long story short

wifey drained battery listening to music without car running (we assume).
jump start her jeep from mine no problem
she calls an hour later because her jeep wont start
i drive to jump her off and all good
take it to advance auto
they say batter is good just at around 435 CCA when it should be 615
they also test alternator and it is great

had it on trickle charge all day yesterday AND overnight

VERY hard start this morning even though trickle said fully charged

any thoughts? my knowledge base on the electrical side of things is pretty minimal but I can't understand why it was a hard start?

battery terminals are clean and connections are snug.
charger is a "battery tender by deltran" and does 12V and 6v. yes I had it on 12V setting

any idea?

 

Trickle chargers do just that, trickle. Typically at quite low amperage rates. It could be that your battery is either on the weak side, or not fully charged. If it were me, I would get a new battery with the proper CCA. I try to change batteries as a preventative maintenance rather than waiting for them to die and leave me stranded.
Also, for just playing music, a healthy battery should be able to last many hours without going dead, that the fact that it died playing music would be my first clue that it may be time to replace the battery.

 

it was on the trickle for 20 hours or so. you think it still wouldn't be fully charged?

advanced auto ran their diagnostics on it and said the batter was good just needed to charge?

 

How old is the battery? I still stand by my assessment that the battery is the first thing I would change. A quick google search says that a typical new battery should have about 750 cca. You don't have data from advance saying your battery is anywhere near that.
Another possibility, though less likely, is an issue with the starter. A starter that is hanging up can mimic a weak battery. But if your battery is 3 or more years old, just replace the darn thing anyway if you plan to keep the Jeep for awhile

 

planning to keep a while. no doubt. it is an auto so if the battery is good i figure it could be the starter or the neutral safety switch?

i'll check the age of the battery

 

Is it cranking or no? Can you be more descriptive of what happens when you turn the key.

 

yea so it acts like the battery is low on juice and just kind of struggles to turn over. you have to hold the key in ignition for a few seconds, it struggles, and then eventually fires up. but you have to hold it onto ignition for 3-4 seconds before it finally kicks. like it feels like it isn't going to get turning over.

 

so it did actually crank this morning finally

BUT it fires up VERY easy when i hooked my jeep up to jump it off. so maybe it is just the battery?

 

so its from 12/17 - probably just need to replace it

 

I don't know if you can trickle charge with the battery hooked up, It might prevent the computer from fully going to sleep. Both my chargers state to disconnect the vehicle negative terminal before hooking up the charger.