Physicsman

This modification works but it was a little slapstick.

This modification allows you to plug in a battery pack that can be used with or instead of the internal batteries. It also give you the option to add the voltage of the external batteries to that of the internal batteries. This modification only needs to be done to the battery tray thus eliminating the need to open the blaster. Though I did remove all the safeties so a prolonged overvolt on an un-moded blaster might cause the thermistor to cut out the motors.



To do this I use an DPDT switch and a mono headphone jack along with wire, solder, hot glue, tools, etc..

Here is the wiring diagram I drew up.



Here is the link to the album showing a few stages of install: http://imgur.com/a/lthrB

This required electrically isolating the contacts on the outside of the tray from two new contacts placed right on top of the stock ones.

Here is a brief video demonstrating the finished concept:

Wired in four AA's in series using a SPDT switch (http://en.wikipedia.org/wiki/Switch)

I should have wired it with a DPDT switch so I could use all the batteries all the time. i.e 2X4AA's in parallel or in series.