"Bob" <lester11221@comcast.net> wrote in message
news:htednY58zuDnkRDfRVn-vQ@comcast.com...
> Does anyone have any info on the long-term reliability of hybrids. Any
> brand. Batteries?
>
>
I have a 2002 Prius. So far (2 1/2 years, 45 K miles) it has been the most
reliable car I've ever owned. Disclaimer: my daughter's '93 Accord has been
a clear second, considering it had 8 years and 163K miles at the time. I've
put a couple axles, a timing belt, brakes, a window regulator and an ignitor
in it in 4 years.

The question of hybrid battery life comes up all the time. The bottom line
is that everybody wonders and practically nobody has had problems. One
battery was destroyed by an insane hybrid control computer (both replaced
under the 8 yr/100K mile hybrid system warranty), another was punctured by a
stereo installer. Otherwise the Toyota_Prius' Yahoo group's 11000 members
have had no main battery failures, even though several are over the 100K
mile mark. I like to illustrate the point by pointing out a Google search
for "Acura transmission fail" brings up 17000 hits relating to why the Acura
transmissions fail and what to do about it, while a search for "Prius
battery fail" brings up about 9000 hits speculating when a battery would
fail but seemingly none on any that actually did. One hit refers to a
battery failing at 245K miles, but the reference doesn't take you to the
original source. I'm not aware of that happening, although a Prius taxi in
Canada was bought back by Toyota at about that mileage... the battery was
still good.

The Prius does have a 12 volt aux battery that is more troublesome and twice
the price of a normal 12 volt battery, though. Ours is still okay, but when
it croaks I'm going to make the adaptation to a more normal battery. The 12
volt battery just boots the computers and runs the brake pressurization pump
before the converter kicks in. I guess Toyota figured that meant they could
use a lawn tractor sized battery. The pre-2004 model also came with tires
that had a treadwear rating of only 160 (!) which lead to complaints of tire
life. I understand the current model has more normal tires.

There is no alternator, starter or even a transmission in the conventional
sense. The power steering and brake booster are electric, as is the A/C in
the current model. 12 volts for accessories and recharging the aux battery
comes rom a 100A converter when the hybrid system is "ready." Cruise control
is nothing more than an extra brake pedal switch and a control switch
assembly - everything else is just lines of code already in the hybrid
computer. Reverse is still the same gearing as forward, but the hybrid
computer tells the power train to back the car up, so it does. There is even
forward (or backward, in reverse) torque when in gear, very much like a
conventional auto tranny.

Honda's IMA system can be suped up, since it is essentially a conventional
power train with a boost from an electric motor. Toyota's can't, since the
entire system is under control of the hybrid computer. Adding a turbo, as
one turbo mfr has suggested doing, would certainly destroy the hybrid
transaxle. The engine is coupled to the transaxle by a torque limiter that
looks very much like a conventional clutch without a throwout, and the
"transmission" is simulated by generating AC from one motor/generator,
rectifying it and inverting it to drive the other motor generator. There is
some direct torque coupling but significantly increasing the engine output
would destroy one of the electronic parts immediately if the torque limiter
survived. Even putting headers on the engine can't improve the output,
because the hybrid computer would simply get in a snit about the power not
being as prescribed. For related reasons, the engine max rpm is held to 5000
rpm (maybe a little more on the current model?) by the hybrid computer. Not
the choice of teenage boys everywhere, but a huge plus for engine life I'm
sure.

The Honda system is adaptable to either manual or automatic transmissions.
The Toyota system is not available with a manual gearbox or automatic
transmission, only their "electronic CVT". Since there is no actual
transmission (it is a fixed planetary differential with two electric
motor/generators) there is no place to put a gearbox. Even if you found a
trick to do that, it would be hard to shift a car that won't even let you
decide when the engine runs. With the car in "park" I can press the
accelerator to the floor. The engine always starts, if off, and gradually
builds speed to some specific speed around 2000 rpm in a minute or two.

Mike