LOS ANGELES -- Jon Spallino is leasing his third Honda hydrogen fuel cell vehicle, and says he hasn't had to make any changes to his life or driving habits because he doesn't have a standard gasoline car.

Sure, his FCX Clarity's interior doesn't heat up very fast on chilly days; with no engine to generate heat, a heat pump must suffice. And finding a nearby hydrogen fueling station can be a chore.

But the 48-year-old Redondo Beach, Calif., resident has never questioned his move to fuel cell mobility.

As part of Honda's decade-long beta test of hydrogen technology, Spallino may be the dream brand advocate, routinely putting 1,000 miles a month on his FCX Clarity and helping Honda better understand what changes need to be made for fuel cell technology to reach the mainstream.

"People always ask me the same questions: How do I get one? How much does it cost? How far does it go? How long does it take to refuel?" Spallino said.

Those answers soon will become clearer as Honda, Toyota and Hyundai prepare to launch retail-ready fuel cell vehicles over the next 18 months in California. Sales are expected to be modest, but still a jump from the few dozen beta-test prototypes now circulating in controlled fleets.

The upcoming Toyota fuel cell sedan is projected to have total global volumes of 5,000 to 10,000 units over three years. By contrast, Hyundai has limited aspirations for its fuel cell Tucson, hoping for 300 global sales per year for the next three years. Honda has declined to give a sales forecast.

But even that small sales jump will require some changes in how the automakers approach this tiny, but possibly revolutionary, portion of the market.

"This is really sophisticated stuff, but it's built on the customer expectation of the internal combustion engine," said Steve Center, vice president of American Honda's Environmental Business Development Office.

"Everything is different about it, but it has to behave seamlessly the same. We're beyond beta testing now, in terms of less patience customers will have for something going wrong."

What are some lessons that Honda and Toyota have learned in their small-fleet tests?

Honda discovered that a range of 220 to 240 miles per tank wasn't enough to keep customers happy, so its fuel cell model coming in 2015 will have a range of 300 miles. And it will have room for five, compared with the four-passenger Clarity. Acceleration will need to be sufficient to feel the torque of the electric motor, but not so much as to sacrifice range.

And, in a touch of refinement, the tailpipe won't "exhaust" water on garage floors after the vehicle shuts down, keeping it in a reservoir instead to expel on the street during the next drive, said Steve Ellis, Honda manager of fuel cell vehicle marketing.

Also, not all hydrogen-fueling stations work the same way in teaming with vehicle software or maximizing hydrogen fuel pressure in the tank. When one Clarity owner started seeing her range readout drop from 240 to 220 miles, she wrote Honda saying, "I want my 20 miles back."

At Toyota, recent innovations allowed for the deletion of the external humidifier that keeps the fuel cell stack moist. Instead, a proprietary design allows water to move through the cells' membranes without freezing in cold weather, said Craig Scott, national manager of Toyota's advanced technology group.

More important was Toyota's ability to re-engineer existing hybrid-vehicle parts to work with the upcoming fuel cell car. For instance, the boost converter to crank the fuel cell stack's 200-volt output up to the 600 volts needed for the motors comes from engineering learned with the Prius.

"A lot of the powertrain comes now from our hybrid vehicles, which are our fundamental core architecture and technology," Scott said. "Everything we do now finds its way back to that architecture. That results in monumental cost cuts."

Hydrogen control systems firm Proton OnSite in Wallingford, Conn., has been driving a dozen demo-fleet fuel cell Toyota Highlanders since late 2010, amassing about 220,000 miles.

Larry Moulthrop, Proton's vice president of hydrogen systems, describes the prototypes as "impressive," with more than 300 miles of range and a three-minute refueling time.

"If we didn't have stickers saying 'Hydrogen Power,' you wouldn't know the vehicle is any different, other than it's quiet and water squirts out the tailpipe," Moulthrop said. "You may have a flat tire, or a headlight go out, but as far as the powertrain is concerned, it has worked flawlessly."

Although Hyundai will be first with a showroom-ready car, due this summer, it hasn't had a practice fleet to work with. That's one reason it is using the existing Tucson crossover's architecture: to reduce building complexity as it comes down the main Tucson assembly line in Ulsan, South Korea.

"Customers are often intimidated by technology, or think they need to relearn how to drive," said Gil Castillo, Hyundai Motor America senior group manager of advanced vehicle strategy. But with early focus groups, "People walked away thinking it's almost anti-climactic."

All three automakers are most worried about the lack of a refueling infrastructure. Stranded cars mean unhappy customers.

California has proposed a "Hydrogen Highway" of 100 fueling stations statewide, but budget constraints may curtail that plan. There now are nine public stations open; 12 private or demo stations; and 19 public stations in development, according to the California Fuel Cell Partnership.

"Infrastructure is going to make or break these cars," said Honda's Center.

Added a Toyota insider: "We would be marketing these cars totally differently if those 100 stations were already in place."