I purchased an XB-700li in October 2008 and used the unit, daily, until May 2009. Since then the unit has been stored away. The battery has also been stored inside the home in an area that is - well - room temperature.
The battery had NOT been charged on a monthly basis. This year I decided to bring the bike out again. When I went to get the battery I noticed it was 'bloated'. After speaking with a sales rep. she advised me to check the physical batteries themselves.. I opened the battery and removed the green wrapping. Each of the batteries at the end where the circuit boards are located are distended.