My wife’s B5 Passat put the final nail in its coffin when it decided to free all the coolant from the heater core so we decided that it might be time to pick up something newer. I found a dead Civic Hybrid at a nearby auction and decided to buy it and attempt to repair it.
The Civic Hybrid was a 2003 model with just over 80,000 miles. It was sitting in the corner at the Copart auction yard near a recovered flooded boat and a pile of metal that had resembled a car at one time. I flipped the key and nothing happened so I get out my mini jumper pack and stuck it on the battery. Once it got power I notice the Christmas tree of lights that included the IMA Battery light and the check engine light. I plugged in my Bluetooth OBDII reader and pulled codes, which amounted to a few IMA errors and a bad oxygen sensor. I recorded the codes and went home to do some research before the car went through the lane the next day.
The codes I recorded lead me to believe that the hybrid battery was bad so I took a look at replacement prices and a refurbished battery from the dealer was around $3200. I also found a few aftermarket options for around $2000 but decided to search on. I ended up at the InsightCentral.net forum and found lots of information on charging and rebuilding battery packs. This led me to 99mpg.com, ran by Mike Dabrowski, who offered ready built grid chargers as well as plans to build your own.
With my new found knowledge, I logged into the auction the next morning and bid $2200 on the derelict Civic. I sat there for the next few seconds watching to see if I would be outbid but the green light popped up shortly and I was the proud owner of a 2700 pound yard ornament. I received the final invoice shortly and was on the hook for $2600 after all the auction fees. I got dressed, went to the bank then got together with a buddy that had a trailer and went to pick it up.
I brought the car into my shop and replaced the dead 12V battery and got it cranked up and cleared all of the codes. I gave it a short drive around the neighborhood and all of the error lights came back on as well as a new one. I also found out that the CVT transmission was jerking and trying to escape from the car. At this moment, I thought that the guy with the big gold chains that was at the auction preview and crossed the car off his list might have been right but I decided to continue on.
I went ahead and replaced the oxygen sensor for $60 as that was an easy fix and that code went away for good. I also found the procedure that Honda techs did to repair the CVT transmission called burnishing. I went to the Honda dealer and picked up a double order of the revised CVT fluid. I dumped what was in the transmission and filled it with the new fluid. I drove it around for a few miles and it felt slightly better. I dumped the fluid again and filled it up with more fresh fluid. I performed the burnishing procedure and went out to test the car. I was happily surprised that the car was not shaking any longer and satisfied with the repair.
Note: The Civic Hybrid uses a 144 Volt DC battery that can and will kill you if you are not careful. Please follow all precautions for working with high voltage and be careful when dealing with these components.
I decided to build a grid charger myself and I hopped on Amazon and ordered 2 90V DC power supplies that would be the power source to juice up the hybrid battery. I also bought a 12V DC power supply that would run a cooling fan and voltmeter. The remaining components were a potentiometer to control fan speed, and an aircraft style locking connector. I also dropped by the local Radio Shack, walked through the tumbleweeds and picked up some diodes, fuses and an inline fuse holder.
I found an old computer power supply in storage that I would use as a case. It was handy because it already had a switched plug and perforations for cooling. Once all the stuff arrived I followed this thread and started by gutting the power supply and cutting a hole for the fuse holder. I wired up the 90V drivers and hooked them up to the aircraft connector that I had made a hole for on the side of the case. I also hooked up the 12V driver and connected it to a cooling fan and ran a wire for the potentiometer.
I had to use a potentiometer as the Civic Hybrid uses a PWM signal for the battery pack cooling fan. I found that the range was around 20k ohms so I got one rated for that range and installed it into the side of the case. I used some Deutsch connectors to modify the fan hookup in the car so I could connect it to the charger easily. I also added a voltmeter so I could monitor voltage and packed everything up inside the case. I plugged in the grid charger in outside the car to test it and it came to life. The voltage display showed that it was outputting 186.5 volts and the cooling fan was spinning.
I went into the car and removed the rear seat to access the battery compartment. I noticed the sticker telling me I would die but decided to keep going. I measured the distance from the terminals to an accessible area in the trunk and used the other end of the aircraft connector to build the harness that goes into the car. I switched off the main switch for the battery and put on my rubber gloves and hooked up the wires. Everything looked good so I flipped the switch back on and was happy that nothing blew up.
I decided to test the battery cooling fan first so I plugged in that harness and turned on the grid charger. I was happy to hear the hum of the fan and even happier when it would speed up and slow down as I adjusted the potentiometer knob. I figured I would give the charger a test so I shut it off and plugged in the aircraft connector that went to the hybrid battery. I flipped it on and it showed 163.4 volts on the display and nothing started smoking. I went to grab a beer and pulled up a chair and watched in excitement as the meter slowly started to rise. Success!
I did a few other things around the shop but kept watch of the battery and after a few hours it was up to 174 volts. I disconnected the charger and disconnected the 12 volt battery to reset the “State of Charge” meter and put everything back together. I took the car for a drive and the charge slowly rose to full. I drove it around that afternoon and the next day and was elated to see that the gas mileage was staying at over 50 miles per gallon! I checked the codes a few more times and they had not come back so I cleaned the car, got it inspected, and handed it over to my wife.
The car had cost me about $2750 after replacing the oxygen sensor and the CVT fluid and the components to build the grid charger ran another $100 so all-in I was at $2850 and the car was running. My wife drove the car for about two weeks after the initial charge and it ran well and averaged about 48-51 MPG. After that point, I would connect the charger every few weeks for a few hours to top up the battery and was able to maintain it while we owned it. She drove the car happily for 2 years and recently we decided to get something bigger so I took it to Carmax and got a quote and then went to a local dealer that had the car we wanted, a Saturn Vue Hybrid. I was able to negotiate a $2700 trade in value for the Civic at 97,000 miles and turned it over to the dealer.
I checked back on the Civic through AutoCheck like all normal people do and saw that the dealer sold it off at auction where it was bought by a smaller dealer. It was then sold by the smaller dealer a few months ago and shows up as registered by a new owner recently. I actually enjoyed the car and playing with something different and the best part was that we only had a $150 net cost on the car after driving it for 2 years and 17,000 miles. I may pick up another one in the future to add to my collection of cars that every normal person would pass over.
[Photo Credit: Copart, Bozi]