Greek taxi and traction battery

...we have 2 threads going on this, Grumpy's thread had a good finding of a new Toyota customer car program in Europe potentially allows battery warranty coverage up to 10-yrs I believe (unclear if this applies to Taxis). I have been asking for something like that here (I'd like to see 10-yr batt 150k miles coverage in non-CARB US states)

 

^^^ good work! I was just trying to make a tie-point in case EU drivers were interested

 

Just

Just for information there are many many prius taxies (25-30% by observation) in New York City starting with Gen II GenIII and now I can see GenIII -V as well. Also private car companies are using them as well ... so does the police various city agencies running them as well.

Unfortunately I do not have personal contacts there. Most be a few interested people there. I do have the blue tooth odbII reader and torque on an android tablet, but have not used them lately the tablet is kind of awkward in the car. And have not really tried to seriously gather data ... just was for my amusement. If there is some how-to on this would be able to provide new york city driving data 25 miles each way to mid-town daily (but I am not driving as a taxi driver for sure but temperature and average load can be gathered I guess).

 

And it's appreciated that you want to investigate the issue and haven't just pooh poohed it as anti Toyota fud. It is looking like the gen3 is suffering some battery related issues and more likely related to heat rather than lower standard parts.

I'd have offered to collect the data for you if I were still using the car for taxi work. I do know the area above the battery got warm/very warm to touch when the car had been worked. Sometimes I would leave the boot floor hatch open giving easy access to the area below as this made loading with shopping/groceries easier. I guess the lid laying over the battery would also act as an insulator and keep the heat in!

The other point I'd add was that the battery vent could often be blocked by a passengers coat or arm. You could ask them to move it, but they'd soon block it up again. This too could cause lack of air flow to the battery, esp if it can only vent via the backseat vent. Over the miles this will cause damage. Not much you can do about it in taxi work though.

 

That won't cut it I'm afraid. The battery needs a good 6 or 7 hours of 'taxi' driving in a busy town/city for it to get warm/hot. That's more likely where the issues occur.

 

This might be more of an issue for LHD models too if my RHD experience is anything to go by. The reasoning is thus;

In my RHD car the passenger will get in on the passenger side, and usually sit in the rear. Now in a RHD car I only have a problem with the vent being blocked if there is more than one. On a LHD car the passenger will board on the passenger side and more likely block the vent and block it more often. This will lead to battery overheating.

The car needs more vents, probably one at each side and maybe some under the seat where the passengers legs would be. If you've been working your car hard and someone then sits and blocks your vent, you have a problem.

 

Both gen 2 and gen 3 have a vent on the right of the rear seats (facing forward)where air is leaving the cabin, not entering. The gen2 vents to the traction battery from there to the 12v battery and then out of the vehicle.
The gen3 vents to the traction battery and the spare tire well then to the 12v battery and then out of the vehicle.
My observation of the gen3 is the spare tire well needs to be sound proofed to keep echos from entering the passenger cabin.
My advice to cabs and warm weather prii would be to tweak the air supply flowing(external duct or silent powerful fan at the exhaust point), and with any luck, as Toyota definitely monitors this site, an oem refit and future upgraded air channels are not out of the question.

 

Using a car as a taxi is always a good way to show any weaknesses in the design. What affects a taxi in numbers in the early days will probably start to affect private vehicles later. The question would be whether it's the use (and subsequent heat) or just the miles that's causing the issues.

Will a significant number of gen3's start failing at the 80,000/100,000 mile mark in the next few years, or will the problem be restricted to hard worked vehicles only?

My worry, and I appreciate it's just that, is that Toyota UK only felt able to provide a 5 year/60,000 mile hybrid system warranty to the original batch of gen3's. Why? Why reduce it from 8 year/100,000 miles like provided on the gen2? Know something we don't Toyota? Later with all the who-ha about recalls they increased it to 8 year/100,000 miles for gen3's built AFTER June 2010! Again, why? Is there something affecting the first years production of gen3's that was subsequently improved in 2010? Are the failing vehicles all 2009/early 2010 gen3 Prii or just gen3's?

I always thought it weird that the warranty was increased from June 2010, but not for the couple thousand gen3's already on the road. It didn't make sense other than for some sinister reason - a reason that early, higher mileage users are now finding to their detriment.

Why have a hybrid warranty that goes 8 years/100,000 miles for the period 2002 - July 2009 and then Jun 2010 onwards, leaving owners in that blip with 5 years/60,000? I'm now starting to smell a rat.

Here's the official UK warranty info;
Toyota Warranty | Insurance & Warranty | Toyota UK

 

Here is a test performed according to DOE requirements.
The item: Prius 3 gen HV battery
Condition: BOT (beginning of test) and EOT (end of test - 160,000 miles)

http://www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/hev/batterygenIIIprius0462.pdf

Shows 20% degradation in capacity.
MPG not significantly changed.
Not many information about daily use pattern, though.

 

Not so Prius taxis in Melbourne, Bendigo, Sydney. Not as common as in Brisbane.

 

Don't like to disagree with Bob with his obvious engineering background the Prius HV battery heat vents behind the lower luggage compartment and through the wheel well and then to the outside through the pressure relief flaps Bob mentioned previously, unless, of course, the outside cabin vent is completely shut off.

 

I doubt it would have been gas, brake, gas, brake, brake, gas, more gas, brake hard, gas x 10 hours.

More like, gentle acceleration, slow to a stop. Gentley accelerate upto 25 mph at a constant, nice and easy speed.

 

Perhaps relevant to this thread, Carolyn at Luscious Garage in San Francisco last year wrote a detailed blog post on their work on Prius taxis.

"Between both day and night shift we see between 40-60 cars every day, of which the vast majority are Prius. Of those cars, easily a third are Prius taxis, with high demand for auto service."

 

That entry is from 2012 and deals mostly with 2nd gen I'm afraid.

 

Bob. I've been thinking about this issue and wonder if it's something else other than heat. I'll try and explain this with my non electrical engineer head on.

Could the premature failures be caused by the stress of continued cycling of the engine being switched on and off? I'll try and explain. With a household fridge there is a large spike or draw of power when it first switches on. Does something similar happen with the Prius? When stationary or going slowly, does switching the engine on take a hit on the HV battery? Now if one was driving at 60 mph the inverter is switching between battery and engine nice and gently and the battery won't be under as much strain. However, European town/city driving involves lots and lots and lots of having the engine start, stop, start, stop in very small distances. Our roads are narrow and you are always having to slow down or stop because a parked car is blocking your way etc. I just wonder if that surge or increase in power required to boot up the engine all the time to actually get the car moving again could be taking a hit on the gen3 HV battery? In the US a nice gentle drive, even at low but continuous speed might be easier on the battery. On, off, on, off is not?

That might explain why issues are occurring in the UK where the weather is anything but hot and gen3 cars in heavy traffic in the US where roads are generally more open and free flowing seem fine.

 

Starting electric motor with inverter doesn't produce any spikes on the electrical grid, maybe the inverter it self takes a hit?