Gen II batteries -- a worrisome trend

I credit the limited supply to the Gen I's whose repairs can use the newer modules.
quoting from the Luscious Garage site
......The modules come from young Gen 2 Prius (sourced from early totals or plug-in conversions) which have an upgraded design over the original Gen 1 module (pic: metal sided is Gen 2, all plastic is Gen 1) with better heat dissipation and lower internal resistance. The difference is evident in the cars we service: all Gen 1s will have an HV battery failure; Gen 2s rarely do (despite many with very high mileage). (Sept 2 2010)

Anyway, thanks for the ongoing technical expertise.

 

Good stuff Seilerts. We sure have see a spate of 05's with pack failures lately.

 

Interesting observation that suggests that buyers are being found for these packs, but confounding factors cannot be excluded yet. E.g., we know that the packs reversibly age when they sit on a shelf. I wonder if these older packs are being removed from inventory.

The earlier post mentioning G2 cell use in G1 Prius makes a lot of sense too.

Something to keep an eye on, but for now $600 for a pack is still dirt cheap.

 

Thanks again for exposing another battery related issue. :cheer2:
(The other being the 12V battery dissection in your avatar.)

How far afield does your survey of available HV batteries go?
I'm wondering if the paucity exists mainly in areas that experience
numerous, and worse yet continuous, days of 100+ degF air temps…
like where you are.

A digression...
As part of considering buying an EV, I've been doing some self-
edjamacating on HV batteries, Li-ion in particular. I've come to
understand that typical high temp failures, at least in those type of
batteries, is the result of electrolyte breakdown from high internal
battery temps.

Which in turn leads to a non-ionically porous coating being deposited on
the anode. (I hope i got the anode/cathode thing right!) And that's
where the reduction in capacity comes from. Further, there is no way to
drive the chemical reaction backwards, so the coating is permanent and
the problem is terminal.

Since arriving at my understanding noted above -- I sure hope its
correct -- whenever I see a thread on potential HV battery issues, I
look to the posters avatar to see where they are located. Most often its
where extreme summer heat is typical...

 

Our experience has been similar in the last year. Used to be a used gen2 battery was good, with very few exceptions.

We started seeing failed gen 2 batteries first in cars that spent their lives in the mountains. Now, we are seeing them across the spectrum.

Given the relative volume of gen 2 cars to gen 1 cars, the future of rebuilding batteries is a lot more difficult if the gen 2s are bad.

Our experience supports your suggestion, just replacing one weak cell in a battery pack will give you mixed results. It is imperative to load test and match every module in the whole pack.

Eric
Adopt A Part/MileHybrid Automotive.

 

Any idea how many of those failed battery pack have EV button installed? I have it installed in mine but uses it very carefully. I could see how someone could "abuse" it.

Gen II Prius doesn't come with an EV button (like Gen III, v or c). We can hack and add a button to enter EV mode. Gen II EV mode allows higher speed 34 MPH (vs. 25 MPH) and probably uses the HV battery more aggressively.

 

Slight correction.... "gen II Prius doesn't come with an EV button in the US" it's standard over here... I don't have any figures on US v rest of world failure modes though. Does anyone?

 

I almost never see an EV switch installed in a car that comes in here for service.

Heat is the enemy of NiMH batteries. The deep charge/discharge cycles that mountain cars experience raises battery temp. I believe that is a key factor in failures.

Another interesting tidbit to be researched if someone had the time is: The Ford Escape Hybrid has a dedicated AC system just to cool the battery. (up to model year 2008, anyway). Those battery packs have extremely low failure rates. Correlation?

Interesting, we usually see blown up gas engines on these.

Eric
Adopt A Part/MileHybrid Automotive

 

(whistling in the Dark, here )
My '05 just crested 265k miles: original batteries, no problems as yet. Only a couple of times have I even heard the battery cooling fan come on, although we sometimes go three weeks straight with highs over 100 f.
Yes, I do have the EV mod hack installed, though I tend to use it for about a mile on each end of my daily commute.
Apparently I'm easy on the car: original brakes still look new and the latest tires have 100k miles and still going strong. So, the dilemma is obvious. Buy a new one before the apparent odds catch up with me, or see how far I can push my luck??

 

welcome to priuschat! i say stay the course, sounds like you've got a creampuff there. all the best!

 

I really want to clean the battery fan on mine, but I don't want to screw anything up. I've heard it costs about $120-200 to get it done at a dealer, but that's about as much as I make in a week if I'm lucky. Maybe I could just stick a Lint Lizard into the vents?

 

you probab

Geez well you ain't going to get too much for the trade at those miles! But you probably saved $20000 in gasoline so who cares? If you poke around here, you will see the EV mode hack is not considered to be a good thing re: maximizing MPG. It's best for short move of the car in the driveway, that kind of thing. But heck why risk telling you how to maximize batt life, as it is you that has a successful formula.

 

any forced EV mode driving unless driveway or other short distances like 100 yards or less will reduce your milage.


iPad ? - now Free

 

...if he uses EV mode to go "the last mile", he is parking the car with low SOC and the HV battery is apparently long life despite the 100F heat. So maybe he has hit on something. That's why I say, keep on with the same habit, or at least, I do not recommend any changes.

 

You may have a point there tracy as it seems that when the battery is full and hot, it gets even hotter when parked. Being on a low SOC might make a difference. Interesting point for sure. I should have studied physics better...

 

I used to get the battery packs for about $600 at the yards. Very rare now and what ever pops up gets bought and resold for about $1200. I stop servicing the batteries as I could not get them at a reasonable price.