B# Battery Emulator

Principal Investigator: Professor Pai H. Chou, UC Irvine
Student Contributors: Chulsung Park
Jinfeng Liu

Thanks also to Jae Park and Kien Pham, and NSF for sponsorship as part of the OMA project.

B# (pronounced B-sharp) is a battery emulator. It is an intelligent power supply whose voltage response to current load mimics that of a real battery. Currently we use dualfoil as the simulator for lithium ion batteries. Details of this board can be found here.

[news 7/14/03] B# is a winner of this year's ISLPED 2003 Low Power Design Contest.

  • Technical Paper:
  • Download:
  • Data Files:
    • FullChargeLongRun.txt (1.2MB) -- voltage and current samples taken by B# (@33ms/sample over 27 minutes). This is an iPaq from fully charged to fully drained. The variation in load was achieved by changing the backlight brightness over four levels. Five levels available: A(super bright) > B (high bright) >C (Medium bright) > D (Low bright) >E(Power Save, which is actually same as off); we use levels A,B,C,E.
      E(1min), A(1min), C(1min), B(1min), A(1min), E(1min), A(1min), C(1min), B(1min), E(2mins), A(2mins), C(2mins), B(2mins), E(3mins), A(3mins), C(3mins), A(less than 1min)
  • Protocol

Why B#?

B# was developed to support in-situ experiments of battery-aware power management techniques. With small systems becoming so low power, it is now taking over 12 hours to completely discharge even a small battery pack. This became painful to take measurements for a large number of experiments, and results are difficult to reproduce due to aging effects of the battery. On the other hand, simulating the battery + system together, while reproducible and controllable, is slow and inaccurate.

B# combines the speed and accuracy advantages of measurement based approaches with the flexibility and controllability of simulation based approaches. We can set the battery model to any charge state (e.g., fully charged, half-way charged, almost drained) instantly. With the playback feature, it can mimic not only different types of batteries (by plugging in different battery models) but also solar panels and other power sources.

Related Links

Penn State University Battery Simulator (PSU-BS) is the only other battery emulator we are aware of. However, we did not find publications on this project.

B# Features

  • B# can mimic lithium ion batteries (using dual foil), or any other battery if the simulation model is available
  • B# can be used as a data acquisition device for collecting power profiles (voltage, current)
  • B# can be used in playback mode to reproduce a power profile
  • B# can be used in training mode to train a battery model
B# 2.0 Specs
  • Interfaces: 10 base/T Ethernet, USB 1, RS-232 (for programming)
  • PIC microcontroller, flash programmable
  • 3 channel, 10-bit ADC
  • up to 4.5V, 750mA
Last Modified Mon, Jul 14, 2003 3:01 PM