Just received the kitchenaid 5 cup food chopper and cannot figure out how to remove the lid. manual was no help. what is the secret to taking it off

Push up with your thumb UNDER the BLACK part of the pulse/on power button and turn the lid with your left hand to disengage. To put the lid back on, position it to the left side of the handle and push the pulse button back in place until it clicks. Use both hands to disengage lid from the bowl. The bowl does not need to be on the base. This step should have been part of Step 1 in the disassembling the food chopper section in the manual.

About how long will charge last-runtime? I know it depends on what you are chopping, but just a rough estimate? 40 onions doesn't mean much to me, tx

I think they mean 40 onions gives a poor frame reference for actual run time. If you were to fully charge it and then run it empty, how long would it go?