One of the best items of value in the BMW Aftermarket Parts catalog is the $69 BMW Advanced Battery Charging System.

I purchased one but do not have a manual. Other threads have discussed that this charger/tender goes thorough a diagnostic phase (light flashing sequence(?). Can anyone share how it should be working? I plugged it in with the right 'handshake: key on - plug into accessory outlet - plug charger into power, initially the power button flashed once and then indicated that I had power to the unit. It was at 2/3 (yellow) and took over night to get to 3/3 (green). When it was -40 I checked it in my unheated shed and it would be green for 10 seconds or so and then it would cycle through the Red (1 second) - Yellow (1 second) then Green (10 seconds again).

It has now warmed up to a balmy -10 C and the green light is now constantly on. Drivers Ibm Aptiva Windows 98. Does this sound normal? Could anyone possibly post the manual? I purchased one but do not have a manual. Other threads have discussed that this charger/tender goes thorough a diagnostic phase (light flashing sequence(?). Can anyone share how it should be working? I plugged it in with the right 'handshake: key on - plug into accessory outlet - plug charger into power, initially the power button flashed once and then indicated that I had power to the unit.