Leave car for week = dead :(

[sizzl3r 10+ year member]

Hi everyone. Alright so I went out of town last week and just came back today to find my car dead. I have an Alpine head unit (model doesn't matter) and a 15'' MA Audio Sub (MTX amp running close to 800 watts)

This isn't the first time that I've left for a while and came back to a dead car. The only time it didn't die was when I had to leave my car in a parking lot for a week, so I deattached the face plate for the deck. For future reference, should I deattach the face plate to save power?

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[goingdef 10+ year member]

settings are retained in the HU body not the face so removing or not does not change a thing sounds more like a bad battery.

 

[i2ain2thunder 10+ year member]

Yeah mang noway a battery dies in a week based off the HU u gots a bad battery, bad alternator, short, ground, something like that.

 

[ramos 5,000+ posts]

Sounds like you may have a parasitic drain. Time to break out the dmm //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[sacsking916 5,000+ posts]

Yeah mang noway a battery dies in a week based off the HU u gots a bad battery, bad alternator, short, ground, something like that.

please do elaborate how a bad alternator kills a battery when the car is off??

 

[bhsdriller 10+ year member]

he probably meant that it's not charging the battery properly when the car is on....I think

how old is your batt

 

[justafifteen 10+ year member]

he probably meant that it's not charging the battery properly when the car is on....I think
how old is your batt

If it wasn't charging the battery properly, then the guy would never be able to start his car.

Check to make sure you don't have any lightbulbs on, etc -- like the light in the trunk may always be on. You most likely just have a parasitic drain like mentioned above

Also bust out a DMM and look at the voltage your battery has both with the car on and with the car off. With the car on, it should be above 13.9v and with it off, it should be above 12.5v. If it's below 13.9v with the car on, your alternator is bad. If it's below 12.5v with the car off, you need a new battery.

(Obviously, let the battery "charge" fully before checking the voltage...)

 

[i2ain2thunder 10+ year member]

Yeah I get it, I knew that before I posted, but you never know the exact situation, can't ecactly rule the alternator out right away.

 

[justafifteen 10+ year member]

Yeah I get it, I knew that before I posted, but you never know the exact situation, can't ecactly rule the alternator out right away.

Yeah but the alternator really doesn't make the battery go dead after a week. The battery obviously started his car that day so it had good (enough) voltage. So he either has something draining the battery, like a lightbulb, or the battery is bad and can't hold a charge. The alternator has nothing to do with it really.

 

[i2ain2thunder 10+ year member]

Yes you are probally right. But there is a possiblilty the alternator went out and wasn't charging the battery before he left, hence why it is dead when he got back, another possibility is that it is a very weak alternator and he is draining more power than he is charging due to his sound system (not likely again) but a possibility. I'm just saying that it's possible don't rule it out.

 

[slammedincouch 10+ year member]

Dead?! You better call it in

They'll investigate the scene for you.

I would check to make sure there aren't any lights that are staying on for an odd reason. Like the glove compartment

 

[i2ain2thunder 10+ year member]

Anyway the guy that said to hook up a DMM is right gotta see if ur draining.

 

[DonWan 10+ year member]

I would say bad battery just take it to auto zone have them test it.