Lithium batteries age rapidly if they are kept above 80% SOC (state of charge) most of the time. TAO BMS has a new feature to manage the charge cycles and extend battery life. Just set it up and forget about it.
The best way to use a lithium battery and keep it healthy:
- charge it
- stop charging when it is full
- do not start charging again until the the battery is close to empty.
In addition a lithium battery does not need a full (100%) charge every time
Easy to say, but none of the chargers we have onboard are designed to do that. They charge to 100% SOC, then switch to “Float”…. and start charging again the next day until 100% SOC. That was good for lead-acid / AGM batteries, but that will shorten the life of your new lithium battery.
TAO BMS has a new feature to manage the charge cycle and do what is best for the battery. Just a few parameters to set and you are good to go (the current shunt option is required to enable that function).
How it works:
- to start, TAO BMS lets the chargers do their job until the battery is fully charged (100% SOC has defined in the SOC parameters)
- then the “Relays to disable charge” are activated (and / or a CAN message is sent to the chargers to stop them – needs TAO monitor and CAN compatible chargers)
- the chargers stays disabled until the battery is discharged to the set “Low SOC” value (35% in the example above) – at that point the TAO BMS enables the chargers (relays and/or CAN)
- the chargers stay enabled until the charge of the battery reaches the set “High SOC” value (80% in the example above)… then it keeps going steps 2, 3 and 4 until condition for step 5 is true
- when the number of days since the last full charge reaches the set “Time between full charges” value (30 days in the example above), then TAO BMS wait until a full charge is done (step 1).
This is possible because:
- TAO BMS keeps accurate State of Charge information using self learning algorithms
- The State of Charge relies on high precision current measure (current shunt with self ranging amplifier that has an accuracy of 5 mA)
- TAO BMS can command up to 6 independent relays or external equipment / chargers
- TAO BMS with the TAO Monitor option can directly command external equipment via CAN