You can connect to the 123\SmartBMS with your phone or tablet. Download the 123\SmartBMS app, which is available in the Google Play store and Apple App Store.

First connection #

Go to the App store for Apple devices and search for “123SmartBMS”. Install the 123SmartBMS App on your Apple device. For Android devices go to the Play store and search for “123SmartBMS”. Install the App on your Android device. Enable Bluetooth on your device.

Start the App, You will see the dashboard. Tap on Settings in the right bottom corner to open the settings section. 

Tap on the discovered 123\SmartBMS device to make a connection. The App will ask for a password. This password is stored in the BMS to prevent anybody with a phone/tablet from accessing your BMS. The default password is “1234”. After the connection has been made it’s time to configure the system.

To disconnect, tap again on the BMS ID with the checkmark next to it.

Dashboard #

The dashboard displays most important battery information, next to the battery drawing. When a second current sensor is connected and the loads and chargers are separated, the dashboard will display extra information for charging/solar/MPPT and discharging/loads. The extra information is visible next to the solar panel and light bulb icon.

Battery #

In the middle of the dashboard is the battery. Next to it is important information about the battery:
-SoC (%). The amount of remaining energy.
-Current going in or out of the battery (A). When the battery is being charged, this value is positive. When current is flowing out of the battery, the value should be negative. If this is reversed, then the direction of the power cable through the current sensor is probably reversed.
-Remaining energy in the battery (kWh)
-Power (W). A positive value means the battery is being charged, a negative value means the battery is supplying energy to the loads.
-Voltage (V). The voltage of the complete bank, which is a sum of all cell voltages in series.

Charging #

When a second current sensor is connected, “current sensor 1” is seen as the current sensor mounted on the power cable where all charging sources like MPPT, AC charging etc are connected to. The solar panel with sun icon displays this information.
Displayed parameters are:
-Charging current (A) – this value should be a positive value when charging
-Charging power (W)
-Charged/produced energy today (kWh) – this value can be reset at Settings->Clear energy counters
-Charged/produced energy total (kWh) – this value can be reset at Settings->Clear energy counters

Discharging #

When a second current sensor is connected, “current sensor 2” is seen as the current sensor mounted on the power cable where all discharging sources like inverter, motors etc are connected to. The light bulb icon displays this information.
Displayed parameters are:
-Load current (A) – this value should be a positive value when discharging
-Load power (W)
-Consumed energy today (kWh) – this value can be reset at Settings->Clear energy counters
-Consumed energy total (kWh) – this value can be reset at Settings->Clear energy counters

Relay status #

The status of the “Charge” and “Load” signal relays on the BMS are displayed as icons. Between solar panel and battery icon is the “Charge” signal relay. Between battery icon and light bulb icon is the “Load” signal relay.

When the two dots in the icon are connected with a wire, the relay is closed. This means that the relay is turned on and current can flow.

When the two dots in the icon are not connected with a wire between them, the relay is open. This means that the relay is turned off and thus, current cannot flow.

Be aware that this is the status of the signal relays. It is up to the installer to connect anything to the potential free contacts of these signal relays, for example an energy efficient power relay to control the high currents from inverter and/or charger.

Details #

The details overview is contains more information about the battery.

Battery info #

The battery info contains information about the whole battery including state-of-health (SoH), usable battery capacity and discharge cycles.
The battery info block is only visible when for gen3+ and firmware v3.3+. If you have gen3 and do not see the dialog, ensure you ave updated the app and updated the firmware to v3.3.0 or higher.

State of Health: the health of your battery. The BMS bases the SoH on the measured capacity and factory capacity. The BMS measures the capacity from fully charged (Vfull/Vbalance, 100%) to empty (Vlow) and keeps the whole battery capacity in mind. This means that even when you do not set Vlow and Vbalance/Vfull to the battery’s extremes, the BMS still can determine the full capacity (outer edged of the battery).

Usable battery capacity: the still remaining usable battery. In general the more the battery is used (more cycles), the lower the usable battery capacity is.

Discharge cycles: the amount of complete discharge cycles. Discharging the battery from full (Vbalance/Vfull) to empty (Vlow) counts as a full cycle. Partly cycles are also counted. For example when the battery is discharged for 25% and then charged again, repeating this 4 times gives a full cycle (100%).

Active errors #

Status lamps display the active errors.
E: When no other error lamps light up, there probably is a communication error between the cell boards
Vh: one or more cell voltages are over Vmax. Vmax can be set in the app at Settings
Vl: one or more cell voltages are under Vmin. Vmin can be set in the app at Settings
Th: one or more cell temperatures are over Vmax. Vmax can be set in the app at Settings
Tl: one or more cell temperatures are under Tmin (charge or discharge). Tmin can be set in the app at Settings

Individual cell values #

For a quick overview of the most important data, you can see the voltage extremes: the lowest and highest cell voltage with the associated cell number.

Below are all individual cell voltages and temperatures. When the cell voltage is green, the cell voltage is between Vmin and Vbalance.
When the cell voltage is orange, the cell voltage is above Vbalance. This means that the cell is balancing.
When the cell voltage is red, this means that the cell is either under Vmin or over Vmax.

When a cell temperature is green, it means that the temperature is between Tmin and Tmax.
When a cell temperature is red, it means that the temperature is below Tmin or over Tmax.
Please be aware the measured cell pole temperature during balancing can be higher than without balancing, because balancing produces heat. After balancing is finished, the temperature will go back to the normal temperature.

Log #

The Log contains error logging and multiple history graphs.

SoC History #

The SoC history contains a SoC graph of the last 7 days.

Errors #

All critical events are logged into the error history. The most recent events are displayed here. Information includes which cell (if applicable), which value and the timestamp when the event occured.

Settings #

At Settings, you can connect to any nearby 123\SmartBMS’es and change all configurable BMS parameters of the connected BMS.

Devices #

All found 123\SmartBMS systems near the phone/tablet are displayed in a list. Tap on a device to connect. A checkmark next to the device displays that you are connected to that device.

Expert mode #

Show expert settings: the standard settings are always visible. If you need extra flexibility, you can enable expert settings. With expert settings enabled, you can change parameters like hysteresis, assign a different function to a relay or force a relay to stay off.
Please only change expert settings if you understand exactly what the setting does. Configuring a setting incorrectly can result in unexpected behaviour, for example not being able to protect your battery.

System configuration #

Solar peak power: Set the maximum power of your incoming energy source, for example solar panels. If the system contains 10 solar panels of 250 Watt each, the total power of 2.50 kW has to be configured.

Inverter peak power: Set the maximum power of the consumers, for example an inverter. When your inverter can supply 5 kilowatt, 5.00 kW has to be configured.

Battery factory capacity:  The factory battery capacity, in kWh. Example: you have 4 LiFePO4 cells, where the cell capacity is 90Ah. The battery factory capacity is 90Ah x 3.3V x 4 cells = 1188Wh. Set the Factory capacity to 1.1 kWh.

Current sensor (Expert mode): Please set the current sensor type you are using. The standard current sensors supplied in the set and are “dual range 500A – 20A”. If you loop the cable 2x through the current sensor, select “dual range 250A – 10A”. For 4x loop, select “dual range 125A –5A”.

Invert charge sensor (Expert mode): This is the current sensor from Begin Board “sensor 1”. If the power cable is going through the current sensor the wrong way round, turn this setting on. The current value will be inverted. Example: if the system is charging but the current value in the app next to the battery image is a negative value, reroute the cable the other way around or turn this setting on. The current should now be positive while charging.

Invert discharge sensor (Expert mode): This is the current sensor from Begin Board “sensor 2”. If the power cable is going through the current sensor the wrong way round, turn this setting on. The current value will be inverted. Example: if the system is discharging but the current value in the app next to the battery image is a positive value, reroute the cable the other way around or turn this setting on. The current should now be negative while discharging.

Critical mode:

Changes the algorithm when “allowed to charge” and “allowed to discharge” turn on and off, which will have affect on the assigned signal relays.

In normal mode, charging is stopped when the pack is full (all cell voltages >Vbalance) and turned on when the SoC is below “charge restart SoC %”.

In critical mode, charging is allowed as long as all cells are below Vmax and within configured Tmin and Tmax. Discharging is allowed as long as all cells are above Vmin and within Tmin and Tmax.
In Critical Mode, the BMS will only switch charging and/or loads off when there is a critical error. See the algorithm section for more information on when loads and/or charging is allowed.

Critical Mode is recommended for combined chargers/inverters with only one + cable to the battery pack because otherwise when the pack is fully charged, the combined charger/inverter is switched off and thus discharging is also not possible.See Appendix section C for more info.

Use measured capacity for SoC (Expert mode): The BMS measures the discharge energy capacity from full to empty. This is the “usable battery capacity”. When this setting is turned on, the SoC is calculated based on this measured capacity instead of the “battery factory capacity”. This is especially useful when the battery gets older. The older the battery, the lower the usable capacity for the battery.

Correct SoC based on cell voltage (Expert mode): The BMS uses energy counting, also known as coulomb counting, for estimating the energy left in the battery and calculating the SoC. However, battery self-discharge and accumulated current sensor measurement errors can result in a SoC drift (incorrect SoC).
When this setting is enabled and the battery cells are in rest, the battery idle voltage (called OCV, open circuit voltage) is used to look up the expected SoC. When the expected SoC differs from the actual SoC, the SoC is corrected. This idle voltage correction contains multiple specially for 123\SmartBMS developed algorithms like Band Lookup and Multistage Correction to ensure proper working, even for LiFePO4.

Sync SoC to full below charge rate (Expert mode): The SoC is synced to full (100%) when all cell voltages are at least Vbalance and the charge rate is below this value. The charge rate is defined as charge power / battery factory capacity x 100%. For most applications, the default value of 5% is sufficient.
High currents flowing into a cell can lead to instantaneously high cell voltage. This can lead to a cell voltage being above Vbalance, while the cell is not full, yet. To prevent the BMS from falsely changing the SoC to 100%, the BMS will ignore the cell voltages above Vbalance when the charge power/current is still high. Instead, the BMS will await the charging until the charge current has dropped enough (also called the tail current). When all cell voltages are above Vbalance AND the charge power/current is low enough, the system knows the cells are really full.

Change name: When using multiple 123\SmartBMS’es closes to each other, your phone/tablet will display all found BMS’es in the app. To easily distinguish between them, you can give each BMS it’s own unique name.

Change PIN: We recommend to change the PIN of the BMS to prevent intruders accessing the system. The PIN consists of 4 digits.

Clear energy counters: The BMS measures and counts information like battery cycles, current sensor 1 (solar panel) and current sensor 2 (inverter) produced and consumed energy (kWh). If you want to reset these total counters to zero, tap on the “Clear energy counters”.

Battery parameters #

Charge restart:  “Allowed to charge” turns ON again when the SoC is below the programmable “Charge restart” and the BMS is in “Normal mode” (Critical Mode off). This is to prevent toggling relays.

Charge pause delay (Expert mode):  Before turning off “allowed to charge”, a critical charge error needs to persist at least for this parameter value. In general, 8 seconds is the minimum value. If you want to use a prealarm before switching off, set this value for example to 30 seconds. When a critical threshold is passed, for example Vmax, the BMS will wait 30 seconds before “allowed to charge” is turned off. You can use the app or a signal relay configured as prealarm (see Relays) to warn the user. This gives the user some time to turn off the charger manually, before anything like the main relay would disconnect the battery.

Charge restart delay (Expert mode):  When “allowed to charge” is turned off and the critical threshold error is cleared, the BMS will wait this delay time before turning “allowed to charge” on again. A good value is 60 seconds.

Discharge restart:  “Allowed to discharge” turns on when the capacity is above the programmable “Discharge restart” and the BMS is in “Normal mode” (Critical Mode off).

Discharge pause delay (Expert mode):  Before turning off “allowed to discharge”, a critical charge error needs to persist at least for this parameter value. In general, 8 seconds is the minimum value. If you want to use a prealarm before switching off, set this value for example to 30 seconds. When a critical threshold is passed, for example Vmin, the BMS will wait 30 seconds before “allowed to discharge” is turned off. You can use the app or a signal relay configured as prealarm (see Relays) to warn the user. This gives the user some time to turn off the load(s) manually, before anything like the main relay would disconnect the battery.

Cell parameters #

Battery chemistry: Select the battery chemistry, for example LFP (LiFePO4).

Custom parameters: The default parameters should work fine for most cases. Enable this toggle to see the default parameters, or to modify a cell parameter.

V min: If one of the cells gets below this minimum cell voltage threshold the  “Vl“ warning indicator on the battery details screen is switched on. “allowed to discharge” will turn off and the corresponding relay, by default the “Load” relay, will switch off.

V low: The 0% SoC synchronisation voltage. This value should be the same value or a little higher than Vmin. When a cell voltage is below this value while the battery discharge current is low, the battery is empty and thus the SoC is synced to 0%.

V max: If one of the cells gets above this maximum cell voltage threshold the  “Vh“ warning indicator on the battery details screen is switched on. “allowed to charge” will turn off and the corresponding relay, by default the “Charge” relay, will also switch off.

V balance: This is the balancing voltage where you want all the cells to end up. Above this voltage the cell modules start to dissipate 1 ampere to balance the cells. This setting can be changed with the option switches on the Begin Board.

T min charge: If one of the cells gets below this minimum cell temperature threshold the  “Tl“ warning indicator on the battery details screen is switched on. “allowed to charge” will turn off and the corresponding relay, by default the “Charge” relay, will also switch off.

T min discharge: If one of the cells gets below this minimum cell temperature threshold the  “Tl“ warning indicator on the battery details screen is switched on. The discharge/load signal relay, to control external devices, will be switched off. “allowed to discharge” will turn off and the corresponding relay, by default the “Load” relay, will switch off.

T max: If one of the cells gets above this maximum cell temperature threshold the  “Th“ warning indicator on the battery details screen is switched on. Both “allowed to charge” and “allowed to discharge” will turn off. The corresponding relays, by default the “Charge” and “Load” relay, will turn off.

V min hysteresis (Expert mode): To prevent “allowed to discharge” from toggling on and off when a cell reaches Vmin, the BMS uses hysteresis. When a cell is below Vmin, the Vmin error turns on. When the lowest cell voltage is above Vmin + this hysteresis value, the error is cleared.

V max hysteresis (Expert mode): To prevent “allowed to charge” from toggling on and off when a cell reaches Vmax, the BMS uses hysteresis. When a cell is above Vmax, the Vmax error turns on. When the highest cell voltage is below Vmax – this hysteresis value, the error is cleared.

Relays #

The 123\SmartBMS has two signal relays on the End Board, which you can use to switch other devices. For example, to switch a power relay to disconnect loads and/or chargers in case of a critical battery parameter value.

By default, the “Charge” relay turns off when “allowed to charge” is disabled and the “Load” relay will turn off when “allowed to discharge” is disabled. However, it is possible to change the function of a signal relay, for example when you have a combined charger/inverter and only have one power relay: the main relay. Another reason why you may want to change the function of a signal relay is when you need a prealarm, which gives a headsup before the BMS turns off the main relay.

Force relay position (Expert mode): When you want to force the position of a relay to stay on or off, you can use this setting. A good example when it can be handy is when you store the battery away and want the power relay, connected to this signal relay, to stay off. This prevents any devices connected to the power relay to draw any idle current.

Relay function (Expert mode): By default, the “Charge” signal relay is set to “allowed to charge” and the “Load” signal relay is set to “allowed to discharge”. However you can select a different function for each relay. The following options are supported:

• Allowed to charge – turns on when “allowed to charge” is on
• Allowed to discharge – turns on when “allowed to discharge” is on
• Main relay – active when both “allowed to charge” and “allowed to discharge” are on
• Prealarm – as soon as a critical error threshold is reached (Vmin, Vmax, Tmin, Tmax, BMS cell communication error), prealarm turns on

Invert relay open/close (Expert mode): It is possible to invert the relay. This changes the relay from “normally open” to “normally closed”.

Firmware version #

Firmware update channel (Expert mode): When you want to test upcoming firmware version, select “latest release candidate”.
The latest release candidate may still contain bugs and is for testing only

Current version: Displays the installed firmware version on the BMS (only for gen3 and newer). When connected to internet, the latest available firmware version will also display. If a newer version is available, the update button becomes active.
For safety reasons, during a firmware update, the charge and load signal relay will turn off.

App settings #

Prevent auto-lock:  Enabling this function prevent the device goes into sleep mode.

Show simulator:  If you don’t have an 123\SmartBMS but you like to discover the App, you can run a simulator.

Support #

You can contact the app developer and give your feedback. The App version will be showed here.