AC Coupling Grid-Tied Backup

home backup

web solarStore



  • Blue Pacific Solar Products, Inc. BBB Business Review


SMA AC Coupling 2695 Watt Battery Based Grid-Tied Kit #BP2893150AC

home backup
  • SMA AC Coupling
  • SMA / MidNite Solar emergency AC coupled solutions for string or micro inverters, 2,000 to 24,000 watts. The system is shipped pre-wired ready to install. The package includes a line drawing showing how to wire the system to your home or business. An automatic transfer to a generator option is also available. This is a self-contained prewired AC coupled system complete with a Sunny Island SI 6048 120VAC 60 Hz inverter, master 250 amp MidNite Solar E-Panel with triple relay module, MNX-240 6,000 watt autoformer and lightning arrestor to protect the circuitry. AC coupling can be used in grid tied, grid interactive as well as off-grid applications.
  • Only: Buy Now
  • Product Details:
  • Specifications:
  • Videos:
  • Resource Documents:

SMA / MidNite Solar AC Coupled Kit with 2,695 Watt Solar Panel System

Model Item Code # Solar Panels Pass-Through
Peak AC Surge Battery Storage Power Supply No Load Draw
MNSMA#1-AC BP2893150AC 11 245W 56 Amps 11,000W 12,480 Watts AGM Solar / Grid 25 Watts

Half the country have recently experienced serious utility blackouts emphasizing the importance of a home or business battery backup system. Backup power from SMA and MidNite Solar provide a scalable solution for any sized home, it simply depends on the energy usage. The most critical electrical devices in a home are placed on a separate critical load sub-panel so in the event of a storm, utility blackout or other grid interruption, with the SMA AC Coupling 2695 Watt Kit, power will stay on for critical loads.

UL 1741 islanding protection - In the event of a grid blackout, it is required that any grid-interactive inverter automatically turn off. This prevents the inverters from continuing to feed electricity into the grid near the home, known as "islands". Electrical islands present a risk to utility workers who may expect the area to be unpowered. The SMA/MS AC coupled architecture has built into the E-Panel a grid-active relay to automatically disconnect the system from the utility power during blackouts. When the grid comes backup, the system is automatically reconnected to the grid.


SMA / MidNite ac-coupled solutions are driven by the bi-directional Sunny Island inverter / charger and pre-wired circuits pre-built within the MidNite E-Panel enclosure. The Sunny Island is equipped with sophisticated ac grid-management functions and highly developed battery management that includes full system monitoring. The Sunny Island continuously tracks the batteries’ state of charge, and as system manager makes ongoing decisions based on those states. For example, during operational periods where the battery are discharged and there is little solar generation, the Sunny Island can remotely and automatically start a backup generator, or even switch off consumer loads using a built-in load-shedding relay parameter. The Sunny Island also determines the optimum strategy for charging the batteries and in doing so increases their service life.

The single inverter systems come pre-wired with a 6,000 watt toroid autotransformer which is not needed for the dual Sunny Island systems. The toroidal design assures minimal magnetic stray field leakage, and, because of its 98% high efficiency, a very compact size for its rating. The toroid autotransformer circuitry monitors the incoming voltage with each cycle, comparing it to an internal voltage reference.

ac coupled

The systems architecture continues with the SMA Sunny Island SI6048-US 6kW inverter. SMA Sunny Island inverters are highly advanced with peak efficiencies above 95% and surge-protection for starting large loads such as motors, deep well pumps and most household and shop equipment you may choose to add later down the road. For example, the Sunny Island 6048-US model, which is standard, can provide 7 kW output for 30 minutes, 8.4 kW for 1 minute and 11 kW for 30 seconds. Sunny Island inverters systems by themselves have single phase 120 VAC output but are 240 VAC when stacked.

SMA, the oldest and most experienced inverter manufacture in the world, begin developing AC coupled systems beginning with its Sunny Island product in the 1990’s. AC coupling uses micro or string grid-tied inverters which allow electricity generated by solar panels to be NET metered which means it flows in both directions. One of the great things about AC coupling is you can either add the battery based backup to a home with or without existing solar panels. The architecture of the system is flexible enough to add future modules and battery storage although batteries should be installed as a matched string from the onset. SMA products are unique in the inverter world because the Sunny Island and Sunny Boy communicate with each other to insure proper battery charging during a power outage. No other inverter combination can claim this. If the batteries are fully charged, the Sunny Island will instruct the SMA Sunny Boy Inverter to derate their power output to regulate the deep cycle battery charge. SMA America asked MidNite Solar to design an integrated plug-n-play pre-wired E-Panel system to use with the Sunny Island inverter. The top matching color NEMA box houses the autoformer. SMA Sunny Island is sandwiched between the MidNite Solar autotransformer box and the MidNite Solar E-Panel below the Sunny Island; the complete system comes pre-wired mounted on a long back plate.

