Electric/hybrid question

[R Sweeney]

Just asking in case some folks here have a clue. i don't kow if there
is a "correct" group. Since cars like the Subaru have a lot of owners
who expect high service life I'm wondering about hybrid batteries. Has
anyone seen anything on how long the battery packs last? or what
replacement costs will be?

The batteries have the same life as all the other rechargeables in your
life.
Maybe 1000 recharges (3 years) before their loss of capacity becomes
untolerable.

as for the cost... think of the price of your cellphone battery and multiply
by 100.

hybrids are a social-political statement, not an economically justified one.

 

[Guest]

Just asking in case some folks here have a clue. i don't kow if there
is a "correct" group. Since cars like the Subaru have a lot of owners
who expect high service life I'm wondering about hybrid batteries. Has
anyone seen anything on how long the battery packs last? or what
replacement costs will be?

A very good question, that only time will accurately tell.
As others have said rechargeable batteries become less effective with
time.
Those who have battery powered portable computers know that after about
3 years the battery becomes noticeable less powerful and leaks charge
more easily. A portable computer battery is usually considered trash
after 4 or 5 years, although they still work for a short time.

That brings up the point of at what point is a hybrid car battery
considered not useful? Certainly the battery will probably still work
somewhat after 4 or 5 yrs, but what will be the efficiency of the hybrid
system when the battery is weak. Even if a battery is weak and be not
very effective, I doubt the manufacturer will want to replace it.

As for the hybrid vehicles themselves I feel they have already gone
silly with their designs. This system does best with an ICE which is
too small for desired acceleration and hill climbing. However recent
models are just hybrid technology added to an ICE which already has
enough power.
The Honda Accord hybrid is an example of this. A hybrid sold more for
improved acceleration than fuel savings.
Marketing is heading us in the wrong direction.

Another concern I have with current hybrids is the real world mileage
when air conditioning and heat are required.

New diesels with new clean fuel may be in our future.
Practical fuel cells are too far in the future to think seriously about.

A hybrid lover, but cautious over some current designs.

 

[YKhan]

I think the reason that rechargeables become less and less effective
after a few years is probably because they are charged upto and beyond
the 100% mark continuously. The electronics on these cars try to keep
their batteries at around 80%.

I saw a website which showed the microscopic structures of
rechargeables, and compared a new rechargeable with an old one. The
difference seems to be in the buildup of some crystalline structures
which act as barriers to chemical reactions. The site said that there
are techniques available to breakup those structures and thus renew the
batteries back to near original state.

Yousuf Khan

 

[R Sweeney]

I think the reason that rechargeables become less and less effective
after a few years is probably because they are charged upto and beyond
the 100% mark continuously. The electronics on these cars try to keep
their batteries at around 80%.

I saw a website which showed the microscopic structures of
rechargeables, and compared a new rechargeable with an old one. The
difference seems to be in the buildup of some crystalline structures
which act as barriers to chemical reactions. The site said that there
are techniques available to breakup those structures and thus renew the
batteries back to near original state.

Yousuf Khan

limiting the charge/discharge depth to just a few tens of percent kinda
defeats the point using batteries doesn't it?

 

[Ed P]

limiting the charge/discharge depth to just a few tens of percent kinda
defeats the point using batteries doesn't it?

The simple answer is No. As an owner of an '04 Prius who follows a
couple of Prius Yahoo Groups, I can tell you that the Toyota software
keeps the high-voltage, or traction, battery at a state of charge (SOC)
between 40% and 80%. Remember the car is *not* an electric car that is
intended to go substantial distance on battery power alone. Rather the
battery is a reservoir that in most situations is intended to be able to
take in regenerated electricity (e.g. by braking) as well being able to
supply energy for the electric motors to provide power when appropriate.
When the traction battery reaches "full" charge, as in descending a
long grade, the regenerative brake function cuts out and the car must
rely on friction brakes alone. This doesn't happen in most normal
driving but is an example of why the battery isn't intended to be kept
at full charge.

I would stress that the Toyota hybrid design is an integrated approach
wherein having the supplemental power from electric motors allows for
the use of an smaller than normal internal combustion engine (ICE) that
is optimized for efficient operation. Such operation is not possible
for an ICE that has to provide start-up torque from a stop as well as
power at hightway speeds.

Ed P
'96 Outback

 

[YKhan]

The simple answer is No. As an owner of an '04 Prius who follows a
couple of Prius Yahoo Groups, I can tell you that the Toyota software
keeps the high-voltage, or traction, battery at a state of charge (SOC)
between 40% and 80%. Remember the car is *not* an electric car that is
intended to go substantial distance on battery power alone. Rather the
battery is a reservoir that in most situations is intended to be able to
take in regenerated electricity (e.g. by braking) as well being able to
supply energy for the electric motors to provide power when appropriate.
When the traction battery reaches "full" charge, as in descending a
long grade, the regenerative brake function cuts out and the car must
rely on friction brakes alone. This doesn't happen in most normal
driving but is an example of why the battery isn't intended to be kept
at full charge.

How long a grade does it have to be before the regenerative brakes
fully recharge the batteries?

Yousuf Khan

 

[Ed P]

How long a grade does it have to be before the regenerative brakes
fully recharge the batteries?

Yousuf Khan

I don't know. I live in Northern VA and my only personal experience on
a big hill has been coming down Rt 211 from Skyline Drive to Sperryville
and the battery did not max out. When some Prius owners were
contemplating driving up and down Mt. Washington, the Prius chat group
had all sorts of ideas about how best to deal with the situation.
Certainly running the AC/heater, headlights, etc. expends some of the
electricity and extends the time the brake regeneration takes to "fill"
the battery. The car is equipped with a "B" mode wherein the ICE is
spun to create engine braking.

Ed P

 

[Michael Pardee]

Ed P wrote:
How long a grade does it have to be before the regenerative brakes
fully recharge the batteries?

Yousuf Khan

Our 2002 Prius "fills up" sometime shortly before we complete the 2700 ft
descent from Flagstaff to Sedona, Arizona. I think the current model Prius
has the same capacity, but allows higher regenerative braking rates so the
hill could be steeper/faster and still not use the friction brakes.

Mike

 

[Ed P]

Our 2002 Prius "fills up" sometime shortly before we complete the 2700 ft
descent from Flagstaff to Sedona, Arizona. I think the current model Prius
has the same capacity, but allows higher regenerative braking rates so the
hill could be steeper/faster and still not use the friction brakes.

Mike

For anyone interested in detailed discussion of hybrid cars, I recommend
the Yahoo Groups Prius-2G and Prius_Technical_Stuff at
http://groups.yahoo.com. One of the contributors, a Julian Edgar, is a
writer for an online auto magazine and has reported on his experiences
and results in super- and turbo- charging a Prius.

For those especially interested in regenerative braking in a Prius, see
message # 44794, posted 10/26/05 at 11:53pm.

Ed P