Funky battery conundrum

starting
batteries

#1

“Joe Friday” style “just the facts”: 93 Mazda MPV. Battery only 6 months old. Left light on and ran battery dry. Hooked up trickle charger, charged to 100% (12+ hours) but wouldn’t start. Jumpstarted and drove 30 miles, but wouldn’t restart. Re-hooked-up the charger, which now showed 50% charge. Ran back up to 100%. Tried to start it, got only two weak turns of the starter motor, and then the charger showed the battery’s charge back down to zero. Battery does have water in it. Aaarrrgh! Any ideas? THANK YOU!


#2

When you attach the charging clamps, the clamps touch the battery posts; otherwise, it couldn’t recharge the battery. The battery terminals aren’t making ELECTRICAL contact with the battery posts. Disconnect the battery cables and scrape them where they contact the battery posts.


#3
While I do suggest making sure both ends of each battery cable are clean and tight, I suspect you killed your battery.  Car batteries are not [i]deep discharge[/i] batteries and they can be damaged if totally run down.  Your is showing classic signs.

#4

I agree, most auto batteries will not survive being completely discharged. I killed on a few months ago due to a failed alternator, about a week later I ended up replacing the battery because it would not hold a charge. My battery was less than one year old.