I turned for help with your question to my friend Craig Van
Batenburg, hybrid education resources director at the Automotive
Career Development Center in Worcester, Mass. (www.auto-careers.org).
He replies: "The nickel metal hydride (NiMH) batteries used in
today's hybrids last a really long time, more than anyone thought
"The oldest battery packs are now nearly 10 years old in Japan.
Most are still original, and still working fine.
"In the U.S. they are over seven years old. ACDC, my
hybrid-training company, owns two 2000 Insights, a 2001 Prius, a
2003 Civic Hybrid, a 2004 Prius, and a 2005 Ford Escape Hybrid. ACDC
also bought two other hybrids for experimental purposes, a 2000
Insight, and a 2001 Prius. All of the battery packs are original.
"ACDC owns the factory scan tool to monitor and test the battery
packs, and all signs are OK on all of our vehicles.
"My suggestion is to look at a NiMH battery pack like you do a
transmission. It should last the life of the car -- many do -- but
after 200,000 miles and 10 years, it really doesn't owe you much."
Seven years ago, the estimated replacement cost of a hybrid
battery pack was $10,000. Today, it's between $2,500 and $3,000; yet
price is nearly moot because few are replaced.
According to Toyota (www.toyota.com):
"The Prius battery (and the battery-power management system) has
been designed to maximize battery life. In part this is done by
keeping the battery at an optimum charge level -- never fully
draining it and never fully recharging it. As a result, the Prius
battery leads a pretty easy life. We have lab data showing the
equivalent of 180,000 miles with no deterioration, and expect it to
last the life of the vehicle.
"We also expect battery technology to continue to improve: the
second-generation model battery is 15 percent smaller, 25 percent
lighter and has 35 percent more specific power than the first.
"This is true of price as well. Between the 2003 and 2004 models,
service battery costs came down 36 percent. We expect them to
continue to drop, so that by the time replacements may be needed, it
won't be much of an issue.
"Since the car went on sale in 2000, Toyota has not replaced a
single battery for wear and tear."
The Canadian website, The Hybrid Experience Report (www.hybridexperience.ca),
lists expenses for the British Columbia government's fleet of 2001
Toyota Prius hybrids. Comprising 64 vehicles, the fleet traveled
1.59 million miles during the study; the average cost per mile for
maintenance and repairs was $0.043 USD per mile.
The study states: "There were no costs identified that were
specific to the hybrid components of the vehicles."
Initial reports are certainly encouraging, but as the Canadian
study observes: "Only when tens of thousands of hybrids have been
operated for many years, and over 400,000 kilometers (about 248,000
miles) each, will reliability issues become clear."