The EZ-B uses 5 volts to operate, anything above that is really not needed. In fact higher voltages like 12 volts and higher cause the voltage regulator to really work hard to control the voltage @ 5vdc. The 6-pack battery holder is a trade off for voltage and capacity so that the EZ-B can operate for longer periods than 4-pack 6 volt battery holder

EZB is recommended to use a 7.2v battery pack, it operates from anything between 5v and 17v. Depending on your project will probably impact the power supply you use.

Personally I use a 7.4v LiPo battery pack, these are very light and come in a range of sizes.

The higher the voltage the hotter the regulators get but it's easily cooled down with a mini pc fan if the heat is too much.

Using a 5v supply will probably cause more brownouts than using a 6v, 7v, 9v or 12v supply.

Now factor in if you are going to runa hbridge which needs it's own dedicated supply to feed the motors, if you are, what voltage motors are you using? You can take the supply from the same battery just not from the EZB.

Also, if you plan to run 6v to the servos power to increase torque and reduce current running through the EZB you also need to think about the supply.

In short, you haven't missed anything but the EZB can use a supply of 5v to 17v. Don't be put off using a higher voltage supply because of the regulators, that's why they are there

I use a 12vdc power supply powering my EZB and it's working wonderfully. The regulations run a little hot but I have a 5vdc PC fan blowing on it (Powered right from the EZB) and that takes care of that.

I use a LiPo 7.4v 1500mAh. This battery was used RC helico (crashed!). Works great on my rover.

this is what i have done, the battery packs will power the Thumper motors with 3 H-Bridges and the EZ-B, you can see the pigtail. One side to charge and the other side to power the EZ-B.
I can charge the batteries and not have to worry about taking them out.

That's like what I plan to do, make it so battery/batteries are fixed for good. Mounting the lipo balance charger in the bot too and extending the 12v barrel jack up to the original charging barrel jack on teh back of the torso, then just plug in the 12v supply and charge him up

Do you charge with it connected to the EZB?

haven't done that yet, barely started the project.

But from ready other posts it will work without any problems.

What are your batteries rated at that you use in thumper? What the amphour rating?

I have run both 6 V and 12 V batteries in all of my projects and have had no issues what so ever. I do recommend soing as dschulpius suggested and put a 5v fan on the heat sinks. Good luck!

the batteries I'm using are 6C 7.2V 2000mAh NIMH Sticks, 4 of them.