AERL Link

Document

This guide is for installers and service technicians who set up and service AERL products with AERL Link. It covers installing AERL Link, connecting a unit, every page and setting AERL Link shows for each product, calibration, firmware updates, settings files, the support bundle and troubleshooting.

What each setting should be for a particular site comes from the product's user manual and the battery manufacturer. Read the product manual before you change a unit's settings: this guide explains what AERL Link does, the product manual explains what the product does.

AERL Link is updated from time to time. Use the latest AERL Link: the pages in this guide are from the current release, and an older release can look different. The screenshots show AERL Link's demo units, so the readings in them are examples only.

Windows is a trademark of Microsoft Corporation. Other names are trademarks of their respective owners.

1.1What AERL Link Does

AERL Link is AERL's configuration software for Windows. It connects to an AERL unit over USB and lets you:

• see the unit's live readings and status, with an explanation of any warning or fault code;
• set a CoolMax charge controller's battery charge profile and communication settings;
• set an EarthGuard's trip sensitivity and earth type;
• calibrate a CoolMax charge controller's battery voltage reading against a multimeter;
• update a unit's firmware, on site and without an internet connection once the firmware has been downloaded;
• save and load settings files, and step back through a unit's earlier settings;
• save a support bundle for AERL support.

1.2Supported Products

1.3What You Need

• A PC running Windows 10 or 11, with a free USB port.
• A USB data cable: USB-A to USB-B for a CoolMax SRX or SRX-R, USB-A to USB-C for an EarthGuard. Some USB cables carry power only and no data: AERL Link cannot see a unit through one of those.
• An internet connection when you install AERL Link and before you go to site, so that AERL Link can download the latest firmware and battery presets. On site, AERL Link works without one.
• A digital multimeter, for calibration and for any update that asks for calibration.
• The product's user manual.

2.1Download and Install

1. Go to aerl.com.au/professionals and open the AERL Link download page.
2. Click Install for the current release. Windows downloads and installs AERL Link, and adds it to the Start menu.
3. If the Install link does not start, download and run setup.exe from the same page instead. It installs the same release and also installs Microsoft .NET Framework 4.7.2 if the PC does not already have it.
4. Start AERL Link from the Start menu.

2.2Updates to AERL Link

Each time AERL Link starts, it checks for a newer release. When there is one, it shows the new version and asks Would you like to update now? Accept it: a newer release can be needed to update a unit to its newest firmware, and it carries AERL's latest battery presets and help.

The version you have is shown at the top of AERL Link's SETTINGS page.

Note

AERL Link releases published before mid-2026 check an earlier update address and never offer the current release. If AERL Link has not offered an update for a long time, install the current release from the download page.

2.3USB Driver

Windows normally installs the USB driver the first time a unit is plugged in. If AERL Link does not detect your unit, download and run Install Drivers.exe from the AERL Link download page, then unplug the USB cable and plug it in again. The same driver works with every AERL Link release.

3.1Connect the USB Cable

AERL Link finds a unit by itself within a few seconds of the USB cable going in. There is no COM port to choose.

CoolMax SRX. The USB-B port is inside the access cover, on the internal board. Remove the access cover as the SRX user manual describes, and plug in the USB cable.

CoolMax SRX-R. The USB-B port is on the backplane board, beside the USB Change-Over Switch. Only one module talks over USB at a time: set the switch to the module you want to connect to (MPPT 1 or MPPT 2). To connect to the other module, change the switch over; AERL Link then lists the other module.

EarthGuard EG-600 and EG-600-SC. The USB-C port is on the bottom edge. The EarthGuard can be powered from the USB-C port alone (4.5–5.5 Vdc), so you can set one up on the bench before you install it.

3.2Power the Unit Up

A CoolMax SRX or SRX-R must be powered up to talk to AERL Link: follow the start-up procedure in its user manual. For a firmware update or a calibration, the battery must be connected.

3.3More Than One Unit

AERL Link can have several units connected at once, each on its own USB cable. Each appears as its own card on the DEVICES page. Settings, calibration and firmware updates apply only to the unit whose page is open.

4.1Menu

The menu on the left of the window opens AERL Link's pages.

4.2Devices Page

Each connected unit has a card that shows its name, model, serial number and firmware version. The card's colour follows the unit's status (section 5.2). Click a card to open the unit's page.

If no unit is connected, the page shows NO DEVICES FOUND and a TROUBLESHOOTING button, which lists the usual causes (chapter 13).

4.3A Unit's Page

A unit's page opens on its STATUS tab. The unit's serial number is at the top; the arrow beside it goes back to the DEVICES page. The tabs depend on the product:

Changes on a settings tab wait on the page, flagged in orange, until you press Apply. Before it sends anything, AERL Link lists every change as before → after and asks you to confirm. The unit then restarts to take the new settings, and AERL Link reads them back to check that they were saved.

