MorningStar TriStar 60 MPPT Solar Charge Controller Review

Price: £620 inc VAT (+ £135 inc VAT for the remote meter) in March 2021, similar price in 2024

Having tried several solar charge controllers in the past, and been underwhelmed by their logging capabilities and openess, a completely different make and model was chosen to control the solar system that will be used to power some of Go Green IT's infrastructure in their datacentre.

MorningStar have been in the running for previous Solar Charge Controller purchases, but in the end were not chosen.

This time, the MorningStar TriStar 60 MPPT Solar Charge Controller was chosen for the following reasons:

• Ethernet connection with web gui so no poorly written or OS-specific apps would be required
• Industry standard protocols used - RS-232, RS-485/MODBUS, and SNMP
• Passive cooling, so no moving parts that could wear out
• MorningStar reputation
• Good documentation written in proper English

Build quality seems good, and unlike other cheaper charge controllers, all the cable termination is hidden behind the meter/display section (see product picture). Cable entry and exit points are available behind push-out sections of the white case on the left, right and bottom, and the smaller ones take standard M20 grommets.

The controller was connected to 8x275W TrinaSolar panels in a 2p4s configuration to give ~70V input. More will be added as time allows.

The web GUI is basic, but functional, and needs a javascript-enabled browser (likely due to the real time statistics that are displayed). It displays current values, networking information, and historical data for 90-120 days. Unfortunately, this interface was buggy, and several times over the first few days of installation, the interface crashed and most of the web page sections were blank.

Disappointingly, on the first one I bought in 2021, firmware was "v18", even though "v32" has been available since November 2018. It was decided that the firmware should be upgraded to try and fix the problem of the buggy web GUI. Unfortunately this is only possible via RS-232, and although the manual doesn't tell you, can only happen when the device is booting. Since the upgrade, the web GUI has been perfectly stable.

The last one I bought (in 2024) did not need upgrading.

There is a reset button on the device, which can be pressed using a thin pencil or similar, but this doesn't seem to do a lot, and certainly didn't fix the problem of the buggy web GUI. The only way to properly reboot the device is to disconnect it from the battery.

Pros:

• Display / meter can be attached locally (as in picture to the right), or connected via a 30m cable
• A second display can be daisy-chained off the first
• Supports standard protocols for configuration and statistics
• Good documentation, good official YouTube videos, including an introduction to MPPT and their version of MPPT here
• Notifications can be sent via email (not tested)
• Statistics can be logged to CSV files via the MSView software which communicates via MODBUS/TCP. (Wireshark has a good MODBUS decoder so can see what registers are being requested by MSView, and what raw values are being returned)
• Most values can be tweaked using the MSView software, including LED states and warning levels (Windows only, wine not tested yet)
• Someone has written a python module which outputs most of the current values to JSON. We use this to log statistics to a database, which is then displayed in a Grafana dashboard
• Hardware DIP switch to disable changes via the Web GUI (although this is the only security offered)
• Support seems OK. We contacted Morningstar to say that one of the modbus values was not documented, and they said they would update the documentation to reflect this

Cons:

• Antiquated process for updating the firmware
• Unit cannot be powered from solar directly, a battery must be connected. Also if the battery is totally dead, an external source would need to charge the battery a little so that the device will boot and start charging from the panels
• SNMP support actually only means SNMP Traps. No polling is supported unless you buy a Morningstar Ethernet Adapter (EMC-1) at the cost of ~£150 extra
• MIB could not be checked for completeness before purchase, as it is only available from the device web GUI, and file only contains the following: device serial number, hardware version, firmware versions, and TrapReceiver address, so no power stats can be read.
• Pushing the reset button quickly, which should reboot the device, does nothing (long press to start equalisation process was not tested)
• Doesn't have a built in RTC, so it calculates the day history by resetting the counts after "Night" mode is exited (probably decided by panel voltage changes)
• Quite a large device due to the massive heatsink, which may mean it is not practical for mobile situations

Conclusion:

This is definitely the best charge controller I have tried in terms of functionality and reliability.

Since writing the review we have made a couple of updates to it as we have tried more functions

We have bought a second and third device for a separate solar installation on site.

The last device we bought (June 2024) has a slightly different board layout, and the Modbus connection is now via a removable terminal block

So we don't need to buy extra remote displays, we have also bought a MeterHub to link at least two of them together, although this has not been installed yet.