Trying to make sense of the batteries!
For the camcorders, the batteries themselves carry a charge of 7.2V and 4.9 Wh. But, the AC adapter's output is 8.4V and 1.7A. Which to use? Perhaps the adapter is higher because there is some resistance in the cord going to the camcorder, but maybe I am just making that up.
Here is a link to a promising product, a 8.4V NiMh battery with a charger included! 40 bucks, though, so it would be $400 for all 10 cameras. Well, this may be worth it...would love your thoughts on this, SW.
There is a nice primer on choosing batteries here.
For our purposes, we can calculate battery capacity using the formula:
Ah = Watts x Time (h) you want to run the camera / voltage needed for the camera
Ah = 3W x 8h / 7.2 V = roughly 3.3 Ah or 3300 mAh
Here's a nice closeup of styles waving in the breeze and some shameless anthers shedding pollen: