Okay, let's break down the problem and explore some replacement options for your AE 3TL-16 inverters, keeping in mind your desire to avoid re-stringing and maintain a compatible voltage range.

Understanding the Constraints and Requirements



Current Inverter

AE 3TL-16 with 10 string inputs and 500VDC input voltage. This suggests each string contributes around 50VDC nominal.

Desired Outcome

Replace the inverters without re-stringing the existing panels.

Solis Inverter Limitation

Recommended Solis inverter has only 6 string inputs and a 1000VDC input voltage. This means, at a minimum, the strings would need to be combined and, even if that happened, the voltage would be too high.

String Configuration Preservation

You want to maintain as much of the existing string configuration as possible to avoid labor costs and potential performance impacts.

Key Considerations for Replacement Inverters


Input Voltage Range

This is paramount. You need an inverter that can operate effectively with an input voltage near your existing system's 500VDC. Look for inverters with a wide MPPT voltage range that encompasses this. A range like 200-800VDC or 250-750VDC would be ideal.2.

Number of String Inputs

Aim for at least 5-6 inputs (if you can get close by combing strings), but ideally 10 inputs to avoid any re-stringing.3.

Power Rating

The replacement inverters should have a similar power rating to the AE 3TL-16 (16kW) to maintain the system's overall capacity.4.

MPPT Trackers

Consider the number of MPPT trackers. If the 10 strings are connected to two or more MPPT trackers in your existing AE inverters, you would ideally match this with the replacement inverters. This helps optimize power harvest from different parts of the array if they have different shading conditions or orientations.5.

Cost

Inverter prices vary significantly. Balance performance, features, and your budget.6.

Reliability and Warranty

Choose reputable brands with good warranties.7.

Monitoring and Communication

Ensure the replacement inverters have compatible monitoring systems (e.g., Modbus, Wi-Fi) for data logging and performance tracking.

Possible Replacement Strategies and Inverter Options

Given the constraints, here's a breakdown of strategies and potential inverter options (note: availability and specific models change rapidly, so verify current models with distributors):

Strategy 1: Find Inverters with More String Inputs and Matching Voltage Ranges This is the most direct and least disruptive approach. It minimizes the need for re-wiring. Brands to Investigate (and their common attributes)



SMA

SMA Sunny Tripower CORE1 is a possibility. It may have voltage and string capacity that lines up better than the Solis.

Fronius

Fronius inverters are known for quality and flexibility. The Fronius Eco or Fronius Symo series might have models that align.

Sungrow

Sungrow inverters are becoming increasingly popular due to their reliability and competitive pricing. They often offer models with multiple MPPTs and string inputs.

Huawei

Huawei inverters (while facing some market access challenges in certain regions) are also a strong contender and typically have multiple MPPTs and string inputs.

Delta

Delta is a well-established industrial power solutions company that offers PV inverters for commercial and industrial use.

Action

Go to the manufacturer's websites or contact distributors and use their inverter selection tools. Input your 16kW power requirement and voltage/current characteristics of your existing strings to filter for suitable models. Pay very close attention to the DC input specifications.

Strategy 2: Combining Strings (with Careful Voltage Calculations) This requires meticulous planning and safety checks. It involves connecting two or more strings in parallel to reduce the number of inputs needed. Important Considerations



Short-Circuit Current

Combining strings increases the short-circuit current. Make sure the replacement inverter and all wiring are rated to handle the increased current. Use appropriately sized fuses.

Voltage Drop

Parallel strings can have slightly different voltages, especially if they have different panel types or shading. This can lead to circulating currents and reduced efficiency. Ensure the voltage drop is minimized. It's usually best to combine strings that are geographically close and experience similar shading.

Fuse Protection

Each combined string pair must have its own fuse. This protects against reverse current flow if one string has a problem.

Strategy 3: Using Multiple Smaller Inverters Instead of replacing each AE 3TL-16 with a single 16kW inverter, you could replace each with two 8kW inverters (or a similar combination). Pros

This might provide more flexibility in terms of string input options and voltage ranges. It also adds redundancy (if one inverter fails, the others continue to operate).

Cons

Higher initial cost (more inverters). More complex installation. More points of potential failure.

Steps to Take


Panel Specifications

Gather the exact model number and specifications of your solar panels (especially Voc, Vmp, Isc, and Imp). This information is crucial for determining string voltages and currents.2.

String Voltage Calculations

Calculate the maximum voltage (Voc at the lowest expected temperature) for your strings. This is critical to ensure you don't exceed the inverter's maximum DC input voltage.3.

Contact Distributors

Reach out to multiple solar equipment distributors (e.g., CED Greentech, BayWa r.e., SunPower, etc.). Explain your situation and provide the panel specifications and string configuration. They can help you identify compatible inverters and provide pricing.4.

Review Datasheets Carefully

Thoroughly review the datasheets of any potential inverters. Pay close attention to the DC input voltage range, maximum DC input current, number of string inputs, and MPPT specifications.5.

Consult with a Qualified Electrician/Installer

Before making any decisions, consult with a qualified electrician or solar installer experienced in commercial PV systems. They can assess your site, perform necessary calculations, and ensure the replacement inverters are installed safely and correctly.

Example Calculation (Illustrative)

Let's say your panels have a Voc of 45V and you have 11 panels per string: String Voc = 11 panels 45V/panel = 495VIn this case, you would need to look for inverters that can handle at least 495V and ideally have a safety margin.

Important Safety Note: Working with electrical systems can be dangerous. Always disconnect power before working on any electrical equipment. If you are not qualified to work on electrical systems, hire a licensed electrician.By following these steps, you should be able to find suitable replacement inverters for your AE 3TL-16 units without having to re-string your entire solar array. Good luck! Flag for review