As you probably know, before I got my Honda Fit EV, I drove a Honda Civic Hybrid. For the most part, the Civic Hybrid was a great little car that saved me lots of fuel. However, about a year and a half ago, the battery started to act up.
The Civic Hybrid keeps track of the IMA battery’s state-of-charge (SoC) in an interesting way. What it does is start with a full battery and keeps track of the SoC by calculating it based on how much power it has put in or taken out of the battery. However, this method isn’t perfect, and the battery will eventually end up at a lower SoC than the car thinks. When this occurs, the car recalibrates the battery pack. During the recalibration process, the car uses the gasoline engine to recharge the battery pack, which not only inhibits fuel economy, it inhibits the car’s acceleration to a dangerous level. A new vehicle will only do this occasionally, maybe once or twice per year. At that rate, it’s not a big deal for the driver. However, as the vehicle ages, the battery pack deteriorates and begins to calibrate more often.
About a year and a half ago, the battery began recalibrating about every week, which got pretty annoying as I’m sure you can imagine. I read up on the issue online and decided that my best course of action was to replace the 12V battery as a bad 12V battery could be putting a larger load on the IMA battery (the car has no alternator and the 12V battery is charged from the 158V IMA battery through a DC-DC converter). Unfortunately, the new battery didn’t help. I was seeing recalibrations at the same frequency.
In December 2011, I started to record the frequency of the recalibrations. I recorded all sorts of data including time, temperature, and odometer miles (Siri made recording this all very easy during my drive). I wasn’t able to find any pattern as to when the battery would recalibrate. At this point, the battery was recalibrating about once every three days. After a few weeks, I got sick of logging the recalibrations and put that on hold.
In February 2012, I began logging the recalibrations again. At this point, the recalibrations were occurring about every other day on average. I started to notice a pattern at this time. The longer the car sat between drives, the more likely the car was to recalibrate. The length of time was shortened in warmer or colder climates. Remember, I’m in San Diego so cold is 40F and hot is 85F. The chance of a recalibration occurring was also greater if the AC was running, as the AC puts an extra load on the IMA battery pack.
In March 2012, I was still logging recalibrations. I took a 900-mile road trip and the car only recalibrated once on each 450-mile trip. After the first recalibration the car essentially drove normally. (Note: There have been several shorter trips where the battery recalibrated twice). At the end of March, I once again got sick of recording the recalibrations and took a break.
Not much changed between March 2012 and August 2012. The recalibrations became more frequent, but I hadn’t done anything about it. Once I received my Fit EV, I was able to take the car in and not worry about being car-less. I took the Fit into Hoehn Honda in Carlsbad in early September. When the tech turned the car on, he noticed that it started using the starter motor. Generally the Hybrid motor will start the engine, creating a softer, quieter, more efficient start. However, if the IMA battery is too low, the 12V starter motor starts the car. I’m glad this happened to the tech, because it really shows what shape the IMA battery is in.
Hoehn Honda’s explanation was that my ScanGauge (an OBD-II trouble code reader, that reports faults, MPG, temperatures, RPM, and all sorts of info) was putting too much of a drain on the battery. There are a few problems with this. First, the OBD-II port is powered from the 12V battery, not the 158V IMA battery. A drain on the 12V battery will not affect the IMA battery while the car is sitting because the DC-DC converter (what charges the 12V battery from the 158V battery) only operates when the car was running. However, let’s assume that the scangauge was somehow linked into the hybrid battery. The dealership gave me current drain numbers (though they were initially in Volts, then Amps, then I corrected them to milliamps). I did some quick calculations based on the numbers they gave me (60mA drain over 12 hours at 12V = about 9 Whrs, or 1.0% of the original pack capacity). That is about two iPhone batteries worth of energy storage. But remember, this is irrelevant because the scangauge isn’t draining the IMA battery at all.
Still convinced that the ScanGauge is the issue, Honda disconnects it and charges up the hybrid battery. The next morning they turn the car on and the dash is reading 100%. They say it’s fine and ask me to come get it. At this point, I should have asked them to drive the car, because I knew it was not fine. It always shows a good SoC in the morning, but once the car is driven for a few minutes the recalibration process begins. I went to pick the car up and within 20 seconds, the battery dropped to two bars and began recalibrating. This further proves that the ScanGauge was not causing the issues, so I left the car at the dealership for the tech to look at again.
