Read on the forum that its an existing problem
http://forum.rapiro.com/thread/177/

Has anyone found a solution?
Some people are suggesting I split the power supply so that the Raspberry will draw its own power so the not have a voltage drop when the camera is acive.

I am using Pi2 and Pi Cam with my Rapiro. But I don't have such an issue. I am using the Eneloop batteries and the Digikey KTPS36-0940DT 3P AC adaptor.

I have done some testing, and Batteries its fine but looks like I am only getting about an hour of operations before I have to recharge.

Disabling Wifi Power Management seems to help a bit and it does not reboot as frequent.

I am now trying a powered USB hub and so far so good... if it survives a day without a reboot then I would have to either resolder one of the USBs to a Internal connection and attached a powered USB hub or try another power supply.

@luzhuomi, do I keep the batteries in while I connect the adaptor? I always take them out because it seems to drain them...

Are you able to check the syslog to find out what causes the reboot?

Using enloop batteries, my Rapiro can last for 3 hrs + with Wifi on. The Pi Cam is turned on based on demand.

I take the batteries out while I am using the AC adaptor.

After some testing the reboot is due to the Edimax wifi not getting enough power.
Once I plugged in a stable USB hub that can supply enough power, the rebooting stopped.

I am using Enloop pro batteries, but I need the camera and wifi always on so that could be sapping the power.

For now I am going but an additional battery compartment and modify it to hold the hub and some storage but I guess the range of movement would be limited a smaller area due to it having to stay plugged in.

I've been experiencing the same issue.
Not only camera and wifi, audio amplifier can also result in lack-of-power reboot/hang.
My solution:
http://forum.rapiro.com/thread/445/
In short, feed another power source into the micro-usb of your PI instead of relying on the GPIO input from Rapiro board alone.

And if you want longer battery life, forget eneloop.
Try to buy a pair of 18650 batteries and charger, they can power Rapiro for about 3 to 4 hours with not very intense movement/camera usage.
The battery box is made to contain 18650.
The only thing you need to do is relocate the metal connectors and perhaps one simple wiring.