Battery light on.

[Gduerson]

So I’ve been experiencing some problems with my battery dying. It was an old and defective battery so I replaced it. When I put the new battery in the battery light came on. It may have been on before and I just didn’t notice but I think it just came on. The battery folks told me I should check to make sure the alternator is good. I checked the alternator and starter. Both are good and I have a new battery as well. However, the battery light is on and will not go off. I’m wondering if anyone has any thoughts about why this might be so and any possible fixes.

I am wondering if there might be a drain on the battery somewhere I suppose I will know within the next few days if the car starts dying overnight.

2011 sedan

 

[Gduerson]

So I’ve been experiencing some problems with my battery dying. It was an old and defective battery so I replaced it. When I put the new battery in the battery light came on. It may have been on before and I just didn’t notice but I think it just came on. The battery folks told me I should check to make sure the alternator is good. I checked the alternator and starter. Both are good and I have a new battery as well. However, the battery light is on and will not go off. I’m wondering if anyone has any thoughts about why this might be so and any possible fixes.

I am wondering if there might be a drain on the battery somewhere I suppose I will know within the next few days if the car starts dying overnight.

2011 sedan

It also seems I’m getting a message to run the multimedia center with the engine running to avoid discharge except that screen flashes when the engine is running

 

[joegr]

What is your battery voltage when the engine is running?

 

[Gduerson]

Voltage was 13.5 I think. I thought I replied to this earlier today but it apparently didn’t post.

 

[joegr]

Voltage was 13.5 I think. I thought I replied to this earlier today but it apparently didn’t post.

Then your charging system does indeed have a problem. Usually, that problem is the alternator. What test were you using to say that it was okay?

 

[Gduerson]

Then your charging system does indeed have a problem. Usually, that problem is the alternator. What test were you using to say that it was okay?

I took it to Goodyear. They tested it. Said it was fine.

 

[Gduerson]

I took it to Goodyear. They tested it. Said it was fine.

I used a multimeter when I got that Reading of 13 something. I’m a newbie to this. What should it be when engine is running?

 

[joegr]

I used a multimeter when I got that Reading of 13 something. I’m a newbie to this. What should it be when engine is running?

Ideally, 14.0 to 14.4. Below 13.8 (engine running) is a problem. Your alternator is partially working (which is possibly what fooled their test), but it is weak, and not handling the load. This is why the light is on and you are getting the discharge warning.

Note that bad batteries wear out alternators, and bad alternators can kill batteries. Interrupt this circle sooner rather than later...

 

[Gduerson]

Ideally, 14.0 to 14.4. Below 13.8 (engine running) is a problem. Your alternator is partially working (which is possibly what fooled their test), but it is weak, and not handling the load. This is why the light is on and you are getting the discharge warning.

Note that bad batteries wear out alternators, and bad alternators can kill batteries. Interrupt this circle sooner rather than later...

Makes sense. My only question would be why it started doing this only AFTER I had the new battery installed and not when I was driving on the bad battery.

Thank you by the way for you help on this.

 

[joegr]

Makes sense. My only question would be why it started doing this only AFTER I had the new battery installed and not when I was driving on the bad battery.

Thank you by the way for you help on this.

Your old battery probably had high internal resistance since it was old and weak. The new battery being very new, probably has very low internal resistance. This means the alternator has to supply higher current to charge it. This sudden higher load was possibly the last straw for your alternator. I wonder if it blew one of the diodes?

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[Gduerson]

Your old battery probably had high internal resistance since it was old and weak. The new battery being very new, probably has very low internal resistance. This means the alternator has to supply higher current to charge it. This sudden higher load was possibly the last straw for your alternator. I wonder if it blew one of the diodes?

So the company that out the battery in actually said today that the battery was defective and that the whole shipment seemed to be bad. So they put a new higher quality battery in. Still the light was on.

In reviewing this however would you still say that it would be unlikely that the defective “new” battery would be the cause of the battery light / warning coming on. It would because my alternator was bad and this new defective battery being hooked up was just the last straw? Problem is that I don’t know what the condition / reading of the alternator was prior to the battery being put into in.

 

[joegr]

Yes, I'm still betting your alternator is failing, and the new/bad battery was the last insult.
Since they admit to the batch of batteries being bad, you might appeal to them to pick up part of the cost of the alternator replacement, or to at least cover a diagnostic charge to determine for certain that the alternator is the problem.

 

[Gunkk]

Alternator or short in the charging system. Get the car in front of a competent mechanic.