[RE-wrenches] Midnite AIO First Impressions

[Jason Szumlanski]

Now that I have a single inverter installation and a triple inverter
installation under my belt, I'm ready to share my first impressions. Here
they are in no particular order. Both systems were in off-grid settings
with backup generators connected to the generator smart input. The single
inverter is paired with Pytes batteries in closed loop. The second has
Lithionics batteries using voltages only.

I hope this information and some of these tips are helpful to others.

The monitoring system is seriously underwhelming. I was shocked to find out
that you can only view each inverter in a system individually. You can't
see the total plant solar production or consumption. This makes data
gathering pretty useless with this inverter system for multi-inverter
installations. Even with single inverter installations, the data is not
very robust. And there is no download option (unless you want a picture of
a chart, which has very limited utility). On a good note, the programming
interface in the app is speedy and fairly intuitive. There is no way to
resend login information to the system owner. You can't have multiple
logins for people to view the system. The owner has to share their
credentials if multiple people want to view data. I know this is all in
development, but I feel much of this should have been in place before this
product was launched, especially the combined inverter data. "Use Solar
Assistant" is not an acceptable workaround for me. I don't need more
devices out there to manage. That is the whole appeal of an AIO.

I have had issues with connecting all four inverters installed to date to
WiFi. They will not work with networks with no password (which Starlink can
often be in remote settings). They only play with 2.4 GHz. On my Samsung
Galaxy Fold 5, you can't see some information on the connections screen
when the phone is open, and you cannot see other information when the
screen is closed. I had issues with this device, but also tried with a new
iPhone, and it still didn't work. Setting up WiFi immediately after a
Factory Reset seemed to work, so maybe that is a best practice.

The inverters do strange things at times when "reconnecting" after an
off/on cycle, even in an off-grid scenario. Sometimes when you switch a
paralleled inverter on, it will start counting down from 900, although it
will turn on when the others turn on.

Some settings are unclear and not well-documented, if at all. For example,
with parallel inverters, you can set a maximum generator input power, which
is then propagated to all inverters. But when I set the maximum charge from
the generator, it did not seem to propagate that setting, so I changed it
manually on each inverter. Maybe this is by design, since you might want to
limit charging from the generator on an inverter that has heavy smart
loads. I'm just speculating here. I'm still not clear on whether these
settings are system-level or per inverter. I have not had enough time to
play with the settings and test it out.

I had to factory reset inverters in a triple inverter setup when they
simply would not turn on, even when taking them out of parallel mode. This
might have been due to out of date firmware, which seemed to resolve this
issue.

The firmware update process performed remotely from Midnite was pretty
quick and painless. It factory reset the inverters, but reprogramming goes
pretty quickly once you get accustomed to the interface.

For some strange reason, in the single inverter system, the smart load
output did not energize immediately as expected. It came on suddenly after
at least 30 minutes with no explanation why.

The app persistently throws an error message that says Generator Abnormal
when the generator is off in a off-grid system, even if the generator is
supposed to be off.

The app has no options for alerts of any kind (push/text/email).

There is a real lack of battery integration information out there. Midnite
doesn't seem compelled to put out integration guides or offer up much
support in this area, understandably because they would want to promote
their own batteries. To be fair, Sol-Ark only provides information for
battery manufacturers that have partnered with them to establish reliable
closed loop comms. When the AIO inverter(s) do "talk" to the battery, there
is no obvious indication that closed loop communications have been
established. There is no information screen or tab that displays battery
information received through the communication bus.

The AC wiring is easy and obvious. I really like the simplicity. However,
do the AC connections AFTER the AC connections if you want to keep swearing
to a minimum. For the individual PV strings, it is hard to read the +/-
inputs, and they are hard to see in an awkward location in the enclosure.
The order of the battery connections from left to right is +/-. However,
the individual PV string inputs are ordered -/+. The combination of these
issues makes the PV connections difficult and borderline dangerous.
Fortunately, there are test probe holes for each input. Sadly, they are so
close together that it is not easy to ensure you have the right one, and it
is difficult to get larger probes into them side by side. The parallel
communication wiring terminals should be illegal. They are ridiculously
hard to get wires into. The terminal block should be removable at a minimum.

The plastic bushings supplied are too large for my 2" punch kit. The
bushings fit through the AIO openings, but not the wiring trough knockouts
I made. I had to use chase nipples instead. The 1-1/4" bushings worked fine
with my knockouts.

The battery torroids are too small. I had to wrestle with getting two 4/0
cables through the torroid with MagnaLugs, which are a bit thicker than
other brands. If you have the option to install lugs after pushing the
cables through the torroid, do that.

Pro Tip: Install the WiFi dongles before you set your inverters on a wiring
trough, especially if you don't have a stubby Phillips screwdriver handy.
You will thank me later.

Bonus Tip: Don't try to bring the battery cables into the enclosure through
any knockout other than the leftmost pre-knocked-out opening.



Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208
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