I have a 2007 civic now with 27k miles and am the original owner. I live in the DC commuting area and drive 90 miles a day. Since new, the hybrid system works ok when the weather is cool. As soon as the temp gets above say 85, the pack will start to overheat. The charge and boost indicators will not reach to the top and often stop working altogether. I have brought the car to the dealer several times. They claim it is functioning as designed and quote a page in the manual describing a safety feature that protects the batteries when they get too hot. This appears to be true but I still consider it a defect in that the pack should not be that heat sensitive. If the pack gets too hot to operate just from sitting, what is this doing to the life of the batteries?
I can start in the morning and everything works fine. If the car sits outside all day and gets hot in the sun, the trouble starts. After a hot day in the sun, the hybrid system may work for a minute or two but sometimes not at all. Both charge and assist are affected. This can be a problem when trying to go at a light and the car wont get out of its own way. After 15 -20 minutes of driving with the AC on high, it will start to regain function.
On a side note, during summer months my MPG drops to 35 - 36 for a tank because of the batteries and using the AC. Without AC and normal driving I get 38 - 40. The best I have seen for a tank is 42 MPG.
When driving in bumper to bumper traffic in the city with AC on, I often get full discharge of the pack and the car then goes into "constant on" mode.
I was thinking of piping an AC vent directly to the pack for cooling. Anyone have the same issue or a solution other than parking in the shade all summer?

I'm in Utah. It's been mid-high nineties for the last week straight. It was frequently over 100 last summer. I've never experienced any of these problems. Occasionally if I'm sitting in traffic with the AC on it will drain the battery, resulting in sluggish acceleration and no auto-stop, but nothing like you describe. It sounds like something is wrong to me.

Scott, you allready have vents direct to the pack. The vents are in the rear window sill. That is why it is important to use auto climate control set at about the highest level you can live with. H

Harold is dead on.

In the warmer days, the FE hit is inevitable but it is also VERY important to keep the IPU happy and thermally well managed. While it may not look like it to some, there is much we as drivers can do to make it all work well.

Placing the climate control in AUTO and setting the temperature for the highest value it can be not only cools the passengers rather effectively but also cools the IPU with the lowest stress possible on the AC driver.
If you set the AC too aggressively, the IPU will overheat and it will go into managed mode (limited assist and regen). Likewise, if you don't use the AC at all then you are back in the same pickle spot sooner or later as well which is still not good. So use the AC correctly and you'll get the best possible balance even in the warmest of days.

Cheers;

MSantos

I usually set the air to auto but keep it around 68 - 70. Yesterday I set it to 75. It helped with the battery drain but I still got the same problem with overheating the pack. There is a page in the manual that gives the specific temp for the protection. I want to put a temp sensor on the battery to check it myself. The dealer referred me to the safety feature and said it was working properly. I was hoping they actually did some testing but think they just drove it. For the record they were able to recreate the issue.

I've driven around at 95F or so at the end of the day of work (having sat out in the sun all day) with no AC on and the car behaves fine. I'm not recommending this (as msantos points out, it's not ideal), but certainly it should drive, regen, and assist completely fine. Tell your dealer to stop being a jerk.

smhch,
Which dealer do you go to? I have been constantly having similar issues and Criswell Honda basically printed out a page in the manual saying I am the problem!!

I also informed them this is a heat related issue.

----
1987 Chevy Spectrum - 200,000+ Miles -Junk Yard
1994 Honda Civic DX Coupe - Truck Hit it
1998 Acura 2.3 CL - End of Lease
2002 Acura TL 3.2 - End of Lease
2004 Acura MDX - End of Lease
2007 Mercedes ML350 -Lemon
2007 Honda Civic Hybrid w/Navi - Active

Have you considered getting your windows tinted? 20% tint in the back will help keep the interior of your car 10-20 degrees cooler.

2008 Honda Civic Hybrid w/Navi, Magnetic Pearl
1996 Acura NSX-T Red\Tan
2002 Dodge Ram 1500 Quad Cab

My windows are tinted. I use AC (usually managing it myself, but lately I've tried the Auto mode 77 degrees). And I'm still having this issue, too. The issue seems NO BETTER on Auto than when I was managing AC myself. I can imagine that it IS better for some in Auto, as they may have otherwise been keeping the cabin too hot for too long, but not me!
It's been about 2-3 weeks or so for me. It was pretty rare last year for this quick discharge to occur, but it's happening almost every day now. Interestingly, one day last week the high temp was only 85 (instead of the usual 95+). That day, no quick discharge. I'm almost sure that it's a heat-related thing too, but I cannot figure out why it didn't happen in 2007. Or 2006.
I'm also almost sure this is a problem of some sort, since it didn't happen in prior years.

BTW, nothing is blocking the rear deck vent, either.

Steve

STOP terrorism - Drive a HYBRID

Vehicles:
350 miles a week ------------ 2006 HCH II, Magnetic Pearl, w/NAVI (born on May 25, 2006)
350 miles a month ---------- 2003 Mazda Tribute ES-V6
350 miles a year (for now) - 1986 Mercedes 560SL

Not seen this yet in my car and I live really close to gumby. I haven't used AC in a while. My 7 mile commute plus how cold my office is; I can just make it home in the afternoon without getting too damp. Getting 50-53mpg is the norm these days. I am parked almost underground at work so that may be keeping the battery cool enough for my short trip home with windows open and close to 100F out.

I have noticed in the past when I was AC off in the morning and AC on in the afternoon I did see alot of SOC drops but not to down to 1, more like 3 or 4 almost every other day (which is enough to get it to force regen).