Shaken-Not-Stirred Technology Mixed Right!

I was an early adopter of Hybrid Cars. I actually owned the first Gen 1 Prius delivered to a customer in the United States, or so the dealer told me. Sadly that car was totaled in a flash flood at the corner of Carol Street and 4th Avenue while I was rehearsing an opera a block away.

I replaced it with a brand new 2006 Generation 2 Prius which 110K miles and 13 years later started to show traction battery troubles.

In addition to the reduced MPG I was seeing issues I had come to know from my experience with NiMh batteries in 2 way radio service. Discharge was happening quicker, even self discharge when parked. Often the battery would become fully charged (according to the dash display) in a very short drive, and then be down in the purple 1 or 2 bar danger zone after being parked for a very short time. The issues seemed to be worse in warm weather. I could leave the car parked showing fully charged and return in as little as an hour to find the battery down in the danger zone. Clearly it was time to do something before I got stuck someplace with a non-functional car.

I hold an Extra Class Amateur Radio Operators License and a Commercial General Radio Telephone Operators License with Radar Endorsement, so one can say I know a thing or two about the flow of electrons in circuits and the ways of batteries. Armed with my knowledge in the field of electricity and electronics I hit the web for answers on Prius Generation 2 battery replacement.

I found rebuilt batteries for as little as $400 from a small time operator in the Rochester, NY area all the way to New 8AH (1.5 AH more than stock) at $2149 without installation.

The advantage of the larger than stock battery is the ability to capture more regenerated energy and a higher MPG in normal operation. While I was very tempted to order an 8Ah battery from the west coast the realities of trying to do the install parked on the street in Brooklyn and it being my first time tearing the car apart that much had a big influence on my decision. I decided to opt for a BRAND NEW battery of 6.5 Ah, just as when the car was new. A big plus was that I could get it installed in nearby New Jersey.

I ordered a new 6.5 Ah battery from Greentec Auto for drive in installation at their Livingston, NJ location.

Knowing I would be driving to NJ, I of course ran my gas tank down to bare minimum in anticipation of a cheaper fill up on the other side of the Holland Tunnel.

Stopping in NJ for fuel proved to me that I was not getting my 13 year old battery replaced too soon! In addition to my usual milage being down to between high 30s to low 40s and the fast self discharge, now after a fast fuel stop, the hybrid system refused to come back on line. Eventually after 3 attempts the system came on line, showed me the pump jockey did not fill my tank, but rather gave me a 1/4 tank, and the system was READY but at the dreaded 1 purple line on the battery meter.

On arriving at the Greentec Auto location I met a personable gentleman named Amir who asked me why I thought the battery was in need of replacement. He then checked the codes out of the diagnostic port from the onboard system and asked me if I changed my own oil and if I had been resetting the codes. It seems no battery faults were showing in the system in spite of all the obvious symptoms. It seems that when I have taken the car to PEP Boys they have been clearing all the codes with each oil change. This little nugget has convinced me to get a code reader so I can regularly check codes and note them in the car log book.

After confirming to Amir that in spite of the lack of computer log data in support of a battery change I wanted to change the battery I signed the work order and Amir pulled the car halfway into the garage bay. He said he was going to leave the back out of the garage because it was a nice day and he could tell that I wanted to watch how the job was done.

In short order the two of us moved my storage box out of the back of the car and I removed all my ham radio antenna cables and the cable from the 12 volt battery to my radios in the front of the car. Amir next removed the carpet in the back and the cover over the spare tire as well as the small cargo tray that sits on top of the spare tire.

Once that was done Amir unbolted the seat backs of the rear seat and removed the trim over the traction battery. Once the battery case was totally exposed he removed the high voltage interlink on the port side of the battery to allow unbolting the HV cables with no voltage on the terminals. He also removed all the trim from the rear of the car and disconnected the 12 Volt battery. Then it was time to make heavy use of his power driver removing the multitude of screws that held covers over the various wires and air ducts leading to the battery as well as the screws that held the battery in place.

In short order, while we listened to a podcast by Neil DeGrasse Tyson, Amir had the old battery out of the car and sitting on a cart ready to be wheeled away to the outbound recycling pile. Amir then swapped in a battery that consisted of NEW 6.5 Ah cells in a Toyota battery frame that had been painted green. I was pleased to see that Green Tec paints the battery cases they install as there was surface rust on every piece of unpainted steel in the rear of the car. I see another teardown in my future to clean and paint much non-painted steel.

In short order Amir had the new battery bolted down, ventilation ducts reconnected and wires firmly screwed down. He then connected the 12 volt battery and installed the BIG ORANGE INTERLINK to allow my 13 year old Prius to come back to life. Amir then stepped up front and started the hybrid system. The Prius lived!

In an amazingly short amount of time Amir had the car put back together. I connected my radio antenna and power cables and we put my big box in the back of the car. We were ready for a test drive.

Amir explained that we needed to run the AC at MAX with the windows down to really put a strain on the system while we drove 7 to 10 miles and observed the way the car operated.

On getting on the road out of the shop I saw an immediate improvement in operation. The battery did not slump down on acceleration and when we hit the highway the battery climbed steadily from 1/3 to 2/3 on a combination of ICE operation and regeneration. When we turned around to head back to the shop I floored the accelerator and quickly ran up to 60 MPH. This was a test to see if the battery was "stiffer" than the old battery. It was, the battery did not show any change on the in dash metering.

On returning to the shop I paid the $2132.50 bill, which included the new battery, installation, and taxes. I then reset the onboard computer to zero miles and zero mpg so I could monitor my performance on the trip home. The results are in the photo attached to this posting. The display shows 56.2 MPG on the return trip while the trip to Livingston was only 42 MPG.

It is worth noting the best millage I got when the car was brand new was 54 MPG.

So for the price of a new Green Tec battery installed by a nice, knowledgable professional who listens to Neil DeGrasse Tyson podcasts I have a Prius that is preforming like a new car.

Considering that the only other work the car has required in 13 years has been one replacement of brake pads and oil changes the cost of ownership for a Prius makes the investment in a battery, that I will probably get another 13 years out of, a win.

If you have a Prius that is showing the signs of battery fatigue I highly recommend Green Tec Auto. Tell Amir I sent you and he may play Neil DeGrasse Tyson for you as well.

-Brett
wynkoop--at--tekhq.com