The issue of power supply in the event of power failures is becoming increasingly important. Especially weather extremes or overloads of the power grid can cause power failures. Even with a photovoltaic system you are not automatically protected against a power failure. However, if you use your photovoltaic system with a battery with emergency power, backup power or UPS function, you can still rely on a stable power supply.

In this article, we define the terms emergency power, backup power and UPS and provide information on the advantages and disadvantages of both functions. We will also show you the suitable products, as many of the inverter manufacturers that we have in our Krannich product portfolio offer an emergency power backup function or non-certified UPS (more on this later) together with the appropriate storage units.

Storage systems with backup power are capable of independently switching all consumers to the in-house battery storage in the event of a failure of the public grid. Depending on the structure of the system, the backup power supply is provided in 1- or 3-phase. The automatic switch-over devices / disconnecting devices required for this must be designed in accordance with local regulations (3-pole, all-pole, etc.). After the changeover, it takes a few seconds until all consumers are supplied again. This can be done, for example, by means of the Enwitec mains switch box or the Kaco HY-SWITCH.

Pro:

• Continues to supply consumers in the normal household network
• 1- and 3-phase design Various requirements e.g. all-pole, 3-pole isolation can be realized

Contra:

• Separate switch box
• Switchover time

Find the right product sets consisting of inverter and storage unit with backup power function and the right power switch box - Battery Backup Box - in the Krannich portfolio.

Storage packages including inverter:

BYD HV + Fronius:
BYD B-BOX HVM + SYMO HYBRID
BYD HVM / HVS + Fronuis Gen 24 PLUS
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Power switch box for Symo GEN24 and Symo Hybrid

Storage package LG Electronics
ENERGY STORAGE SYSTEM HOME + LG HB
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Power switch box for LG ENERGY STORAGE SYSTEM

Axitec + SMA storage packages
AXISTORAGE LI + SI
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Power switch box for AXISTORAGE LI + SI

Storage packages BYD + SMA
B-BOX HVM/HVS + SB STORAGE
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Power Switch Box for B-BOX HVM/HVS + SB STORAGE 

Storage packages Pylontech + Solax
Pylontech 48V H48050 HV + Solax-HYBRID
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Storage packages Solax
Solax T-BAT H 5.8 + Solax HYBRID
Solax TRIPLE POWER + Solax HYBRID
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Power switch box for Pylontech 48V H48050 HV + Solax-HYBRID, storage package Solax

Please clarify the use of the appropriate power switch boxes on site with your responsible Provider.

Confusion occurs here repeatedly, as this term is not regulated in a normative way. However, the following definition is the one most frequently used. Emergency power means the property of a storage system to provide electrical energy via a separate connection in case of a power failure. It is implemented via a separate AC-side output or phase on the inverter. This phase can then be used to supply critical (emergency power) consumers.

Pro:

• Short changeover time
• No separate switch box necessary

Contra:

• emergency power consumers to be supplied must be redirected manually or wired via an extra phase

Find the right product sets comprising inverter and storage unit with emergency power function in the Krannich portfolio

Storage packages BYD + Goodwe
B-BOX HVM / HVS + GW-ET(WIFI/DC-SWITCH)
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Storage packages Pylontech + Solax
Pylontech 48V H48050 HV + Solax-HYBRID
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Storage packages Solax
Solax T-BAT H 5.8 + Solax HYBRID
Solax TRIPLE POWER + Solax HYBRID
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Storage packages BYD + Fronius
Fronuis Gen 24 + BYD HVM/HVS
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Storage packages BYD + SMA
SMA SB + B-BOX HVM / HVS
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The primary function of a UPS is to provide power in sensitive or very critical consumption systems without major quality or time interruptions. Classical areas of application are e.g. hospitals, server rooms, pharmaceutical production processes etc. In addition, there are also non-certified/classified UPS systems which, for example, have only a short switching time. IEC 62040-3 was created to define the increased demands on UPS systems.

With a certification according to the standard, it must be ensured that the conditions can be met in every situation. This classifies the UPS in three levels. Within the levels, different categories/classes are classified. The first level deals with the dependence on the mains current. Here the following categories are distinguished: voltage and frequency independence (VFI), voltage independence (VI) and voltage and frequency dependence (VDF).

The VFI, also known as online UPS, provides comprehensive protection against power failures, voltage dips, voltage surges, undervoltage, overvoltage, lightning effects, switching peaks, interference voltages, frequency changes and harmonics. The VI, also known as a single conversion UPS, protects against all voltage problems (power failure, voltage dips, voltage surges, undervoltage and overvoltage).

The VDF also known as offline UPS protects against power failure, voltage dips and voltage surges. The second stage included the difference in voltage curve shape between UPS and normal mains operation. The third stage was the dynamic or time tolerances of the UPS output. There are 3 classes here. 1st class means no interruption, 2nd class, interruption up to max. 1 ms. 3rd class means interruption up to 10 ms.

Not certified/classified UPS systems:

Storage packages BYD + Goodwe
B-BOX HVM / HVS + GW-ET(WIFI/DC-SWITCH)
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Currently no IEC 62040-3 classifiable/certified devices are available.

Pro:

• Optimum voltage and frequency quality possible
• Very short switching times

Contra:

• Very complex and expensive depending on the design

Here you can also download our storage overview.

If you have any further questions, please feel free to contact your personal contact person at any time. We are looking forward to your call.