been the alternator.

That's my humble opinion as a semi-retired air cooled VW monkeywrench.

It's possible the alternator is faulty but the battery definitely is....

If you were driving with headlights on for sure it's just the battery.


----------



## Luvapottamus (6 mo ago)

A little tip...Interstate sells blemished batteries at their warehouses....no label, no warranty..but cheap and it's just a defect un the casting a little scar on one of the terminals and internally the same as an interstate battery.

I judge a car battery by how much it weighs....

The lawn tractor battery I got from them weighs 3x what auto parts stores sell, and it charged up after leaving it dead 2 years....LOL

The way I select a car battery is the heaviest that will fit in the form factor. If a 450cca is recommended, I get the 1100 if it fits...look at all the batteries in the same form factor like group 24...get the most CCA you can afford beyond the minimum.

"Just enough to last the warranty period" is what they market, when you get extra...you barely tap the capacity when you start it so it lasts longer....


----------



## SeniorSitizen (Sep 10, 2012)

i unknowingly load tested a battery with the key fob . i'll xplain . 
the battery tested 12 .4 volts but the key fob wouldn't un- lock the door . just a pizzy click . too bad we can't pull the driving light knob to load test batteries anymore .


----------



## schreibdave (Jun 12, 2016)

Thank you for all the replies. I removed the battery and brought it to Advanced Auto parts. They put their tester on it and it came up "replace battery." So I did. Installed new battery and it started up. Drove it 45 miles, got home, started it multiple times with no problem. Let it sit 3 hrs and went out and restarted it with no problem. 

After my 45 mile drive I put the multimeter on it and got 13.9v while running and 13.2v with motor off. I will restart and read voltage in the morning but hopefully this is the solution.

The battery was almost exactly 5 years old - judging by the date on it.

"To test, turn everything off, even the cabin light, unscrew one battery pole, and carefully remove an put back on and look for spark. More scientific, put the multimeter to Amps, and check between removed battery plug and battery" - Runagate

I was wondering how you would do this. With everything off I should have had zero amps between cable and battery? What if it showed some current? What would the next step have been? I was thinking maybe start pulling fuses until the current disappears? I don't think I need to do this but I am curious.

"Your ignition system would have drained it to stalling on a 60 mile drive....had it been the alternator." - Luvapottamus.

My son reports that when he picked it up it stalled 3x on the way home. Each time it eventually restarted but with some difficulty. Battery light never came on. Is this event consistent with a battery that wont hold a charge?

Thanks for all the replies.


----------



## HotRodx10 (Aug 24, 2017)

schreibdave said:


> My son reports that when he picked it up it stalled 3x on the way home. Each time it eventually restarted but with some difficulty. Battery light never came on. Is this event consistent with a battery that wont hold a charge?


That would be consistent with an alternator with a bad diode (and a bad battery), which will charge a little, but not enough to keep up with the demand . Could it have been the battery? Maybe, but while it's still working ok, I would drive it over to Advance and ask them to test the charging system. The correct voltage doesn't necessarily indicate the alternator is capable of producing the current (amperage) necessary to meet the demand. The tester checks the output amps from the alternator.


----------



## HotRodx10 (Aug 24, 2017)

It's hard to know whether the bad battery overstressed the alternator, or the alternator went bad and drained the battery to the point of damaging it, but fairly often, they need replaced together. A new, fully charged battery will start the vehicle multiple times, and keep it running for quite a while, but if the alternator output is not keeping up, the battery will be toast fairly quickly. BTDT, but at least in my case, the battery was still within the free replacement time.


----------



## Luvapottamus (6 mo ago)

schreibdave said:


> "Your ignition system would have drained it to stalling on a 60 mile drive....had it been the alternator." - Luvapottamus.
> 
> My son reports that when he picked it up it stalled 3x on the way home. Each time it eventually restarted but with some difficulty. Battery light never came on. Is this event consistent with a battery that wont hold a charge?
> 
> Thanks for all the replies.


It;s consistent with a used car that's sat around a lot lately undriven.

