123electric Smart BMS gen 3, Manual

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19
123electric
The Netherlands
E-mail: info@123electric.eu
www.123electric.eu
Algorithm
SOC calculation
The SOC is calculated by constantly measuring
the in- and outgoing currents and integrating
these currents. This is called Coulomb
counting. The SOC is recalibrated every time
the pack is full and empty. This is done to
reduce SOC calculation deviations.
In BMS “normal mode”, the SOC is set to 100%
when all cell voltages are >= V-balance.
In BMS “critical mode”, the SOC is set to 100%
when the total pack voltage is >= V-balance x total number of cells. In other words, when
the average cell voltage is >= V-balance.
When one of the cell voltages is below V-min
for a longer time while discharging is not
allowed, the SOC is set to 0%.
Charge and discharge/load relay
The tables below display the conditions for
each relay to switch on or off, depending on
the selected mode.
Normal mode
Charge Discharge/load
Enable Disable Enable Disable
All cell voltages < V-
balance Cell voltage >= V-max All cell voltages > V-
min
Cell voltage <= V-min
AND SOC < charge
restart All cell voltages >= V-
balance AND SOC >= discharge
restart
AND cell temperature
> T-min Cell temperature < T-
min AND cell temperature
> T-min Cell temperature < T-
min
AND cell temperature
< T-max Cell temperature > T-
max AND cell temperature
< T-max Cell temperature > T-
max
AND cell
communication No cell
communication AND cell
communication No cell
communication
Critical mode
Charge Discharge/load
Enable Disable Enable Disable
All cell voltages < V-
max Cell voltage >= V-max All cell voltages > V-
min Cell voltage <= V-min
AND cell temperature
> T-min Cell temperature < T-
min AND cell temperature
> T-min Cell temperature < T-
min
AND cell temperature
< T-max Cell temperature > T-
max AND cell temperature
< T-max Cell temperature > T-
max
AND cell
communication No cell
communication AND cell
communication No cell
communication