APsystems Equipment Selection Guide

Build your solar PV system using the YC600Y or the QS1 (or both) microinverters.

We created this APsystems equipment selection guide to help you with the system design process. Some accessories are required, others are optional; some parts look similar, and we know it can get confusing. Through this article, we show you that navigating the APsystems manuals and the component list is easier than you think.

The Microinverters + The Accessories

We consider the microinverter to be the main component of an APsystem energy system. To safely and effectively operate the microinverters in the system, there are other parts that we call the accessories or components.

This guide covers single-phase 240VAC solar installations only. For such applications, APsystems offers two microinverter models: the original Dual YC600Y and the newer Quad QS1. Other components in the system are cables, caps, and the Energy Communication Unit (ECU).

Mixing and Matching

Good news, all the components are interchangeable between the QS1 and the YC600Y inverters. To be more specific, both inverter models use the same AC Bus trunk cable and communicate through the ECU-R gateway. In other words, what this means is that you can mix and match microinverters in the same system. All the components and microinverters are fully compatible with each other.

Required or Optional

The microinverter and the AC Bus trunk cable required and always paired. An AC Bus End Cap is required for every branch in the system.

What is a branch? We identify as a branch, a group of panels and microinverters connected in parallel with a single combined AC output of 240V and 20A max.

For multiple reasons, we highly recommend using an ECU-R in the system; however, it is optional. The system will operate without it.

The AC TCONN Cap is only needed when a connector in the AC Bus cable is left unused. Similarly, you require a pair of MC4 Caps when a PV input on the microinverter is not used. The AC Unlock Tool comes handy when you want to disconnect an inverter from the trunk cable.

In summary, we have:

Product	Part Name	Application
	YC600Y Dual Microinverter	Inverter for two solar panels, maximum combined output of 548W
	QS1 Quad Microinverter	Inverter for four  solar panels, maximum combined output of 1,200W
	YC3 AC Bus – 2m	Trunk cable for microinverters branch AC output. 2 meters between connectors. One connector per microinverter.
	YC3 AC Bus – 4m	Trunk cable for microinverters branch AC output. 4 meters between connectors. One connector per microinverter.
	ECU-R  Communication Unit	Communicates wirelessly with the microinverters in the system. Sends performance information to the online portal. Compatible with YC600Y and QS1 units.
	AC Bus Cable End Cap	Electrical termination for branch AC Bus cable. One cap per branch.
	AC Bus Cable YCONN Cap	Protects unused connectors on the Y3 AC Bus cable from dust and water. Optional, not needed if all connectors in the branch are plugged to a microinverter.
	MC4 Connector Caps	Protects unused MC4 connectors on the microinverter from dust and water. Optional, not needed if all connectors on the microinverter are plugged to a PV panel.
	AC Connector Unlock Tool	Used to disconnect the microinverter from the AC Bus trunk cable. Not required but handy to have.

Difference Between the QS1 and YC600Y Microinverters

Here is a reference table showing the main specs and difference of both microinverter models:

	YC600Y (240V)	QS1 (240V)
Number of MPPT channels	2	4
Maximum power per channel	300W	300W
Maximum continuous output power	548W	1200W
PV compatibility	60-cell and 72-cell panels	60-cell and 72-cell panels
Maximum input voltage	55V	60V
Maximum input current per channel	12A x 2	12A x 4
Recommended PV power	410W	440W
Communication	Wireless Zigbee	Wireless Zigbee
Recommended Communication Unit	ECU-R	ECU-R
Weight	5.7lbs	9.9lbs
Standard limited warranty	10 years	10 years
Rapid Shut Down compliant	Yes	Yes
Max number of inverters per branch	7	3
Max number of PV panels per branch	14	12
Branch breaker size	20A	20A

More Resources

APsystems offers a comprehensive library of technical documents, including datasheets, manuals, design guides, warranties, and more.

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