Please note all photos for this instructable were taken after I had finished the modifications so you will have to look closely at the parts you have after disassembly of the battery box and compare them to the images supplied here before modifying anything.
I would also recommend reading each step fully (several times) and only proceed if you understand what is being said. i.e. don't drill, cut, solder anything until you are confident you fully understand the step.
Also all usual disclaimers apply, I take no responsibility for you breaking your (probably dead anyway) Pleo RB, burning your house down, injuring yourself etc. etc......
This instructable should only be attempted by people who are capable of using (and old enough to safely use) a Soldering Iron, and Electric Drill.
If you need help ask an adult to help you rather than destroying your beloved Pleo RB, Pleo RB's were not cheap (Originally) however I found mine on eBay for less than £30! Albeit with a dead battery, other than this and following these modifications it is 100% fully functional :-)
P.S. this instructable would almost certainly apply to an Ugobe Pleo as well as Pleo RB however the battery internals on Ugobe's original Pleo are different as it is not a Lithium battery but a Nicad battery, this will mean that the references to the BMS board in this instructable will refer to the connection board (housing the required thermistor) other than this I would expect everything else would be identical. (same PSU requirement, same battery disassembly steps etc.)
Tools/Items required, PleoRB + (probably dead) lithium battery, soldering iron + solder, wire cutters, small (rifler) file, packing foam, Sony PS2 Slim 8.5v 5.45A PSU.
Step 1: Purchase an Appropriate PSU
After a little investigation I discovered that the PlayStation 2 Slim PSU provides 8.5v @ 5.45A, perfect for our needs and can be had for less than £10 on eBay.
Step 2: Disassemble Your Dead Lithium Pleo RB Battery
The Pleo RB battery consists of four small lithium pouch cells and a BMS board (Where the three gold connector pads are), the cells are wired 2S2P (2 in Serial 2 in Parallel) although this is irrelevant for this instructable as we are going to remove the cells completely.
The battery housing is in three parts, the top part holds the turn key locking mechanism in place, I found the best way forward here was to use a thin metal ruler to prize the top part off (Starting from the gap where the locking prongs swing out), it is glued so a little acetone (nail varnish remover) should soften the glue, as I was not so worried about the aesthetics I did not bother with this (I would use acetone if I did this a second time though as I broke a couple of internal locating tabs) but be careful not to break it completely as we need the battery compartment in good shape (its got to fit back in place when we are done) the second part is levered off in the same way again take care not to break the plastic housing completely, if using acetone wet the cracks that run around the top two parts focusing on the corners and shorter ends as this is where most of the glue was, the shorter ends have plastic tabs that stick up from the second part into the first, I broke one of these completely but it does not affect performance or aesthetics at all.
Once these two parts are off you will see the bottom of the four Lithium cells and the whole lot should simply slide out.
Cut the cells free and put them to one side (carefully, shorting these can be very dangerous, tape the lose ends up to be sure, we don't want any fire hazards on your tech bench!) they are not required for this instructable, two of mine were dead completely and two were serviceable, however the BMS board also appeared to be dead despite replacing the cells, my initial thoughts were to replace the cells and run Pleo RB from a freshly repacked battery, alas it was not to be.
Using a soldering iron remove the wire stubs from the BMS board, don't break the board as we definitely need this part due to the integration of a thermistor (the third gold pad) for battery over temp protection.
Right battery in bits case and BMS board recovered on to step 3.
Step 3: Drill Holes for PSU Wire and Solder PSU Wires to BMS Board.
Read this whole step before proceeding.
Use a drill to put a hole in the top (externally visible from Pleos belly) part of the battery case lid that is the diameter of the PSU cable thickness and in the location shown in the photo, that way it will not foul the locking mechanism, we need the lock to work when we are finished. Then using a small file extend the hole to the center so that it breaks out into the large circular hole in this part of the lid where the lock turnkey goes, and makes a nice "U" shaped notch.
