"Typically, the charge is terminated at 7% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and typically needed at least two hours to fully charge. Current-generation cells can be fully charged in 45 minutes or less; some lithium-ion varieties can reach 90% in as little as 10 minutes." -
Lithium-ion battery - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Lithium-ion_battery#cite_note-40
Some people do not know how Lithium Ion batteries work.
Most people use the OLD way of charging
NIMH cell phone batts. 8 hours is for the init charge on
NIMH batts, and irrelevant for Lithium Ion.
Lithium Ion batteries have multiple stages of charging so they do not leak/explode. The charger will adapt per the charge the battery needs.
Lithium ion batteries are charged before storage/shipment at least 40% to keep the batteries in working condition for longer storage. These 20-45 minute initial charge is due to an overcharge for storage, but you should give them a full charge before use, not 8 hours.
If you never let your cell phone drop below 7-15% charge, the battery will even last 6 months longer (although not like it was new, just not 4 hours of standby and then dead).