Wirelessly posted (My IV to the Net: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0) BlackBerry7250/4.0.0 Profile/MIDP-2.0 Configuration/CLDC-1.1)
For my 7250, I have drivers and desktop mngr installed on laptop. Charges fine.
Nothing BB related installed on my desktop and it charges fine, although seems to charge more slowly. No time trials run to confirm though.