Nickel-metal hydride is a very stable technology

I recently repaired a hybrid pack from an 2002 Prius. When I saw it, the check engine light was lighted and the master warning light (red triangle of death) was displaying and the following ODBII codes: P3000,P3006, P3020, P3023, P3024. It has been driven after the the warning lights were lighted and probably extensively. (recent change of ownership so missing data) All of the modules were within a tenth of a volt except two. The two modules were reading about 1 volt low. When I pulled them out I saw that one cell in each module had exploded and and emitted a black substance. However there was no obvious deterioration to the surrounding cells even the other cells in the same module. They were just blackened.

On the same page I have a picture that explains ODBII codes: P3011, p3012 etc. These are the codes that indicate out of spec differences in internal resistance or voltage in parts of the pack. The 2001 manual just refers to block 1, block 2, etc. but they are not fully defined. Later manuals probably have even less information.
With this picture the P3011+ codes can be more fully understood.

I think you will like the pictures A LOT! Just go to Hybrid Battery Repair = Repair is far cheaper than replacement or rebuilt AND SCROLL DOWN TO THE BOTTOM OF THE PAGE!

 

Our warranty rate on the Yellow tops been running less the .5%. This is very low for a lead acid battery. Yes there have been some failures and some customers not happy but the over all failure rate is very low. Also, I am not get much repeat business from my customers and I started selling the Optima battery to the Prius community in 2007. That is now seven years ago. One customer whose battery failed after four years told me that it was ok because the OEM battery only lasted for two year for him. (He spends a lot of time with the car in accessory mode.) Another customer recently wrote me and said that after two or three years his Optima Yellow top battery was still showing over 100% of the rated Cold Cranking Amp spec.

One important datum is that the Optima Yellow Top is a deep discharge battery. Lead Acid Batteries can be chemically configured to to delivery lots of cranking amps or more deep discharges. It cost a little more to create a deep discharge battery. You do not need cranking amps on a Prius because the battery never cranks the engine, the High voltage battery does. So a deep discharge battery is ideal for a hybrid.

Basically I am like the Maytag repair man. A customer asked me to repair his Hybrid battery in August on his 2002 Prius which I did and he was and still is very happy. Usually just a few cells have failed you replace a few modules and from red triangle of death and car running very badly you have a normal Prius again! But it is a lot of work. If you are in the Los Angeles area I am happy to do it. Give me a call at 818 364 9810 Bernie