Does battery effect voltage?

[Kross6622 10+ year member]

Currently I have the stock alt and stock battery in my 07 Grand Prix along with 1/0 wire from the pos of alt to pos of battery and battery neg to chassis. I plan on wiring my engine block when i get some extra money/time.

My voltage reads 13.7 ~ 13.8 with the car on

I have a friend who has an 06 grand prix (Same engine etc...)

He has 1/0 wire from the alt to battery and from the battery neg to a bolt on the engine and an autocraft titanium battery and his voltage with the car on is 14.4~14.5

Why is his voltage higher? The battery? We both have the same alternator, etc.

Would it be more beneficial to upgrade the battery first or would running the 1/0 gauge from the engine block to the negative of the battery like he did.

I plan to do both but for the next 2-3 weeks i can only afford one of these. There is a reason behind this if anyone is curious PM not a big deal just have to wait for some money etc...

Also i plan to run ~2000 watts rms when all said and done. I plan on upgrading my Alt, and I want to keep it to 1 battery up in the front. What battery do you think would work good, I know adding a second in the back would work the best, but this is a daily driver and i think with an alt upgrade and a good battery up front i wont have any issues.

Thanks in advance for the help.

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[finkster 10+ year member]

it depends on the car. The battery should not matter. I have a high output alt and still only charge around 13.5. its whatever the engineers chose really.

most cars charge between13.5 and 14.4

 

[Kross6622 10+ year member]

its the same car though.... Same engine same make etc.. there is no engine differences in the car only things diff are a few things are located differently and some things are labeled different ( examples the antenna is in the front on 06 and in the back in 07, and the steering wheel in the 06 has GP and mine has a Pontiac symbol)

 

[finkster 10+ year member]

The battery is only around a 10 amp load on the alt. When the car is running, the alt does all the work until the amount of power required in the vehicle surpasses what the alt can put out. Then thats where the battery comes in.

 

[bubbagumper6 5,000+ posts]

Alts should charge at 14.4

When the car is on it doesn't matter what the voltage of the battery is because the alternator voltage is greater. If your alt is only charging at 13.8 you might want to have it tested.

 

[finkster 10+ year member]

Alts should charge at 14.4
When the car is on it doesn't matter what the voltage of the battery is because the alternator voltage is greater. If your alt is only charging at 13.8 you might want to have it tested.

cars have been charging below 14 for a while. Reason being it prolongs the life of the battery.

my car will be lucky to ever get above 13.8...anyone with a 3000gt or stealth can vouch for this.

 

[Kross6622 10+ year member]

Alts should charge at 14.4
When the car is on it doesn't matter what the voltage of the battery is because the alternator voltage is greater. If your alt is only charging at 13.8 you might want to have it tested.

Car has 12k miles on it. Its an 07. The alt seems fine, I dont think I need to get it tested... Its under warranty still but I have put a few systems in friends cars and all theres read around 13.8 too. I think alts CAN charge at 14.4 but with certain loads they dont. Im just trying to find out if my stock battery is putting the load down to 13.8

 

[bubbagumper6 5,000+ posts]

cars have been charging below 14 for a while. Reason being it prolongs the life of the battery.
my car will be lucky to ever get above 13.8...anyone with a 3000gt or stealth can vouch for this.

hmm, never heard of this. But I suppose you learn something new every day?

But if you've got a friend with an identical vehicle and his alt charges at 14.4 I'd say you've got a problem. Voltage shouldn't depend on load (current will, but not voltage). Age of the car/alt doesn't matter, it could still be dying...

I really doubt it's the battery, but if your really concerned, start the car and disconnect the battery, then check the voltage with a DMM.

 

[Kross6622 10+ year member]

hmm, never heard of this. But I suppose you learn something new every day?
But if you've got a friend with an identical vehicle and his alt charges at 14.4 I'd say you've got a problem. Voltage shouldn't depend on load (current will, but not voltage). Age of the car/alt doesn't matter, it could still be dying...

I really doubt it's the battery, but if your really concerned, start the car and disconnect the battery, then check the voltage with a DMM.

The only difference is he has the alt neg to chassis upgraded I do not. You think that would make the difference?

Im just trying to figure it out myself. I will try to start my car and undo the battery tmw, its to late to try tonight.

Any other ideas?

 

[finkster 10+ year member]

trial and error man. take 5 mins and try it real quick.

 

[finkster 10+ year member]

oh yea dude, you should run a wire from your alt neg and batt negative. this will increase current flow.

 

[Crownvicon28s 10+ year member]

I thought 13.8 was normal. When I first start my car my voltage is around 14.4 to 14.6 then as I drive and the batteries charge it charges at 13.8.

 

[Kross6622 10+ year member]

I got my alt + to battery + in additional 0 gauge and stock then I have Battery - to Chassis with 0 gauge and stock.

The only part of the Big 3 i havent done yet is run the Alt - to the chassis. But since there is no place on the frame to bolt to I will do what my friend did and run it to the neg of the battery. I need to find someone with the right equipment to remove this bolt on my engine and I need to buy some good 0 gauge etc... If doing that will up my voltage thats all I need to know.

I am just trying to figure out why his was higher...

 

[finkster 10+ year member]

no need to run your alt - to the chassis when your battery is nearby, running it to the battery is the best ground you can get //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Compjake 10+ year member]

I really doubt it's the battery, but if your really concerned, start the car and disconnect the battery, then check the voltage with a DMM.

I'm not sure about newer cars but I know for a fact on older ones this is a bad idea.

I tried that on my car, with the battery i read 13.0-13.3 as soon as i unhooked the battery voltage went to about 23-24 volts.. That much power can easily kill electronics in your car..

Get your shit tested right, go to a place like Allied Battery or Battery's Plus and have them do a load test.