Single Cell Battery Board 4-Cell Battery Board
These boards monitor cell voltages, and :
- If a cell goes overcharged (over 3.7V), switches a bypass resistor across it, lights an LED and sends an alarm report.
- If a cell becomes under-discharged (below 2.6V), it lights up LED and sends remote alarm report
- If its temperature sensor detects hot battery, it lights LED and sends remote alarm report too.
It is an optically-isolated output, from battery boards, it reports the cell states to our Master Display unit or to our
Charger and Motor Controller.
Battery Management Systems (BMS)
1. Resistor-Bypass type BMS:
- Switches a resistor to bypass charge current away from the overcharging cell (top Balance)
- Periodically, or on operator demand, switches the resistor across the cell to empty it
- Optically isolated report wires to Display Panel and other remote units.
- LEDs to identity Troubled Cells
- Signals the charger to Reduce Charge current when a cell is full ( for low- loss balancing).
- Signals EV Motor Controller to stop after a timeout (to move the vehicle to safety).
2. Distributed Lithium Cell Charger /
This innovative combined Charger / BMS features isolated parallel Cell
chargers and a BMS chip on the battery boards. The BMS chip switches
OFF each Cell Charger when its cell is full.
Similar to our traditional BMS, this system consists of 4-cell Battery
boards and a Master Display. However, the bypass resistors are
replaced with the Cell Chargers. The Master Display is the same.
The input supply, to all battery boards, is either a common 115VAC
(directly from AC line) or a common 24VDC (directly from solar panels).
Obviously, this system does not need a separate charger. In
solar model, the common inputs of all battery board connect
directly to the solar panels. This is also less energy wasting
compared to resistor type BMS.
However, due to cost and complexity, it works best for
low-voltage battery packs (fewer number of cells).
CELL-BMS System Wiring:
Our Modular BMS protects Lithium Batteries from over-charge and
under-discharge, with minimum cost and minimum number of wires.
It automatically performs Top Balancing; i.e. it controls charging so that all
the cells charge to the same level. It also periodically (or on operator
demand) perform Bottom Balancing; meaning it empties all cells of battery
to the same level then charges them to the same level.
The system consists of:
- Battery Boards: installed on or close to the battery.
- Remote Unit: It can be a Smart Charger, Smart Load or a Master Display unit.
This board is installed on or close to each battery and wired to cells. It is offered for Single-Cell, or 4-cell battery.
SMART CHARGER / LOAD CONCEPT:
The alarm report outputs of all battery boards are connected to the alarm
inputs of our smart charger and smart Load (e.g EV Motor Controller).
The firmware of smart charger, when one cell is full, lowers the charge
current. This reduces cell by-pass resistor heat. And, since cells charge
rapidly at the end of cycle, it does not increase overall charge time a lot.
The firmware of the smart load (e.g. Motor Controller) starts a timeout when
one cell is empty (to move EV to safety). After timeout, the load turns itself
We can equip Lithium versions of our EVC203 and EVC207 chargers
with alarm inputs and firmware to perform this task.
Also, our EVMTC Motor Controllers can be offered with an alarm
input port and firmware to shutdown.
This makes our Charger, Controller and BMS family compatible.
They operate in the simplest way and offered at lowest price.
The Master Display Panel:
This panel is installed in operator dash. It is used with our 4-cell battery boards.
The panel displays each 12V battery block state for 15 seconds and advances to the next. A numeric display identifies which
is shown. It also sounds a buzzer if the displayed battery has an alarm.
The cell status display is by color coded LEDs. LED color is Green in safe range (2.9V to 3.5V), Red for unsafe range
(below 2.7V or above 3.6V) and Yellow in near unsafe (2.6 to 2.7V or 3.5 to 3.6V).
The Battery Boards and Master Display are connected with an optically isolated daisy-chain network.
Optionally, the unit can have outputs to control the external charger and load.