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Best ac coupled inverter

Top 10 “AC Coupled” energy storage models which can connect to an existing grid tied inverter 

The name “AC Coupled” is confusing to any layman. They are also called “Retrofit” or “Storage” only. Still confusing? These types of solar inverters cannot connect to solar panels.

If you want to know more what are AC coupled inverters read here in our blog

AC Coupled inverter models are popular in countries where the home owner requires only an intelligent energy storage system capable of self consumption ( solar only), time of day operation ( escape evening and morning peak tariffs) and peak shaving ( high household load invites penalty).

Here is a list of highly recommended AC Coupled (also known as AC Retrofit or Storage Tower) series, based on thousands of reviews, evaluation of Bill of Material and PathToGreenHomes expert opinion.  

Brand  Series What we like about this model …  Installer near you
SMA 1Φ (2-6)kW  Sunny Boy   Smart Heat Pump, Wireless connection, EV Charger.  Send Enquiry
SMA 1Φ (4-8)kW Sunny IslandSmart Heat Pump, Wireless connection, EV Charger.  Send Enquiry
Sonnen 1Φ (3-7)kW  eco Gen3   Smart Heat Pump, SunSpec Protocol, EV Charger, Smart Inverter.Send Enquiry
Tesla 3Φ/1Φ (5-8)kW  Powerwall   Smart Heat Pump, Wireless connection, EV Charger, Smart Inverter, Weather Data Integration, Revolutionary Compact Design. Send Enquiry
Enphase 1Φ 1kW  IQ Battery 3 Smart Heat Pump, Wireless connection, EV Charger, Smart Inverter. Send Enquiry
LG 3Φ (5-7)kW  RESU Prime   Wireless connection, EV Charger.Send Enquiry
SolarEdge 1Φ (4-5)kW  StorEdge  (AC Coupled Smart Heat Pump, Wireless connection, EV Charger, Weather Data Integration. Send Enquiry
E3/DC 3Φ (4-14)kW  Quattroporte Smart Heat Pump, EV Charger, System is compatible with future products.Send Enquiry
Sofar  1Φ 3kW  ME  Flexible configuration of lead acid or lithium battery, battery energy management system, Outdoor IP65 design. Send Enquiry
Generac 3Φ (4-9)kW PWRcell  SunSpec Protocol.Send Enquiry
Huawei3Φ (2-5)kW LUNA2000Smart Heat Pump.Send Enquiry
Growatt3Φ (4-10)kW SPA-TL3-BHEV Charger, Weather Data Integration. Send Enquiry
Alpha1Φ (3-5)kW SMILESmart Inverter. Send Enquiry

AC Coupled inverters cannot connect to solar panels directly but may work in parallel with an existing grid tied inverter. Usually they can work with a max of 1 grid tied inverter like below.

what is ac coupled inverter
AC Coupled inverters can synchronize with an existing Grid tied inverter.
AC Coupled inverters can work independently without any Grid tied inverter.

Recommending specific brands to customers for purchase, like Top 10 Brands of inverter manufacturers is over-simplistic. Each inverter manufacturer makes 5-10 series, widely varying, based on functionality and quality. Path To Green Homes, recommends specific “Series” and “Models” based on exhaustive research over 1000s of points.    

Micro Grid Function : Avoid fire.

Micro Grid function is the critical tango between battery storage (1pc) and an independently functioning grid inverter (1pc) to work together in a household, without catching a fire.

what is grid forming inverter
If they can’t communicate they will fall.

Energy storage battery is connected to the AC Coupled solar inverter for charging and discharging. An existing grid tied inverter ( connected to solar panels ) wants to keep on charging the battery even when battery charge ( SOC) is high. This can lead to a fire unless the grid tied inverter is asked to slow down.

energy storage batteries for the home
Don’t charge me too much or I will explode

The Grid tied and AC Coupled inverter are from different planets, have no common communication , so its easier said than done. By frequency modulation , micro grid function , this feature can be made safe. Not all inverters can achieve such safety but the above recommended AC Coupled / Retrofit / Storage only inverters have micro grid function.

High and Low Voltage battery of AC Coupled inverter

Storage only inverters come in both low voltage (48V) and high voltage systems (200-400V+) depending on battery configuration. A low voltage (48V)system is suitable when the backup needs to be 1-2 hours (<5kWhr battery capacity). The advantage of a high voltage battery system is low power loss and relative ease of adding more battery modules , in series.

Plan now : You may need additional battery later

When household load increases, like with the addition of an EV you may need to add more storage. Its possible to later add more low voltage battery modules (e.g. +2,54kwhr), by paralleling of battery. But the inverter , you choose today , must be capable of adding more batteries in parallel in the future without purchasing a 3rd party paralleling device . Such paralleling feature is supported by a very few models.

2.54kWhr battery unit eachSeries ( 3-8) —> use 6 nos15.24kWhrInstaller near you
2.54kWhr battery unit eachParallel ( 1-6) —> use 6 nos15.24kWhrSend Enquiry

A high voltage inverter system is preferred due to ease of future battery capacity additions.

Storage only inverter common Safety issue

Is highly recommended to have fuse at battery terminals (not just slow acting MCB) for higher safety. As per PathtoGreenHomes NOT many storage only manufacturers are providing this in built fuse so we suggest use an internal / external fuse.

Integrated battery and inverter

The battery can be supplied by the manufacturer along with storage only inverter, in a nice integrated tower (IP55 rated indoor unit). Alternately, the home owner can purchase the storage inverter and a 3rd party compatible Lithium Ion battery separately. If Battery is not compatible with inverter, it may lead to fire. The advantage of an integrated solution are higher especially when combined with a wireless solution to manage loads.

Note: Click on SUGGEST in PathToGreenhomes.com and apply FILTERS to get more recommended models. Use ☑ [Get Quote] to send your “Selected Models” to your nearest installer to receive a competitive quote !!  

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