THE SIMPLEST, MOST RELIABLE AND COST EFFECTIVE LARGE FORMAT LITHIUM ION (LFP, LiFePO4) BATTERY MANAGEMENT SYSTEM

Lithium Ion batteries require cell balancing during charging and protection from over-charge and over-discharge. This seemingly simple function is of utmost importance in mission critical environments. It is also one of the most difficult functions to achieve with absolute safety and reliability.

The EV Power Battery Balancing System has been developed specifically for large format Lithium Iron Phosphate batteries such as Thunder Sky and Sky Energy (CALB) LFP cells. It can also work with other Lithium Iron Phosphate battery brands with minimal modification.

This system has been in continuous development for several years and has evolved to the point where we can claim it to be one of the most reliable and effective battery management systems available.

For a quote on a system please contact us

All lithium Ion batteries require a battery management system (BMS). There is no way around this. There are numerous examples of catastrophic failures where no BMS has been used.

At a minimum a BMS must have the following basic functions:
1) Balance the cells during charge to level the state of charge of all cells in the pack.
2) Protect each cell in the battery from going outside its safe voltage range.

The EV Power system is known as a distributed BMS. That is, the functionality is distributed across the battery, not centrally located.

The system consists of two main parts:
1) Cell Modules - one per cell, act as standalone shunt regulator balancers and link together to provide cell level voltage monitoring.
2) Master Unit - one per battery pack, monitors the signal line to the cell modules and takes action to prevent charging or discharging if the heartbeat signal is broken.

EV Power BMS Features:

• Modular - one small balancing module bolts directly to each cell.
• Simple - A one wire interface is all that is required. No wiring birds nest.
• Scalable - Battery balancing from one cell up to any number.
• Fail Safe - a unique one wire NC loop safety interlock system prevents any cell from going over/under voltage.
• Hermetically sealed - potted cell modules resist dust and moisture
• Flexible - the master control unit can work with almost any charger.
• Reliable - analog electronic cell modules, no computers in high EMI environment.
• Safe Installation - No high voltage signal wire connections.
• Easy Cell Status indication - An indicator on each cell.
• Cost Effective - low cost per cell for large format Lithium Ion batteries.
• Invented, designed, refined and manufactured in Australia since 2007

A smart device in a small package this control unit is designed to work with the EV Power Paks to deliver trouble free power for portable power applications. This is the first of a new range of microprocessor controlled master units, now called battery control units.

Features:

• Low power consumption (<15mA) even when discharge contactor is on.
• Monitors battery voltage 12V minimum, 15.1V maximum.
• Monitors the battery management system.
• 120A contactor, 500A optional isolates the battery if there is a problem.
• 12V and 24V versions available.
• Can control battery packs in parallel

Optional High Current Contactor 500A +

This battery control unit interfaces with EV Power cell modules to provide complete protection for 16 cell (48V) LFP battery systems. It is suitable for Neighborhood Electric Vehicles, golf carts, electric boats and remote area power systems.

 Powered directly from the battery. No DC-DC required.
 Detects both battery low and high voltage limits
 Monitors the cell module string via the EV Power one wire NC interface.
 Can directly control an Elcon type charger.
 Can directly power external 12V contactors and relays.
 Optional external bar graph fuel gauge for dash mount.
 Optional latching relay output for zero quiescent current draw.
 Designed and manufactured in Australia

This master unit is designed to operate specifically with our Elcon range of chargers. It makes the BMS system plug and play... well solder and play.

BMS-MCU-EV2-ELC Features:

• Enclosed ABS box, IP54 rated against dust and splashing water.
• Operates directly from the traction battery (120-350VDC) or optionally a 12V auxiliary battery.
• Isolated- signal wires are completely isolated from the 12V auxiliary system for safety.
• Failsafe- the normal state of the system is disabled unless every cell in the battery is OK.
• Complete Package includes enclosure, warning lights, internal buzzer
• Elcon control wire plugs directly into an Elcon charger, no heavy relays for switching high currents.
• Internal alarm buzzer for audible warning.
• Simple to understand and install.
• Throttle disable output
• Low power requirement
• Reduced overall cost for BMS and charger

Contact us for pricing

A simple microprocessor based master unit for controlling LFP batteries.

Features:

• Simple to install and use, microprocessor control.
• 12V power input
• Prevents overcharge and over-discharge of LFP batteries.
• Version A for three wire latching relays, Version B for normal and Solid State relays (SSRs)
• Uses the unique EV Power developed one-wire NC loop interface.
• User programmable using a standard three wire interface
• Can directly control relays with 12V coils requiring up to 2A hold current.

The heart of the EV Power system is the cell module. Simple and elegant.

A battery consists of two or more cells. There is one cell module for each cell in a battery. The cell modules perform the function of balancing and monitoring the cells.

EV Power developed its unique one wire system that connects each cell module to the next. This provides two ends that interface back to a master unit which controls charge and discharge if there is a problem with one cell.

Features:

• Epoxy Encapsulated to prevent moisture and dust interference. Also keeps out bugs, dropped spanners, loose cables, nuts and fingers!
• Gold plated cell terminal connectors for perfect connection and professional looks.
• One wire link between cell modules. We developed this system.
• Soldered signal connections for lifetime reliability.
• Low profile, does not protrude above terminal bolts.
• Up to 2A shunt current capacity.
• No heat buildup when regulating, no bulky hot resistors.
• Small footprint the actual circuit is the size of a postage stamp! Does not interfere with mounting hardware.
• Low power consumption <3mA for the green LED. Ultra low consumption (<1mA) available by special request.
• Reverse polarity protected.
• Internal fuse to prevent cell damage from incorrect installation.
• Simple to install and easy to understand.
• Suitable for LiFePO4 cell chemistry.
• LOW COST compared to more sophisticated systems.
• Sizes suitable for Winston Battery and CALB

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A cell module can operate as a standalone shunt regulator or in combination with other modules to monitor and balance a LiFePO4 battery with any number of cells.

