A Original LG Li-Ion battery is sometimes limp after about 5 years. So a new was needed, and it should again be an original LG battery. Exactly this battery now I ordered I ordered in April 2011 already on our second LG KP 500 and is still blameless. Both batteries keep a standby time of about 10 days. I assume that the batteries hold also 5 years.
The good price / performance ratio, I can recommend this very battery.