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Article: Fix for Civic hybrids' dying batteries may hurt gas mileage, acceleration

Hello -

It looks like the current-gen Honda Civic Hybrid is having battery problems :

Fix for Civic hybrids' dying batteries may hurt gas mileage, acceleration - Los Angeles Times

Quote:

When Honda Motor Co. rolled out its latest-generation Civic hybrid, it was sold as the automaker's green car of the future.

But five years into production, Honda has discovered that its high-tech batteries can die years early, a potentially expensive flaw that the automaker has been addressing with a software update that many owners claim has made the car less environmentally friendly.

Jason Marchesano of Overland Park, Kan. said the battery in his 2007 Civic hybrid started losing its ability to hold a charge last year. Rather than replace the battery, which was under warranty, Honda loaded a software program into the car's computer that he said made the car sluggish and slashed the vehicle's gas mileage.

When he complained again several weeks ago, Honda installed a second software update, cutting efficiency further. Today he gets just 33 miles per gallon, compared with 45 when the car was new.

...

CarloSW2

Are they just fixing it by eliminating the IMA system altogether? That's a major decrease in mileage.

Quote:

"It sounds great for Honda but bad for us if we're losing the hybrid part of our hybrids," he said.

Not at all. More reluctant assist leads to better fuel economy. That guy who is getting 33mpg in a Civic hybrid is doing something wrong.

Also, while they've changed the throttle position at which assist kicks in, they haven't changed the total amount of assist available. If you want moderate acceleration, it's going to give you more gas engine and less electric motor than before. The car will sound and feel less powerful than before. But if you want full acceleration, that's still available, you just have to press harder on the throttle.

Quote:

Honda had swapped out more than 4% of the batteries in the 2006-08 Civic hybrids in California

That does sound a little high for such new batteries. However, I'd wager they've swapped out much more than 50% of Insight batteries during the 10 year / 150kmi warranty on those.

Based on data from 2006, the cells for a 1KWh NiMH battery were going for $400-600 at the OEM level. People have a perception that these are $3000 packs (because the dealer charges that much to swap them), but having a NiMH battery that requires service is not that big of a deal.

Only because I'm curious, I have no ax to grind, does anyone have a technical description of the software change(s):

2005->2006 - I see the manual HCH were dropped but what about the control laws?

2008->2009 - Did they change the control laws to what they want to put on all the HCHs?

I'm mostly interested in technical descriptions of the laws, not the "they did it and the smoke escaped and now I hate Honda" type posting. For example, did they change the maximum charge to "nC" and discharge to "pC"? How about the SOC? Do they track the Ahr capacity of the pack or modules? Has anyone outside of Honda (aka., they can report) analyzed a failed Honda traction battery?

Thanks,
Bob Wilson

Bob -

I'm confused. When you say "control laws" do you mean the programming or state emissions laws or ... ???

CarloSW2

Sorry, when I refer to 'control laws' I mean the software algorithms that manage the electric and engine system. For example, the Prius control laws require the engine to run at speeds over 42 mph. They also limit discharge below 40% or charge above 80%. There is a long list that we could go over that have been discovered by various owners.

We don't have a Honda Civic Hybrid so I was wondering what are the control laws and what changed that seems to have led to the current problem.

Thanks,
Bob Wilson

Bob -

I don't know. My off-the-cuff theory is that they went with a cheaper battery in the current gen Civic to make it more profitable. Here is a much better article :

Honda's fix for prematurely dying Civic hybrid batteries hurting fuel economy, performance? — Autoblog

Quote:

...

Honda has not revealed details of the changes to the software other than to note that it limits cycling of the battery. Some owners are claiming that the revised software has cut both performance and mileage, in some cases by up to 20 percent. While this is clearly making some drivers unhappy, it has also caught the attention of the California Air Resources Board (CARB) because the battery is considered to be part of the emissions control system.

...

http://www.blogcdn.com/www.autoblog....aoperation.jpg

CarloSW2