Does battery effect voltage?

[finkster 10+ year member]

x2...mechman himself told me this can kill a cars electronics. to see if your alt is charging, hold a compass over the negative battery terminal and start the car. if the needle spins the opposite way, the alt is charging. but duhhhh we know its charging because voltage is 13.5 or higher....you're good dude.

 

[Korn4Life 5,000+ posts]

One of my friends today tried telling me that a Alt dosent charge the battery in your car. He said it just keeps your car running.

I LOL'ed

 

[jon_k 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.

You could say the batteries only purpose is to start the car. The alt should always meet the demands, else it's a slippery slope to a dead battery.

 

[plugitin 5,000+ posts]

You could say the batteries only purpose is to start the car. The alt should always meet the demands, else it's a slippery slope to a dead battery.

^yes, and to provide power when the vehicle is off...those are the batteries only job

 

[Stalin-ohaulic]

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

Epic fail. All electronics in your car are chassis grounded. By not doing the alt - to chassis part of the big 3, you are not reducing the resistance on anything that is chassis grounded. In essence you have wasted your time doing the big 3 without this unless you run heavy gauge wire as your ground, which in most people's case is a waste.

 

[plugitin 5,000+ posts]

Epic fail. All electronics in your car are chassis grounded. By not doing the alt - to chassis part of the big 3, you are not reducing the resistance on anything that is chassis grounded. In essence you have wasted your time doing the big 3 without this unless you run heavy gauge wire as your ground, which in most people's case is a waste.

alt ground is usually the bracket any how...

 

[Kross6622 10+ year member]

Epic fail. All electronics in your car are chassis grounded. By not doing the alt - to chassis part of the big 3, you are not reducing the resistance on anything that is chassis grounded. In essence you have wasted your time doing the big 3 without this unless you run heavy gauge wire as your ground, which in most people's case is a waste.

So your saying until i upgrade my alt neg to chasis there will be no electrical upgrade?

the reason I am holding off is 1 money is tight and two some indicator light went on in my car nothing major my cars under warranty and im going to have them take a look. The guy said it can be from a burnt out light bulb or something of that nature. Could be a sensor is messed up or something..

regardless, once i upgrade the engine to chassis ground i will have an upgraded electrical system until then, its not really helping.

I have the Battery grounded to the chassis with stock + 0 guage and the alt postive to pos battery in 0 guage + stock.

 

[Stalin-ohaulic]

So your saying until i upgrade my alt neg to chasis there will be no electrical upgrade?
the reason I am holding off is 1 money is tight and two some indicator light went on in my car nothing major my cars under warranty and im going to have them take a look. The guy said it can be from a burnt out light bulb or something of that nature. Could be a sensor is messed up or something..

regardless, once i upgrade the engine to chassis ground i will have an upgraded electrical system until then, its not really helping.

I have the Battery grounded to the chassis with stock + 0 guage and the alt postive to pos battery in 0 guage + stock.

It's not literally NO upgrade. I often slightly exaggerate to help reinforce my point. You have already taken out SOME resistance but you have to remember that there really isn't a whole lot to begin with anyways because you can't measure it. Since all electronics draw current through the stock alt to chassis ground, IF under this current draw it drops some, then there is resistance and adding a wire in parallel would help significantly. If it really doesn't drop much to any current, then the wire isn't needed. In my opinion, you need this wire as 2 of the big 3 wires are there to establish your ground.

 

[Kross6622 10+ year member]

Thanks for the info. I plan on doing it soon. I went to a local shop to get it done and they kept saying that these two wire upgrades is all they have ever done and never seen anyone do the alt ground etc... But they did is cheap surprisingly. They charged me 10 bucks for the wire ( Streetwire 0 gauge) since it was scraps left over from peoples kits, and 10 bucks for 2 pairs of ring terminals. I would have done it myself but not having the tools, and if anything goes wrong its there liability, etc... For 90 bucks i got my dash kit, wireing harness, antenna adaptor and those two wires done. I know its not as cheap as if i did it myself but still, for me not having to do anything except install my own radio etc.. The kit,ant,harness is worth like 25 and wire,term for 20.

 

[finkster 10+ year member]

It's not literally NO upgrade. I often slightly exaggerate to help reinforce my point. You have already taken out SOME resistance but you have to remember that there really isn't a whole lot to begin with anyways because you can't measure it. Since all electronics draw current through the stock alt to chassis ground, IF under this current draw it drops some, then there is resistance and adding a wire in parallel would help significantly. If it really doesn't drop much to any current, then the wire isn't needed. In my opinion, you need this wire as 2 of the big 3 wires are there to establish your ground.

yo man i thought about what u said and **** you're right. I forgot about everything else seeking ground through the chassis. I guess that would make a shitty place to run the negative huh. Thanks for the reminder, i **** near almost ran my alt that way.

 

[tRiGgEr 5,000+ posts]

Why don't you throw your friends battery in your car and find out //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Kross6622 10+ year member]

Just installed a redtop and now my voltage is 14.7 solid. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I also had some service engine soon light and saw a wire broke when i was putting in the battery, connected it back up and light is off. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[truckramrod 10+ year member]

Your car has a computer controlled alternator, this is copied straight from the GM Service Information website. Your car is charging correctly, if you want higher voltages, you can get an MLA module but it may cause issues with your car.

Charge Mode

The BCM will enter Charge Mode when ever one of the following conditions are met:

• The interpreted fuel rate is greater than 21 g/s and the throttle position is greater than 90%.

• The headlamps are ON, low or high beam.

• The wipers are ON for more than 8 seconds.

• The electric cooling fans are on high speed.

• The rear defogger is ON.

Once one of these conditions are met, the generator battery control module will set the targeted generator output voltage to 13.4 volts and then ramp that voltage up to 14.5 volts at a rate of 50 mV per second.

Fuel Economy Mode

The BCM will enter Fuel Economy Mode when the calculated ambient air temperature is above 0°C (32°F), the calculated battery current is less than 15 amperes and greater than -8 amperes, and the battery SOC is greater than 80%. Its targeted generator output voltage is 13.0 volts. The BCM will exit this mode once the criteria are met for Charge Mode.

Voltage Reduction Mode

The BCM will enter Voltage Reduction Mode when the calculated ambient air temperature is above 0°C (32°F); the calculated battery current is less than 2 amperes and greater than -7 amperes, and the generator field duty cycle is less than 99%. Its targeted generator output voltage is 12.9 volts. The BCM will exit this mode once the criteria are met for Charge Mode.

Start Up Mode

After the engine has started the BCM sets a targeted generator output voltage of 14.5 volts for 20 seconds.

Windshield Deice Mode

After the engine has run for more than 10 seconds the BCM sets a targeted generator output voltage of 13.8 volts if the calculated ambient air temperature is less that 0°C (32°F). The BCM will stay in this mode until the engine coolant temperature reaches 75°C (167°F) for 10 minutes.

Battery Sulfation Mode

The BCM will enter this mode when the interpreted generator output voltage is less than 13.2 volts for 45 minutes. Once in this mode the BCM will set a targeted output voltage of 13.8 volts for 5 minutes. The BCM will then determine which mode to enter depending on voltage requirements.

 

[bw_audio 10+ year member]

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