Parents just bought 2009 Honda Civic Hybrid... against my advice. Hmm.

[MetroMPG]

And 1st gen Prii are more failure-prone than 2nd gens. Whether from age or from different design/management, I dunno. Haven't done the research.

[S Keith]

U.S. Gen1 modules are different than Gen2 and 3. There was a flaw in the terminal design that allowed KOH to leak out the terminal to case interface at a pressure lower than the blow-off pressure of the vent. Toyota developed a "sealing" procedures that did nothing but make it all gooey as heck, IMHO. The Gen1 failures are most associated with this loss of electrolyte causing reduced capacity.

They improved the terminal design and internal resistance in Gen2 significantly by providing an additional connection between cells on the bottom of the module in addition to the top. Gen3 internal resistance is a touch better than Gen2.

Prius uses 40-80% SoC with an aggressive effort to maintain 60% thus minimizing cycles. IMA originally used 20-80% SoC with a tendency to keep the SoC as high as possible. The new scheme is unknown, but it is expected to use less than 20-80% SoC range for improved life.

The same manufacturer made both Prius and IMA battery packs. The cells are very different. The IMA are literally "D" cells. The Prius are prismatic rectangular modules that have a common "vent" space. All NiMH produce Hydrogen when charged. When the cells settle the Hydrogen is reabsorbed. Within an IMA pack this means that each cell behaves independently. In the Prius module, the six cells vent to the same space, so they all reabsorb according to their potential. This improves uniformity across cells, particularly when an actual high-pressure blow-off occurs. All six cells are affected the same. In an IMA module, only the individual cell(s) is(are) affected. In the prius, this creates a diminished capacity, but it's fairly uniform across all 6 cells. In the IMA, the capacity hits only the affected cells thus creating an imbalance between cells. The reduction of capacity of the affected cell(s) has the same effect as ALL cells having reduced capacity. Of the hundreds of IMA sticks I've had in my hands, almost all module failures are due to 1-2 cells in the group performing very poorly while the other 4-5 perform very well.

With the '06-11, the modules are now 12 cell, so the failure rate essentially doubles. the design was changed in '09-11 with a greater spacing between the sticks for better cooling. This should have improved life over the 06-08 packs, but they were about 3X as bad. Personally, I attribute this to a quality issue at Primearth (Toyota) as they didn't give a squat about "D" cells anymore.

When cell imbalance worsens, individual cells are run outside the 20-80% range... literally 0% for the weakest with polarity reversals and 100% for the strongest cells and a greater risk of venting.

IMHO, a grid charger as a preventative maintenance tool conducted every 3-6 months is KEY to maximizing life of an IMA pack. Regular grid charging and discharging will help keep the state of imbalance minimized, thus preventing individual cells from being operated outside the 20-80% SoC range and avoiding the accelerated deterioration.

Steve

[MetroMPG]

Interesting reading. Thanks for the lesson, Steve.

[MetroMPG]

Yup, this latest replacement-replacement pack has started showing signs of trouble (frequent recals).

I wonder if it was a new or rebuilt pack.

[S Keith]

IMHO, it doesn't matter. Probably a rebuilt, but new has a very high failure rate too.

[Daox]

Wow, its only been a few months! Thats horrible.

[KrautBurner]

Originally Posted by cRiPpLe_rOoStEr

If I would ever have to get a hybrid, I'd rather get one which wouldn't seem so obviously-hybrid as the Prius because of all the hybrid driver negative stereotypes, so the Civic would fit better to my Almost Politically-Correct Redneck way of life. I actually got to believe the OP's dad also considered the same factor...

Originally Posted by MetroMPG

You'll accept worse fuel economy because you're concerned about what other people think your car says about you? Not me!

having owned 2 prius' (2001 and 2010)

its not about what others think the car says about you
its more about how other drivers expect you to drive.

I drive with my cruise on (normally 5-10mph higher than the posted speed limit)
I consistently get passed, then have the person that just passed me, slow back down (something in peoples core makes them think that the prius must be driven slow and with no regard to traffic safety)

[KrautBurner]

btw,

I'm bumping this thread up because I'm thinking about picking up a 2005 Civic Hybrid
but it's a manual (seems that the CVT is one of the main complaints)

and the 05's seem to have a more reliable battery system than the 09-11

the one I'm looking at has had the battery replaced
(I'm waiting on info about that)

I've yet to drive the car as well
I'm really curious what a manual hybrid is like

[MetroMPG]

5 years since the last post... time for a thread bump!

Did you end up getting the manual trans Civic hybrid, KrautBurner?

My parents ended up giving their Civic to my brother. It's still running on that 3rd battery pack and closing in on 300k km = 186k miles. The engine is getting a little rattly. And the body is pretty beat up (teenage kids) and starting to get rusty around the edges.

I drove it this week for the first time in a long time, owing to everybody in the extended family swapping cars around for various reasons.

For me to enjoy driving it, I need a way to defeat IMA assist. In a manual trans Civic/Insight, it's easy: do the clutch switch (Calpod) mod! IMA computer sees "clutch pedal is down, therefore no assist!" ... regardless of what all the other sensors are reporting.

I don't use regen enough -- I anticipate red lights & slowdowns and do a lot of coasting -- so I don't do enough high-current regen/braking to make up for all the little assists. As a result the car often goes into "recharge mode" to top up the pack.

I tried a couple of things.. thinking maybe if I lightly pressed the brake while accelerating it would cancel assist? That doesn't work. Same with having the handbrake lightly engaged.

Time to research... what does google say...

[S Keith]

Actually, "engine braking" as you potentially describe is a better and more efficient way to charge the IMA battery. With only 13kW of braking power, more often than not, one exceeds the regenerative threshold and engages the binders rather than capturing the kinetic energy as chemical.

I've owned two of these. If you're seeing forced recharges, it's likely not you, especially if they start at 2 bars. It's likely recalibrations. With a healthy battery, best results are obtained exactly as you describe UNLESS you're doing it in neutral. If you're coasting in neutral, stop. Just back off the throttle as needed and use "engine braking" as much as possible. I quoted that because normal engine braking is actually regenerative braking.

If you are not using neutral, it's the sh!t battery in the '09. They are horrific turds.

There is no way to disable assist. Stop trying.