2003 Civic Hybrid: refurbishing/cycling the hybrid battery pack

[Formula413]

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Admin note: for background/more information about "reviving/refurbishing" Honda hybrid battery packs, see also: http://ecomodder.com/forum/showthrea...ems-13610.html

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A word of caution:
Working on a battery pack from a hybrid car can be extremely dangerous if you do not know what you are doing. They produce very high voltage and current and can easily kill you if not handled properly. Do not work on a hybrid battery unless you are very well versed in electricity and how to work around it safely.

Background:
I purchased a 2003 Honda Civic Hybrid in fall of 2009. It has a manual transmission and had 68,000 miles when I bought it. I am the second owner. The first sign of battery trouble came about a year later with 85,000 miles when the car set IMA trouble code P1449, which can indicate battery deterioration or battery overheating. I cleared the code and it stayed off for several months then eventually came back. It gradually began to recur more and more frequently and the useable capacity of the battery pack declined. Eventually the pack could provide almost no assist before the P1449 code was set. To keep the IMA light from coming on so I could pass inspection I wired a switch in parallel with the clutch safety switch, which disables electric assist and regenerative braking, and added a relay that would bypass the switch when I stepped on the brake so I would still have regenerative braking. This kept the battery topped off and essentially masked the problem so the IMA light would not set. This also left the task of moving the car up to the 1.3 liter, 85 horsepower engine, which is manageable but not much fun to drive. I made the decision to disassemble the battery pack and cycle the 20 subpacks with a specialized battery charger/analyzer. The unit of choice for this task is the MRC Superbrain 989, which is designed primarily with radio controlled vehicle batteries in mind.

I was about to tear down and start refurbishing my battery pack this weekend. I unpacked the Super Brain I just bought, plugged it in and found that the power supply is dead out of the box. Not exactly confidence inspiring to say the least. Can't reach MRC or the place I bought it from until Monday. So I lost an entire weekend plus of time working on the pack.

[MetroMPG]

Not necessarily?

Doesn't the power supply just convert 110v AC to 12v DC?

If so, you could power the super brain from a spare battery supported by a 12v charger.

[Formula413]

It's actually 15v, but it can run off a 12v battery. However, the only battery charger I have is a trickle charger, so obviously it won't support the amperage needed to cycle the subpacks.

[MetroMPG]

Jumper cables to the car?

[Formula413]

No sense in burning all that fuel unnecessarily, I'll just wait until I can get a working power supply. I just can't believe they would have such poor quality control to ship a defective unit.

[Formula413]

Update on my pack cycling progress. I got my Superbrain issues squared away, the vendor I purchased mine from was very helpful and promptly sent out a new power supply. I got the battery out of the car and disassembled on Friday night and started cycling subpacks Saturday morning. So far I've run six subpacks and the seventh is in process right now. The subpacks have returned capacities ranging from 6,252-6,806mah. A few questions for anyone who has any insight (no pun intended...ok maybe somewhat intended LOL)

A: Some of the subpacks had excellent capacity after just one cycling. One was 6,747mah, another 6,806mah. Is it still worth running those subpacks through some additional cycles? Since my weakest one so far was 6,252mah, and that after four cyclings, would any additional capacity I can coax out of the stronger subpacks be essentially useless?

B. Has anyone else found that the Superbrain is not capable of sustaining the 10 amp discharge rate recommended for cycling? On mine I can start a discharge cycle at 10 amps but the internal temperature regulating software seems to reduce it to about 5.3 amps after a few minutes. The internal fan on the Superbrain works and I have a fan blowing on the unit as well.

[MetroMPG]

Originally Posted by Formula413

Since my weakest one so far was 6,252mah, and that after four cyclings, would any additional capacity I can coax out of the stronger subpacks be essentially useless?

Yup. The pack capacity is limited by the weakest subpack.

B. Has anyone else found that the Superbrain is not capable of sustaining the 10 amp discharge rate recommended for cycling? On mine I can start a discharge cycle at 10 amps but the internal temperature regulating software seems to reduce it to about 5.3 amps after a few minutes.

I didn't see this, but I had a second cooling fan duct taped right on the vent area of the unit helping to draw air through it to aid the internal fan, not just blowing at it.

[Formula413]

Another update: I'm at the halfway point, and I think I may have found a big part of my pack's problem. Subpack J (I used letters instead of numbers) returned only about 800 mah on its initial discharge, while most subpacks were around 3,000 mah, and one as high as 4,000 mah. Obviously with over 3,000 mah of capacity separating the strongest and weakest subpacks there was very little useful capacity. That weak one showed a capacity of only 4,349 mah on it's first charge, but subsequent cyclings brought that to 5,955 mah, 6,001 mah, and 6,069 mah. It's still the weakest subpack so far but well within established tolerances for a useable subpack. I'm giving it one more cycle to see if I can pull some more out of it. So far the results I've seen make me very optimistic about how the pack will perform once I'm finished.

[MetroMPG]

Formula - I'm going to split your posts into a new thread with a link back to the original, generic one. I think it's worth separating your process/results as a distinct project that future Civic hybrid owners can look at.

[MetroMPG]

Originally Posted by Formula413

Another update: I'm at the halfway point, and I think I may have found a big part of my pack's problem. Subpack J (I used letters instead of numbers) returned only about 800 mah on its initial discharge

I think you're right! That seems like a dud.

Your earlier subpack reports had me scratching my chin since they seemed like pretty good numbers.