WON'T START, BATT READS ZERO

are the inside of the battery terms dirty,corroided? do you know if motor alt is charging batt? how long did it run when you put new batt in? if it lasted about two days, its proubly not charging, also make sure nothing is being left on draining batt down, to check that, leave batt nuhooked pos side over night.

not sure what you said but.
seems the battery is discharging,? 12.6v is fully charged,
own a voltmeter?
try a good loaned battery , does it start the car,?
i think you meant?
i can jumper cable start my car at any time. (off another running car)
but after running my car, the battery discharges and it will not crank at all. right?
this means ,the charging system on your car is bad.
if the starter cranks great, then the engine is flooded or is in great need of a tune up (sparkplugs etc)
if flooded try the super secret in the op guide, crank with throttle wide open , this magic trick cuts all fuel injection allowing the flooding
to purge away, and eventual starting.
my guess 2 is the car wont start, so you crank the battery flat
you jumper start it and it runs. (luck)
then day 2, same deal cranks ok but wont start.. ever tune up the engine?

Sounds like you have a toasted battery or alternator. Have you performed a load test on the battery? Have you tried to charge the battery? First remove the battery and charge it externally from the vehicle. If the battery won't hold a charge, or won't hold a charge of 12 volts, replace it. Once you have the vehicle started, test the operation of the alternator. It should be putting out at least 13 volts back to the battery to keep it charged - if it is putting less than 13 volts or more than 16 volts, replace the alternator.

completely charge the battery , most things in the car will run on low amps,, but the starter requires a bunch, if you have a walmart near you they will charge and do a LOAD test on the battery for free,, I suggest a Load test anyway, since it can read 12 volts yet a cell in the battery can be dead , also, make sure all battery connections are clean and tight, if possible have the OBD codes read, there are places that do this for free ,, so check around,

Battery might seem fine on a routine check, but the crancking amp power is not there anymore, seems that your alternator is not charging it anymore, have the alternator checked and replaced if needed, the battery might need replacing too.

Get the battery & the alternator checked (Autozone, O'reilly's or even Pep Boys can do that for free). If the alternator is out or going out, it's not charging your battery - that means everything electrical in your car is now trying to run directly off the battery & draining it (it doesn't take long - especially if the lights or A/C is on). If those check out ok, take it into a mechanic & have them run a diagnostic - you may have a relay out. Good Luck.

It sounds like you have a charging problem-alternator is not recharging batt when drive, batt will only go so far before it runs out then you get your symtoms. you would need a volt meter to double check this. Fully charged batt will be about 12.7volts once car is started and running you should see about 13.8 to 14.2 volts at batt terminals if alt. is chariging batt. the other item that can cause this is the volatge regulator that controls alt. which are sometimes built-in alternator and sometimes they are external to alternator. and of course make sure your belt is turning alternator to allow it to work. One other small note if you do the engine running test-somtimes- if your car idles low(600 or 700 rpm) you need to give a little throttle (1000-1200rpm) to make sure alternator is turning fast enough for output test.

If your battery gauge went to zero whilst driving it sounds like your alternator stopped charging. Either the alternator itself failed or you chewed a fan belt. If you jump started it, and the battery light stays on or the gauge still reads zero then that would confirm the above.
Driving or running the car without alternator charge will simply run the battery to zero. it will be quite hard to even jump start after that.
Check for broken,lost belt and get it running again and watch the gauge/batt light. If its on, its not charging, if its off then you most likely have a battery going bad.

Sounds like your battery is tired and isn't holding charge as deeply as it did. As batteries get older they don't charge as deep into plates. Your reading of 12.6 is just surface reading. Have local parts store load test it -- they do it for free

change the starter motor.