victro energy SmallBMS With Pre-alarm Instruction Manual
- June 6, 2024
- victro energy
Table of Contents
victro energy SmallBMS With Pre-alarm
General Description
A simple and low cost alternative to the VE.Bus BMS
The smallBMS can replace the VE.Bus BMS in several applications. It is however
not suitable for use with VE.Bus MultiPlus and Quattro inverter/chargers: it
has no VE.Bus interface.
The smallBMS is intended for use with Victron Smart LiFePo4 batteries with M8
circular connectors.
The smallBMS has three outputs, similar to the VE.Bus.BMS.
Load Disconnect output
The Load output is normally high and becomes free floating in case of imminent
cell under voltage (default 2,8V/cell, adjustable on the battery between 2,6V
and 2,8V per cell). Maximum current: 1A. The Load output is not short-circuit
protected. The Load output can be used to control:
A high current relay or contactor.
The remote on/off input of a BatteryProtect, inverter or DC-DC converter or
other loads.
(a non inverting or inverting on/off cable may be required, please consult the
manual)
Pre-alarm output
The pre-alarm output is normally free floating and becomes high in case of
imminent cell under voltage (default 3,1V/cell, adjustable on the battery
between 2,85V and 3,15V per cell). Maximum current: 1A (not short circuit
protected).
The minimum delay between pre-alarm and load disconnect is 30 seconds.
Charge disconnect output
The Charger output is normally high and becomes free floating in case of
imminent cell over voltage or over temperature. Maximum current: 10mA.
The Charger output is not suitable to power an inductive load such as a relay
coil.
The Charger output can be used to control:
• The remote on/off of a charger.
• A Cyrix-Li-Charge relay.
• A Cyrix-Li-ct Battery Combiner.
System on/off input
The system on/off input controls both outputs. When off, both outputs will be
free floating so that loads and chargers are turned off.
The System on/off consists of two terminals: Remote L and Remote H.
A remote on/off switch or relay contact can be connected between L and H.
Alternatively, terminal H can be switched to battery plus, or terminal L can
be switched to battery minus.
Protects 12V, 24V and 48V systems
Operating voltage range: 8 to 70V DC.
LED indicators
• Load ON (blue): Load output high (cell voltage >2.8V, adjustable on the
battery).
• Temp or OVP (red): Charger output free floating (due to cell over
temperature (>50°C), cell under temperature (<5 °C) or cell over voltage).
Safety instructions
Installation must strictly follow the national safety regulations in compliance with the enclosure, installation, creepage, clearance, casualty, markings and segregation requirements of the end-use application. Installation must be performed by qualified and trained installers only. Switch off the system and check for hazardous voltages before altering any connection.
1. Do not open the Lithium Ion Battery.
2. Do not discharge a new Lithium Ion Battery before it has been fully
charged first.
3. Charge only within the specified limits.
4. Do not mount the Lithium Ion Battery upside down.
5. Check if the Li-Ion battery has been damaged during transport.
Things to consider
Important warning
Li-ion batteries are expensive and can be damaged due to over-discharge or
overcharge.
Damage due to over discharge can occur if small loads (such as: alarm systems,
relays, standby current of certain loads, back current drain of battery
chargers or charge regulators) slowly discharge the battery when the system is
not in use.
In case of any doubt about possible residual current draw, isolate the battery
by opening the battery switch, pulling the battery fuse(s) or disconnecting
the battery plus when the system is not in use.
A residual discharge current is especially dangerous if the system has been discharged completely and a low cell voltage shutdown has occurred. After shutdown due to low cell voltage, a capacity reserve of approximately 1Ah per 100Ah battery capacity is left in the battery. The battery will be damaged if the remaining capacity reserve is drawn from the battery. A residual current of 10mA for example may damage a 200Ah battery if the system is left in discharged state during more than 8 days.
DC loads with remote on/off terminals
DC loads must be switched off or disconnected in case of imminent cell under
voltage.
The Load Disconnect output of the VE.Bus BMS can be used for this purpose.
The Load Disconnect is normally high (equal to battery voltage) and becomes
free floating (= open circuit) in case of imminent cell under voltage (no
internal pull down in order to limit residual current consumption in case of
low cell voltage).
DC loads with a remote on-off terminal that switches the load on when the
terminal is pulled high (to battery plus) and switches it off when the
terminal is left free floating can be controlled directly with the Load
Disconnect output.
See appendix for a list of Victron products with this behavior.
For DC loads with a remote on/off terminal that switches the load on when the
terminal is pulled low (to battery minus) and switches it off when the
terminal is left free floating, the Inverting remote on-off cable can be used.
See appendix.
Note: please check the residual current of the load when in off state.
After low cell voltage shutdown a capacity reserve of approximately 1Ah per
100Ah battery capacity is left in the battery. A residual current of 10mA for
example may damage a 200Ah battery if the system is left in discharged state
during more than 8 days.
DC load: disconnecting the load with a BatteryProtect
A BatteryProtect will disconnect the load when:
input voltage (= battery voltage) has decreased below a preset value, or when
the remote on/off terminal is pulled low. The smallBMS can be used to control
the remote on/off terminal Contrary to a Cyrix or contactor, a BatteryProtect
can start a load with a large input capacitor such as an inverter or a DC-DC
converter.
