Tj Won't start if below freezing

[vito2772]

Hey guys,

In the northeast, we were just hammered with some snow and cold whether. My battery is 2 years old, a delco battery. I noticed as soon as it goes below freezing, when I go to start, the dash lights come on, but no crank, don't hear the starter, nothing. I measured the battery voltage: 12.5v. I put an amp clamp on on the leads to see if there is any passive draw draining the battery, there isn't. Here is the strange part.

I have this battery jumper that tells you how much battery is left in the jump. Like I charge my phone from it sometimes and it will go from 100% to like 70 or something.

When I hook up the battery jumper, let it sit for 30 seconds, and start it, it starts right up. I have started several times and the jumper battery says 100% still as if it is barely using the jumper battery to start. And then for the rest of the day it will start perfectly fine. But the next day, if it was freezing over night, No matter how much I drove the day before (1 hour+), I'll have to jump it again. Yesterday was the first day above freezing, and it started right up. Is my battery freezing??

 

[JEEPCJTJ]

I don't think a battery actually freezes until it's not charged. I may be wrong there, maybe it's just the lower the voltage the quicker it freezes.

Either way, have you removed and cleaned any of the large wire terminals? If not try that first.

 

[Jerry Bransford]

A couple things... a battery with a higher CCA will perform better in cold weather and changing the engine oil to a 5W-30 synthetic or 0W-30 synthetic will help too by making it easier for the battery to turn the engine over. Extremely cold weather is pretty much the only time I will recommend a synthetic engine oil.

 

[Mrhp]

If the starter motor does not engage, then does with a charger or jump box, I would check for loose or corroded connections. If all those are good I would suspect the starter. If it cranks with a charger on it, the charger is supplying extra amperage and overcoming a poor connection most likely in the starter solenoid itself.

 

[vito2772]

If the starter motor does not engage, then does with a charger or jump box, I would check for loose or corroded connections. If all those are good I would suspect the starter. If it cranks with a charger on it, the charger is supplying extra amperage and overcoming a poor connection most likely in the starter solenoid itself.

The battery doesn't say it loses any charge after multiple jumps though! Even when I just charge my phone I can watch the percentage go down on the battery, but after multiple jumps it stays at 100%? It seems it just warms the battery up enough to let is start. And then starts perfectly the rest of the day! The connections are clean and tight but I will take them off and clean them and see if it helps.

 

[Mrhp]

It is possible you are experiencing an open circuit inside the battery. I have seen these symptoms two or three times over the years. Do you have another battery to install and test your thoery? That would tell the story.

 

[Jerry Bransford]

The battery doesn't say it loses any charge after multiple jumps though! Even when I just charge my phone I can watch the percentage go down on the battery, but after multiple jumps it stays at 100%? It seems it just warms the battery up enough to let is start. And then starts perfectly the rest of the day! The connections are clean and tight but I will take them off and clean them and see if it helps.

Have your battery "load tested", that is the only way to know your battery's true health. Make sure the battery is as charged up as possible before having that done though so the test can be performed properly. A nearly dead battery can still measure 12 volts without a load on it. A load test places a heavy load on the battery for 10-15 seconds while the battery's output voltage is measured. If the voltage stays up high enough after that 10-15 second load test it's ok. If the voltage drops off too much the battery is bad.

And few auto parts store employees know how to properly conduct a load test, I'd take it to an automotive battery specialty store to have it done. That type of store's employees are far more likely to be able to properly conduct that test.

My suspicion is your battery is going bad.

 

[Mrhp]

Have your battery "load tested", that is the only way to know your battery's true health. Make sure the battery is as charged up as possible before having that done though so the test can be performed properly. A nearly dead battery can still measure 12 volts without a load on it. A load test places a heavy load on the battery for 10-15 seconds while the battery's output voltage is measured. If the voltage stays up high enough after that 10-15 second load test it's ok. If the voltage drops off too much the battery is bad.

And few auto parts store employees know how to properly conduct a load test, I'd take it to an automotive battery specialty store to have it done. That type of store's employees are far more likely to be able to properly conduct that test.

My suspicion is your battery is going bad.

Even if it passes a load test is still could have an intermittent open in the battery. I suspect that is the case, but a load test may find it. They also have a digital tester that tests resistance inside the batteries plates and connections. When I test a battery I do both tests. If it fails either, the battery is N.F.G..