1g not holding charge

[supermanvick]

Someone help just got my car runnning today and after about 20 min its not holding a charge the batterys new but the alt is old that is probably the problem. Are there any other suggestions?

 

[zrk666]

Someone help just got my car runnning today and after about 20 min its not holding a charge the batterys new but the alt is old that is probably the problem. Are there any other suggestions?

you guest it its the alt. my alt stayed on there until a few months ago. it was the original oem alt.

 

[supermanvick]

is there anything else it could be like a ground wire or what cause i need to get this car on the road tomorrow. could it be a ground wire or some wire loose or something?

 

[RiceKiller_TSi]

Take your volt meter to the back of the alternator while the car is running and see what kind of voltage its producing. You should be seeing between 12-14 on your meter. If you're seeing less than that then you need a new alt. Diode must be blown in it.

 

[chrisfrye]

Yeah definitely check your grounds off your battery, 1 to the firewall 1 to the block. check the connectors on the alternator itself, they might have become loose.
Good ways to check your alternator:
Get your car running, take off the negative battery cables, if it dies its your alternator.
IF you have means to charge your battery do it, take a voltage reading, let it sit for a little while and take another one(to make sure the battery isnt draining). Then take a voltage reading with it running. should be 12-13v
good luck!

haha you beat me to the post by like 5 seconds!

 

[Julioluko]

Also, A battery on a full charge should last I think 24 hours, anyway it will get you to an autoparts store, charge up your battery and have Advanced Auto check it or Auto Zone for free. Also make sure your post clamps are tight.

 

[chrisfrye]

Also, A battery on a full charge should last I think 24 hours, anyway it will get you to an autoparts store, charge up your battery and have Advanced Auto check it or Auto Zone for free. Also make sure your post clamps are tight.

Maybe if your not using the battery of course itll last 24 hours, but there's no way driving it'll last 24 hours. I've bought the biggest battery Autozone had, and the so many times my alternators been dead, i'd say it lasted less then an hour driving good on it.

 

[thilaksharma]

u may do this simple test
if u have a multitester, u can test the amps that is being received from ## alternator

another way to test ## altenator
start ## car
do not on the aircond or any power su_cking devices
remove one of the battery terminals
see if ## car stays up , if nop , ## alternator is gone
if it stays on , then ## battery has a problem n doesnt get charged.

 

[steve]

Good way to check your alternator:
If you have means to charge your battery do it, take a voltage reading, let it sit for a little while and take another one(to make sure the battery isnt draining). Then take a voltage reading with it running. should be 12-13v

This is good, but pulling the battery terminals off while running it a good way to blow alternators, ECU, radios, etc. It also won't tell you jack about why it isn't working.

The most common cause for no charging is blown alternator fuse followed by a bad alternator. People forget to disconnect the battery before working on the car and blow it.

Steve

 

[OR Talonted]

you should first try to check your main fuse for your alterternator before testing it. It is located on your positive terminal. The square looking one.

 

[OR Talonted]

very correct steve

 

[chrisfrye]

This is good, but pulling the battery terminals off while running it a good way to blow alternators, ECU, radios, etc. It also won't tell you jack about why it isn't working.

The most common cause for no charging is blown alternator fuse followed by a bad alternator. People forget to disconnect the battery before working on the car and blow it.

Steve

You'd be the first i've ever heard spoke against that, and a lot of people have suggested using that method and used it. I haven't fried anything to date, although voltimeter's always my prefered choice. And it does eliminate the battery as being a culprit.

As i dont want to doubt your expertise, can you provide proof that this has fried things?? When I've gone through all of my electrical problems over a dozen mechanics probably suggested that in a list of things to check. I wouldn't suggest something i havent heard from a dozen reputable mechanics, two of them old stock car mechanics. Also isnt your radio and alterntor, etc on fuses? wouldn't it blow them if a surge went throguh?

 

[steve]

You'd be the first i've ever heard spoke against that ...

Do a little searching on the internet and you'll see that companies like Bosch and various industry leaders tell you not to do this anymore. It was a simple test back in the days of mechanical voltage regulators and non-computer controlled cars but very dangerous to a modern automobile.

Just a couple of references.

http://www.boschautoparts.com/FAQS question 10 under Alternators and Starters.
http://www.cartalk.com/content/columns/Archive/2003/April/02.html
http://www.batterystuff.com/tutorial_battery.html#11
http://www.sto-p.com/pfp/pfp-transients.htm
http://www.asashop.org/autoinc/april2005/collision.cfm
http://www.aa1car.com/library/2003/us20310.htm

Steve

 

[chrisfrye]

Ah, so now a days i cant do this anymore. The transients is an interesting article. I might try to verify if it can really peak that high.
I guess i stand corrected, I'm sorry i suggested it. I was only going on what many had told me, and from doing it several times on all my cars without any damage.