In ac-coupled systems, if the Sunny Island is matched with a SMA inverter, SMA Sunny Boy inverters communicate with Sunny Island battery-based inverters via a shielded RS485 communication cable. When the batteries are completely charged and the ac-load demand is low, the Sunny Island uses frequency-shift power control to gently throttle down the power output of the grid-direct SMA inverters. These frequency shifts prevent battery overcharging and are independent of any other communication functions between the inverters. Unlike the operation of ac-coupled solutions from other manufacturers that use frequency shift to completely drop ac-coupled grid-direct inverters off-line, SMA’s fully integrated approach allows the ac-coupled string inverters to remain online during frequency shift while operating at lower power levels.

magnum power center

What's On The Truck

  • SMA/MS 2695 AC Coupled Kit; BP2893150AC
  • 1 MNSMA#1-AC Single Pre-wired AC Coupled Power Center
  • (Incl) Sunny Island SI 6048 Inverter
  • (Incl) Master 250 amp E-Panel w/Triple Relay Module
  • (Incl) MNX-240 6000W Autotransformer
  • (Incl) Long back plate
  • (Incl) MNSPD300 Lightning Arrestor
  • (Incl) Pre-wired By Factory Trained Technicians, Delivered Ready to Hang and Connect.
  • 1 MNBE-8D2X2 Battery Box with 250A Breaker and Cabling
  • 1 MNSPD300 Midnite Lighting Arrestor
  • 1 AWG-PV Wire - 100' cable extension
  • 1 Multi-Contact MC4 Unlocking Tool
  • 6 1/2" Strain Relief for #10 or #12 wire
  • 11 YL245P-29b POLY 245 Watt Yingli Solar Panels
  • 4 FullRiver DC260-12 260 AH 12V Batteries (12,480 Watt 48V Battery Bank) Delivered with Cables; Not Installed in Included Enclosure
  • 3 4/0 - 12" UL Cable, Battery Interconnect (black)
  • 1 4/0 - 120" Battery Cable, Dual Kit (1 red, 1 black)
  • 1 Line Drawing


midnite solar


Options & Accessories Part # Price  
1 Set Basic IronRidge Roof Racking Option D (1 Rack Set Required Per Solar Panel 4 Panel MIN)ironridge solar racks BP6932304solar roof rack
1 Set Basic IronRidge Ground Racking Option D (1 Rack Set Required Per Solar Panel 4 Panel MIN)dpw BP6932304solar ground rack
MidNite Solar MNBE8D2/2 Enclosure w/ 4 FullRiver AGM DC260-12V Batteries Includes Cables Provides Additional 12,480 Watt Energy Storage BPMNDC26012inverter cable
SMA Sunny Beam Wireless System Monitorinverter BP2958232inverter cable
Sunny Beam Bluetooth Piggy Back Cardinverter BP9931215inverter cable
SMA Sunny WebBox With Bluetoothinverter BP1960493inverter cable
Technical Data Sunny Island
Sunny Island
AC output (loads))))    
Rated grid voltage / AC voltage range 120 V (105 V – 132 V) 120 V (105 V – 132 V)
Rated frequency / frequency range (adjustable) 60 Hz (55 Hz - 65 Hz) 60 Hz (55 Hz - 65 Hz)
AC power at 25 °C / 40 °C for 3 hours 5000 W / 4000 W 6000 W / 5000 W
Rated power (@U(nom), f(nom) / 25 °C / cos f = 1) 4500 W 5750 W
AC output power at 3 s 25 °C (77 °F) for 30 min / 1 min / 5300 W / 8400 W / 11000 W 7000 W / 8400 W / 11000 W
Rated current / Max. output current (peak) 37.5 A / 180 A for approx. 60 ms 48 A / 180 A for approx. 60 ms
Total harmonic factor output voltage / power factor at rated power 3% / -1 ... +1 3% / -1 ... +1
AC input (PV array or grid))    
Rated input voltage / AC input voltage range 120 V (80 V – 150 V) 120 V (80 V – 150 V)
Rated input frequency / allowable input frequency range 60 Hz / 54 Hz ... 66 Hz 60 Hz / 54 Hz ... 66 Hz
Max. AC input current / adjustable 56 A / 0 A ... 56 A 56 A / 0 A ... 56 A
Max. AC input power 6.7 kW 6.7 kW
Battery DC inputt    
Rated input voltage / DC voltage range 48 V / 41 V - 63 V 48 V / 41 V - 63 V
Max. battery charging current / DC rated charging current 100 A / 85 A 130 A / 110 A
Battery type / battery capacity range Lead, NiCd / 100 Ah - 10000 Ah Lead, NiCd / 100 Ah - 10000 Ah
Charge control IUoU charge procedure with automatic full charge and equalization charge IUoU charge procedure with automatic full charge and equalization charge
Efficiency / self-consumptionn    
Max. efficiency / CEC efficiency 96% / 94.5% 96% / 94%
Self consumption with no load / standby 25 W / 4 W 25 W / 4 W
Protective Devicess    
DC reverse polarity protection / DC fuse yes/yes yes/yes
AC short-circuit / AC overload yes/yes yes/yes
Overtemperature / battery deep discharge yes/yes yes/yes
General dataa    
Dimensions (W/H/D) 467/612/235 mm (18.4/24.1/9.3 inch) 467/612/235 mm (18.4/24.1/9.3 inch
Weight 63 kg /139 lb 63 kg /139 lb
Operating temperature range –25 °C ... +60 °C (–13 ° F ... +122 °F) –25 °C ... +60 °C (–13 ° F ... +122 °F)
Features / functionn    
Operation and display / multi-function relay Internal/2 Internal/2
Degree of protection (according to IEC 60529) internal assembly (NEMA 1) internal assembly (NEMA 1)
Three-phase systems/parallel connection yes/yes yes/yes
Integrated bypass/multicluster operation no/yes no/yes
State of charge calculation/full charge / equalization charge yes/yes/yes yes/yes/yes
Integrated soft start/generator support yes/yes yes/yes
Battery temperature sensor/data cable yes/yes yes/yes
Warranty: 5/10/15/20 years yes/opt./opt./opt./opt. yes/opt./opt./opt./opt.
Certificates and approvals
Battery cables/battery fuse opt./opt. opt./opt.
Interfaces (RS485/Multicluster PB) opt./opt. opt./opt.
Extended generator start "GenMan" opt. opt.
Load-shedding contactors/external battery current measurement opt./opt. opt./opt.
Type designation SI4548-US-10 SI6048-US-10