Connecting the signal output from a cell module in series with other cell modules and a master unit provides complete battery protection from overcharge and over-discharge.

CM60/90/160 Datasheet

LiFePO4 Battery Management Cell module suitable for cells with 60-63mm terminal spacing and an M6 bolt. Suits LYP40AHA, SE40AHA, (some) LYP60AHA

800 mA shunt bypass capacity.

LiFePO4 battery management cell module for cells with 81-83mm terminal spacing. M8 terminal bolt. Suits SE60AHA (M6 bolt), LYP90AHA, SE100AHA

800mA shunt bypass capacity.

LiFePO4 battery management cell module for cells with 105.5-107.5mm terminal spacing. M8 terminal bolt. Suits LYP90AHA, SE180AHA

800mA shunt bypass capacity.

LiFePO4 Cell module for cells with terminal spacing 70-150mm and with an M6 or M8 terminal bolt. Suits LYP160AHA, SE180AHA

1 amp shunt bypass capacity.

Battery Management Cell module suitable for cells with 100- 300mm terminal spacing. Suitable for SE400AHA, LYP200AHA and larger.

• M12 Bolt size hole.
• Shunt regulation capacity up to 2 Amps.
• Fly lead and ring terminal attached, 210mm bolt spacing.
• Can also be used on SE180AHA and TS-LFP160AHA cells if an M8 centering collar is inserted in the M12 (13mm) hole.
• Signal line PCB holes are for soldered one wire connection but spade terminals can also be supplied.

There is a lot of hype about battery management systems for Lithium Ion batteries. Should a BMS have cell by cell voltage monitoring and reporting to a central display unit? Should cell temperatures be recorded and reported? Should the BMS be able to bypass large charge currents? What about active balancing and a CAN bus interface?

The answer is, NO. These functions are not essential.

Sophisticated BMS’s may provide an impressive list of functions but are prone by their very complexity to problems both in installation and usage.

SIMPLICITY = RELIABILITY.
SIMPLICITY = LOW COST
SIMPLICITY = EASY TO UNDERSTAND

The EV Power BMS is the simplest system in the world that will actually provide balancing and fail safe voltage protection of large format LiFePO4 batteries

Extra monitoring functions can be easily layered on top of a simple BMS. A simple BMS should form the core of any large format LFP battery.

Modern LiFePO4 cells are very safe and manufactured to close tolerances. With a BMS they will not explode or catch fire. They should be highly reliable and operate with the minimum of intervention from the BMS. It is there as the last line of defence.

The EV Power system designed for LiFePO4 cells of 40Ah and larger performs the basic functions simply and well. It does not rely on digital microcontrollers on each cell but to date has proven itself to be fail-safe and highly reliable. This has been proven in many road going electric vehicles which are demanding applications for a BMS.

Our cell modules are epoxy encapsulated against moisture and dust. This IS important because it is moisture and dust that will cause electrical problems in other systems down the track. Also important is that it does not rely on any connectors which can wriggle loose and fail. The EV Power BMS is a genuine one wire system where all the connections are soldered. It can monitor any number of cells in up to four banks and has provision for temperature monitoring also.

As well as high quality with gold plated terminal connectors it is reasonably priced. This is all you need in a BMS.

Q: Why do I need a Battery Management system?

A: Lithium Ion batteries are made up of two or more cells connected in series. Each cell has a slightly different capacity due to manufacturing tolerances and environmental conditions. After several charge/discharge cycles the cells begin to go out of balance and so a balancing system is required to keep the cells all at the same state of charge. The BMS also prevents overcharge and overdischarge of any cell in the battery which is essential when using Lithium Ion batteries.

Q. Why does the EV2 master unit use the battery pack for its power. Why not 12V input so it can run off the vehicle auxiliary 12V supply.

A. It can be modified to run from any voltage 12V - 350VDC. However first and foremost it is most important that the cell module signal loop must be isolated from the master unit power input otherwise a signal wire accidentally contacting a battery terminal can make the 12V auxiliary system live at potentially fatal voltages. Some imitation BMS systems do not do this, dangerous!

Q: Why does the EV Power system use solder connections for the signal loop rather than removable terminals.

A: For complete reliability. The cell modules are there for the life of the battery so there is no reason to use removable lugs.

Q: What digital outputs does the BMS provide?

A: It simply balances the battery pack and provides connections to the charger and motor controller to prevent over charge and overdischarge. Digital information can be obtained from the TBS Battery Monitor.

Q. What charger should I use?

A: Almost any switchmode SLA charger with the correct peak voltage is suitable. However there may occasionally be problems with cell balancing due to the incorrect charge curve.

Q: Will the BMS work if the batteries are in different locations around the car?

A: Yes... However, it is advisable to keep all the cells in one physical location if at all possible. Cable resistances, temperature and moisture differences in different locations of the car can result in unforseen problems and shortened battery life. This has nothing to do with the BMS, it is about design and common sense. Also placing batteries in car crumple zones SIGNIFICANTLY COMPROMISES SAFETY in the event of an accident. Remember that batteries are the fuel tanks of an EV and due consideration should be given to locating them, even at the expense of load space. It is also important to maintain weight distribution between the front and rear axles of a car.