Wrong, the InFo supersedes the AC. Read the link above.
[one last "corporate" hijack from me, sorry]
The InFo states that you must comply with FSIMS "and/or" AC120-76A. I didn't see in the InFo where you have to have the thing strapped to your knee. Can you site a reference?
We'd rather be "in line" with the federales from the get-go rather than hustling to get into compliance when/if someone decides we're doing it wrong. If, in fact, we DO need to have it on a "kneeboard" those mounts are very inexpensive, so I can't imagine having too much of a problem with going that route if we needed to.
[/corporate hijack]
FWIW, our "policy" (one plane two pilots about 95/5 on the 91/135 ops) as written is to plug them in at our office at the FBO when we leave.
If we're on an overnight, each pilot takes one to the hotel to plug in. That means if I'm single pilot on the trip, I only have to charge one at the hotel.
With power in the cockpit, plugging the second one in with the GPU on prior to departure usually does the trick for charging it. And as others have said, battery life isn't a problem. I flew a weekend trip single pilot last weekend and with the 2nd unit in the plane all weekend, I came back to preflight with the fully charged unit and the 2nd unit was at 98%. That was 70-ish hours unplugged.
Our policy for updates is to check during every preflight. We do have 3G if we needed it for updates, but like others, we don't seem to have a problem finding wifi. I'll agree that simpler is betterer.
-mini