After being driven ~15-20 minutes yesterday, today the battery is 12.3v at rest at 60F, with electronics and headlights on and engine off, it's at 11.7v. It may not had been fully charged after a 15-20 min drive. I should drive it for longer (~30 min), rest, and test again. My multimeter doesn't do min/max. When a friend comes over I can have him crank the engine and while I watch how low the voltage drops. I suspect this battery is borderline and should be replaced.
Is my battery bad?
- Thread starter wcbh
- Start date
Also make sure you understand the alternator. I assumed my F150 had a bad alternator, only to find out its "Smart" and kicks on and off, and seems like it doesn't work
That Voltage is suspect……..what’s the age of the Battery in question?
I don't remember the exact age of this battery, it's probably 5+ years old in a northern climate.
I did further testing this morning. While cranking the voltage drops to btw 9 and 10v. I couldn't get the exact reading since it flashed so quickly. Upon start up with the engine running it's 14.2v. I let the car idle for 10 min and then drove it for 40 min, after which voltage at the battery nodes is 13.5v with engine running. After resting for 4 hours, the voltage is 12.45v with everything off.
My conclusion is the alternator is working appropriately and changing the battery. The battery is borderline but not 100% trash. With the upcoming winter it may be safest to replace it.
I did further testing this morning. While cranking the voltage drops to btw 9 and 10v. I couldn't get the exact reading since it flashed so quickly. Upon start up with the engine running it's 14.2v. I let the car idle for 10 min and then drove it for 40 min, after which voltage at the battery nodes is 13.5v with engine running. After resting for 4 hours, the voltage is 12.45v with everything off.
My conclusion is the alternator is working appropriately and changing the battery. The battery is borderline but not 100% trash. With the upcoming winter it may be safest to replace it.
it would be better to fully charge the battery, observe it, then draw a conclusion.
https://www.interstatebatteries.com/blog/how-long-you-have-to-drive-to-charge-your-car-battery#:~:text=How long does it take,actually charge a car battery.
This may be overkill for your situation rn, but it is an excellent battery charger/car start/reconditioner.
https://www.amazon.com/DEWALT-DXAEC...-lpcontext&ref_=fplfs&smid=ATVPDKIKX0DER&th=1
https://www.interstatebatteries.com/blog/how-long-you-have-to-drive-to-charge-your-car-battery#:~:text=How long does it take,actually charge a car battery.
This may be overkill for your situation rn, but it is an excellent battery charger/car start/reconditioner.
https://www.amazon.com/DEWALT-DXAEC...-lpcontext&ref_=fplfs&smid=ATVPDKIKX0DER&th=1
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It soulds to me like you might want to find a way to disable the smart charging system on this vehicle.
Using a battery charge is a hassle because I don't have a garage. The battery will need to be taken inside to charge and then reinstalled. Although given my recent driving pattern, I only drive the car once or twice a week, mostly short distances, a charger would be ideal to keep any battery healthy.
In that case, I would just replace it anyway
Agreed.
Have you considered a solar battery maintainer?
What is the vehicle? My 3 Honda's all have a alternators that adjust to load. Short around town doesn't work great UNLESS you turn the headlights on. Mine sit at 12.6V on a normal drive and jump to 14.4V when I coast/step on the brakes. Turn headlights on and it stays /charges at 14.4V the whole time.
I've had THIS Solar BA-9 capacitance tester for 7 years already. Dealers use a version like it. The old school load above might not test it.
Watch Kent Bergsma video. There are like 4 of them.
5+ years old, replace it anyway. Costco has best prices I found. Interstate batteries.
I've had THIS Solar BA-9 capacitance tester for 7 years already. Dealers use a version like it. The old school load above might not test it.
Watch Kent Bergsma video. There are like 4 of them.
5+ years old, replace it anyway. Costco has best prices I found. Interstate batteries.
A lead acid battery that is deeply discharged will take several hours at a minimum to fully recharge. A half hour drive can put some power back into one but it won't bring it all the way up. The last 20% of charge takes as long as the first 80%.
You can take it out and have it load tested, or you can buy a hydrometer and check the Specific Gravity of each cell and compare to the other cells. Those are really the only 2 ways to gauge the health of a battery.
Turn that crap off with ForScan..... You lose Auto Stop/Start but who likes that? Nothing like having your vehicle keep your batteries SOC at ~80% to make it last a good long time.
Interesting, I didn't know it was something you could turn off. I'll do it tomorrow
Disable stop/start. It shuts down the whole BMS.