Demo units

A demo unit's page shows DEMO and its firmware reads Demo. If you see these, you are not looking at your own unit: click DEVICES and open your unit's card.

5.1Live Readings

The STATUS tab shows what the unit is doing now. It only reads: nothing on it changes the unit.

• Power (Watts): the charge power into the battery.
• Solar: the PV input voltage and current.
• Battery: the battery voltage and current at the unit's battery terminals, and the battery temperature when the unit has one (from a battery's BMS over CAN or an AERL Battery Sense).
• Device: the status indicator and the firmware version, and the unit's temperatures.

5.2Status Indicator

The status line gives the unit's state in plain words, with its code in brackets, for example Charging [0]. Its colour matches the unit's LED:

Where AERL Link can say more about a code, a ? appears beside the status. Click it for what the code means, whether the unit will recover by itself and what to change. The full list of codes, with the LED patterns, is in the Troubleshooting chapter of the SRX and SRX-R user manuals.

5.3Common Status Codes

6.1The OUTPUT Tab

The OUTPUT tab holds the battery charge profile and the unit's protection settings. Each value opens an entry box: change it with − and + or type it, then OK. Nothing reaches the unit until you press Apply.

Set the battery preset or the battery voltage first: it sets the range every other voltage must sit in. AERL Link checks that the values fit together and suit the battery voltage before it sends them, and will not send a profile it cannot check.

6.2Battery Presets

Battery Presets lists AERL's profiles for common batteries. Choosing one fills in the charge voltages, the absorption time and the temperature compensation with AERL's recommended values. Custom Charge Profile keeps the values you set. AERL Link refreshes the presets from AERL each time it starts with an internet connection.

Presets are a starting point

Check every value a preset fills in against the battery manufacturer's charge specification before you apply it, and set Max Charge Current yourself: no more than the battery manufacturer's recommended charge rate, and no more than the battery cables and fuse are rated for.

6.3Charge Profile and Charge Stages

The SRX and SRX-R user manuals (Battery Charge Profile chapter) show how the stages fit together.

6.4Equalisation

Equalization Enabled, Equalization Voltage, Equalization Duration and Equalization Interval (days between equalisation charges) control a periodic over-charge for flooded lead-acid batteries.

Equalisation

Leave equalisation off unless the battery is flooded lead-acid and its manufacturer asks for it. Equalisation will likely damage LiFePO₄ and other lithium batteries.

6.5Ground Fault Detection

Ground Fault Mode must match how the system is earthed: Floating Earth where nothing on the DC side is earthed, Positive Earth or Negative Earth where that PV pole is bonded to earth, Disabled only for commissioning and test. The wrong mode hides a real earth fault or reports a false one on the earthed pole. The SRX and SRX-R user manuals (Ground Fault Detection) describe each mode.

On firmware 2.0.1 and later the controller trips at a fixed 50 kΩ whatever the sensitivity buttons show. Units on earlier firmware had a Low / Mid / High sensitivity: update them to get the fixed 50 kΩ trip. Check that 50 kΩ meets your local standard.

6.6Temperature Compensation and Cutoff

Temperature Compensation lowers the absorption and float voltages as the battery warms, and raises them as it cools, by the amount set in mV/°C. The factory default is 50 mV/°C; lithium batteries usually need little or none.

Low Temperature Cutoff Enabled stops charging while the battery is below the Low Temperature Cutoff Point, which many lithium batteries need. It is off by default.

Both need a battery temperature

Temperature compensation and the low-temperature cutoff work only when the unit has a battery temperature: from a battery's BMS over CAN (for example an AERL LiFe²), or from an AERL Battery Sense. Without one, the unit charges to the uncompensated voltages, and with the cutoff on it reads the battery as 0 °C and holds charging (status −1103).

AERL Link shows temperatures in °C or °F, set on its SETTINGS page.

6.7Blackstart Guard and Output Enabled

Blackstart Guard lets the unit start charging a battery bank whose voltage is below the unit's normal "no battery" threshold, such as a known-good lithium bank that has run flat. It is off by default. AERL Link asks you to confirm before it turns Blackstart Guard on, including when a settings file turns it on.

Turn Blackstart Guard off again

Use Blackstart Guard only to recover a known-good bank, and turn it off once the bank has recovered. Left on, the unit no longer refuses to run into a disconnected or faulty battery.

Output Enabled turns charging on or off. Leave it on for a working system; turn it off to hold the output off for maintenance.

6.8Apply the Profile

1. Press Apply. AERL Link lists every change as before → after.
2. Check the list and confirm. AERL Link sends the profile and the unit restarts to take it.
3. After the restart, check on the STATUS tab that the unit shows the state you expect (charging, or waiting for sun) with no fault code, and that the battery voltage reads correctly.

