A while back I posted a comment regarding dissapointing gas mileage for my HCH. My theory was that there might be some manufacturing quality issue with the HCH, and particularly the CVT, that was causing an unusually high rate of low mileage experiences compared with other make/model hybrids.

My post was met with several "here's how to drive your hybrid" responses but none that really responded to my hypothesis. (I'm glad for the driving advice, but I still think there is something else at work here.)

Anyhow, I have another hypothesis to share: I wonder if there may be design issues in the HCH with respect to keeping the batteries cool. I live in Houston, so it is hot and humid which maximizes the challenge.

I was meeting with the head of maintenance for our local transit authority and discussing diesel-electric hybrid buses. Apparently, the biggest issue for the performance of the hybrid drive on the vehicles they've tested is temperature control. If the batteries get too hot, then they do not recharge and the bus effectively runs on the diesel alone. So one of the models they tested, which is well-regarded in some other cities, actually had worse gas mileage than the conventional buses running on the same route.

Anyhow, I have no idea how to investigate this and no vehicle-based facts to support my hypothesis. So it isn't even a theory, yet.

you might want to scan through the database quickly and see how may people are in the houston area and what their mpg is. that would tell you if you stand out or if there is something common about all your mpg.

I have posted and experienced the same concern. Clearly, when I park over a hot parking lot the battery does not function well for quite some time until you run the car with the air on and the back vents cool the battery. This is going to become a bigger issue when summer hits. We are already in the 80s as you know with high humidity and I doubt it will drop until end of October like last year. We had temps in the 90s about a week ago as well. My solution will basically be to park in the garage at work, and live with it the rest of the way.

I also live in Houston.

My mileage here in Hot Georgia has been pretty good, although it's a different kind of hot over here.
This is the wet, humid sticky stuff.
66K miles on my '04 and have not noticed any battery difference at all since new.

I will also add that I purposely use Assist as sparingly as possible, as I hope to take my car across 350K miles over 10 years.
I can't remember the last time I did a hard, 100% Assist acceleration.

Efficient drivers do it better.
1003 miles a tank personal record. 74MPG calculated. HCH1 CVT

I live in AZ and I never noticed such an issue with my '04 (traded in) nor have I noticed it with my '06 (current car). I have noticed with my '06 that it usually stays about 2 bars from full. My '04 however, varied quite a bit but I never noticed a problem getting it to charge. In the summer here it is about 120 with 10% - 30% humidity.

Humidity in Houston runs beween 40-100%. I used to love the Arizona summers, as you could actually breathe even if it was 110, but youd burn in an instant without even knowing.

This issue with a hot battery is gonna become more prominent as we move into the HCH II's first true summer.

In the mornings my auto stop works within 2 minutes of start up or sooner.

When parked over a hot parking lot after being drivien to work that day it consistently will not function for a good 15 minutes after start up. The result is the same every time and every day and the difference is the heat.

Otherwise the car is really great and works wonderfully.

How can you say there is an unusually high rate of low mileage experiences with the HCH with CVT as according to the database at the time of this post, the std deviation for the HCH II w/ CVT was 4.6 vs. a std deviation for the Prius II is 4.4

Without running an ANOVA analysis, this looks pretty close.

Relative to the other cars in the database, the size of the group may be affecting the accuracy of the variance - there are only 3 groups with a significant data set population (HCH I w/ CVT, HCH II w/ CVT and Prius II). It can be noted that the HCH I w/ CVT has the "highest" std. deviation of 5.1 but a statistical analysis (i.e. ANOVA and ANOMA) should be completed to test any hypothesis.

When we want to write an academic publication we will be sure to call you. Anyway, the issue isnt one of overall mileage as much as it is the autostop function/battery function and hot temperatures. My contention is that hot temperatures at a certain level causes the battery function as far as autostop to be inoperative by design until it cools down.

This would be a case report in the academic world and when there are three folks observing the same thing then that would make it a case series.

I've considered that issue, which is why I tinted my windows, bought a light interior, one of those reflective doohickeys that you put on your dash, and do my best to find shaded parking. I haven't yet experienced autostop kickin failure due to a hot day (and I'm not looking forward to doing so).

I found a couple posts about folks who modified their Insights - one with computer fans for the battery and the other with a solar set up. Perhaps you can get some ideas from them. Heck, I might have to take a second look for my car!

http://www.insightcentral.net/forum/...pic.php?t=2020
http://www.insightcentral.net/forum/...pic.php?t=1796

Glad to see Houston represented

Jeff

Yep. The funny thing is that there are so few Hybrid Civics driving around in Houston that I would probably know you just by your car these days, assuming we saw each others vehicles. Mines the Opal blue one.

The math is interesting. At 28,000 2006 HCH IIs, that about 28 per dealer per year ( 2006), or about 2-3 a month. So if there are seven Honda dealers in Houston, thats about 15-20 a month on the road max. Out of millions and millions of cars.