I want to sell the original cobra car windshield, never use. Where will i sell?

No, you pay for the upgrade through the Dealer or Manufacturer.

https://www.cobra.com/support call their customer service number, I didn't see the chargers for sale individually here, but I would think they'd sell them since they sell the radios.

USD 75 is what other used ESD 9210s are current going for here.

I have found 2 links for you to look at, amazon seems to be selling it for much cheaper than eBay. http://www.amazon.com/Cobra-19DXIV-Channel-Mobile-Compact/dp/B00083KUVS

http://www.ebay.ca/ctg/Cobra-Electronics-19-DX-IV-40-Channels-Base-CB-Radio-/54837100

Did you ever fix this problem I have a 03 mustang cobra same problem Please help

there may be a small screw or if not, its a metal clip, you may need to pry the clip up and slide the metal piece out. the auto parts store sells special glue just for the mirror.

You can purchase a compatible battery on eBay for $13.99:

http://cgi.ebay.com/BATTERY-FIT-BK-71216-Cobra-LI-3900-700mAh-BRAND-NEW_W0QQitemZ270509452146QQcmdZViewItemQQptZ2_Way_Radios_FRS?hash=item3efb9eab72

Or get the original through a Cobra dealer for $19.95:

http://cobra.com/index.cfm?fuseaction=product.display&product_ID=283

I dont know of any radar detectors that need to be calibrated. To calibrate the radar, you would need a source of RF energy like a radar gun and a ton of specialized equipment.
Just turn it on, place it up high enough on the windshield or dash so that it has a clear "view" of the road. Suction mounts on windshields get the detector higher and it offers you a better view and an earlier warning as it can "see" over the hill better.

Has it got to below freezing in your area recently? If so, your fluid is probably frozen and will need to be replaced. That is the only thing I can think of. It happened to me recently! Good luck I hope this helps