ok i got a red top under the hood now an still voltage dropping like it was b4

[Austin175]

ok as in my sig i have a stock alt an battery now during the day when bumping real hard it drops from 14 or 14.5 to like 13 or 12.8 somewhere in that area but at night with my head lights on an dash lights on it drops almost down to 9 or 10 but idk if i should upgrade the battery an try that bc i dont want to if auto zone wont refund it if its not the battery but i dont wanna buy my alt if it is the battery so idk which would u guys recommend right at this point

Edited November 1, 2009 by Austin175

[Guest]

whats the voltage of the battery when its been sitting for a few hours after you shut the car off? i would buy either a new battery and do the big 3 or buy a 2nd battery and do big 3.

cant autozone "test" the battery for you to see if its good?

[Austin175]

well idk about a few hours after but when i start the car it goes up to like 14.5 or 15 then after bumping it gradually goes down an down

[missinglink]

well idk about a few hours after but when i start the car it goes up to like 14.5 or 15 then after bumping it gradually goes down an down

Sounds like to much demand for your alt and not enough storage to help cushion the draw

If your jumping up like that from stock voltage at start up chances are:

1)the batt's going bad and loosing and/or not holding charge.

2)your alt my be going out

3)To much demand and alt is just can't keep up.

To rule out the battery 1st check its (resting voltage) use a volt meter first thing in the morning before you ever start your car (do not charge battery over night then test)

Simple #'s are 12v dead , 12.5 55%full , 13v full , if your pumping 14.5 to 15 volts into your battery it should be (resting) a solid 12.9+

Your car will try and compensate for a low battery by raising voltage at start.

It drops lower with lights on at night just because the demand is greater on the alt and prolly just can't keep up.

Hope this helps shed some light on things

MLA

[Iraggi Alternator]

Sounds like you may need a battery and an alt.

Dropping to 12's indicates needing an alt.. dropping to 9's indicates needing both.

How much power are you running on your subs?

[Austin175]

um i believe 1100 x2 at 2 ohm not bridged

[Austin175]

an yes thankx u guys its helping but mom needs to borrow money so i think im just gonna buy a new battery for under the hood for now then in 2 weeks get my alt

[Austin175]

well i just bought a optima red top for under my hood until i can get my alt an the batts i want bc moms needed money for some bills so i got what i could get its not a permanent battery just a temp until i get the funds

Edited October 29, 2009 by Austin175

[Austin175]

well as title states i kno its the alt i need to upgrade bc with the red top under there now it still drops like it was b4 so in 2 weeks ill get the alt an we shall see if that fixes if not imma buy the alt an idk what else to do after that

Edited November 1, 2009 by Austin175

[SojiaRaggs9000]

Did you try adding a battery in the trunk as well as doing big 3? reason I ask is because I had a similar problem. I had 3000watts @ .5 droping my front battery down to the 9's. So I add a XS D3100 in the back and took out the 4ga and reran everything with 1/0 wire. Now my voltage on both bats are 14.5 -14.45 when the bass is hitting hard.