Not Just a Simple BMS

TAO EMS is a Comprehensive “Energy Management System”

 

It is unique on the market thanks to the level of protection it provides and to its numerous features designed to maximize battery life.

It has been designed specifically for off-grid installations including boats, RVs, remote sites, and industrial premises.

 

The lithium-ion (LiFePO4) cell is very sensitive to voltage and temperature.

 

It has a nominal voltage of 3.20 volts. There are 3 ranges of voltage to be considered:

 

 

Range	Description
Extreme	Cells may not survive outside this range
Recommended	Typical manufacturer’s recommendation
Optimal	For long battery life (cells age faster outside this range)

To maximize a battery’s life, keep its voltage and temperature within the “optimal” range.

 

TAO EMS is the only product on the market with all the features needed to ensure maximum battery capacity and lifespan.

 

The features that make TAO EMS unique:

• up to 20 definable ranges for cell voltage, cell temperature, or battery state of charge
• close integration with external pieces of equipment to control their operation (6 relays and CAN message)
• alarms are activated and custom commands are sent to external equipment when a range limit is reached
• early warning before a command is issued
• warnings for cell voltage and temperature differential
• control of the charge cycle
• dynamic cell balancing (4 A) as soon as there is a voltage differential between cells
• diagnostics and simulation mode to indicate that the EMS and all external equipment units are functioning correctly
• detailed lifetime history of events and measurements to analyze cell behavior and identify slow drifts
• battery state of health based on individual cell resistance and measured battery capacity
• access to battery state and historical data from anywhere in the world

 

plus, easy installation, with only 5 wires to connect to the battery—just
“Plug & Forget”

 

 

TAO EMS	Base system with remote control panel to protect a 12 volt battery
EMS Shunt	Device to measure battery input and output current
EMS Monitor	Touchscreen display, measurement and event logger, and connectivity hub (wifi and CAN)
EMS Extension	Extensions for batteries up to 48 volts (one extension for each additional 12 volts)
EMS Config	PC and Mac application for system configuration, monitoring, and diagnostics

 

The Drawbacks of Most BMS

 

A Single Protection Range

• usually that single range is close to the “extreme” range
• they will not prevent situations that speed up cell aging

No Early Warning

• no time to take corrective measures before the power goes down

 

No Relay Outputs

• the BMS will only shut down the battery, leaving you in the dark

 

Only Two Relay Outputs

• no possibility of connecting directly to equipment with different control requirements
• do not allow for controlling energy production, energy usage, or environment (battery cooling and heating)

No CAN Integration with External Equipment

• charge and discharge rates cannot be adjusted based on battery condition

 

No Validation that Commands Sent to External Equipment Have Taken Effect

• no assurance that the BMS is sending the right commands at the right time
• cannot validate that external equipment has been correctly wired
• cannot determine if external equipment is functioning correctly

No Charge Cycle Management

• best charge practices cannot be enforced (charging the battery up to a threshold, then stopping and waiting until the state of charge goes down before restarting charging,  for example, stopping charging at 80% SOC and restarting it at 25% SOC)
• no ability to order a periodic full charge

Passive Cell Balancing

• energy is dissipated in the BMS, heating up its components and rendering its measurements inaccurate

 

Balancing Start on High Cell Voltage or Large Cell Voltage Differential (100 mV or more)

• balancing always starts above the “optimal” range (unless the imbalance is very large)
• balancing is active only for a short time before the chargers go to float or the BMS shuts down the battery

Low Balancing Current (less than 2 A)

• If balancing starts on high cell voltage or a large cell voltage differential, there is not enough current and not enough time to bring the cells back into balance.
• Cells with the most charge will age faster and ultimately bring the battery down.

No Measurement or Event History

• battery warranty cannot be invoked because it is impossible to show how the battery has been used
• slow drifts are detected only when it is too late and the battery has been damaged
• cannot identify situations that do not warrant an alarm but can damage the battery over time (example: keeping the battery or a cell above 80% SOC or above 30°C)

No Warning for Cell Voltage or Temperature Differential

• no alert if there is a difference in cell characteristics or a faulty cell interconnection that may damage the battery over time