# Dead Battery or Alternator? Cold Weather



## wrbrb (Aug 18, 2020)

2002 CRV, battery is a few years old. The vehicle was sitting outside for a couple nights in freezing weather, when I went to start it the engine cranked slowly but there wasn't enough power to get it to start. Someone with a portable battery charger gave me enough charge to get it started again. I have since started it a couple times and made trips of around 30 minutes total with no problem. We had another fairly cold day and it cranked slowly but did start on the second try. Now today, after having not driven it for a few days again, it cranked very slowly and didn't start, battery is dead again.

Is this definitely a dead/dying battery, considering that after a jump I was able to make a few trips different places without a problem? Or could it be the alternator?

I could jump start it and drive it to AutoZone so they could check the battery and alternator, or remove the battery and take that to them for testing. Or if there's a way to test the battery with a multimeter I could do that, but I don't have any charging or testing system. What should I do?


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## wrbrb (Aug 18, 2020)

I actually just found that the battery has a 9/17 sticker on it, so I assume that is the problem. Four and a half years old.


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## SW Dweller (Jan 6, 2021)

I live in a hot climate, eats batteries. I get my batteries at COSTCO. The two year warranty works out well for me. About the time the battery gets weak I get a new one. Usually for free.
Occasionally I have to pay <$30.00 because of the time since purchase.
You were fortunate with a 4 year old battery


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## BillyMac59 (Oct 19, 2021)

A good way to determine battery or alternator is this. Once you have the dead battery boosted and the car running, turn on all the electric loads - heat/AC/lights - the works. If the battery slowly dies, your alternator is questionable at best. (By having boosted it, you've proven it will take a charge.) If this drain doesn't shut you down, look for a new battery. Or, quicker and easier, look for the "installed date" sticker. Three years for a battery is not a bad deal....


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## joed (Mar 13, 2005)

The battery is five years old. Most likely the problem is the battery age.
If you want to check the alternator, measure the voltage on the battery when the car is running. If it is 13.5-14 volts the alternator is working fine.


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## pumpkin11 (Oct 31, 2020)

it is simple to test,

test the DC voltage at the battery terminals with the engine running,

it should read 13-15 volts,

if it does, your alternator is fine,

a portable multimeter/voltmeter is cheap

**** edit....didn't see post above


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## Nealtw (Jun 22, 2017)

The alternator needs power to make power, take the lead off the battery if the engine doesn't die the alternator is making power for itself and the engine.


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## FM3 (Aug 12, 2019)

Nealtw said:


> The alternator needs power to make power, take the lead off the battery if the engine doesn't die the alternator is making power for itself and the engine.


Don't do that. Newer cars especially can be very touchy with their electronics, and that can create a voltage spike and potential damage.

Voltmeter as mentioned can somewhat show battery condition. Full is about 12.7v. If a car battery is down around 12.0 or 12.2v, that's already quite low. Car on as mentioned should read 13.x if the alternator is starting to go out, ideally, 14.x - 14.4v. Some cars will charge 15+ for a certain amount of time.

If a battery is charged and reads up around 12.6, 12.7 but the next day drops a lot, it's a bad battery. Bad battery might be saved by adding distilled water. I can't remember any battery of mine that didn't last at least 5 years, but I'm in the north, and hotter climates wear batteries faster. And batteries die sooner if they've been allowed to discharge too much in the past.

The $20-ish battery load testers are really great to tell the condition of a battery, since voltage alone on a voltmeter only tells so much.

Starting the vehicle multiple times but only driving 30 minutes total is probably barely enough time to even recharge the power it took to start the vehicle those multiple times. Drive it more or get a solar powered battery charger or something to help it out. 

Ideally, connect a trickle/float charger to charge the battery slowly for 8 or however many hours it takes and then keep an eye on the battery after that. Though at 4.5 years old and having doubts about this one, may as well not mess around and just replace it -- after making sure the alternator is working properly. Otherwise a bad alt will kill a new battery.


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## Brainbucket (Mar 30, 2015)

With alternators, you NEVER remove the battery cables. It kills the alternator. Old school generators you can do that. I believe your battery needs to be replaced. Season changes will kill an old battery,


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## HotRodx10 (Aug 24, 2017)

I discovered through painful experience that measuring 13.5-14 voltage across the battery is not always an indication that the alternator is outputting adequate *current*. I suggest you do as you proposed, and take it to Autozone (or most any other auto parts store) for a charging system test.


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## guyakaguy (Aug 10, 2021)

HotRodx10 said:


> I discovered through painful experience that measuring 13.5-14 voltage across the battery is not always an indication that the alternator is outputting adequate *current*. I suggest you do as you proposed, and take it to Autozone (or most any other auto parts store) for a charging system test.


This. Unless you have a charging system analyzer or one of those testers with a toaster oven coil in it, you can have an alternator putting out 14.7 volts that falls flat under the slightest load.


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## joed (Mar 13, 2005)

You need a new battery. Remove and take to your nearest auto parts store. They usually will test them free. When they tell you it is bad buy a new one.


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## HotRodx10 (Aug 24, 2017)

joed said:


> You need a new battery. Remove and take to your nearest auto parts store. They usually will test them free. When they tell you it is bad buy a new one.


Batteries that haven't been charged properly will test as bad, even if they aren't. I think the better approach is to get the vehicle running and take it to the auto parts store. They can test the alternator and battery, and determine which is bad.


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## wrbrb (Aug 18, 2020)

Picked up a replacement battery today from Menards and it's an AC Delco with date code S101P, which I understand now to be October (10), 2021 (1). How concerned should I be that the battery is at least three months old already? It was the last one of the size on the shelf - the whole battery area was pretty picked over.


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## FM3 (Aug 12, 2019)

It's fine. Especially if you're lucky to have even gotten that one.


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## HotRodx10 (Aug 24, 2017)

wrbrb said:


> How concerned should I be that the battery is at least three months old already? I


 Not at all. 3 months removed from when it was manufactured is about as new as you're going to get. Plus, lead acid batteries don't go bad from age sitting on the shelf (at least not for quite a few years); they fail due to use, abuse (getting drained way down) and getting bounced around alot.


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## wrbrb (Aug 18, 2020)

Got the new battery put in and tested 14.35V DC with the engine running so I think we're good! Thanks everyone. 

Also noticed a hose was disconnected from the left side of the air cleaner housing to the top of the engine around the intake area. Maybe that will fix the check engine light related to the IMRC solenoid. Fingers crossed.


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## Pishta (11 mo ago)

Nealtw said:


> The alternator needs power to make power, take the lead off the battery if the engine doesn't die the alternator is making power for itself and the engine.


This is old school, can damage newer electronics but I have done it successfully.


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