If AERL Link reports that the unit did not confirm the settings, they may not have been saved: check the USB cable, wait for the unit to reappear, and apply them again.

7.1Communication Settings

The COMMS tab sets the unit's addresses and bus speeds for Modbus RTU (RS485) and CAN bus, as far as the unit's firmware allows (section 7.3). The SRX and SRX-R user manuals (Communications Protocols) describe the buses and their wiring.

Press Apply to send them. The unit restarts briefly.

Update the master to match

A changed address or bus speed cuts the unit off from any master still using the old one. Change the master to match before you leave the site.

7.2CAN Role

CAN ROLE sets how the unit takes part on the CAN bus. It is locked. Change it only with AERL support, who will give you the password for your site; it then opens with Unlock. The CAN role appears only on units that can use it.

7.3Settings the Firmware Can Store

The COMMS tab shows only the settings the unit's firmware can store. On the current SRX and SRX-R firmware releases it shows the RS485 ID (and the CAN role) only: the RS485 speed, CAN ID and CAN speed keep their values, and a unit on a shared CAN bus takes a free CAN ID by itself. Contact AERL support if a site needs other bus settings.

8.1When to Calibrate

Every unit is calibrated at the factory. Calibration corrects the unit's battery voltage reading against your multimeter, so that the charge voltages are held where they are set. Calibrate when:

• AERL Link asks for it after a firmware update that needs it;
• AERL Link's Battery Voltage Calibration Check finds the reading does not match your meter (below);
• the battery voltage AERL Link shows differs from your multimeter by more than 0.1 V.

When a unit with solar input is first opened, AERL Link may show the battery voltage the unit reads and ask whether it is within 0.1 V of the measured battery voltage. Measure the battery voltage at the unit's battery terminals and answer. No starts the calibration.

8.2Before You Start

• A digital multimeter with 0.1 V resolution or better.
• The battery connected, at a voltage in its normal range, and the battery breaker closed. AERL Link refuses to calibrate below 15 V on the output, or when the unit reports No Battery Detected.
• A steady battery voltage: switch off or isolate other chargers, inverters and large loads on the same battery for the few minutes calibration takes.
• The USB cable and power left connected until calibration finishes.

8.3Procedure

1. Open the unit's page and click CALIBRATE.
2. AERL Link checks that a battery is connected and asks Are you sure you want to start the calibration procedure? Click Yes.
3. AERL Link switches the unit's output off and waits for the voltage to settle (a few seconds). With the output off, the voltage at the terminals is the battery's own.
4. Measure the voltage at the unit's battery (output) terminals with the multimeter. Enter the reading in the Output Voltage box and click OK.
5. AERL Link writes the new calibration, restarts the unit and checks the result. It then switches the output back on, and shows Calibration complete.

Do not interrupt calibration

Do not unplug the USB cable or switch off power during calibration. If calibration is stopped part-way, AERL Link gives the unit back the calibration it had before and switches its output back on.

8.4What AERL Link Checks

8.5When Calibration Is Refused

If a unit's reading still disagrees with a known-good multimeter after a successful calibration, save a support bundle (chapter 11) and contact AERL support.

9.1Status

The EarthGuard's STATUS tab shows the insulation of each test circuit: the EG-600 has two, the EG-600-SC one.

• Insulation: a bar for each pole (+ and −) of each circuit. A full bar is good insulation; the bar shortens and turns orange, then red, as the insulation resistance falls.
• Test Circuit: the circuit's Voltage, and its Earth Resistance + and Earth Resistance − in MΩ. During a fault, the faulted pole is named and its insulation is shown in kΩ.
• Device: the Status and the Firmware version.

On some earlier EG-600 hardware, AERL Link marks the circuit voltage * Voltage readings can be subject to error. Use a multimeter where you need the circuit voltage.

9.2Settings

The SETTINGS tab has two settings. Press Apply to send them; the EarthGuard restarts to take them (about 15 seconds).

Earth type

Positive and Negative stop the EarthGuard monitoring the bonded pole. Use them only where that pole is deliberately and permanently bonded to earth; otherwise leave Floating. The EG-600 and EG-600-SC user manuals describe each mode and how to test the alarm.

The EarthGuard has no Comms or Calibrate tab. Update its firmware as in chapter 10.

10.1How AERL Link Offers Updates

AERL Link keeps a list of AERL's released firmware, and the firmware files themselves, on the PC. When you open a unit's page, AERL Link compares the unit's firmware with the list and, if a newer release is available for that unit, offers it:

• Firmware update available. Click Update to install it now, or Cancel to carry on without it. AERL Link offers it again the next time you open the unit.
• Important firmware update available. An important (critical) update. AERL Link installs it straight away, with the message An important firmware update is being installed.

The offer names the unit and shows the release notes. If the update needs a calibration afterwards, the offer says so: go ahead only with a digital multimeter on hand.

