johnny_2X

All:

Short story:
Tried to start the car, clicking from starter but wouldn't start! Jumped it and started fine, drove the car for 20 miles non-stop. Stopped and then tried to start it to return home and needed a jump again! Drove home 20 miles, turned off car and won't restart!

How can I tell if it's my battery or alternator?

John

Mike

put a volt meter across the battery terminals. it should read at least 12 volts+ if i remember correctly. you have to pull the alternator and get it tested at an auto parts store to determine if it's working or not.
anywho, sounds like a dead battery.

TypeS_boi

battery no clicky=dead

RaviNJCLs

iTrader: (4)

Battery needs to be changed.

wwg6983

Depends on how old your battery is. If you ran the car for 20 mins nonstop and the Alternator didnt put any charge into the battery then IT possibly could be an alternator. If the battery old then no matter how good an alternator it can push the juice into a DEAD battery.

phipark

If it's the original OEM battery, then I would bet it's dead.

cltypeSLOW

mine did the same thing...change your battery

nongque

I'm thinking its your battery to.

To test, heres what i would do.

Jump the car again, start it up, take that wires off the battery, if car dies then its alternator, if cars still running, then its the battery,

Hope that helps

gsrblack

same thing with mine....battery was dead. jumping it gets it going, but after you shut off the engine, it would need another jump.

Slimey

Likely battery.

If you go to Sears, AutoZone, or PepBoys they'll do a quick check of your electrical system and answer your question before they sell you a battery.

johnny_2X

Thanks all!

New Castle Acura so happen to send me a coupon for $100 which includes: battery, clean cables, check alt belt, and rest of system.

I sware they can send a signal to the car to make things "appear" as failed.

LOL,
John

Allout

Quick way to tell if it's your battery or alternator is by the intensity of the headlights. Turn on your headlights before you start the car and note the intensity. Once you jump start the car, if the lights are brighter, then you have alternator output and you've got a dead battery. If light intensity is still dull, then it's your alternator.

e30cabrio

iTrader: (6)

As nongque said

Easiest way to tell is disconnect the battery. Car does not run with no electricity. If it does not die the alternator is putting out sufficient juice to give spark to the coil. This does not mean it is putting out enough to charge the battery but it gives you a starting point in the process. I would have both checked at a competent AUTOMITIVE ELECTRICAL shop (not Pep Boys.)

Zippee

Put a voltmeter on the battery terminals with the engine off. Probably read 11.5-12 volts or so. Start the engine and look again; if the voltage is the same as before the alternator is not putting juice to the battery. If the voltage is now up to 12.5-13 volts or so the alternator is working and it's time for a battery.

e30cabrio

iTrader: (6)

While this is mostly correct it is possible that a good alternator and a good battery can discharge if there is a greater draw than charge. By this I mean if you have lights, stereo, a/c etc. running and are only receiving 11.4 (for instance) volts at the battery you will be discharging the battery. There can be a ground issue that would cause what I describe.

I know this because I had a similar problem when I first installed my system in my 325. Battery & alternator new and good, at idle with nothing running 13.4v but when I ran all of the electrical items I state above I was running at 11.1-11.4 which means I was eating the battery. I added some grounds and all was well.