How to measure production by simple microinverters

[BanjoMan765]

Hi folks. I'm building a low-cost, dead simple grid tied system on the roof of a workshop using some discount solar panels and inexpensive 4-channel, 240V microinverters. I'm planning to connect three 1400W microinverters in parallel to have a maximum of 4200 Watts on a single 240V breaker. And I will have three such arrays. I'm still waiting for the microinverters to be delivered, but I'm pretty sure they don't have a built-in means of monitoring power production (no wifi or bluetooth). So you can only monitor production by tapping into the output line.

I don't need to closely monitor production, but I would like to be able to check that everything is working from time to time. I've seen folks using Kill A Watt meters to check microinverters, but those sorts of meters max out well below 4200 watts. I'm going to have all of the microinverters on the roof underneath the solar panels so I will only have easy access to the line running to the breaker box (I can't check the inverters individually unless I pull up panels).

So I'm looking for a cheap way to check on power production from a set of microinverters. I found this clamp style multimeter on Amazon, which has plenty of range. I'm thinking that with several coils and some kind of channel switch I could install one meter to monitor all of the arrays one at a time. But I hesitate, because I don't see any examples of folks doing this. Has anyone done this sort of thing? Do you all think it will work? I realize that I can only measure one wire (half of the 240V circuit) and that I should expect something like 10% error from this method. But those things are acceptable. I just want to know that the system is working as expected.

 

[sunshine_eggo]

You linked the microinverter, but a clamp style ammeter will allow you to measure current out of each microinverter.

 

[BanjoMan765]

The microinverters will be connected in parallel on the roof, so I can't check them individually unless I go up on the roof and lift up the panels. The ammeter I'm looking at is meant for permanent installation--the loop is solid and is fixed on a wire once installed. Just wondering if anyone has thought about this sort of setup. Thanks for replying.

 

[svetz]

The link you gave says they have it built in:

 

[BanjoMan765]

Yes, that would be great, but somewhere else I read that bluetooth and Wifi are options that are not installed on the base models. I also found a little cartoon of a set up with a monitoring device (watt meter) of some sort attached, which suggests there's no wireless monitoring. Hope I'm wrong though.

 

[zanydroid]

Old thread but did you consider IotaWatt or Emporia Vue. I use a Vue. It can measure up to 50A on branch circuit. And if you need more you can hook up the service/feeder CTs to measure 200A

IotaWatt is more flexible but harder to install. I have one too.

Clamp ammeter, I also have. I use it for real time debugging on one circuit. These energy monitors are much much much better for gathering data over time. Since they do it automatically. And the clamp meter…. Doesn’t