Zeva BMS16 v2 User manual

ZERO EMISSION VEHICLES AUSTRALIA 8-16 CELL LITHIUM BATTERY MANAGEMENT SYSTEM
ZERO EMISSION VEHICLES AUSTRALIA
http://www.zeva.com.au
BMS16 v2
8-16 cell Lithium Battery Management System
Introduction
The ZEVA BMS16 is an integrated battery management system for lithium battery packs
containing 8-16 cells in series and 5-1200 Ah capacity. It is suitable for both electric vehicle
and battery storage applications. The BMS16 includes an internal power supply to allow it to
run directly from the battery pack, internal shunt resistors for automatic pack balancing, dual
solid state relay outputs for switching power contactors to protect charging and discharging
of batteries, built-in current shunt interface for measuring current and calculating battery
state of charge, and a CAN bus port for optional colour touchscreen interface or integration
with third party control systems.
The BMS16 Monitor provides information such as voltage, current, power, battery state of
charge, and all individual cell voltages. It can also be used for conguring the operating
parameters of the BMS16. It may be installed up to 50m from the BMS16 (if correct shielded
twisted pair cable is used).
Battery management systems are the last line of defence for your battery pack. In normal
circumstances it should not interfere with the battery pack’s operation, only intervening
when something goes wrong and protection is required.
Safety Warning
Although 8-16 cell lithium battery packs do not involve lethal voltages, they frequently
involve dangerous amounts of current and power. Proper precautions and electrical
safety procedures should always be observed. Please read this manual carefully to ensure
correct installation and operation. If you are unsure of anything, please contact us before
proceeding.
We have endeavoured to make a safe and reliable product which performs as described,
however since ZEVA has no control over the integration of its products into a battery system,
we can assume no responsibility for the nal safety or functionality of the completed
installation. It is up to the end user to determine the suitability of the products for the purpose
employed, and the end user assumes all risks associated. Products should only be installed
by suitably qualied and experienced persons, and should always be used in a safe and
lawful manner.
Specications
Number of cells: 8-16•
Battery types: LiFePO4, LiCo, LiMn, NMC, etc•
Accuracy: Within 0.002V per cell•
Battery capacity: 5-1200Ah•
Current measurement: 0-500A via shunt interface, 0-1200A with external sensor•
Dimensions: 120x80x16mm, 2x Ø4mm mounting holes 116mm apart•
Outputs: Dual solid state relays, 60V 1.3A max, internally fused•
Power consumption: Approx 30mA when running (with both output relays closed and a •
monitor connected to the CAN bus), 8mA when sleeping
Installation
The BMS16 should be mounted securely using screws through the holes on the case anges.
Install the BMS16 in a location protected from direct sun and water, and close to the cells if
possible to minimise cell wiring lengths (under 1m recommended).
The BMS16 has a pluggable screw terminal block for the cell connections, with the most
negative point of the battery pack connected to terminal 00, and successive positive
terminals connected to 01–16. Wire gauge around AWG20-26 is recommended for sufcient
mechanical strength and suitable current rating. We recommend wiring up the plug and
verifying all voltages before connecting to the BMS. The plug requires a signicant amount
of force to fully engage; ensure it is plugged all the way in for reliable connections.
If you need to disconnect the cell plug from the BMS, signicant force is required for removal
as well. For easier removal, a at blade screwdriver may be used to lever the positive end of
the plug out rst, which should then be loose enough to remove by hand.
Ensure that all wiring is secured so it will not become damaged from vibration or abrasion.
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ZERO EMISSION VEHICLES AUSTRALIA 8-16 CELL LITHIUM BATTERY MANAGEMENT SYSTEM
Optionally small fuses (~1A) may be used to protect wiring, best installed close to each
cell terminal. Device power is always taken from the most positive input 16. If using the
module with fewer than 16 cells, simply add a short jumper wire from your most positive cell
terminal to 16. An example wiring diagram for 14 cells is shown below.
Relay outputs are oating / isolated, and have a maximum rating of 60V and 1.3A continuous.
Be sure to include a yback diode (if not built in to the relay/contactor) to suppress inductive
voltage spikes from switching the relay coil. In installations with a single “battery enable”
relay, the LV and HV relays may be wired in series such that either an over-voltage or under-
voltage condition will open the relay to isolate the battery pack.
