When replacing the D cells within the feet with rechargeable cells the feet are less heavy. This causes an issue when the robot attempts to walk. The solution is to add weights to each foot to compensate.

The legs have been replace with the rover 5 chassis. My main goal is an autonomous security robospaien that roam around freely when I am not home and annoy my GF cat in the process. Weight is my main concerns, which is the reason why I have strip it from it's plastic case. The next step is to replace the 4 d cells with one single rechargeable batteries that I remove from an R/C helicopter. It is a 7.2v. Each leg carried 2x d cells, so it have 3v per leg, total of 6v. I have two voltage regulators, input 3v per leg, but so far have no luck. I am feeding it voltage directly trough the output wires coming out of the D cells.

My comments were about the Robosapien V2 which has 4 D cells per foot. So it does not really apply to your need of an answer for the earlier model.

Frankly , I do have one but still did not have time to upgrade it with EZB . I received my 2 kits and all possible accessories to move on.

What is your main concern ? Does the robosapien work on 6v or 3v ? Can you check the voltages from the batteries , and feeding what ? If they are added up into 6v and goes to Mainboard as 6v , in this case you can use your 7.2 battery with 6v regulator such as 7806 feeding the mainboard and no issue should be encountered. However, you need to be carefull , have the proper tool ( multimeter ) to check the voltages and connectivities at different points startmg from battery terminals . I hope others that did the actual work can give you better hints.

I recall reading a few topics about the robosapien and power, I'm sure a search would come up with a few topics that cover the voltages... I have a vague recollection of @Robotmaker mentioning something (which means you need to enable ghost posts in your settings)

thanks RICH