We have poor performance in our 8821 series phones, like many seem to have had or have currently. Checking articles on the cisco webpage, we see battery life rated 13.5hrs or 9.5hrs "talk time" depending on which link you click. Most of our several hundred devices can't go 24hrs standby with 15 minutes of talk time. In doing some research, I've noticed sites list batteries, as 3.75v 2000mAh as well as 4.35v 2060mAh. Hard to tell if there actually is an extended battery (as they had for the 7925 series (1100mAh to 1450mAh) when the cisco site states "Rechargeable Lithium ion 4.35V, 2060mAh smart battery (minimal capacity 3.8V, 2000mAh)", is there a fabled 4.35V, 2060mAh "smart battery" or is all of this just manufacture wording?