Hybrids - Toyota vs Honda

I don't think that is a safe conclusion at all. With a number of Prius approaching the 200K mile and 5 year mark, there have been few enough outright battery failures that validating them is difficult (obvious hoaxes are common). It is more likely as Toyota indicates; most will never need a replacement battery. If somebody does need one, used batteries are often offered for $400-$1000 US on ebay, courtesy of road accidents. To test the battery, the multi-function display includes a diagnostic screen that reports individual cell health (one of those secret sequence things) and the cells are individually replaceable.

Every vehicle dies of something. I've scrapped a Mercury Capri because it needed a new driveshaft (integral u-joints!) and the price was over $200. To assume HV batteries will be the death of most hybrids is quite a stretch, especially given their track record.

Mike

Can you pass on the sequence, please? I'd love to have it handy for my UK-spec T4 Prius (new Aug 2005), for occasional checking.

More generally: there are so many ignorant people, ready to make sweeping and ignorant statements about hybrids that I've learned to disregard them, or (for fun) pick out the weasel-phrases used to insure against contradiction. The bleeding things work, now. I am assuming Toyota (with Honda, and whoever else undertakes to manufacture advanced vehicles) do accelerated life testing &c &c with a view to ensuring customers don't get mightily cheesed off before they've had value for money. Time, not ignorant opinion, will tell.

FWIW my Toyota dealer tells me today that the UK price for a new main Prius battery (w/o labour charges or taxes) is GBP 1321.35, which I hope helps to focus the discussion. (Side note: earlier this year I posted a substantially lower price, also supplied by my dealer; but I think he must have misunderstood the question.) I would expect this price to fall as design refinements are made and production ramps up -- what to, who knows.

But what problems do they solve, and what other solutions are there for the same problems?

They solve exactly one problem: recapturing braking energy to re-use on acceleration. There's only one place where that works: city driving.

The requirement for braking came from the burning of petrol to create acceleration in the first place. Must we burn petrol to create the acceleration? Can anything else solve that problem?

They're also more expensive to make and to buy. That's a problem in and of itself. If we're trying to save on petrol, can we use any other motive source for acceleration?

If so, can that other motive source be purchased cheaper than the hybrid?

For example: can a diesel engine solve the problem better/cheaper/more reliably than a hybrid?

Can I run a diesel and spend less money, or no more than the same money, as a hybrid? Let's say I spend the exact same amount of money per mile to motivate the diesel as the hybrid. Now it comes down to maintenance and reliability. Is the diesel cheaper or more expensive to maintain? What about the reliability--can I get the diesel fixed cheaper? What happens when I go out in the country somewhere--can I rely on the magic black box of software that the hybrid depends upon, or will a diesel be more reliable because it doesn't depend on a computer just to run?

There are so many questions to ask yourself once you dig down.

I prize reliability and simplicity. The Toyota hybrid fails the simplicity test horribly, the Honda hybrid much less so, the diesel virtually not at all.

And frankly, it's all about MY pocketbook. Which one, over 200K miles, cost me the least out of pocket to buy, maintain, repair, and insure?

You forgot one very impotent part of that equation....REPLACEMENT cost. The hybrids, all of them, cost more to buy than conventionally power vehicles of the same size and equipment. They will cost more to replace as well. Especially if the batteries are depleted. The fact is the premium one pays to acquire a hybrid will generally buy ALL of the fuel, used by a comparable conventionally power vehicle, for three to four years. For the average new car buyer in the US that replaces their new vehicle with another new vehicle in three to four years that can mean all of the fuel for as long as they generally own their vehicles. Personally I hope more buyers choose hybrids to save the planet, that will stretch the supply of fuel for those of use that prefer high powered, safer, large vehicles. The only problem I see is if the consumption of fuel, in total, is going down the price of fuel will rise for those that have trouble buying fuel at todays prices evn for hybrid owners. ;)

mike

"Elmo P. Shagnasty" > And frankly, it's all about MY pocketbook. Which one, over 200K miles,

My satellite phone has the same type of battery as used in the Pruis. It is about the size of a thick postage stamp and it costs $52 to replace. ;)

mike hunt

Wanna bet the replacement cost is prorated, not fully covered by the warranty?

mike hunt

Probably closer to 8 years, the life expectency of a hybrid battery pack.

Or longer.

I'm not. It's a diversion from hydrogen technology. Besides, battery production is an incredibly toxic industry. Your trading one plague for another.

nb

hybrids don't just work by capturing braking energy.

