We stock decent quality laptop batteries and they tend to give 2.30 hours on full charge.
Ofcourse not as cheap as ebay £10 ones but we ensure quality and reliability. Feel free to give me shout for any needs.
Usually battery life is 1 year if it's used every day, all the time. After this period, cells inside tend to become weak. Since you have had laptops for 2 years, most likely its time to change batteries.