Gen 2 Epic Failure--Dealer Perplexed--Need Real Help

I believe @bwilson4web disassembled some failed modules a few years ago.

 

It is just one fan, and the opening on the seat is the inlet. The duct exhausts to the inside of the RH rear fender.

 

Prius Battery Photos

Bob Wilson

 

Note that Bob's photos are from a Gen 1 Prius but the modules should be similar.

 

Comparing to a typical lead acid 12v car battery where if one cell of the six goes bad due to short circuit, sulphation, erosion or insufficient electrolyte, it renders the whole battery unusable because they are in series and a chain is only as strong as its weakest link. We cannot change out 1 cell due to the unitized construction of the case and even if we could the other cells are not far behind. The Prius pack having modules of 6 cells allows us to replace as few as 6 cells out of 168, but how often is it that one cell goes inoperative while the others have a significant amount of service life left? This is why I replaced a couple modules last year. Each whack only bought me a few months. Clearly, the cells in a Prius battery age out and/or deteriorate at roughly the same rate. At least in my case.

This is my first hybrid car and I'm thinking that the electric transmission was a noteworthy experiment but in the end it only makes a small contribution to the highway fuel efficiency (City fuel economy, of course, benefits more) of the Prius and battery replacement remains a significant investment in a car that is 10 to 12 years old and probably has 140k to 200k miles on it . Despite the greater longevity of the coachwork, and the more economical battery options offered by people like 2k1toaster, I'm afraid that as time marches on many otherwise serviceable hybrid cars will increasingly find their way to the recycle yards due to battery issues alone. My friend has an older Jetta TDI and consistently gets around 50mpg. It can be done without all the electronic wizardry. I don't see the added investment of buying a hybrid coming back in the form of fuel savings.

This all means that work needs to continue to find more economical battery options for electric hybrids. 2k1toaster has demonstrated the ability to do this and hybrid and EV owners need him and others to continue this search. John B. Goodenough, yes that is his real name, is the inventor of the lithium ion battery and at 95 years old he continues to work on safer and cheaper versions of his battery. And he is reportedly having success with solid state electrolyte which totally removes the fire danger, allows very rapid charging with no ill effects, has high capacity and high discharge capacity. If so, and commercial production commences and prices are affordable then we may all be looking to remove the antiquated engine and electric transmission from our hybrids in favor of an electric motor.

 

Great explanation. IMHO if you replace individual modules, the car is no longer dependable.
How many miles on the new kit pack now?

 

About 100 or so miles on the new pack and all is well. It's averaging around 50 mpg. +or- a little depending on speeds and how happy my foot is. I just noticed that the engine keeps running when I stop if I leave the car in B mode. Is this normal?

 

It may be if the engine is in its warmup cycle, charging the battery, or warming back up to replace heat lost due to running the heater in the cabin.

 

None of those conditions. Just off I-75, 75 degrees ambient in southern Florida. B mode, engine runs at stoplights. I change to D mode and it shuts down until I hit the gas hard. Once shut down, changing back to B mode does not cause a restart. This works every time like clockwork leading me to believe it is normal. I guess I should read the manual.

 

Why use B mode? I believe it is designed for long downhill stretches to avoid overcharging the battery.

 

After some reading of the manual it is still unclear to me whether B mode increases electric dynamic braking thus increasing charge rate to the hybrid battery or simply bleeding off energy through the engine, or a combination of both. Does anyone here know for certain? I tend to use B mode in heavy traffic to lessen the wear on the service brakes. I was hoping that I also was storing the energy for reacceleration.

 

Light braking uses regeneration fro braking to charge the battery. Heavy breaking uses the friction brakes too. Regenerative braking is part of Toyota's "secret sauce" for the high fuel economy. Since there is a danger of overcharging the battery on ling downhill stretches, B mode was introduced that uses energy to have MG1 spin the engine.

 

No it won’t really increase the charge rate of hybrid battery.

B acts as shifting to lower gear in automatic transmission car. So if you just lift your feet off the accelerator in B Prius slows down a bit faster than in D. In B the extra energy is then waste by just spinning the engine.

Only time B is useful is when you’re driving on long downhill that other vice would fill the hybrid battery before getting all the way down. So basically B is there just for mountains.

 

Who doesn't like Click and Clack? Click and Clack Explain the Prius "B" mode!

 

Perhaps for entertainment, but for a factual reference?

 

Now, considering the source, "Click and Clack", what are we to make of this comment;

"RAY: When you shift into the "B" mode, you increase the drag created by the regenerative portion of the brakes. And while that extra friction does produce some electricity to help recharge the battery, the "B" mode's primary purpose is to simulate downshifting, or engine braking, when you're going down a long, steep hill.

TOM: The "B" mode's secondary purpose is to give guys something to fiddle with while they're driving. And after THAT comes creating more electricity to recharge the battery."

Has anyone here actually put an ampmeter in the battery circuit to measure if and how much charging is taking place in B vs. D modes?

 

You can use the Torque Pro app along with and android device and OBDII bluetooth reader to see this data live in the car.
Cost you less than $60

 

If you have Scangauge or some other tool plugged into your diagnostic port you can see that current.

But that current is wasted in B. After the hybrid battery has charged to maybe 4 bars or hybrid battery is trying to charge at anything but very slow speed. System stops charging the hybrid battery and just wastes the energy by spinning the engine.

In D all the possible regenerative energy goes to hybrid battery until it’s “full”.

There just is no reason to use B in anything but very long downhills.