As I got into my car at my local YMCA recently, I noticed a Prius parked next to me with a For Sale sign in the window. It read: “’05 Prius, $14,999, 97,000 miles.” This beige Prius looked to be in good condition. And with gas prices topping $4 a gallon, it certainly seemed like a good deal for a gas-electric hybrid that gets 48 mpg in the city and would cost about $23,000 new. But one question nagged at me: as the odometer approaches the century mark, how much life is left in this car’s electric battery? And then an even scarier question occurred to me: if the battery runs out of juice, how much would it cost to replace it? Those concerns short-circuited any interest I had. So I put the key in the ignition of my far less fuel-efficient car and drove off.Hybrids these days are hotter than a laptop battery, with sales up 58 percent last month. But what happens if the battery on your hybrid goes dead? After all, hybrids have been on the road in America for eight years, racking up hundreds of thousands of miles. Automakers say those big batteries under the seats are holding up well. But when they power down, replacing them will cost you thousands. That thought might have been a caution light for me, but it isn’t for the growing gridlock of used hybrid buyers. On the car Web site MyRide.com, the number one search term last month was “Used Toyota Prius”–up 944 percent since January. “People are ignoring the concern about battery life,” says J.D. Power auto analyst Michael Omotoso. “Their immediate concern is, ‘Oh my God, gas is $4 a gallon. I need a hybrid. I’ll worry about battery replacement five years down the road.'”When hybrids first hit the road in 2000, there was plenty of fear-mongering, especially here in Detroit, where the Big Three were drunk on cheap gas and big SUV sales. Back then Motown execs warned darkly that rescue workers could be electrocuted trying to save trapped motorists who crashed in these high-voltage contraptions. And those giant batteries could cost $10,000 or $15,000 to replace once they ran down, maybe after 100,000 miles or less.It turns out those safety fears were nonsense. But while the battery replacement cost was overblown, it is not insignificant. Philip Card of Utica, N.Y., says a Toyota dealer wanted to charge him $3,900 to replace the battery on his 2001 Prius, which had 350,000 miles on it when he bought it used on eBay this year for $4,357. Card knew the battery might be running on empty when he bought the car, but the retired engineer hoped to convert the car into a plug-in hybrid that could get 100 mpg. Before he had a chance, though, his Prius had a brownout. “It lost power drastically,” he says. “It still moves around, but with no pep at all.” He’s decided to park the Prius rather than replace the battery. He’s going to scavenge parts from it to fix up two other Priuses he owns. What’s his advice for other used Prius buyers? “If they’re going to take it to a Toyota dealer for service,” he says, “they better have deep pockets.”The stiff cost of replacing a battery at your dealer helps explain why an underground aftermarket in Prius batteries is emerging. Since last year eBay has seen an 850 percent increase in Prius batteries changing hands. Prices for used Prius batteries–which come from junkyards and auto body shops–range from $450 to $1,700, says Famous Rhodes, director of eBay Motors parts and accessories. “As hybrid vehicles hit the tipping point in age,” he says, “the demand is growing significantly.”The hard part about these cheap batteries: once you buy them you have to figure out how to install them. That’s labor-intensive work for which dealers can charge $900. But Rhodes does not recommend that amateur mechanics try to tackle this high-voltage repair job. “This is not something where a DIY can just open up an installation manual and put in their own batteries,” says Rhodes. “You need to have a mechanic or an electrical technician do it.” News source: NewsWeek