SMA / MidNite Solar AC Coupling 2695 Watt Battery Based AC Coupled Grid-Tied or Off-Grid Power Center

The Sunny Island 6048-US is a bi-directional battery-based inverter / charger that can be used completely off-grid, or for battery backup in grid-tie systems with Sunny Boy grid-tie inverters. The Sunny Island MidNite Solar combination is a complete high efficiency pre-wired power center all in a compact wall-mounted package. It includes 6kW of pure sine wave output power, low idle losses, and a 100 A battery charger, and offers an integrated data monitoring system with battery disconnect.

Grid-Tie System Backup - The Sunny Island can provide back-up power for critical loads during utility grid blackouts. Combined with any grid-tie inverter system and a bank of batteries, the Sunny Island will enable the solar array to power loads and charge the batteries. As an "AC-Coupled" system, the AC output of Sunny Boy grid-tie inverter is connected to a critical-loads subpanel rather than the main panel. The subpanel is also connected to the AC output of one or more Sunny Island inverters. Under normal conditions, the power from the solar array and the Sunny Boy inverters passes through the subpanel and the Sunny Island's built-in transfer switch on its way to the grid, without loss of efficiency. Likewise, grid power can pass the other direction when needed. During a power outage, the Sunny Island isolates itself from the grid and provides AC power to the emergency subpanel, drawing energy from the battery bank. The grid-tie Sunny Boy inverter will shut down during a blackout, but will turn back on (after a 5-minute period) when AC power from the Sunny Island is present. AC power from the Sunny Boy inverter(s) can be used by the Sunny Island to charge the batteries. If the batteries are full, and the solar system is producing more power than the loads require, the Sunny Island will communicate with the Sunny Boy inverter to decrease its power output. If there are no loads and the batteries are full, the Sunny Boy inverter will automatically shut off to prevent battery over-charging.

Off-Grid Power - In off-grid systems, the Sunny Island works with Sunny Boy inverters exactly as it does with grid-tie systems during a grid outage. A generator can be connected to the Sunny Island's AC input to provide back-up and battery charging. The battery bank can also be charged using a solar array with a standard PWM or MPPT charge controller, or by other power sources like microhydro and wind turbines. Data Monitoring The Sunny Island utilizes removable SD cards to store performance data from the integrated data logger and to perform firmware upgrades. State-of-charge metering helps with battery management to ensure maximum battery life. The Sunny Island SMA AC Coupling 2695 Watt Kit works with the SMA Sunny WebBox and SensorBox monitoring accessories. The Sunny Island SI6048-US is Listed to UL 1741 for the U.S. and Canada and carries a 5-year warranty expandable up to 20 years.