This is an external battery pack for the Revo I built based on the one featured at Revoworld, D-I-Y External Battery Pack for the Revo by Peter Rand at http://www.revoworld.com/dbShowNews.asp?ID=109 As a Revo user who uses the Revo away from power sources able to charge it, I was quite interested in Peter Rand's article on Revoworld about the external battery pack. No offense to Peter Rand's design because he did all the leg work, but his design is a little too exposed for my liking...too much potential for an electrical short which would drain the batteries, so I went about looking for a better design. When I found this battery case at Radio Shack (Tandy), I knew I found the right case for the job: In Canada it goes under the Radio Shack catalog number of 270-409 and is described as, "Battery Holder with Cover, holds 4AA". The cover of this unit has a screw you have to remove to open it...I like that way because the cover won't come off in the luggage exposing the batteries (however, you can leave the screw out and the cover will remain on...just not locked). Also, the battery case has an on/off switch on it, again reducing the chances for draining the battery when not in use. In doing this project, I wanted to make it as neat as possible. In other words, I didn't want the new lead attached to the ends of original case leads with strips of electrical tape...so that meant replacing the wires inside. After removing the main battery cover, there is a separate cover for the wire compartment that is attached by a screw in the middle, and melted plastic at the ends as seen here: After removing the screw that holds this cover in place, you have to get something to pry off the cover and break the seal of the melted plastic: This is the area where I attached the new lead to the old connection points. When doing this, make sure to pay attention to the positive and negative, and what part of the power connector to the should positive and negative...the Revo will be damaged if the polarity is backwards!!! After the new lead is connected up and double-checked for short-circuit and correct polarity, the wire compartment cover needs to be reattached. Place the cover into position and reattach the screw. Then the plastic posts need to be remelted to the wire compartment cover. This is the completed unit with the batteries in: and a picture of the unit with the top cover on: In building this, I'd be the first to say that charging the Revo's batteries with batteries isn't very efficient...after one recharge of the Revo's batteries the battery pack has dropped from the original 6 volts to 5 volts. I haven't tried to see how many charges I could get out of the battery pack, but the Revo did have trouble recognizing that it was 100% full...but then I've also had this problem with recharging with the AC (mains) adapter, and it is a recognized problem with some Revos. The main purpose of such a battery pack is to charge up the Revo when you don't have a proper power source available, so you can still use the Revo in those cases and not take a chance of losing the contents of the Revo's memory. I just want to thank Peter Rand for the work done he did on the original, and Revoworld for being such a great resource for Revo users...myself included. If you're a Revo, Revo Plus, or Mako user, please visit Revoworld at http://www.revoworld.com and you won't regret it. (Note: PEAT and Michael Fellhauer accept no responsibility for any damage that may occur by performing the steps described in this document, or at any of the Revoworld links provided above. Anything you do is at your own risk.) [ Top of page ]