Lots of reasons it can stall, son not used to driving a stickshift, or used to driving one that feels a lot different, old borderline or bad gas....but it did restart which implies the battery held a surface charge and the alternator was trying to charge it...

I can think of one car that started and died and would do that over and over and it needed an alternator...but odds are here you just needed a battery. It may end up stalling from time to time now, but it won't be the charging system it'll be fuel....

LOL

Add some heet next fill up...go by the package formula not too much or too little, lok up the tank capacity on the car go by that put it in before you add the gasoline, then top up the tank....

If it has water in it you'll gothrugh s few tanks before it's all out...

But it'll drive better pretty quickly...water doesn't mix with gasoline well, it puddles on the bottom of the tank...pump will suck a blob of it in after hard cornering....

LOL

The heet breaks surface tension helps it mix so you can burn it out.


----------



## FM3 (Aug 12, 2019)

Luvapottamus said:


> A little tip...Interstate sells blemished batteries at their warehouses....no label, no warranty..but cheap and it's just a defect un the casting a little scar on one of the terminals and internally the same as an interstate battery.


Those used to be cheap. Now, maybe not. I checked prices on them not too long ago, and the blemish ones cost more than a new one with full warranty from other places. Was disappointing. They also sell "refurbished" ones or whatever they call them for somewhat cheaper, (still not cheap), but from the evidence I've seen including from people who work there, those are just used batteries they put a tester and fresh charge on.


----------



## schreibdave (Jun 12, 2016)

The car definitely sat for a while before I bought it.

And my son would have been driving it aggressively so if that promotes sucking water from the bottom of the tank, that makes sense.

I will bring it back to Advanced Auto and ask them to test the charging system. How do they do that?


----------



## Steve2444 (Sep 28, 2020)

schreibdave said:


> The car definitely sat for a while before I bought it.
> 
> And my son would have been driving it aggressively so if that promotes sucking water from the bottom of the tank, that makes sense.
> 
> I will bring it back to Advanced Auto and ask them to test the charging system. How do they do that?


In the parking lot with they hood open, they hook up their machine, I believe they have you step on the pedal to increase the rpm at a particular time.


----------



## 660catman (Aug 25, 2019)

schreibdave said:


> Thank you for all the replies. I removed the battery and brought it to Advanced Auto parts. They put their tester on it and it came up "replace battery." So I did. Installed new battery and it started up. Drove it 45 miles, got home, started it multiple times with no problem. Let it sit 3 hrs and went out and restarted it with no problem.
> 
> After my 45 mile drive I put the multimeter on it and got 13.9v while running and 13.2v with motor off. I will restart and read voltage in the morning but hopefully this is the solution.
> 
> ...


Voltage while engine running should be at least 14.2 volts. Reading may fluctuate very little with change in voltage demand. If it drops it’s the alternator. At 13.9 volts you can run it for quite a few miles until battery drains down. My son had this very thing happen to him on a 2000 mile drive back home. His was an 08 Accord V6. Not sure of his exact numbers but car stalled on the highway 1500 miles into the trip and it was completely dead at the side of the road. Alternator light did not come on either. Got it towed, 4 year old battery was toast and alternator was changed. 10 months later it’s still going strong. 
FYI, some GM vehicles have alternators that fluctuate output based on demand. You may see voltages in the 13-16 range while running. 


Retired guy from Southern Manitoba, Canada.


----------



## chandler48 (Jun 5, 2017)

Talk about battery prices !! I haven't bought one in years, but my Kubota ZTR battery died last week. It is a mid sized battery, but I wasn't expecting $144. Gee, they used to be $65.


----------



## FM3 (Aug 12, 2019)

schreibdave said:


> I will bring it back to Advanced Auto and ask them to test the charging system. How do they do that?


If you want to be able to check this kind of stuff any time you want, the $20-ish digital, battery load testers you can now buy are almost as good as the expensive shop kind.


----------



## Luvapottamus (6 mo ago)

FM3 said:


> Those used to be cheap. Now, maybe not. I checked prices on them not too long ago, and the blemish ones cost more than a new one with full warranty from other places. Was disappointing. They also sell "refurbished" ones or whatever they call them for somewhat cheaper, (still not cheap), but from the evidence I've seen including from people who work there, those are just used batteries they put a tester and fresh charge on.


