These Lithium Iron Magnesium Phosphate batteries are intrinsically safer than Li metal oxide batteries and will not heat up or catch fire when physically damaged. Valence XP batteries can be cycled 100% and give about 2,500 cycles of service to 80% of initial capacity. Compared to lead-acid batteries, these are about one third lighter and offer up to 50% greater capacity for the same physical dimensions. Capacity is reduced to about 90% at freezing and 80% at 14°F. These can be efficiently charged in as little as 2 ½ hours or more slowly as needed. Most battery chargers and charge controllers capable of managing AGM or gel cells will properly charge these batteries. To keep the cells equal in capacity, they should be fully charged about once per week, but longer intervals will not damage the cells. Self discharge is about 1% per month, or less if put into storage mode. Capacity for a battery bank can be as large as needed since there is no limitation on the number of parallel strings.
Due to the novelty and unique characteristics of this battery technology, each battery bank design must be approved by the manufacturer. There may be additional devices needed for a complete battery system. Call AEE for assistance with a battery system design.
A Battery Management System (BMS) is required on each battery bank to monitor battery temperature, voltage, current and state-of-charge, and error codes, and to manage the cell-to-cell balance control. One unit can manage up to 54 battery modules. Each battery has RS485 communication cables that can be daisy chained with one end plugged into the BMS. Communication from the BMS to a network is via CANbus.
The CANbus Toolkit is a CANbus to USB converter and software that allows the BMS to communicate with a local computer. Multiple BMS units can be used as necessary.
This Tool Kit allows for battery configuration and firmware upgrades using a computer through the BMS.