Why is my Lenovo y510p SLI not working?

I recently bought a Lenovo y510p SLI laptop for gaming purposes. I bought it the ultra bay that allows you to put a second graphics card in in place of the disc drive. My laptop now contains two Nvidia GT755m graphics cards (one preinstalled, one in the ultrabay). When going into the Nvidia control panel to enable SLI, I click "maximize 3D performance" and it shows that SLI is enabled, and I can tell both cards are working at this point because hot air is being pushed out of both sides of my computer.

The problem is, when I go to play a video game (Diablo III), the SLI runs perfectly at about 130 fps on max graphics for about 10 minutes or less. After 10 minutes, my computer stops reading as being plugged in to the power adapter and drops to about 6 fps. I do not know what is causing my computer to do this. When this happens, I have to unplug the adapter from the power outlet in the wall and plug it back in. My computer then reads as being plugged in again. Because of this, I'm forced to only make use of the single graphics card, and my ultrabay/second GT755m graphics card are useless.

I have posted on the Lenovo forums about this, and I did not receive any responses. I'm thinking the reason for this is that my power adapter does not provide enough power to power the two graphics cards at once. I have very limited computer and electronic knowledge and would greatly appreciate some input on this.

The cord that unplugs/plugs into the adapter brick says 125V

Added (1). Also, the back of the adapter brick says Input: 100-240V ~ 2.0A.

I just recently purchased the y510p with dual 755m cards and can't get the sli to work properly either. While playing bf3 fallout new vegas and goat simulator it spikes in fps from 70 down to 20's in a matter of minutes also. I've searched every where and still no solution… My suggestion is to disable sli and use one 755m until a patch or nvidia update fixes the sli. You may not be able to max out all your settings but it will be stable. Please keep in touch with me at cdelamora@ymail.com so we can both keep in touch if we find a fix.