batt dying when car is off

[skylineTT 10+ year member]

i had this problem with my other battery and i thought it was just the batt. the new batt is about 2 weeks old and i dont drive the car around. its just been sittin in the driveway really. i usually run the car every other day and the voltage on the batt stays fine. now, like on my last batt. i have to jump the car to get it on, ill let it run for a little to charge the batt and the charge lasts a good couple hours until it starts to fade. my amp is off and my head unit is off but it still somehow drains. it didnt do this when the audio system was out. whats up?

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[mtlhead 10+ year member]

i had that problem, and it turned out to be my alternator

 

[skylineTT 10+ year member]

how is that? its still charging the batt. the batts just dying for some reason.

 

[mtlhead 10+ year member]

how is that? its still charging the batt. the batts just dying for some reason.

dunno, but that fixed my starting troubles

but that was just me

my alternator was suppose to put out 90A, only putting out 70, went and got a 150A alternator...next time you have it out, go get the alternator looked at

 

[skylineTT 10+ year member]

alright. yeah i was wonderin if there was a way to get that all checked electronically. like the batt, alt and all that stuff.

 

[mtlhead 10+ year member]

yea, autozone should be able to do it (free)

 

[skylineTT 10+ year member]

alright well ill get up there later.

 

[fwb_1234 10+ year member]

You might be grounding out some power wire, too. I dunno if you've looked for that. Maybe some insulation has worn off and now there is a bit of exposed wiring flopping around?

 

[dB-SPL 10+ year member]

Or your power lead is possibly touching the remote lead at the terminals, which would keep your amp on at all times.

-Bill-

 

[skylineTT 10+ year member]

the light on the amp stays off though. i dont get it!!

 

[mlstrass 5,000+ posts]

a random interior light staying on or some source of current draw is the only reason a good battery should die that quickly.

But have the alt checked first to make sure it's charging properly. Then start hunting for your current draw....

 

[lilmaniac2 5,000+ posts]

sounds like you have a short somewhere. A quick easy way to test is to park the car in the garage, unhook one of your batt wires ( negative is usually the easiest ) when you attach it you may see a light spark, if you do you have a current draw somewhere.

this method is not ideal, but it will help you realize if you have a current draw somewhere. If it does spark have somebody pull fuses under your dash, after each fuse test the battery cable again til the spark goes away.

Ideally you should use a Ammeter, but not everyone has it. If you own a ammeter you can just clamp it onto your negative batt cable, if there is a current draw there start pulling fuses til that current draw goes away.

 

[fwb_1234 10+ year member]

sounds like you have a short somewhere. A quick easy way to test is to park the car in the garage, unhook one of your batt wires ( negative is usually the easiest ) when you attach it you may see a light spark, if you do you have a current draw somewhere.
this method is not ideal, but it will help you realize if you have a current draw somewhere. If it does spark have somebody pull fuses under your dash, after each fuse test the battery cable again til the spark goes away.

Ideally you should use a Ammeter, but not everyone has it. If you own a ammeter you can just clamp it onto your negative batt cable, if there is a current draw there start pulling fuses til that current draw goes away.

Woah.

There are components of your car that always draw current, just very little.

Your HU draws power to retain the settings and maintain its interior clock, stuff like that.

I always get a little spark when I put my neg. back on.

 

[sandbags 10+ year member]

the other thing to check is when u play your system do your lights constantly dim? i had my batt tested and it passed but it turned out that i had a dead cell so unless i was revved above 1200rpm the batt was only seeing 10v

 

[HellsRise 10+ year member]

Woah.
There are components of your car that always draw current, just very little.

Your HU draws power to retain the settings and maintain its interior clock, stuff like that.

I always get a little spark when I put my neg. back on.

Not to mention if you have a light in your hood for when you pop the trunk, or if you have an alarm and an LED for it, etc etc.