10.2Before You Update

• Use the latest AERL Link, and start it with an internet connection before you go to site so that its firmware list is current. The REPO page shows when it last checked.
• Connect the battery and power the unit up.
• Use a PC on mains power or with a charged battery, and stop it from sleeping during the update.
• Do not unplug the USB cable, switch off power or open the PV or battery isolators during the update. On an SRX-R, do not change the USB Change-Over Switch during the update.

10.3During and After the Update

1. Click Update. The unit's page shows Updating Firmware: with the progress. The transfer usually takes 1–2 minutes.
2. While it runs, the unit stops charging and its LED flashes orange.
3. When the transfer finishes, the unit restarts on the new firmware. AERL Link reconnects and shows the new version on the STATUS tab.
4. If the update needs a calibration, AERL Link starts it: follow chapter 8.
5. Check the unit's settings and status. An update keeps the unit's settings.

10.4If an Update Fails

• The firmware update was not started. Something else was running on the unit (a save, a calibration). Open the unit again when it has finished to be offered the update again.
• The update stopped part-way (cable unplugged, power lost). The unit keeps running its previous firmware. Power-cycle the unit, reconnect, and AERL Link offers the update again.
• The firmware update was not installed. The firmware was sent, but the unit restarted on its previous version. Try the update again; if it happens again, contact AERL support.
• The device has not reported back after the firmware update. The update itself completed. Power-cycle the unit and reconnect. If it does not reappear, contact AERL support.

10.5The REPO Page

REPO lists the firmware AERL Link has downloaded: one row per release, with the product, version, date and priority. AERL Link refreshes the list when it starts and every hour while it has an internet connection; Refresh checks now. Because the files are kept on the PC, AERL Link can update units on site with no internet connection.

10.6Beta Firmware and the Firmware Lock

Both are on AERL Link's SETTINGS page and need a password from AERL support.

• Beta Firmware: off, AERL Link offers only Stable firmware. On, it also offers Beta releases: firmware that has passed AERL's release testing but has had less than six months of use in the field. Turning it off later does not return a unit to stable firmware: the unit keeps its version until a newer stable release is available.
• Lock Firmware: holds each product at a highest firmware version, for example on a site that must stay on the version it was tested with. AERL Link then offers nothing above it.

AERL Link never downgrades a unit's firmware.

The AERL Firmware Update Guide covers every AERL product, including updates through AERL Cloud.

11.1Export and Import

On the OUTPUT tab, Export saves the unit's charge profile to a settings file, and Import loads one, for example to set several units on a site the same way.

• An imported file fills in the page; nothing reaches the unit until you press Apply.
• AERL Link checks the file before it uses it, and checks that the file's battery voltage matches the battery connected. It warns you before it applies a file for a different battery voltage, or one it cannot check because no battery is connected.
• If the file turns Blackstart Guard on, AERL Link asks you to confirm.

11.2Undo and Earlier Settings

AERL Link records each unit's settings every time they change, on the PC. Undo and Redo on the settings tabs step back and forward through them: each step fills in the page with the earlier settings as pending changes, flagged in orange. Nothing reaches the unit until you press Apply.

11.3Support Bundle

If AERL support asks for one, a support bundle gives them what they need to look into a problem. Save it from the HELP page, or from the unit's own page.

1. Click Support bundle.
2. AERL Link reads each connected unit's event log. This takes 2–5 minutes per unit; Cancel stops it and saves the bundle without the event log.
3. AERL Link saves a zip file named AERL-support-<serial>-<date>-<time>.zip in Documents\AERL Link support, and lists what it contains. Open folder shows it.
4. Email the file to [email protected], with the site name and a description of the problem.

AERL Link sends nothing by itself: the bundle stays on the PC until you email it.

12.1Help

The HELP page has:

• the SRX User Manual for the connected SRX or SRX-R, with its chapters and a search. The orange ? beside a setting anywhere in AERL Link opens the manual at the section about it;
• the two help tours (below);
• Support bundle (chapter 11);
• AERL's address, phone and email.

12.2Help Tours

AERL Link has two short tours. Both run on a demo SRX, so nothing in them reaches a real unit. AERL Link offers them once, the first time it starts; start them again from HELP at any time.

• Tour of AERL Link: where everything is in AERL Link.
• What to set on an SRX: the battery and comms settings in the order to set them. Then set the same on your own SRX's page.

Press Next to move on, or End the tour to stop.

12.3AERL Link Settings

The page also shows the AERL Link version.

13.1Unit Not Found

13.2Readings, Settings and Firmware

13.3Contact AERL Support

Before you call, note the product, its serial number and firmware version (on its card), the status code, and what you were doing. Save a support bundle (chapter 11) if AERL support asks for one.

AERL support: 1800 950 865 · [email protected] · aerl.com.au

13.4Change Log