I completely drained my car's battery

[jana519]

I have a 2002 Honda Odyssey and I accidentally hit the master switch which turns on all interior lights. It's hard to notice because the lights turn on when you open the door and remain on for about 10 seconds. I didn't even notice the switch was flipped until a couple days later.

Anyway, I brought the battery to an AutoZone and the voltage read 9.5V which is completely drained. The associate put the battery on the charger for an hour and a half. The voltage went back up to 12.3V and I put it on a 500 mA float charger for the night. Next day, I brought it back to AutoZone and the voltage read 12.5V.

Question, is it possible my battery may be damaged from being fully discharged?

Side note: I was told by no less than 2 AutoZone employees the battery was bad, while it charged from 9.5V to 11 to 12.3V. I can't believe how misinformed these employees are.

 

[Skunk-Works]

Question, is it possible my battery may be damaged from being fully discharged?

I asked my dad who was a mechanic many, many years ago and he said that it may depend on how old the battery is. He says it sounds like it could be fine, and he stressed never to charge the battery on concrete or steel as that will pull the charge right out of the battery.

 

[jana519]

I asked my dad who was a mechanic many, many years ago and he said that it may depend on how old the battery is. He says it sounds like it could be fine, and he stressed never to charge the battery on concrete or steel as that will pull the charge right out of the battery.

It's about 4 years old. It's a gold O'Reilly battery with a 3 year warranty, so it's 1 year out of warranty.

 

[Skunk-Works]

It's probably fine. If you have a multimeter you could always check the battery every now and then, but the alternator will keep it charged.

 

[mindless1]

I asked my dad who was a mechanic many, many years ago ... and he stressed never to charge the battery on concrete or steel as that will pull the charge right out of the battery.

100 years ago this was true, back when batteries had wood or carbon in their casings. Anything made in the last several decades has a plastic casing and does not have this issue.

 

[teejee]

A healthy car battery is usually above 13.5V when fully charged. So my guess is that your battery is in bad shape. Is it worth taking the risk?
If you buy a battery now you can search for a bargain price and change battery yourself when you have time. If you wait the battery will probably be dead at worst possible occasion and probably cost you much more in total.

 

[monkeydelmagico]

A healthy car battery is usually above 13.5V when fully charged. So my guess is that your battery is in bad shape. Is it worth taking the risk?
If you buy a battery now you can search for a bargain price and change battery yourself when you have time. If you wait the battery will probably be dead at worst possible occasion and probably cost you much more in total.

Car batteries are 12.6v. Automotive charging systems should run at high 13v to low 14v when the engine is running. Don't confuse the two different measures.

It's about 4 years old. It's a gold O'Reilly battery with a 3 year warranty, so it's 1 year out of warranty.

4 years old is on the downward slope of it's life span. An easy drain test of the battery is to leave the headlights on for around 15 minutes then crank up the car. If you notice significant slowdown in starter or really dim headlights during start up the battery isn't holding a charge well.

 

[shortylickens]

https://www.amazon.com/gp/product/B000BQSIWK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Been saving my ass for about 4 years now.

 

[feralkid]

I asked my dad who was a mechanic many, many years ago and he said that it may depend on how old the battery is. He says it sounds like it could be fine, and he stressed never to charge the battery on concrete or steel as that will pull the charge right out of the battery.

That was true more than 50 years ago, when batteries were encased in hard rubber shells. Not true anymore.

https://www.snopes.com/autos/techno/battery.asp

 

[jana519]

Car batteries are 12.6v. Automotive charging systems should run at high 13v to low 14v when the engine is running. Don't confuse the two different measures.



4 years old is on the downward slope of it's life span. An easy drain test of the battery is to leave the headlights on for around 15 minutes then crank up the car. If you notice significant slowdown in starter or really dim headlights during start up the battery isn't holding a charge well.

Sounds like a good suggestion. I will try that.