Important update to prevent melting of your batteries and other potential damage to gear!I created this battery unit as per the directions outlined in this thread, however I ended up shorting out somewhere due to the specific type of 1/8" mono plug I bought!
After melting my first RC Battery pack and
creating a thread to solve that problem, I inspected things all a little closer and realized that the mono plug I was using had a protruding plastic case which *might* have been preventing it from sitting all the way snug in. The PS2's hole for the phono-plug looks to have been constructed by drilling a hole out of the casing, and then lining up the actual "guts" of the female end with the hole in the case. Thus, if the plastic shielding on my male was too thick, I couldn't get the connection necessary, as the whole male end, tip and all, wouldn't reach easily (God it's hard not to make jokes right now....).
Next step I've taken has been to buy another 9.6V RC battery and build another Tamiya > 1/8" cable, though this time using Radio Shack's
274-0288 1/8" plug instead of their model number
274-286. Now I have my new cable made with my new model number mono male, and everything is testing perfectly with the multimeter. Below I am including pictures of the two products, as posted on Radio Shack's website, enlarged a bit, and presented with guidelines to emphasize difference.