Once your wiring is complete, press the power button on the top left of the case, and the
status LED should come on. A green light indicates all cells are within correct voltage range,
and both relay outputs will be closed circuit. A steady red light indicates one or more cells
are over-voltage, and the HV Relay outputs will be open circuit. A blinking red light indicates
one or more cells are under-voltage, and the LV Relay outputs will be open circuit. Green/
red ashing indicates an over-temperature shutdown.
Packs Smaller Than 12 Cells
Internally the BMS16 uses two voltage sampling
chips which are connected to up to 8 cells each,
one spanning terminals 00 to 08 and the second
from 08 to 16. These samplers require a minimum
of 4 cells each for reliable operation, so for packs
with fewer than 12 cells, some unusual wiring
is required. The most positive four cells should
be connected between 08 to 12, with a jumper
from 12 to 16 (since the BMS draws power from
16 to power itself). Then the remaining cells are
connected from 00 up, with a wire jumper from
the most positive terminal in this group up to
08. An example case for a 9-cell pack is shown
right.
Current Shunt
The BMS16 may be supplied with either a 100A, 200A or 500A shunt, which should be
installed in the positive wire from the battery. The shunt is connected via two wires to the
associated terminals on the BMS16. For best performance, twisted pair wire is recommended.
The sample wire from the anode / positive side of the shunt (closest to the +ve terminal of
the battery) should be connected to the terminal nearest the corner of the BMS. By default,
discharge amps are shown positive, though this can be reversed in settings if preferred. If
your polarity seems to be reversed (e.g discharge current is causing SoC to increase), simply
swap the two shunt wires into the BMS.
Temperature Sensing
A temperature sensor may be connected to the BMS16 between the Temp and Ground inputs.
The scaling is calibrated for a 100Kohm NTC thermistor with B25/100 value of 4540K. These
are available from us, or most large electronics vendors.
It is recommended that the temperature sensor is installed somewhere near the middle of the
pack, since this is typically the warmest location. Wires on the sensor may be extended as
long as necessary. Temperature limits may be adjusted in settings, to warn if the temperature
exceeds safe range, restrict charging if the battery is too cold, or shut everything down if the
battery gets too hot.
Sleep Mode
The BMS16 has a Sleep terminal which may be used to put the device into a lower power
standby mode by connecting a wire from it to a Ground terminal. It is most commonly
used in mobile applications, when the vehicle is neither being driven or being charged.
(Stationary applications typically run 24/7 so the Sleep terminal is often unused.)
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ZERO EMISSION VEHICLES AUSTRALIA 8-16 CELL LITHIUM BATTERY MANAGEMENT SYSTEM
Sleep mode will shut down the CAN bus and turn off both relay outputs. The device continues
to monitor cell voltages and shunt current, and will turn itself off completely if any cells get
extremely low.
Automatic Pack balancing
In battery packs built from many cells, optimum performance is attained when all cells are at
the same State of Charge, also known as pack balance. The BMS16 uses a system known as
“shunt balancing”, which switches on resistors across any cells which are above a threshold
voltage to reduce their charge and bring them into line with other cells.
By default the BMS16 uses a dynamic balance threshold, where any cells more than 1mV
above the average receive balancing. The threshold may also be set manually – if so it is
best to set it to the average maximum charge voltage, so that only cells above average at the
end of a charge receive balancing. Manually setting a shunt threshold below the maximum
charge voltage is not recommended since it may result in all balancers running concurrently,
which actually negates the effect and generates extra heat. Balancing can also be disabled.
The shunt balancers are quite small and can take a long time to correct large imbalances. If
possible it is recommended to manually balance your cells prior to initial pack assembly (e.g
by charging each cell individually, or wiring them all together in parallel to equalise with each
other). However the shunts will get an unbalanced pack incrementally closer to balanced each
charge, and once balanced are able to maintain balance with minimal effort.
CAN Bus Wiring
The BMS16 has four screw terminals for connecting CAN bus wiring: 12V Out, CAN H, CAN
L and Ground. The monitor CAN plug uses a Molex Eurostyle
screw terminal. These connectors require some force to plug in,
so make sure the plug is fully inserted for a reliable connection.
Wiring for the Eurostyle connector is shown right.
Wire gauge around 20-24AWG is recommended for appropriate
current rating and mechanical strength. For best noise immunity
in high EMI environments, shielded twisted pair cable is recommended, with two conductor
pairs – one pair for CAN signals, and one pair for bus power. The shield can be connected to
the Ground terminal at the BMS. We use and recommend Belden 8723 wire, or equivalent.
