Hello all,
My 05 Civ Hybrid had the original battery, 220K miles. It went bad and wouldn't retain charge. My neighbor actually works on those hybrids as a side gig and he replaced the bad cells (18 out of 20 apparently) and rebalanced them.
I reinstalled it in the car, but the problem is worse now. IMA light is constant, red battery light is on, hybrid battery never shows any progress in charging.
I tried resetting by removing the IMA, the ECU, and the backup fuse and disconnecting negative 12V battery terminal for 10 minutes. No joy.
We put all that back and started the car, neighbor then removed the negative 12V terminal while the car was running and the car showed signs of low current and then died.
Neighbor believes the alternator needs replacing.
Does anyone here know whether
1. these cars do indeed have an alternator?
2. whether that might potentially resolve the problem?

 

Going to be blunt.

Based on the information provided, your neighbor is incompetent with regards to your vehicle even if he has experience/competence with other models.

He likely did not do a quality battery build.

No Civic hybrid has ever had an alternator installed by the factory.

What codes are the car reporting?