Recently I just placed a new battery. But when I start the car, the battery gauge would say 12 volts and when I crank it it goes to 8. The battery's new! WTF is going on?

 

while you are cranking it or after it is running??

If your voltage stays low while your car is running, could be your ALT

 

Your battery terminals are corroded, the cables are in bad shape, your grounds are bad, or a combination of all of the above.

 

Every time i crank it it goes down to 8.

 

The car also wont start either...

 

Isn't voltage drop normal when cranking due to the car sucking up so much current?

Check all the wires for corrosion.

 

I would do the following

check and clean all cables
make sure all cables are tight
test the battery, yes its new but it dont mean that is still has a good charge on it
hook up some jumper cables to it and see if the car starts.. if so it is either a bad battery or the charging system is no good and the battery is not being juiced up (i.e bad alternator)

Dave

 

my car is giving similar problems and i changed the alt on sunday
and i drove it around on monday and yesterday the gas finished on me i tried to put in some to make it home and when i got right infront of my house it died on me and since then been acting stupid just like your car

 

Maybe the starter is pulling to much? some of them are stock so thats a 16+ year old starter.

 

check you drivebelt tension...also you should be running around 14-15v...take note your volts will drop if you have excessive draw..ie:aftermarket stereo, heater, lots of accessories etc...

 

How acurrate is your dash voltmeter? You can check voltage at battery terminal with a voltmeter while you crank the car. Maybe there is no problem with the system but the faulty in dash voltmeter is giving your inacurrate readings.

 

Mine does the same thing and read 14v when driving. so its a common thing.

 

Your voltage shall not drop below 10V while cranking. If it does:

- your battery is not fully charged.
- your battery is not sufficiently rated.
- there is too much resistance from battery (+), to starter, to battery (-).

I work at a battery store, it was mentioned earlier by SpooledupRacing that "new" batteries may not be fully charged. That is 100% true. Take your battery back to the place you bought it and make them load test your battery. Also, if you have a voltmeter, take the reading at the battery terminals. It will be more accurate than your voltage indicator in your dash.

If your battery tests out good, is it rated at more than 350 CCA? I believe that is what the stock battery was rated at.

If your battery is good, and of proper capacity, then your problem lies in anyone of the following:

- Bad, corroded (+) terminal.
- Bad (+) to starter wire.
- Bad starter.
- Hard to crank engine.
- Bad engine to firewall ground.
- Bad firewall to battery ground.
- Bad, corroded ground terminal.

 

My starter craped out yesterday and i notice something weird. Even when the starter isn't cranking the volt meter inside still drops under 12. (maybe around 9?). So maybe the reading the volt meter is getting isn't a acurrate reading of the battery. The reason i know the start that failed isn't jamed is because i took the starter apart and it failed because of a set of worn bushs. Hope this helps

 

or you have a bad battery or connections to the battery