Use a drill to put another hole in the second (lower) part of the battery lid in the same place so both holes line up neatly, using a small file extend this hole in the opposite direction (to the top part) so that it breaks out to the outside of the battery case, and makes another nice "U" notch facing in the other direction.
Thread the first top part over the cut cable end, the ferrite choke fits neatly through the turnkey hole, and push the cable into the slot you just created, make sure you put it (the lid) on the right way around (bottom first).
Thread the cable into the second part where you just cut/filed a "U" notch and assemble the top two battery lid parts together (they should clip together nicely depending on how much of a mess you made opening the battery in the first place) slide the two battery cover/lid parts down the cable and out of the way for now.
Using snips cut the AC power jack off the Playstation 2 Slim 8.5V 5.45A PSU.
Make sure you cut it as close to the end of the wire as possible, leaving the ferrite AC noise suppression choke in place, this is important, a) to suppress noise as intended, b) to provided a nice cable securing method, this choke fits neatly inside the battery compartment when we are done.
Strip the cut ends and tin them with fresh solder, you should end up with around an inch of positive and negative wire (leave the insulation in place on the positive wire bar a few mm at the business end) the positive is in the center and insulated (if you are using the recommended PS2 slim PSU) the negative is the shield and can be simply twisted and tinned, trim both tinned ends to remove the last few messy mm's of tinned wire and give neat ends.
using a small metal file, file a notch in the corner of the positive and negative gold pads, we are filing a notch for the cables to pass through from behind the board, to avoid any potential electrical complications I also removed a portion of the tracks (using the same small file) on the back of the BMS board to avoid and possibility of shorting on the unknown (unrequired) BMS circuit.
The BMS board is very thin be careful not to break it in two (don't put it in a vice!) it was so thin that I was able to hold it in one hand and file with the other, it was done in a matter of a few seconds.
Bend your tinned ends of the PSU wires to 90 degrees to create a hook that will fit neatly from the rear of the BMS board through the notch you just filed and onto the front side of the positive and negative gold pads.
Be sure to respect the polarity here and make sure you connect the positive wire from the PSU to the positive pad of the upcycled BMS board, luckily they are handily labelled + and - respectively.
solder the thick (and at 5.45A they are quite thick wires) tinned and trimmed ends onto the front side of the gold pads, this will seem to be way to chunky but don't worry the Pleo has spring loaded battery terminals it will be fine.
You can put a fair amount of solder on here even if it results in a chunky blob, the springs will do their job and make a good connection, you may want to flatten the tinned ends in a vice or pliers to make this a little neater.
Don't mess with the third thermistor pad, no need, again the spring will make contact so leave it alone.
Step 4: Reassemble Battery Compartment With Tethered PSU
Slide the BMS board back into the battery compartment observing polarity so that all three gold pads are visible from the outside of the battery box, the thick PSU wires should be neatly routed through the two notches you filed in the BMS and the ferrite choke should fit neatly inside the battery box.
Pack the rest of the box with a non flammable packing material (I used an old dry hard kitchen sponge but any insulating packing foam will do) clip the inner lid part back onto the battery compartment and secure with insulating tape (don't glue it yet, not until you have tested it) stretch the tape over the circular lug that the lock fits on and down through the two slots that the turn key, turns in.
Clip the outer lid part back in place and voila you are ready to resurrect your Pleo RB!
Step 5: Insert Your Newly Created Battery Defeating PSU Teather and Test.
Slide the battery box (with tethered PSU cable trailing out) back into Pleo RB, plug in and test.
If you don't get a power light straight away, remove battery and check that the BMS board has not been pushed in by the springs, if so use a firmer packing material inside the battery case. I found that the pads needed a little filing/cleaning to get the excess (insulating) flux off the solder blobs, and it took a few goes to get the red light showing on Pleo's belly. Power it up and play with your newly "Re-Born" Pleo for hours on end. You will never need to purchase another expensive (poor quality) Pleo RB battery again.