821
The advanced LiFePO4 battery offers the desired features like charging below freezing, series connected batteries as well as BLE and RV-C connectivity. The batteries are equipped with a Battery Management System (BMS) which is built in the battery housing. The battery management system is a non-power consuming, passive electronic device, that protects the battery against deep discharging, overcharging, over-temperature and ensures cell balancing of all serial switched blocks during charging. This battery has the following features:
RV-C terminal
The two connectors are for inter-battery communication via the RV-C protocol for parallel and series connecting batteries. It connects to RV-C network on an RV.
Reserve Capacity
Reserve capacity of 5 % is provided to allow users to perform emergency actions with the battery even when it is completely discharged. This is accomplished by disconnecting the battery before the battery is completely discharged.
Power Button
Button with LED for indicating and controlling the power mode of the battery. This button will allow transition between the following modes:
| Mode | LED Function | Battery Function |
| ON | LED is solid on | Battery charge and discharge paths are both enabled and BMS power is on (BLE and RV-C both active) |
| OFF | LED is solid off | Battery charge and discharge paths are both disabled and BMS power is off (BLE and RV-C both inactive) |
| Sleep | LED is slow flashing | Battery charge path is enabled but discharge path is disabled and BMS power is on (BLE and RV-C both active) |
| Reserve | LED is slow flashing | Battery charge path is enabled but discharge path is disabled and BMS power is on (BLE and RV-C both active) |
Heater
There is a heater inside the battery on the bottom side of the cells. This heater is controlled by the BMS and allow the battery to be charged in ambient temperatures as low as -20 °C. The BMS implement three modes for heater control.
| Mode | Heater Function |
| Auto | Heater is always on when battery is in sleep mode and always off when battery is in OFF mode. When battery is in ON mode the heater will only turn on when there is a charging source available that is capable of fully powering the heater |
| ON | Heater always turns on when the battery internal temperature is below 2C and it stays on until the battery internal temperature is above 7C |
| OFF | Heater is always off |
Real Time Clock
Real time clock is implemented on the BMS. The battery support RV-C real time clock messages for configuration of the time and date. It is broadcasted via RV-C standard messages and priority.
Capacitor Pre-Charge
Pre-charge and pre-discharge circuit in the BMS allows large capacitor banks to be charged prior to connecting the cells. This avoid damaging inrush currents.
Fault Recovery
If the BMS disconnects the battery due to a fault it will reset automatically when the conditions return to normal. For low voltage disconnect the BMS shall allow up to 10 A of current to be drawn from the battery.
