I've been having trouble with "Change Battery" messages and low battery displays etc. and can't figure out how to get rid of the problem. New Lythium batteries with 1.72 reading on elec. meter. Sometimes I can press the bottom of the battery door and get a better connection. Have cleaned both door contacts and interior battery contacts with q-tip and peroxide but no change. Today, I can't get the camera to start at all. Any ideas on what to look for?
I seriously doubt that peroxide and a Q tip will clean the contacts - you should abrade the metal surface with a piece of 400 grade wet and dry or a proprietary abrasive contact cleaner. If this does not work send it back to Canon for a rather expensive service or get a new one.
And use rubbing alcohol or lighter fluid to clean contacts. Peroxide doesn't really do anything. Look at the battery contacts. If they can be bent up a bit they will make better contact. I once had a camera that had an unbelievable case of metal fatigue in the battery contacts. Had to bend them back up every few days.