However, the tech was still convinced that it was the ScanGauge. He used his DTC tool to measure the battery’s capacity and it read 75%. He explained that there’s no way a 5-year old battery would be in that good of shape, so he knows his reading was wrong. What worries me is that if 75% is not expected at 5 years, Honda must be seeing some extreme degradation. Anyway, he told me that the reason it was reading 75% was that because the ScanGauge had been causing the computer to reset every night, the car didn’t have a good idea of the capacity. After researching online, I found that the cars almost always read 75% after the battery has been charged. They don’t read the true value unless the car has been sitting overnight. I’m not sure if the 75% number is a software bug or another trick that Honda put in with the latest software update. I’m glad the tech realized that number was incorrect, but I wish he knew how to get the right number instead of giving me the car back. He basically told me to drive it for a few weeks and one of two things will happen: Either the car will fix itself or the IMA light will come on.
Knowing that the ScanGauge wasn’t the problem, I doubted that either of those two things would happen, so I asked him what would happen if I kept seeing symptoms, but no light came on. (According to the tech, the light doesn’t come on until the battery pack is at 10% or less capacity, thanks to the latest software update). He assured me that if I was still seeing issues they would work with Honda of America to get me a new battery. I decided what I needed to do was drive the car for a few weeks, so that we could move onto the next step.
Instead of driving on clean, cheap, domestic electricity, I drove for two weeks in the civic hybrid, burning fossilized dinosaur juice like some sort of barbarian. I recorded every drive (on camera) and was seeing about 1.5 recalibrations per day. Before I could take it back to Hoehn Honda, another dealership, Honda of Escondido, emailed me about the Fit EV. After telling them how great the Fit EV has been, I explained the issues I was having with the Civic Hybrid’s IMA battery and that I wasn’t seeing much progress with Hoehn (though Hoehn was not nearly as bad as other dealership I’ve read about online).
After hearing about my Civic Hybrid troubles, my saleswoman scheduled a rep from Honda of America to come down and look at my car. I wrote the rep a two and a half page letter and included spreadsheets of the recalibration frequencies, as well as the documentation from Hoehn Honda. He drove my car and came right back and told my service advisor to order a new IMA battery.
The battery arrived the next day and the repair took an additional day. Three days is the quickest I’ve heard of an IMA battery being ordered and replaced. I was not expecting that at all. Because of the battery pack’s 10-year/150,000 mile warranty, I paid nothing for the repair. My car now drives like new and I’m seeing about 45 MPG again (up from 33MPG during the two weeks before the battery replacement). On my way home from the dealership, my average was over 50MPG! The car drives entirely different now and has recalibrated zero times, even after sitting for several days.
I am super happy that I was able to get this repair done, and now it’s time to sell my Civic Hybrid. However, there are still many other Civic Hybrid owners out there struggling to get their batteries replaced. We purchased the cars with a warranty that we expected to be honored, but many dealerships are refusing to replace the packs (and saying that Honda of America is telling them that they can’t). If you are in this situation, here are a few suggestions:
- Log every time the car recalibrates, so you have historical data of the issue. The earlier you can start this, the better, I had a nice graph that showed the frequency of recalibrations increasing over time.
- Record your drives. I recorded the dashboard and have over an hour of recalibration footage from just two weeks. I didn’t have to use this, but it shows the issue very well.
- Mention that it’s a safety issue. I was nearly rear-ended during the two weeks that Hoehn had advised me to drive the car. They told me to drive an unsafe car, which was a huge liability for them.
- Try a different dealership. If you aren’t getting help from your normal dealership, sometimes another will have more experience with hybrids or just be more willing to help you.
- Bring in small claims court paperwork. I was prepared to do this, with all of the data that I had collected. Luckily I didn’t do this, but others have and just the paperwork was enough for the dealership to do the replacement. If they still don’t, take them to court! Your battery pack is under warranty and is not operating as it should.
With the newer software, which goes much easier on the battery pack, I expect the new battery to last at least 8 years before it needs to be replaced. Similarly, 2009 and up Civic Hybrids that came with the new software shouldn’t have battery issues until after the warranty period is up. Overall, I’m not happy that Honda did a poor job with the IMA battery, but I am happy with the way they handled the situation.
Of course, I’m also very happy with my Fit EV. The Fit EV has an extra robust battery that can take twice the number of charge cycles of a standard EV battery and can operate in wider temperature ranges. The Lithium Ion batteries in the Fit EV also require a much more advanced battery management system than the Nickel Metal Hydride (NiMH) batteries in the Civic Hybrid, which will take care of the batteries much better. It will be interesting to see if Honda learned from the hybrids (I’m sure they did) and made improvements on the battery life of the EVs. I’m sure I won’t see any major issues like this within just three years of driving the Fit EV, but after a few years we will be able to do some rough comparison with the Nissan LEAFs to see how our batteries are holding up.