So we managed to build a small handheld battery tester, which instantly gives the user some insight on the battery it's connected to. Provided the battery can respond, of course, i.e. if it complies with SBS protocol.
Recent portable batteries with a chemistry derived from lithium - like the ones fitting Aaton Cantar-X3 - all incorporate more or less powerful protection systems.
For some of them, the chip protecting the battery for both charge and discharge also performs remaining capacity gauging.
Could you imagine nowadays riding your car in Death Valley with an unknown fuel level, or making a vital phone call - when you ran out of gas - without knowing if the battery can fulfill the task?
Several chip makers gathered in the late 90s and managed to agree on a standard communication protocol, the SBS V1.1 (Smart Battery System), allowing for communication between the onboard battery chip and the outside world. Derived from the I2C protocol, two wires suffice to establish a two-way SBS communication between the master (CPU) and slaves (batteries and chargers).
Several data are accessible by standardized commands
; some return results on the instant status (voltage, state of charge...), and others allow for a comprehensive diagnosis of the battery (number of cycles, effective capacity at full charge...)
These data are of more concern to owners of a battery fleet rather than to the casual user.
Therefore DC Audiovisuel has developed a portable standalone SBS battery poller, which provides the following dynamic data:
- Instantaneous voltage, in volts;
- Effective capacity when fully charged FCC, in Ah;
- Relative state of charge SOC, in%;
- Cycles elapsed, integer.
The following static data are also provided:
- Date of manufacture;
- Nominal voltage;
- Rated capacity.
On top of display, a colorful symbol of AA cell provides information on relative state of charge at a glance:
- Between 0 and 20%, red;
- Between 20 and 50%, orange;
- Between 50 and 100%, green.
The standalone portable SBS battery tester is available for sale and rental at DC Audiovisuel.