User Manual: Backup power wall


The backup power wall exists out of three main parts. These are

  • The 12Vdc/120Vac inverter
  • The battery charger
  • The battery
  • The casing with frond panel

The 12V/120Vac inverter module is responsible to convert your 12Vdc battery voltage to 120Vac, the last one is needed within your house.
The build in battery charger recharges you batteries automatic after you have had a power blackout.
The battery uses is a special lead acid battery. We recommend not to use standard car batteries these are not made for backup applications.
The front panel contain three switches, two power meters two fuses and two general purpose outlets. The front panel informs you about the state of the backup.

How to install

At the back panel or the backup you find a black cable with four wires. One green, One white, One red and One black wire. This cable is to be connected to a dedicated Fuse box with inside the same colors as the cable has. The fuse box is connected to the distribution panel of the house. The fuse box is needed in case the power wall needs to be disconnected from the grid. The disconnect is made on the fuse box not on the distribution panels of the house.
The different colors have the following functions:

  • Green: Earth (G)
  • White: Neutral (N)
  • Red: Line from the street (L-street)
  • Black: Line going into the house L-house

Make sure the distribution box is wired with the correct color’s. If you have doubts connect the fuse box but not the backup and call us or a qualified installer. If your not sure there is a serious risk of damage.

How to use stand-alone

If you use the backup as a stand-alone backup you don’t need to use the fuse box. A normal 120Vac connector needs to be installed on the black cable coming out of the back of the backup. The following wire as are used for this

  • Green: Earth (G)
  • White: Neutral (N)
  • Red: Line from the street (L-street)

Cutoff or isolate the black unused wire. The installed connector can be plugged in to a standard wall socket. This allows the batteries to be recharged after a blackout.
In stand-alone mode the back connector doesn’t have to be connected to a wall socket in order to use the front outlets.
The frond outlets can be used to power your appliances like lights, TV, small drill at any time at any place.
Recharging the battery requires the back cable to be connected with a 120vac wall socket.

How to operate

Ones the backup power wall is installed the backup is ready for operations. There are two mode of operations which are called cold and hot standby. Te two modes are selected with the small on/off switch located on the front of the inverter. The two modes are individual discussed.

Cold Standby mode

Cold standby means the backup battery charger is active but the electronics to convert the 12Vdc to 120Vac is off. This part of the electronics consumes about 8 Watts and is better to be switched of when there is no power failure expected. In this mode to power consumption of the inverter is about about 4 Watts. The fan is most of the time of but can switch on for 30 seconds.

Hot Standby mode

Hot standby means the backup battery charger is active but the electronics to convert the 12Vdc to 120Vac is also on. The inverter consumes now about 12Watts and is ready for coming into action when needed. This mode is selected when you think there might be a reason for power failure. The depending on the ambient temperature the fan is intermittent switching on.

Use of the switches

There are three large red toggle switches on the front plate of the backup and a smaller switch located at the on top located inverter. It is not possible to damage the backup by using the switches in what ever combinations, every on off combination is allowed. From top to bottom these switches have the following functions:

  • Inverter : on/off switch, switches between Holt/Colds standby of the 12Vdc/12Vac inverter unit
  • Front Top : on/off switch, Connects or disconnects the input side of the backup from the grid
  • Front Mid : on/off switch, Connects or disconnects the output to the backup
  • Front Bottom : toggle switch, between battery charge or discharge power meter readings.

The bottom toggle switch allows to use the DC power meter for reading power in either charge mode or in discharge mode. The meter can not automatic switch between charge and discharge readings this needs to be done manually.

Reading the power meters

There are two power meters installed on the backup. The top power meter is a AC meter which measures the total power going out of the backup into your connected appliances. The meter below is a DC meter measuring the total power going in or out of the battery depending the battery is charging or discharging. To read the current and power of the bottom DC meter put the toggle switch in the right position.
The following values are read from the AC and DC meter

  • Voltage in [V]olt
  • Current in [A]mpere
  • Power in [W]att
  • Energy in [Wh] Watt-hour

There is a small button on each of the meters to reset the Watt-hour readings to zero. The procedure to reset the meters to zero is slight different between the two meters.
To reset the meters do the following:
AC meter at the top: Press the button for about 5 seconds till there is one message “PRS CLR” on the display and release the button. The Watt-hour reading is blinking now. Press the button again and the value resets to zero.
DC meter at the bottom: Press the button for about 5 seconds till there is only one message “CLR” on the display and release the button. The Watt-hour reading is blinking now. Press the button again and the value resets to zero.

Fuses and their function

At the right bottom side are two locations for fuses. the backup is fused on the line input and line output side with each 10Amp. If the group of the house consume more than a 1200Whr these fuses will like break first and need to be replaced. The fuse types used are glass 6 x 30mm 10A fuses. Its handy to have a few spare of them.

Estimate the backup time

The backup time you have is the time the backup can produce electricity during a blackout. How long this time is depends on how much energy you consume per unit of time out of the battery. We can estimate the time by the the following Calculations
Backup Time: Tb = battery capacity [Wh] / total power [Watt]
The battery capacity can be read from the battery the power wall has a value of 900Wh,
Example of the total power consumption is the power of a 40″ LED television + internet modem + 2xCFL lights + the capacity of the backup its self = 40Watt + 8Watt + 2*14Watt + 13Watt= 89Watt
The time is calculated as follows Backup Time: Tb = Battery capacity [Wh] / Total power [Watt] = 900 / 89 = 10 hour.
If the battery is not full the backup time is shorter. If more power is consumed than this example the backup time is shorter.

Other things to know

Not more than 360Watts.

It is not recommended to load the system with a total power higher than 360Watts for several reasons. The Battery life time get shorter if the load increases. The battery capacity get lower if it is loaded with a high load. High loads lower your backup time. A high load will not damage the system it will lower its life time.

More backup time

It is possible to increase the backup time by adding a second 900Wh battery to the existing backup power wall.

Switch off the inverter

If you don’t expect an power outage it is recommended to switch of the inverter and go in cold standby mode. Battery charging will continue till the battery is full. See section How to operate

Check the battery power meter

If the inverter goes into backup mode reset the battery DC power meter. Set the toggle switch in right position. Check every now and then what the battery voltage [V] is and what the used capacity is in [Wh]. The battery voltage should never go below 10.5V. When the power indication goes from 0 up to 900Wh your battery is practically empty and the voltage will be around 10.5V. When you reach this point you must switch of the system because your ran out of backup time.