June 18 (Bloomberg) -- Apple Inc. said the battery on its new iPhone will let users talk three hours longer than planned, raising prospects of a successful debut for the mobile device next week. The shares advanced.

The battery will provide as much as eight hours of talk time on one charge, more than rival phones, Chief Executive Officer Steve Jobs said today in a statement. The iPhone, a combination mobile phone and iPod media player that will cost as much as $599, also offers six hours of Internet use, seven hours of video playback or 24 hours of audio playback.

Analysts expect the changes to fuel demand, helping Apple reach its sales goal of 10 million iPhones next year. The original battery life might have forced users to frequently recharge the iPhone, since it's powered by a single battery that can't be swapped out. Apple also said it replaced the product's plastic surface with optical-quality glass to make it clearer and more scratch-resistant.

``Battery life and potential scratching are two of the major concerns we have fielded,'' Benjamin Reitzes, an analyst with UBS AG in New York, said today in a report. Apple may sell 950,000 iPhones by the end of September, he said.

Shares of Cupertino, California-based Apple rose $4.59, or 3.8 percent, to $125.09 at 4 p.m. New York time in Nasdaq Stock Market trading. The stock has gained 47 percent this year.

The iPhone will become Apple's third major business, along with the Macintosh computer and the iPod, which each ring up sales of about $10 billion a year, according to Jobs, 52.

Ten Days

Until today, Apple had said the iPhone would offer up to five hours of talk time, five hours of Internet use, five hours of video playback and 16 hours of audio playback. The company also announced today that the handset can last 250 hours in standby mode, or more than 10 days.

That compares with talk time of four hours on rival offerings from Nokia Oyj, Palm Inc. and Research In Motion Ltd., Apple said, citing battery-life data provided by those companies for the Nokia N95, Palm Treo 750 and BlackBerry Curve 8300.

The iPhone is set to ship in the U.S. on June 29 at 6 p.m. in all time zones. There are two models: a 4-gigabyte version for $499 and an 8-gigabyte model for $599. Both feature a 3.5-inch color display that's operated by a touch screen rather than a physical keypad.

The company will sell the device at its stores and through San Antonio-based AT&T Inc., the largest U.S. mobile-phone service. A two-year service contract from AT&T is required.

To contact the reporter on this story: Connie Guglielmo in San Francisco at cguglielmo1@bloomberg.net

Last Updated: June 18, 2007 16:16 EDT