FWIW, since you're in TX, it seems that some Prius owners in hotter climates esp. w/steep hills have tended to need HV battery replacements. I think the high temps are likely very bad for the batteries. I mention steep hills as this could lead to more frequent "empty" to "full" (Prius only lets the battery get up up to 80% SOC and does funny stuff to prevent overcharge, after that) cycling than someone in a non-hilly area.

When I was living in CA, I unfortunately had no covered parking at work, so I ended up trying to park my Prius in shady areas or ones that would be shaded from the sun, much of the day. When it's hot in my area and my Prius is parked at home (under covered parking), I back into the spot so that the sunlight only hits the front of the hood and not the hatch area where the HV battery is.

Regarding lifetime, if one is curious, although the sample size is small, you can see how various hybrids, including Hondas did in terms of battery lifetime at http://avt.inl.gov/hev.shtml.

 

Thank you for directing us to this useful link. I was not aware of these tests. I looked at the HCH battery test results and I was very impressed. After 3 years and 161K miles, the 2006 HCH battery held 86% of it's original capacity (measured average C/1-rate capacity in Ah). It seems that my battery problem was due to faulty cells. I park my car in an uncovered parking at work, which is extremely hot in Texas during the summer.

 

Can anyone post a link to MSantos post about less assist while drive proves for longer lasting car/battery?

Also, sometimes when I try to accelerate at a "normal" rate of speed, I can't seem to get the assist to stay low, and it depends a lot on the SOC of the battery. If I have a fairly full battery, it will just use more no matter how I drive.

Lastly, I have the June '10 updates on my 2007, and I find them to be totally worth it. It's way better for me than past updates. Only thing I've noticed is in colder climates, it uses the battery faster when fully charged, but when its 60 to 70 degrees, it does fantastically well for me.

 

Not sure exactly where the info you seek would be located, but I would start here, and maybe work backwards a few pages through the thread:

http://www.cleanmpg.com/forums/showt...=33041&page=13

 

After getting the software update on my healthy '08 (30K miles), I was very unhappy. It felt more peppy around a parking lot, but unpredictable (sometimes you hit the gas and it just lugs.. forcing you to nearly floor it to get the acceleration you normally would get, even though the SOC is fine). It's intermittent, and annoying. Dangerous? Not so much for me so far, but I can imagine scenarios where it IS. I feel like I have much less control over how the car is using and converting power compared to before. I also now see some re-cals (where I only saw 2~3 EVER in the first 30K, now I see them a couple times a week). Sometimes, it does weird things like force-charge 3-4bars while cruising on the expressway at 70mph for over half an hour (without ever reaching full charge!). In general, I guess I'm not particularly happy.

However, those opinions aside, I have noticed a few things that deserve mention:

- My fuel economy isn't really much different than before. I can't believe it.. It seems like it'd be much worse with all these re-cals and forced-charging, but the overall numbers seem to be about the same.

- When the SOC gets way up to 7 or 8 bars, sometimes it'll go into a mode where it gets crazy good fuel economy with little effort. I can cruise along at 45-55mph and get 65+mpg with little effort. This doesn't happen often, but is definitely real. (then again, other times I can't seem to do anything to get the economy over 45-50mpg)

- Immediately after a cold start in very cold weather, I used to be able to drop it into 'L' and force 4 bars of re-charge into the pack. I'd do this when I got stuck at a light and the engine was warming up anyway. Now, it won't allow me to do that until after a few minutes of driving (or the battery temp comes up to some amount?). It's only a short delay though, so it doesn't really bother me.

- The auto-stop is much better now. It used to only allow 3 auto-stops, then wouldn't let you have any more unless you drove over 8mph. Now, it seems like there's no limit as long as your SOC is okay. I went through a long drive-thru line the other night and I think it auto-stopped 6-8 times! (my SOC dropped from 8 bars down to 6 over the course of those 5~10 minutes)

Anyway, I just wanted to comment on these minor feature changes, as I hadn't noticed anyone else post about them yet.

Rob

 

hi Rob,

do you do a lot of city driving as well as freeway driving? Have you noticed whether your city driving has been impacted negatively, compared to freeway speeds? I've got the same 2008 model (different color!) but most of my time is spent on city roads; my impression is that the new software takes much more of a bite out of MPG off the freeway.

Philip

 

Philip, you may want to specifically research city driving techniques for the HCH that might help you. I have the new software, and am averaging an indicated 46.1 MPG with about 200 miles on this tank of all-city driving — lots of stop-and-go, full use of A/C in "Auto" mode, and some hills. My actual computed mileage should be a couple of MPGs better. Disclaimer: I am running 44 PSI in my tires and using synthetic 0W-20 oil. Overall, my fuel economy continues to be 5-10 MPG better than before the software update. I think many people try to 'granny' their HCH's acceleration in the city, and therefore never maximize its optimal cruising fuel economy. That single lesson has made a HUGE impact on my city economy.

 

HI Steve, thanks for the tips. I know that I'm doing SOME things right, as my attempts to use 'hypermiling' strategies (hemi-miling?) have increased my milage by about 10 MPG in my city commute, compared to driving 'east-coast style' (my old habit). But I'm also confident that I could do better. I've got my tires a bit lower/wimpier (40 psi), and I try to minimize AC except when needed for defrosting (which these days is a lot). I just had the oil changed by the dealer (0W-20, according to their report), but probably not synthetic (that's pricier, correct? Maybe i should start doing it myself).

Hmm, your point about DLG (driving like granny) is interesting. I've definitely found that when I can use a faster acceleration to speed and then cruise a bit, I do better (as described in Terrabell's lovely discussion), but I have a hard time doing this without chewing through my SOC; I often don't have enough cruising time/distance to recovery the IMA charge that I've lost.

Have you found any tricks that help with this? I've read MSantos's posts about inducing hidden charge to restore the IMA SOC (monitoring the process on my scangauge), but I'm not very good a it in the city; seems like there are always too many other things going on (other drivers, curves, passengers) for me to monitor it carefully enough.

Philip

 

I'd say that 90% of my driving is city and heavy traffic, so I guess my experience isn't the same as yours. I have taken a few long highway trips though since the update and it actually seems noticeably worse now. There's plenty of factors (temp, humidity, wind, etc.) that might affect it, but it seems like it's a lot harder overall to get the same numbers I was before on long trips.

The city stuff seems about the same, even though the car is operating quite differently.

 

Hi Rob, sorry to hear it. Your city driving actually sounds a lot like mine. But it continues to surprise me how much variability there has been with respect to the effects of the latest software on peoples' MPG-- some reporting highest numbers ever (especially on the freeway), others reporting similar disappointing results as yours. Seems like there must be another variable at play. Guess we can hope that the rumored newest software updates might actually improve things for a change.

Philip