For optimum performance, CAN buses should be wired as a single daisy chain of devices
(without branching), and terminated at both ends of the bus with a 120Ω resistor across the
CAN H and CAN L lines. The monitor includes termination resistor built-in. Note that the
CAN bus is referenced to the battery negative and is not isolated from the main battery pack.
The 12V Out terminal is limited to 200mA current and is primarily intended for powering CAN
devices such as a monitor, but may also be used to power other small 12V devices such as
solid state relays.
BMS16 Monitor
The BMS16 Monitor is an optional colour touchscreen which may be used to remotely
interact with the BMS16. The Monitor displays various pages of information:
BMS Status: Running
Voltage
Current
Power
Temp SoC
23˚C 90%
48.5V
12.3A
0.6kW
The BMS Status page is the standard display when
the system is running, showing pack voltage, current,
power, temperature, battery state of charge. This will
only be shown if a current sensor is present.
Tapping the panel on the left or right side will toggle
between the different display pages.
BMS Summary: 16 cells
Avg Volts Temperature
Min Volts Max Volts
3.32V 25˚C
3.31V 3.33V
The BMS Summary page shows the average, minimum
and maximum cell voltages, and the temperature
sensor, plus a bar graph overview of all cells across
the bottom.
If no current sensor is present, this will be the default
page, and Pack Voltage will be shown instead of
Average Voltage.
BMS Details: 16 cells
3.324 3.332 3.327 3.315
3.331 3.313 3.325 3.322
3.318 3.326 3.339 3.322
3.324 3.326 3.337 3.319
The BMS Details page shows all individual cell
voltages, plus a bar graph below. Dotted lines on the
graph show HV and LV thresholds plus hysteresis.
Graph bars will be green when a cell is in range, blue
for under-voltage, red for over-voltage, and orange if a
cell is currently being shunt balanced.
Warning:
Overcurrent shutdown
If the BMS detects an error, this warning page
will be displayed. In most cases, the error can be
acknowledged/reset by tapping the screen.
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Shield
Ground
CAN L
CAN H
12VDC

ZERO EMISSION VEHICLES AUSTRALIA 8-16 CELL LITHIUM BATTERY MANAGEMENT SYSTEM
Reset SoC
Enter Setup
Power Off
Exit Options
You can bring up the options menu by touching and
holding for 1 second. From here you can do a manual
reset of the State of Charge (back to 100%), enter the
Setup mode, switch the display off, or command the
BMS16 to turn off.
ZEVA BMS: Setup
Parameter:
Pack capacity
Value:
100Ah
Exit Setup
<
<
>
>
If you choose Enter Setup, the Monitor can be used to
modify settings for the BMS16. The top row selects the
parameter, and the bottom row adjusts the value, in
both cases by touching the left or right arrows on each
side. Once nished, touch Exit Setup and the new
parameters will be transmitted to the BMS16.
List of Settings
The following table describes the parameters available in the Settings page.
Name Range Description
Pack capacity 5-1200Ah The rated capacity of your traction battery pack,
in Amp-Hours.
SoC warning 0-100% The BMS16 can raise a warning when the
battery’s State of Charge reaches a predetermined
minimum level. (Use 0% to disable.)
Full voltage 1-70V The BMS uses a “full voltage” threshold
(combined with low charge current) to detect
charge completion and automatically re-
synchronize the SoC to 100% when pack
voltage exceeds this value. Typically set value to
just below your peak charge voltage.
Warn current 0-1200A The BMS16 will provide a warning if the current
in or out of the battery exceeds this threshold.
Set to 1210A to disable (will display as “off”).
Trip current 0-1210A The BMS16 will automatically shut down the
battery pack if current exceeds this threshold
(for over 1 second continuously). Note: This
should not replace a physical fuse, but can be
used as a “rst line of defence”.
This is considered a serious error which will
require the device to be power cycled to reset.
Num cells 8-16 The number of cells the BMS should expect to
see in the battery pack. Warning: If this is set
incorrectly, some cells may not be monitored.
Shunt size None, 100,
200 or 500A
Selects the size of current shunt connected to
the BMS’s shunt interface terminals, for correct
current scaling. (75mV shunts only.)
This should be set to “None” if you have no
shunt connected, or are using an external
current sensor on the CAN bus.
Min voltage 1.50-4.00V The minimum voltage any single cell should
be allowed to reach. If any cell goes below this
threshold (minus any hysteresis), the LV output
relay will go open circuit.
