dead battery or alternator
 

so anyways got up this morning to go to work and my battery was dead completely, after i got a boost when i was driving the voltage on the battery ranged from any where from 12.5 to 13.5 volts while to alternator was charging when driving, my question is, is the battery dead or is the alternator going because when driving before it was constintly at 13.8 or 13.9 volts even with the headlights on and my sound system running.

some help would be much appreciated

thanks

first of all, turn off your system when things like this happen, go get it check out, and NO not canadian tire, a check up should be free...what are you waiting for....go now :thumbup:

bring it to check right away... maybe ur personal mechanic... and yeah (hahaha) definitely not cdn tire!!

btw, if its your alternator, i think after you boost/jump start the car, it would die quickly again??? because the alternator wouldn't be charging up the battery or run the power in the car if its dead (correct me if i'm wrong)... do you have other electronics running in your car? also, how long you had the battery for? maybe its old? or maybe its defective?

again correct me if im' wrong, i would love to learn from mistakes

have the battery tested. winter is coming so if the battery is weak you wanna replace it anyways. however, the altenator voltage does sound a lil low as well.

13.8-13.9 is average not the best, but it still holds a charge. But if u have a sound system in your car u are going to kill the alternator really hard. Replace the battery and see what u get. No matter what buy a battery first because i know the battery is done.

Your alternator should be reading around 14.5 but 13.9 is still good but not the best. So change the battery first and see what happens.

check to see if there is any draws on the battery like a trunk light etc...but I would assumer your voltage reg is going out....

its a pretty bad idea to buy a batter winner007. the altenator will suck the life rihgt out of it..get the alt first then the battery

Your Alternator isnt charging right. Should be between 13.9 to 14.4 depending on your cars's electrical load.

12.5 to 13.5 is clear indication that your Alt is on its way out.

And Canadian Tire does have some very educated and experienced mechanics. I know, cause I worked there for 3 months about a year ago.
However, an AVR test (Amperes/Voltage/Resistance) is usualy performed by Lube techs. So yeah....

take out the battery and bring it to ct...if you know what youre doing, take out the alt and bring it too and get it tested aswell.

Off topic a little: How much Cold Cranking Amps should one look into a battery?

i had a similar problem lately.. jus got it fixed today in time for the new year

i turn off my car waiting for a friend and when i tried to turn it back on.. it wouldn turn on.. so i had to get a jump start.. next morning same thing.. so i took it to a mechanic and he charged the battery.. 1 crank and it starts.. he also checked the voltage and said the alternator is not charging the battery

get it checked still