Oh bummer...yeah seems like all my cheapskate tricks are being taken away...thrift stores are getting really bad now too....want more than retail for a used bath towel...and lighting fixtures and other junk are priced high too.

That's hard to quantify, but seems abut double what would be a good deal....

And the habitat for Humanity ReStore.....I think they're now scrapping out the kind f junk I buy....I mentioned to a clerk I was looking for furnace and vent hood blowers, and she said they scrapped some that day, let me climb in the dumpster and look, sure eniugh a bunch of ceiling fans were in there with other seemingly vable electrical, and I fished out a restaurant vent hood...she sold t to me for $10 which was decent but how many garage door openers did they throw away???? 

LOL

I need one, and some track......been looking should I have been checking the scrap bin?

haha...

(vent hood and central heat/air blowers make great fans....I'lll never buy another toastmaster from Walmart...LOL)

Some salvage yards have decent prices on good batteries, kind of depends on the tow truck drivers....in toxic towns the tow truck drivers steal all the batteries and stereos when they haul them to the yard from the auction, and the yard owners tend to put up with it....

But well managed yards have decent used car batteries....


----------



## raylo32 (Nov 25, 2006)

I recently got one of those. Easy peasy to use. As for accuracy, I dunno yet. Used it on my 8 year old AGM which tested good... and the vehicle still starts fine. I wanted to test it before fall and winter rolls around since it is old and these tools are cheap. Should be a good thing to have around.



FM3 said:


> If you want to be able to check this kind of stuff any time you want, the $20-ish digital, battery load testers you can now buy are almost as good as the expensive shop kind.


----------



## Glassit (Jan 30, 2016)

schreibdave said:


> The car definitely sat for a while before I bought it.
> 
> And my son would have been driving it aggressively so if that promotes sucking water from the bottom of the tank, that makes sense.
> 
> I will bring it back to Advanced Auto and ask them to test the charging system. How do they do that?


They don't. They can test the alternator/regulator but that won't tell you if you have a loose or corroded ground, and all these testers at a parts store or service truck are calibrated to sell products - that's their business. I've seen "bad batteries" according to AAA go for another year until we sold the car. And who knows how long after that. 

Hopefully you have basic wrenches or sockets, just pull off a few superficial things and trace the wires coming off the battery to the body and engine grounds, and starter if possible. Bad grounds are a very common source of trouble. Just fixed an intermittent start issue on one of mine by a bolt that worked loose. You can rejuvenate old batteries by desulfating them, pulse method is easy, overcharge method using an old style manual charger is more effective (but only works on wet/flooded batteries)


----------



## FrillyLily (Jun 4, 2012)

I had a honda van do this, dead in the driveway and then charge it and it'd start, then it wouldn't, tested the battery was okay. ect. This frustration went on for months, and cost alot in tow bills before I posted on an online forum about it and someone suggested it as something running and draining the battery. Turns out it was the fuse that runs the clock. But when we pulled that out (I lost door locks-had to do it manually then and some other inconvenient things) it fixed the issue. We didn't bother really fixing it cause the van had 260k at that point and we were fixing to trade it out. I was so irritated how all that time we wasted and money only to find it be that, and still never understood myself how it could cause those issues but apparently it was malfunctioning. 

We also bought a brand new battery once for my husbands truck and had issues, and returned it after it tested bad. So that can happen.


----------



## Langer1 (Aug 24, 2021)

No matter what the outcome, the first is clean all the battery connections, no tests will be accurate until you do.


----------



## jayhanig (Feb 1, 2019)

runagate said:


> Lets investigate:
> 
> Do you have a short somewhere that is draining battery ?
> 
> To test, turn everything off, even the cabin light, unscrew one battery pole, and carefully remove an put back on and look for spark. More scientific, put the multimeter to Amps, and check between removed battery plug and battery.


Don't forget to pull the bulbs under the hood and in the trunk and glove box, if the car has them. Sneaky little bastards.


----------