Max voltage 2.00-4.50V The maximum voltage any single cell should
be allowed to reach. If any cell goes above this
threshold (plus hysteresis), the HV output relay
will go open circuit.
Balance voltage 2.00-4.50V,
Dynamic
or Off
The voltage threshold where shunt balancing will
occur. Balancing should only be performed on
cells which are higher than average, so typically
set this to the average maximum charge voltage
of each cell (i.e max charge voltage divided by
number of cells).
Set to 4.51V for dynamic balance voltage or
4.52V for Off.
BMS hysteresis 0.00-0.50V This settings provides some hysteresis on
voltage thresholds, such that charge and load
relays are not switched on and off too rapidly.
For example, with a 0.2V hysteresis, the LV relay
will be disabled when a cell goes 0.2V below
the Min Voltage threshold, and re-enabled once
the cell recovers to 0.2V above Min Voltage.
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ZERO EMISSION VEHICLES AUSTRALIA 8-16 CELL LITHIUM BATTERY MANAGEMENT SYSTEM
BMS min temp -41C to 100C The minimum allowable temperature for
the battery pack. If a temperature below
this threshold is detected, a warning will be
generated and charging will be disabled.
Set to -41C to disable (will show as “Off”)
BMS max temp 0-101C The maximum allowable temperature for
the battery pack. If a temperature above
this threshold is detected, a warning will be
generated and chargers and loads will both be
disabled.
Set to 101C to disable (will show as “Off”)
Charger voltage 0-70V For CAN integration with TC Chargers only.
The maximum voltage that the BMS will instruct
the charger to reach.
Charger current 0-100A For CAN integration with TC Chargers only.
The maximum current that the BMS will instruct
the charger to reach.
Stationary mode No/Yes Whether the BMS behaviour should be set for
stationary applications. Please see “Stationary
Mode” section for further explanation.
Reverse current display No/Yes By default, the BMS16 displays discharge amps
as positive / charge amps negative. If preferred,
you can reverse the display so that discharge
amps are negative / charge amps are positive.
Night Brightness 0-100% Adjusts the brightness of the LCD display in
low light mode, to reduce screen glare at
night. Toggle between full brightness and night
brightness by swiping a nger up/down.
Buzzer On Yes/No Selects whether the Monitor should sound the
buzzer for alerts. (Safest to leave this on.)
Use Fahrenheit Yes/No Changes display of temperature units to
Fahrenheit instead of Celcius.
SoC Display Percent or
Amp-Hours
The battery State of Charge value displayed on
the Monitor can either be shown as a percentage
of full charge, or as the number of amp-hours
remaining.
Stationary Mode
The BMS16 has two main modes of operation, either normal (for mobile / EV applications)
or Stationary Mode (for off grid / backup battery type applications). In normal mode, if an
under- or over-voltage is detected, the LV or HV output relay will be disabled respectively,
and will remain off until the device is either power cycled or (more commonly) they are re-
enabled whenever the device wakes from sleep.
In Stationary mode, the outputs will automatically reset if the voltage recovers sufciently.
The BMS Hysteresis setting is used to adjust the amount that the voltage needs to recover.
For example, a hysteresis setting of 0.1V will cause the HV output to disable once the
voltage exceeds 0.1V above the programmed Max Voltage threshold, and the output will
automatically re-enable once the voltage has dropped under 0.1V below the Max Voltage
threshold.
BMS Power Consumption Protection
An inherent problem with any BMS which powers itself from the cells it is monitoring is that
the BMS itself can slowly discharge the cells, which can eventually atten cells – particularly
if powering contactors or monitors, and no charging source is present for an extended period.
To prevent possible damage, the BMS16 is able to switch of its own power supply if any cells
get critically low (under 2.0V). If your BMS has turned off due to a critically low cell, simply
attach a charging source to the batteries then press the power button to re-enable the BMS.
Tech Support and Warranty Information
All ZEVA products are covered by a 12 month warranty against manufacturing faults or
failures under normal operating conditions. The warranty does not cover misuse of the
product, including but not limited to: excessive voltage or reversed polarity on terminals,
short circuits on outputs, opening of housings and/or modication of internal electronics,
severe impact damage, submersion in water.
We have taken great care to design a safe and reliable product, but faults can happen. If
you believe your product has a fault, please contact us via our website to discuss. If it is
determined that a hardware fault is the likely cause, we will provide an RMA number and
return address to proceed with repairs.
If you have any questions not covered by this manual, please contact us via our website:
http://www.zeva.com.au
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