Recelling ERA-201b Batteries

WARNING: This guide is for reference only. It will help you in refilling your own ERA-201B battery. It does not guarantee success. Proceed at your own risk, and if in doubt contact someone with experience. The refilling of the ERA-7bx batteries is basically the same with small deviations.

This guide and author do not accept responsibility for damage or injury caused. This is a DIY project and will most likely take longer than some minutes. Do not rush it, take it slowly!

Tools Required:

  • Adjustable temperature soldering iron.
  • The key to success is an adjustable temp iron and good solder.
  • Quality solder. – 63/37 or 60/40 with flux.
  • Utility knife (e.g. Stanley knife).
  • Small screwdriver.
  • Eeprom programmer (e.g. CH341 USB)
  • Multi-use charger for 1-6 Li-Ion/LiPo cells

Let’s go on:

  1. Get yourself 4x 18500 cells (with soldering tags) from branded vendor and same production. 2x 18650 cells (with soldering tags) for the ERA-7bx.
  2. Open battery‘s case carefully. Especially the upper part where the connector is located.  

YouTube: How to open the Battery


  1. Remove carefully the  thermistor from the cell it is glued to. Unsolder the old cells from the PCB. Start with B- then 3,7V (middle connector) and then B+. Unsolder 3,7V and B- at the battery to reuse the cables. The B+ connector has to be unsoldered directly from PCB Be careful not to short circuit anything on the PCB.


If you don’t want do the eeprom programming you can go to step 7

For reprogramming the eeprom we will need an eeprom programmer. You should look for CH341A USB flasher. It’s cheap and sufficient for this job. Additionally you might want to order a SOIC8 chip clip. Sometimes it will be difficult to get a proper connection between PCB and the prommer with this chip clip. (unfortunately the cheap ones don’t work very well) It’s easier soldering connector cables to the PCB (only temporary).

  1. Solder jumper wires to the specified points. Alternative connect a SOIC8 Clip to the eeprom. Connect the jumper wires to your programmer. Simply follow the PINOUT diagram on the programmer.


  1. Try to read the eeprom.


  1. First make a copy of the eeprom by using menu option Save as… to store that file somewhere on your local hard drive. If something goes wrong you have the original configuration.

You have to edit these settings according to the cells you wont to use:

00000010 00-01  Design Capacity – 2300 dez = FC 08 hex

00000060 00-01  Full Charge Capacity – FC 08 hex (should be same as Design capacity)

00000000 0E-0F  Cycle count set to 00 00 hex


You can send me your dump file and I can make the changes for you !

Here you will find the datasheet for BQ2040 !

The ERS7 memory map is a bit different according the BQ2060 datasheet!

Now it’s time to re-program the eeprom with the altered content. Click “write eeprom” and you should have the new settings stored in eeprom. You can validate by “read eeprom” and check your new settings

If everything is ok, remove the cables or the chip clip from the PCB.

  1. Solder in the new cells to the PCB. To reassemble your battery, follow these instructions in reverse order. Before you close the case you should check your work!


  • Connect the AIBO Battery Refill Tool. The tester should show you the new settings, Design-Capacity, Full-charge Capacity, Cycle count. Sometimes it is necessary to “jump start” the new refilled battery. You have to connect the ground from the battery connection with the B- connector. Only a few seconds.


  • If everything goes fine the aibo battery tester goes on. If the battery won’t start, the electrical fuse („SC10“) might be blown because of a mistake when working at the PCB. In that case, the fuse can be removed. (unsoldered) and replaced by tiny wires in a V-shape.

Even if you have double protection on the PCB,
be aware of that you remove one protection circuit !


YouTube: Aibo Battery Tool

  1. Now you have to discharge cells with a extern charger / discharger to close below 6V. This will reset BQ2040 fuel gauge chip. You can’t use Aibo for discharging because the charging circuitry inside the robot disconnects the battery much earlier before reaching those 6V. After discharging the battery, let it rest for two hours.
  2. Now it is time to charge the battery. Hopefully Aibo will charge now for around  2-3 hours and will finish with „full charge“ indicators set.


If everything goes well you have your own recelled Aibo battery! Congratulations!

Thank you for your support: Venus, WolfBob, Ray and Chris 69


Programming the BQ2060, ERA-7bx batteries.

The eeprom will not accept the new values. The bypass caps are sufficiently charged to keep the BQ2060 chip alive for days und he will not read the new values. But by shorting them out you will kill it. You re-program eeprom with the correct FCC value, then with the board unconnected to anything simple short all the pins on the PCB Board (I use aluminum foil to do this) so you really only need to short them a time.  It will come alive when you reconnect the cells and will then read the EEPROM for base data and will get the new FCC value.


Aibo Battery connector:  

If you number the pins from the one nearest the edge is 1 and the on furthest as 6 then:

  • 1= plus
  • 2= I2C clock
  • 3= I2C Data
  • 4= Must be connected to pin 6 to activate Pin 1.
    This protection allows it to meet the requirement of not have voltage available on external contacts.
  • 5= Reserve
  • 6= Minus


0x08 ///< temperature register
0x09 ///< voltage register
0x0f ///< predicted remaining battery capacity as a percentage
0x10 ///< capacity when fully charged
0x18 ///< design capacity register
0x19 ///< design voltage register
0x1c ///< serial number register
0x20 ///< manufacturer name
0x23 ///< manufacturer data
0x25 ///< cell voltage register
0x2a ///< current register


The TI BQ chips actually measure the capacity of the cells but it is reluctant to be too aggressive in updating that value(s) in its memory. A complete full charge full discharge and full charge will reset the BQ2040 batteries

Datasheet  BQ2040

SC Protector (datasheet for electrical fuse used in Aibo‘s battery protection)

Datasheet SC10

Prototype I2C interface to Aibo Battery 

AIBO Battery Refill Tool

AIBO Battery SMBus Reader

Code on GitHub

Modified CH341 prommer connected to the PCB and a fresh refilled battery 🙂 


Programming Hardware and Software from Texas instruments