They run a more fuel efficient cycle with a longer expansion stroke. The Miller/Atkinson cycle. They can do this because acceleration is supplemented by the battery. They also have a smaller engine b/c it can use batteries to accelerate.

By using the Miller cycle they get a higher % of energy out of the gas and into the drivetrain.

It's very ingenious.

Hydrogen is probably never going to "be here". You need a fuel source to get hydrogen. Hydrogen is very hard to transport (harder than natural gas which is difficult enough) and there are no cheap "fuel cells". The advantages of a liquid fuel are great.

I think the next step is using a smaller gas engine and a larger/cheaper battery that you can plug in. You could plug it in for an hour a night and that would take you maybe 30-40 miles. On longer trips and under acceleration the gas engine would turn on. That way you'd be replacing gas with electricity, which can come from nuclear/coal/wind whatever.

Regenerative braking is very far down on the list of values in hybridization. The essential purpose is to use the primary power source more efficiently. Putting a 240 hp engine in a passenger car to cruise around town at 35 mph is extremely inefficient. Using a 50 hp engine to do that is far more efficient, but responsiveness suffers badly. We are in the infancy of hybridization now, but as the power technology advances a 50 hp hybrid can be more efficient than a 50 hp conventional car and provide better responsiveness than a 240 hp conventional car. The difference is made up by stored electric power.

In actuality, a car would have to be pretty small to warrant only a 50 hp engine. The design becomes straightforward, though. The power necessary to climb a 6% grade at the prevailing maximum speed (75 mph in the US) at maximum gross weight is exactly the engine power needed. For a mid-size car that is in the 100 hp range, maybe slightly less.

The side effects of running the engine at higher power levels are valuable, too. Hybridization increasingly separates the engine from the driver control, so there are no issues with suddenly mashing the accelerator. Emissions are much easier to control as the engine comes under computer control.

I can understand why there isn't a lot of enthusiasm for the current generation of hybrids. Not only do they have a limited track record, the level of hybridization is not enough to knock anybody's socks off. (Well, mostly not. See Honda's DualNote

Mike

Your battery has the same basic chemistry, but is a very different animal. In portable electronics the most important design characteristics are power density, light weight, barely affordable replacement cost, and short, spectacular life. The last two are economic considerations. In the Prius power density and light weight are not very important at all, the replacement cost is what it is (since it is not designed to be replaced), and the life is designed to match the life of the rest of the car. If you were willing to have a much larger and heavier battery that used only a third of its potential capacity, and a very sophisticated and expensive charger that was always connected to a charging source when the battery was in use, your battery could easily outlast your satellite phone. I doubt you would like it, though.

Mike

Nope - 100% covered.

Mike

So you would like us to believe the useful life of a Pruis is 8yr 100K? A Corolla that can be had for 5,000 less will easily last to 200k or more, don't you think All the more reason one would be better off buying a Corolla ;)

mike

No - the *warranty* is 8 yr/100K miles. Engine warranties (like the one in the Corolla) are typically 3 yr/36K miles, but I'm sure you expect more.

Mike

We shall see. NiMH batteries typically have a reduced charge cycle lifetime compared to NiCADs. That is one reason NiMH never caught on in power tools where a contractor might cycle a battery several times per day.

Lifetime in cars is going to be highly variable depending upon usage patterns and random manufacturing variations.

John

One problem with that is the fact that the stored electric power eventually runs down. It would not be fun to be in the passing lane on a long uphill section of road going around a vehicle only to discover that your battery storage has just been exhausted and that the available torque is suddenly reduced 50%. Yikes!

One thing hybrids bring into the equation is a significant depenence on near term prior history to a degree which conventional engines do not.

John

It's all a matter of design. In your example, a properly designed hybrid will not run out of passing power because the engine power was enough to maintain full legal speed, while passing power is available because it was not needed to reach the cruising speed. A major reason multi-hundred horsepower engines are used in passenger cars today is to provide that margin, in spite of the economy penalty the vast majority of the time.

Even in the previous generation Prius - the one we have - our battery has never dropped to "empty" (actually something like 50% charge) although we live at 7000 feet and have made trips with ful load to Washington state and the LA area. I've never heard anybody complain about that happening, either. It just isn't a problem.

Mike

The Prius first went on sale in Japan in 1997, 8 years ago. I don't have solid information, but AFAIK no reports have come out about failures of those batteries.

As you say, we shall see.

Mike

I wasn't talking about the Prius, I was talking about your hypothetical vehicle which you say would have a much smaller conventional engine than does a Prius.

John

Clearly not every Prius owner is a happy owner. Look here: