FAQ

01
What are the advantages of the S.USV solutions modules?

During the working process on the single-board computers, the operating system and user data are continuously written to the SD card. A sudden failure or interruption of power while writing files can result in loss and/or corruption of important data. The S.USV solutions bridge these voltage fluctuations and give the single-board computers more stability in the supply through the uninterruptible power supply. In addition, the S.USV solutions have other useful additional functions.

02
Are the S.USV solutions modules fully Plug & Play?

The S.USV solutions modules are intelligent plug and play solutions. No further configurations are required to use the main function of the uninterruptible power supply. The interface and communication between the single-board computer and S.USV are automatically configured via the HAT EEPROM. A corresponding S.USV client and daemon are available for monitoring and controlling the modules.

03
Which single-board computers are the S.USV solutions modules compatible with?

The S.USV solutions series currently consists of three different versions:
– S.USV pi (Compatible with all Raspberry Pi models)
– S.USV UPs (Compatible with all AAEON UP boards)
– S.USV tinker (Compatible with all ASUS tinker boards)

04
How is the power supply of the S.USV done?

The S.USV solutions are powered directly by the GPIO Power Pins of the single-board computers and thus uses a common voltage source, so no further wiring or power supplies are necessary. The “Advanced” variant also offers a mains input for the extended voltage range of 7-24 volts (solar cells, car range, etc.).

05
Which power supplies can be connected via the external input?

All voltage sources with a voltage range between 7-24V and a minimum output current of 2A can be used.

06
What safeguards have been implemented with regard to the power supply?

In order to protect the external power supply, as well as the S.USV module and single-board computer from damage, the following precautions were taken on both the primary and secondary sides:
– ZVD – Circuit
– TVS – Circuit
– PPTC Fuse
– Power Monitoring System

07
What output power do the S.USV solutions modules provide?

The S.USV solutions modules provide the following output power:
– Primary: 5V / 3.5A (+/- 5)
– Secondary: 5V / 3.5A (+/- 5)

08
Which GPIO pins are occupied by the S.USV?

The following GPIO pins are used for the power supply as well as the data transmission of the S.USV:
– Pin #02: DC Power +5V – Power supply
– Pin #03: GPIO 02 (SDA1, I2C) – I2C data line
– Pin #05: GPIO 03 (SCL1, I2C) – I2C clock line
– Pin #13: GPIO 27 (GPIO_GEN2) – Condition Monitoring S.UPS
– Pin #27: ID_SD (I2C ID EEPROM) – ID data line
– Pin #28: ID_SC (I2C ID EEPROM) – ID clock line

09
How does the automatic switch from primary to secondary supply mode?

The input voltage of the entire system is monitored cyclically by the software and compared with an internally configured voltage reference. In order to meet the supply specifications of 5V +/- 5, in case of voltage drops less than 4.75V, the secondary mode (battery operation) is automatically switched to secondary mode. When the primary power supply returns, the S.UPS automatically switches back to primary mode.

10
What kind of batteries are used with the S.USV solutions modules?

Lithium polymer accumulators specifically designed for the system are used. Each product comes with a 300mAh battery, optionally a battery with higher capacity of 3000mAh can be purchased via our online shop for increased bridging times.
For more data regarding battery characteristics, see P.4 – Chapter 2 Technical Specifications. We generally advise against using accumulators with different characteristics.

11
Can higher capacity batteries be used?

There is generally no capacity limit for the use of lithium polymer or lithium-ion accumulators. Positively tested was the current revision 2.0 up to a capacity of 10,000mAh.
For more data regarding battery characteristics, see p. 4 – Chapter 2 Technical Specifications. We generally advise against using accumulators with different characteristics.

12
How does the battery charging circuit work on the S.USV solutions modules?

An intelligent battery management system has been implemented for all S.USV solutions products. The charging circuit is specifically designed for the use of lithium polymer and lithium-ion accumulators. The charging circuit divides the charge of the batteries into four controlled charging cycles in order to charge the battery gently and thereby increase the service life. The batteries offered by us can be charged up to a charging current of 1A, the charging current can be configured by the user via the client software (300, 500 and 1000mA).

13
What safeguards have been implemented with regard to the power supply provided by the batteries?

Thanks to the intelligent Battery Management System, as well as the Protection Circuit modules on the batteries we offer, they are protected from damage (overvoltage, deep discharge and overheating) both via the software and the hardware. With a residual capacity of less than 25, this is indicated by the status indicators, with a residual capacity of less than 10, the system is entered into the shutdown process to avoid deep discharge. In secondary mode (battery operation), the charging circuit is automatically deactivated.
Software and hardware work independently in this scenario to protect the accumulators from damage in any case.

14
Can the S.USV solutions modules also be operated in conjunction with other HATs?

A major focus of the S.USV solutions series is the modularity and variability of the system. All GPIO pins are connected 1:1 and can be reused freely, only GPIO Pin 13 (GPIO27) is reserved for condition monitoring by the S.UPS.
The following product ranges have been tested positive so far:
– HiFi Berry
– FHEM
– HomeMatic
– Enocean
– RPI WWCAM

15
How does automatic shutdown work?

In the automatic shutdown of the S.UPS, the measured input voltage is continuously compared with a reference value (voltage threshold). If the input voltage falls below the internally configured threshold of 4.75V, the S.UPS automatically switches to secondary mode (battery operation). The resulting shutdown process is handled in this mode depending on the configured shutdown timer.
For more information and configuration, please follow p. 17 – Chapter 4.1.1 Daemon Configuration.

16
Will the system automatically restart when power is returned?

A return of the primary voltage immediately leads to a restart when the system is switched off. The system goes into the reboot process. Even during the shutdown process, a return of the primary voltage leads to a direct reboot of the system after the shutdown process is complete.

17
How does the time-controlled switching on of the S.USV solutions modules work?

The user can activate and configure the function of timed power on and off the entire system. After successful configuration, the system can be put into hibernation at the configured shutdown time. The integrated Real Time Clock is evaluated in this state by appropriate firmware routines and reacts to it depending on the configured boot time. If the configured time matches, the system automatically boots.
For more information and configuration options, please follow p. 20 – Chapter 4.2.1 Client Options

18
Is it possible to send a preconfigured mail notification /alarm?

It is possible to activate corresponding mail notification by the S.USV. For this purpose, the user saves his mail data in a predefined Python script, which is sent in case of loss of the primary supply voltage, in order to inform the customer about the failure of the supply source.
For more information and configuration options, please follow p. 20 – Chapter 4.2.1 Client Options.

19
Is it possible to use preconfigured User Shutdown Scripts?

The Config of the S.USV modules (susv.cfg in /opt/susvd) can be used to create corresponding user shutdown scripts by the customer, which are executed when the shutdown process is initiated.
For more information and configuration options, please follow p. 20 – Chapter 4.2.1 Client Options.

20
How is the communication between S.UPV and single-board computer?

Communication between S.UPV and single-board computer takes place via the I2C interface (3.3V level). The S.USV modules work as slaves, so the I2C bus can be easily reused via additional peripherals.
All available data such as input voltage, power consumption or residual capacity of the battery can be processed via appropriate I2C registers or retrieved directly via the preconfigured client commands. This allows the user to respond independently to different events.
For more information or configuration options, please follow page 14 – Chapter 3.2.5.1 Register and p. 4.2.1 Client Options.