Went to leave this morning, almost completely dead battery!

So several months ago challenger had a dead battery. Cant recall date on battery, but it was old..
Bought new battery, installed, no problems. til today. Wont jump, battery says it 10.5, another battery says 11.0. Just so happen to have old battery in shed. Sittting there approx 3ish months. It tests at 10.9. Based on what I know alt/starter? Loose starter wire? Tell me something I am overlooking! Thank you!!
On charger about 15 min, says battery full. Wont start. So starter bad ?

 

Define "won't start."
Do you even hear a click when you hit the starter? If not, your starter solenoid's not actuating, evidently.
It may be a failed relay. You can check the fuse/relay box for them
Or does the starter engage but fail to turn?
In any case, it is not an extremely difficult fix.
If you get a jump off of another car, you can then see if the battery is the main problem. It does not sound like your charging system is doing a great job of keeping your batteries alive.

 

Does not click, wants to start but doesn't.

Will check fuse/relay. Let you know results

Voltmeter read 10.5, fifteen minutes later says completely charged

Thank you!!

 

Will not jump, still wants to try and turn over. Starter fuse is fine.

 

Can you clarify? You mentioned the battery is dead and a jump start doesn't help. This normally means the engine will not rotate or "turn over" and the most you'll hear is a clicking sound every time you push the start button. But your last message said " still wants to try and turn over". Does that mean the engine is rotating and it just won't fire and run? Or does it mean the you hear the engine just start to rotate but quickly stops after one "ugh"?
One last question: Is the 10.5 volts when your trying to start the car or when its just sitting there? A good battery will read at least 12.5 volts sitting. I can see the voltage drop to 10.5 volts if that's when you're pushing the start button.

 

Will not jump.
This means that the car is either not sending any start signal to the starter relay or solenoid or the starter is just flat dead, I think.
I think you may need to actually examine the starter itself.
Three modes of failure:
A) signal to turn on solenoid via relay not operating
B) signal to starter from relay not operating
C) starter not operating
D) starter operating but too weak to turn engine over properly

Since it "tries to turn over" does it partially turn? If the starter is just too weak to do its job, it may just be a starter getting old, especially since jumpin it, which should provide LOTS of power, is not having the desired effect.

 

10.5 sitting there.

when turning key to start, will do its normal try to start noises, then nothing and a click. Sorry first car computerized and unsure of wording. I then have no power and odometer reads zero. Seems like not getting juice from battery outwards.
Give me a carb, I'll rebuild entire engine for you.

 

Does not turn over. Going to put it on ramps tomorrow and get a better idea.

Thank you for your knowledge and answer I really appreciate it. All of the people so far but one have been so great!

 

Although it doesn't happen often, your battery could have a plate that's partially shorted to ground. When that happens, the battery won't take a charge or a jump start. It may be worth your effort to disconnect the battery and
1. have it tested where you bought it (or Auto Zone, Advanced Auto etc.).
OR
2. if you can borrow a fully charged battery, connect it up with the questionable one disconnected... NOT as a jump start.

Good luck, keep us posted.

 

Will do, thanks!