Battery drops to 8 volts on startup, need a new one?

[Supergumby5000 5,000+ posts]

My girlfriends car has been having some issues.

1) The starter sticks if it hasnt been started in a while, makes a loud vacuum-type noise (needa open it up and clean it out)

2) i tested the voltage on her battery when she starts up. I did it twice after jumping her and letting the car run for about 20 minutes

The first time, the car didnt struggle turning over at all, but voltage on the battery dropped to about 9.5 volts

I had her turn the car off, wait a couple seconds, and start it again. This time around, it turned over real slow, and voltage dropped all the way down to 8 volts.

I am aware the car needs to have the starter cleaned up, but will this effect the battery at all? Am i safe going to get a new battery right now, and fixing the starter later, or will the starter cause wear on the battery?

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[Supergumby5000 5,000+ posts]

wow, i definately postd in the wrong section //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif lol

 

[wu501 10+ year member]

you sure the alt is working correctly?

 

[AlpineUser 10+ year member]

fyi dont keep trying to start your car after you have seen that it has been reading 8 volts...it will damage your computer which is expensive...it should read above 9.6 volts which is normal ummm...check grounds...your alt...anything like that...maybe even a bad battery you actually want to see around 10.6 volts

 

[Supergumby5000 5,000+ posts]

you sure the alt is working correctly?

I havent checked the alternator yet.

If i jump the car, and right after the car starts, i turn the car back off. It will slowly turn over and start again.

I jumped it again today so i could bring it to my place to put in the garage. After i drove it here, i turned it off, and when i tried to turn it back on, it started right up.

After a few off-and-ons though, it would gradually get bad until it would slowly turn over again.

And aside form that, all the lights and whatnot work fine, 100%. After the car starts up, everything works 100%. Its just that initial startup thats rough.

 

[DBBOOM 10+ year member]

If it only does this after the car is hot or been repeatedly started, it could be a bad starter.

 

[CRXBMPN 5,000+ posts]

is your battery post corroded?

go get a battery load tester, i have one and its a very very valuable piece of info

 

[Supergumby5000 5,000+ posts]

If it only does this after the car is hot or been repeatedly started, it could be a bad starter.

We've already established the starter is going. I know what the problem is, and i know how to fix.

That shouldnt effect the voltage drop on the battery though, would it?

This is whats up with her starter:

http://forums.vwvortex.com/zerothread?id=2269482

I havent decided if im going just replace it, or if i want to try to fix it first.

It doesnt say anything about side effects regarding voltage and actual difficulties starting up, just the grind noise.

 

[natisfynest 10+ year member]

your battery isnt holding a charge

1 check the water level in the battery if needed fill it and see if that helps

2 if that dont work replace the battery

 

[Supergumby5000 5,000+ posts]

is your battery post corroded?go get a battery load tester, i have one and its a very very valuable piece of info

battery terminals are covered in something ot keep corrosion off. Looks like grease to me.

 

[Moe Lester 10+ year member]

A bad starter can pull much more current than a good one, so yes it may cause excessive voltage drop. Also, after driving around for a while what does the battery voltage float at with the car off and no lights/accessories on?

 

[teamsolo 10+ year member]

sounds like the alternator is not charging the battery

 

[CRXBMPN 5,000+ posts]

i have a cheap 2/6/10a black & decker battery charger that has an alternator tester on it, maybe he has something similar that would help

 

[Supergumby5000 5,000+ posts]

A bad starter can pull much more current than a good one, so yes it may cause excessive voltage drop.

Im pretty sure the starter isnt necessiraly "bad" though. I've been doing some reading about the issue (its fairly common apparently) and the gears in the starter just need to be relubed to get rid of the startup grind noise.

I mean, after a charge on the battery, the car starts right up no problems. The grind is only on the occasional start if it has been sitting for a while.

 

[95ZJ 10+ year member]

I'm having the same problem and just took my truck in for maintenance, yet they found nothing wrong with it.