Charging the LiFePO₄ battery with a battery charger
Battery charging must be reduced or stopped in case of imminent cell over
voltage or over temperature.
The Charge Disconnect output of the VE.Bus BMS can be used for this purpose.
The Charge Disconnect is normally high (equal to battery voltage) and switches
to open circuit state in case of imminent cell over voltage.
Battery chargers with a remote on-off terminal that activates the charger when
the terminal is pulled high (to battery plus) and deactivates when the
terminal is left free floating can be controlled directly with the Charge
Disconnect output.
See appendix for a list of Victron products with this behavior.
Battery chargers with a remote terminal that activates the charger when the
terminal is pulled low (to battery minus) and deactivates when the terminal is
left free floating, the Inverting remote on-off cable can be used. See
appendix.
Alternatively, a Cyrix-Li-Charge can be used:
The Cyrix-Li-Charge is a unidirectional combiner that inserts in between a
battery charger and the LiFePO₄ battery. It will engage only when charge
voltage from a battery charger is present on its charge-side terminal. A
control terminal connects to the Charge Disconnect of the BMS.
Charging the LiFePO₄ battery with an alternator
See figure 6.
The Cyrix-Li-ct is recommended for this application.
The microprocessor controlled Cyrix-Li-ct includes a timer and voltage trend
detection. This will prevent frequent switching due to a system voltage drop
when connecting to a discharged battery.
Battery
In case of several batteries in parallel and or series configuration, the two
M8 circular connector cord sets of each battery should be connected in series
(daisy chained).
Connect the two remaining cords to the BMS.
System examples
Figure 1: Application
example for a DC off-grid system, with on/off switch between L and battery
negative
Figure 2: Application example for a vehicle or boat, with on/off switch between L and battery negative
Figure 3: Application example for a vehicle or boat, with on/off switch between H and L
Figure 4: Solar application with two MPPT 150/85 CAN-bus
The MPPT 150/85 CAN-bus has a remote on-off port which can be be controlled
directly by the VE.Bus BMS
Specifications
smallBMS|
---|---
Normal operating Input voltage range (Vbat)| 8 – 70V DC
Current draw, normal operation| 2.2 mA (excluding Load output and Charger
output current)
Current draw, low cell voltage| 1,2 mA
Current draw, remote off| 1,2 mA
Load output
| Normally high (Vbat – 0.1V)
Source current limit: 1A (not short circuit protected) Sink current: 0A (output free floating)
Charger output
| Normally high (Vbat –o.6V)
Source current limit: 10mA (short circuit protected) Sink current: 0A (output free floating)
Pre-alarm
| Normally free floating
In case of alarm: output voltage Vbat -0.1V Maximum output current: 1A (not short circuit protected)
System on/off:
Remote L and Remote H
| Use modes of the system on-off:
a. ON when the L and H terminal are interconnected (switch or relay contact)
b. ON when the L terminal is pulled to battery minus (V< 3.5V)
c. ON when the H terminal is high (2.9V < VH < Vbat)
d. OFF in all other conditions
General
| Operating temperature | -20 to +50°C 0 – 120°F |
|---|---|
| Humidity | Max. 95% (non-condensing) |
| Protection grade | IP20 |
ENCLOSURE
| Material and colour | ABS, matt black |
|---|---|
| Weight | 0.1kg |
| Dimensions (h x w x d) | 106 x 42 x 23mm |
Appendix:
Loads which can be controlled directly by the Load Disconnect output of
the BMS
Inverters:
All Phoenix inverters VE.Direct
Connect to the left hand terminal of the 2 pole connector
Phoenix 12/800; 24/800; 48/800
Phoenix 12/1200; 24/1200; 48/1200
Connect to the right hand terminal of the 2 pole connector
DC-DC converters:
All Tr type DC-DC converters with remote on/off connector, and Orion 12/24-20;
24/12-25; 24/12-40; 24/12-70 Connect to terminal H of the 2 pole connector
BatteryProtect and Smart BatteryProtect
Connect to the right hand terminal respectively to terminal H of the 2 pole
connector
Cyrix -Li-Load
Connect to the control input
Loads for which an inverting remote on-off cable is needed
(article number ASS030550100) Phoenix 12/180; 24/180; 12/.250; 24/350
All Phoenix VE.Bus inverters rated at 3kVA and more (see fig 4)
Solar charge controllers which can be controlled directly by the Charge
Disconnect output
BlueSolar MPPT 150/70 and 150/80 CAN-bus
Connect to the left hand terminal of the 2 pole connector (B+)
SmartSolar MPPT 150/45 and higher, Smart Solar MPPT 250/60 and higher
Connect to the right hand terminal (marked + or H) of the 2 pole connector
Solar charge controllers for which a VE.Direct non inverting remote on-off
cable is needed (article number ASS030550310)
All BlueSolar models, except the two CAN-bus models BlueSolar MPPT 150/70 and
150/80 CAN-bus
SmartSolar MPPT up to 150/35
Battery Chargers
For Skylla TG battery chargers a Non inverting remote on-off cable is
needed (article number ASS030550200)
For Skylla-i battery chargers a Skylla-i remote on-off cable is needed
(article number ASS030550400)
Other battery chargers:
Use a Cyrix-Li-Charge
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