Good luck!

 

Just completed the discharge to 99V with the two 25W bulbs wired in series. Total time was 35 hours and 42 minutes. Starting the balance charge now.

 

heh... my guesstimates usually aren't that close!

 

Your estimate was not only accurate, but it allowed me to plan the discharge so that it ended during the day and not in the middle of the night. Much appreciated!

The pack started to discharge more rapidly once it dropped below about 150V and even faster from about 146V and down. Once the voltage dropped to about 125V I watched it closely because it was decreasing pretty fast. The discharge is my least favorite part of the process because it's easy to discharge the pack too much if you aren't paying attention. I keep notes when charging and discharging with a record of the time and voltage reading throughout the process so I know what to expect in the future.

Thanks again.

 

Well, I'm really glad it worked out. It was truly a swag. They tend to run longer than I calculate because the current in series-bulbs at > 120V is difficult to predict. It's more like a constant current discharge than a resistor, but you never know until you measure it.

I have good news and I have bad news.

Good news: Data you collected is worth having for comparison, and it can provide evidence of benefit.
Bad news: It is not likely to be predictive of the timing/pattern of your next discharge.

Good news: The discharge behavior is encouraging as it's consistent with the expected discharge of healthy cells.
Bad news: If you had healthy cells, the first charge should have been enough. A discharge pattern you describe does not indicate benefit from discharging.
Good news: Doing it at a low current minimized the potential for damage in the case of reversals. If behavior is improved after this discharge and a subsequent soak charge, it may warrant a deeper discharge to 66V.

Good news: when all of this is done, you'll have a pack start to finish swap time of about 20-25 minutes
Bad news: You'll never actually enjoy doing a swap.

 

Very interesting. Definitely not getting my hopes up. It would be great if I could get this battery to limp along like my previous Insight but we'll see. I've read comments from other owners of the HCH2 with worse battery issues than I'm experiencing. Another thing that I wanted to mention is that while driving with assist, the bars in the battery gauge don't seem to decrease that quickly. This is my first (and likely my last) Civic hybrid so I don't have anything to compare it to other than my old Insight. The Insight battery performed well enough for my mostly highway driving thanks to your advice. I was also very conservative with my use of assist and still am. I'm averaging about 47 mpg currently with my average hypermiling skills. Not too bad for the middle of winter.

Removing the pack from the car is a pain but does take less time now that I've done it multiple times. The temperature has been in the single digits here in Wisconsin all week, so even if I could charge the battery in the car the benefit would likely be reduced because of the cold.

I started charging the battery right after the discharge and plan on allowing it to charge for 32 - 36 hours as you recommended. I'll report back once I drive the car and see if there is any change. Hoping to avoid replacing the battery in this car. Needless to say, it's probably not worth it.

Thanks again for your help.

 

The problem is the HCH2 battery is just so horrible. If you can't get acceptable function, bypass might be an option. it's been awhile, so I may be remembering incorrectly, BUT I'm pretty sure you can just switch the master off (with the battery installed normally) and drive without the battery. The downside is you'll only get 12V charging between about 1500 and about 3500 rpm (the red battery light should turn on when you're not charging and turn off when you're charging), so you'll have to watch your 12V and periodically top it off (a cigarette-lighter voltmeter is very handy) . The Honda 12V charging algorithm is pretty crappy, but you can encourage better 12V charge behavior by always driving with your headlights on. If most of your driving is highway, you will still get good mileage. 47 may be tough but low 40s should be doable. City mpg and power will stink, but it's better than the forced charging behavior/performance when dealing with recals.

You will have to hold the key in the start position for several seconds to engage the 12V starter, and you will also have persistent IMA and check engine lights.

It might still need periodic grid charging because there is some point at which the block voltages get too far out of spec, and it won't permit 12V charging.

 

Thank you for the information. It's too bad that Honda didn't seem to improve their hybrid system after the Insight. It's good to know that I can drive the car without the IMA if I have to. Would upgrading to a 51R battery be a good idea if I end up driving the car with the breaker turned off, or would that put more stress on the DC/DC converter? I remember driving the Insight once without the IMA and it wasn't exactly a great performer from a stop. The manual transmission did help though.

I paid just under $2000 for the Civic, which in retrospect was too much. Definitely qualifies as a "beater" car. The engine seems to run well, it's the hybrid battery and CVT that I don't have a lot of faith in. I don't see very many 8th generation Civics on the road, but I have to remind myself that these cars are nearly 20 years old. Vehicles don't last as long in this area due to the generous use of salt on the roads in the winter months.

We'll see what happens after this grid charge. I spent about $50 to build the charger and discharger so I don't have that much invested at this point.

Thanks.

 

I upgraded both of my '06 HCH2 to 51R from the 151R just on principle. Had to ditch the shrouds, but I was able to make it fit.

Inop IMA CVT might be a little better than your experience with the manual. CVT seeks the optimal power rpm. When the battery is in a negative recal, you lose IMA boost AND have the additional drain of forced charging.

They actually did improve them... just not until the G2 Insight and CR-Z. They ditched the electric A/C and went with a smaller 84 cell pack with much better airflow. The 2012 HCH3 with Lithium performed pretty well except for their inverters. I've never personally heard of a HCH3 lithium battery failing. No. You can't swap the Lithium and NiMH.

 

I've been charging the battery since 10:00 am immediately following the discharge and it seems like it's charging more slowly than my previous two grid charges. Maybe I'm overanalyzing.

Here are my readings:

10:00 am 99.0V (reading with load connected just before ending discharge)
10:35 am 164.7V
11:00 am 167.5V
1:34 pm 175.3V
3:39 pm 177.5V
5:03 pm 178.6V
6:07 pm 179.3V
8:17 pm 180.6V
9:19 pm 181.3V

Does this look normal? Thanks.