shirley

if the alternator was bad then u could jump start the car but it would die after running so long because your entire electrical system would try runnin off the battery and drain it that much faster without recharging....if it runs fine once its started then no way its an alternator

Power6

I haven't found this to always be true. I've had alternators fail, or maybe I should say 'starting' to fail, where they will keep the car running fine, but don't quite put out enough juice to do that *and* charge the battery as well, especially such as, in a snow storm, when you could be running the heater, wipers, rear defrost all at once, the alternator can't keep up but it will charge fine under a light load.

Most of the time these things can be diagnosed with just a volt meter. So here's what you do:

If the battery puts out 12 (v)olts with the engine off you are good. If not it is likely bad.

If good, then start the car...you should have 13.5+v. If not the alternator is bad.

If so leave the car idling and turn on every electrical thing you can think of in the car and load the system. Then check again...13.5+ you're good, if not your alternator is getting weak.

If that's good then take a drive to charge the battery up. Then come back and turn off the engine. Test battery voltage...12v good, less than that is bad.

If things are still good, let the car sit overnight and test the battery in the morning, if you don't have 12v the next day then either your battery is bad or you have a draw. You can either: guess the battery is bad, or if you have a decent voltmeter measure the draw across the battery with the car off, more than 100mA is not good, or alternately you can disconnect the battery negative cable, leave the car sitting overnight, and see if the battery goes dead the next morning, if it does your battery is toast, if not then you have a current draw issue to fix.

Following the procedure above I have been able to troubleshoot and fix almost any cars charging system than I have dealt with. Less common grounding and overcharging issues make things more difficult.

Hope that helps, wouldn't want to buy a new battery, be it Optima or my favorite Sears Diehard Gold, without knowing what the cause of the problem is.

-Andrew

slater442w30

One thing you can do, jump the car to get it running, then unhook the negative battery cable while it is running, if the car dies then the alternator is bad, if not then it is probably the battery.

SamuraiBill

yes optimas are worth the money, but is alot of money a battery

xIntegrax

ok i decided not to buy an optima battery because 1) it is expensive 2) my area has a theft problem. i live at college at a apartment complex with no gate, so thieves tend to break into a lot car like mine. shit my car was already broken into twice the first month i move in and they stole my subwoofer, lucky not my amp cuzz its under the passenger side seat. i dont want those dam theives to see the optima battery and jack that shit too if they open up my hood.

so anyway back to the topic, i went local kragen and got a new battery for $60 buck. everything seem alright until the next day when my car die again. so all i know that there is a SHORT or DRAW in my car. (F*CK) does any know or have any idea wat may be the source or cause of the short and where is it coming from so i can fix it. please help becasue i hate jumping starting my car. thanks

00_gsr

One way to start narrowing down where the short is by removing one fuse at a time. Take out a fuse and leave it over night. If the battery doesn't get drained then you know the problem is on that circuit. I know that is is a pretty painful way of doing this. Good Luck.

xIntegrax

there has to be a better way

Power6

There is...Get a hold decent multimeter and measure current draw with the car off. Then you can start pulling fuses and see which circuit is drawing. Much easier than waiting overnight to see if the battery dies.

-Andrew

GSRRacer95

I have the Yellow top. I think it was worth the money....free!! My Battery supplier @ work gave me one to try out, but I just kept it!!

k.a.y

Man, I've put red tops in my teg, my brother's accord, and my mom's subaru, and a yellow top in my Prelude, and my friend's got a yellow top in his eclipse, and they all kick ass. I'd recommend them to anyone. It's sort of like buying a tool from a reputable company like Snap-On. It more than likely won't fail, but it does, the rep. will take care of you the next time they come. They stand very strong behind their product.