I have a 2006 HCHII that I bought Memorial Day weekend with just 42k miles. It seemed to be working great for a few weeks, and it started to get warmer in the DC area (approx 70 at night and 80-90 during the day).

Now it seems for the past few weeks, every single morning when I go to work I incur a forced regen. Sometimes I will even have one driving home (making this a 1-2x per day average).

It doesn't matter if I take a hilly city route through downtown DC (approx 15 mi) to work, or if I take a mostly highway speeds route (approx 22 mi) depending on my mood.

Automatic climate control is on at around 75-78 degrees, and I don't have any accessories plugged in 90% of the time except for when I need to charge my cell phone.

Any ideas?

 

Just to add on to this, when I first got the car my avg mpg per tank according to the built-in display was between 40-43 mpg... Now this number has dropped to 32-36.

 

One of your batteries (IMA or 12V) may require replacement soon.

 

I know it's difficult to do anything to diagnose the IMA battery myself, but how about the 12V? Can I do anything with a voltmeter?

 

Have you looked at the indicator window on the 12 volt? is it showing blue/red, or just clear?

 

For me using the AC at all is a big factor in how many regens I get. I drive almost exclusively in city traffic, and without using the AC I get regens maybe one every few weeks and about 40-45 mpg average. With the AC once I get regens several times a day and my mpg goes down to 35 or so. Without AC it's great, but do I want to sweat that much? I'm a little disillusioned with the Civic hybrid design.

 

> How many forced regens is too many?

Is there a glossary anywhere around here? I think I know what you mean by 'forced regen' but am not altogether sure...

Benton 22jul09

 

Normally the car will only recharge it's batteries during deceleration or braking. Forced regen occurs when the battery level drops to low, at that point it starts charging the battery during normal driving, which can really hurt fuel economy.

 

You are experiencing something which seems to be "normal" during high temperatures and heavy A/C use. The IMA system is affected by the high demands during hot temperatures.

While a faulty 12V battery can be at the root of the problem you may need to see if easing off the A/C helps out. These issues have been reported frequenrly in the last few weeks. This leads me to think that temperatures are what's causing these concerns.

Good luck!

 

My understanding is that when you see the state-of-charge indicator suddenly drop to the bottom, coupled with forced charging under all driving conditions, what is happening is:

The state-of-charge and the car's computer's perception of that state-of-charge have gotten out of sync. The computer has realized this, and is doing a procedure that recalibrates it's perception to the actual state of charge.

I'm not sure that this means your IMA battery is low or near failure, just that there's this out-of-sync problem. Disconnecting your 12 volt battery (effectively erasing the computer's memory) will precipitate the same recalibration.

OTOH, maybe frequent recalibration cycles are a sign that the IMA is behaving "unpredictably", outside of the computer's expectations, and this might be a sign of an ailing IMA battery. Just speculating.