The slow process of improving batteries is taking yet another step forward today. HP is set to offer laptop buyers more energy efficient, longer-lasting batteries as a premium upgrade for certain systems. The Sonata batteries, which are manufactured by start-up Boston Power, are based on a refined version of the lithium ion technology found in today’s laptop cells and will supposedly offer “like-new” performance for three years.

Not only they’ll keep 80% of its initial charge for 1,000 charge cycles – compared to 300 cycles or less for conventional lithium ion batteries – but the Sonata battery is also able to recharge to 80% capacity after only 30 minutes. HP will begin offering the batteries to customers as an add-on option to its new Enviro line of laptops in early 2009, presumably for $20 to $30 more than current replacement batteries, and is providing a three year warranty on them.