Ouch.
My best guess is that there is either something wrong with the replacement battery, or the wiring.

Suggestions:

Be sure that the negative (has thumb quick disconnect) is locked on properly. If sitting loose on the terminal, it might give you similar issues. If you did not lock it onto the post properly, it could spring loose without coming off of the terminal (looks good, but no proper connection).

Clean the connectors (the ends of the battery leads).

Have the new battery tested.

 

I put my 4C in storage through the summer because of home remodeling issues in my garage, started the car every 2 weeks and let run for 20 minutes each time.

1 month ago, I start the car and the battery is dead…. I’m at 23,000 miles, so I assume battery is bad from age. I replace it. The car starts up and I drive it home. We go to drive the 4C after a few days and it is dead again. I jump off the car and I let it warm up and take it for a drive. Later that day, I go to start it and it starts just fine, but the next day it’s dead.

I jump the car off and drive it to the stop sign next to my house and it dies (puts up a transmission error) , jump it off in the street and take it to my garage.
This morning I have some time, so I jump off the car to take it to somewhere to have electricity looked at, I drive around the block and the engine light comes on. I go back to my driveway and the transmission (!) and engine light are on.
I turn the car off and everything goes dark, when I put my key in, nothing comes up at all. With the key in the ignition I put my battery jumper on the negative terminal only, and the instrument panel comes to life. I remove the battery jumper and I start the car, and it runs fine, no engine or transmission lights. I drive the car to my workplace (that is a glass shop I can work on the car at). I pull the car into the shop and turn off the car and everything goes dead again. I put the negative lead of my battery jumper on the battery, instrument panel comes alive. Try to start the car, and Everything goes dead.

Any ideas where to start looking for issues?

1. Test battery free at walmarts or battery stores. Should be above 12.75V especially new. Make sure connections are all plugged in correctly (lol)
2. Test alternator, can be done various places but they will basically run the car and look for a voltage drop between the in and out... Given how aggressive the lack of recharge, a bad/shorted alternator would mean zero output.
3. Take to dealer to reset computers in case of security lockout of a short somewhere in the harness (which means you either had a vermin chew at something or some tech didn't secure something somewhere major and the frayed wire is just dumping unto a metal ground).

Otherwise you have proof of alien activity, magical gremlins, or your tail light fluid is too low.

 

Found a loose quick disconnect negative terminal, Buying a new negative terminal.

found a blown fuse on a positive cable close to the battery, replacing the fuse

I will go through this process and report back

 

Thank you!

it was low tail light fluid, fixed it right up

 

Had to be that or muffler bearings!

Glad you're back in business!

 

The old negative battery quick disconnect clamp was worn out, refreshed all of the negative battery connections, back in business

 

These cars operate on perfect voltage and some gas. Glad you found it!

 

i agree....but not just ALFA 4Cs....all new cars are extremly dependent on clean power....voltage and amps AND no electronic noise.

 

I was going to suggest that the battery clamp was the culprit....it is important to make sure that that clamp is fully seated on the negativer terminal. However you mentioned a low brake fluid....was it turning on a low fluid warning light....that could cause a drain on the battery but suspect it would take a long time before it would drain the battery..

 

I wouldve suggested battery terminal connectors were oxidized and needed a scrubbing especially if the car sat awhile.

also wouldve suggested that the negative battery connector wasnt seated fully. Simple way to check that is to grab the negative cable near the quick disconnect and try to spin it on the negative terminal to see if it is loose.
side story, i replaced the OEM battery with another OEM battery and the negative terminal quick disconnect had a hard time fully seating securely even though it was an OEM battery.

good that you found the blown fuse.

 

Sounds like parasitic draw if not bad battery. To test, get a reading of amps coming out of battery and remove fuses one after the other. If the amp reading drastically lowers then the last circuit into which the fuse is hooked up is the issue