I got the idea for this instructable from seleziona's golden eclipse mod.
Step 1: Materials .
The materials you will need for this Mod are:
1 stampede NERF gun
2 4 AA battery holders
8 AA batteries
2 Alligator clips
small Phillips screwdriver
Step 2: Removing the Battery Compartment.
First, remove the screws holding the battery compartment in the gun. Next remove the battery compartment from the stock of the gun. then remove all batteries from the compartment and set them aside, you wont be needing them for the finished product.
Step 3: Preparing the Compartment.
To prepare the compartment you will need to cut out the pieces in the middle to allow the battery box to fit in.
Step 4: Time to Wire It Up!
For this step you first need to get the two battery boxes. then solder the fed wire from one to the black wire of the other, it should look like the picture above. then solder alligator clips to the remaining red and black wires. then position the boxes in the battery compartment and connect the red wire to the positive side f the compartment and the black to the negative side.(see picture)
Step 5: Put It Back Together
slide the compartment back into the gun and fasten the screws. Congratulations! you successfully moded a stampede NERF gun!