My battery won’t hold a charge…changed alternator and battery…what is the issue?
Seems like you have a parasitic draw. but first check to see if any lights are staying on. like under hood light, interior light, glove box light, check to see if brake lights are stuck on. a bad brake light switch will cause this. sometimes they get stuck on intermittently
3 Likes
Take it to a qualified shop (not a chain) for a full check of the electrical system.
I’m guessing WW’s good idea above is where a diy’er should probably start. Another idea, maybe there’s a problem w/the wiring between the alternator to the battery. Such a thing can happen. I experienced that problem on my Corolla some years ago.
OP, one tip, if you say the “battery won’t hold a charge” to a mechanic, they’ll interpret that as meaning the battery is faulty. If your symptom is that the car’s battery, even if you start a trip with it fully charged (say by charging w/a battery charger or new battery), but then it completely discharges as you drive it, and never seems to re-charge, telling the mechanic that will be more helpful and probably get your problem solved faster.
To aid the mechanic even more, if you know how to measure voltage, keep a record of the battery voltage over time and at what point in the drive-cycle you measured it. For example
11 am monday, 12.5 volts before first start of day
1 pm tuesday, 12.7 volts after driving to lunch … etc.
Start the engine and measure the voltage at the back of the alternator.
Now measure the voltage at the battery.
If the voltage at the battery isn’t close to the voltage at the alternator, the fusible link in the wire that runs from the alternator to the battery is burned.
Tester
1 Like
Respond…oh yeah brand new battery and alternator…but it started just fine once no clues to starting to die…just got gas and then wouldn’t start…so it makes me think it’s definitely a connection that is crossed or lose…
How did you determine that the battery won’t hold a charge? Was the no start condition caused by low battery voltage?
Unlikely that someone crossed a connection, you need to analyze the no start condition.
If you don’t have a voltmeter and don’t know how to use one, you cannot diagnose this. Why was the alternator replaced. Did the old one teat bad or did you just guess and replace it?
It was tested…I did another of reasearch…wiring an external voltage regulator seems the way to go