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Thanks to a combination of my cluelessness and the virtual blizzard of buzzwords that SMA throws at anyone trying to decipher their technology, I'm very unclear on what kind of performance monitoring I can expect from my system. I'lll be using the SB 3.8-1SP-US-41 unit; I am not planning to install any of the Tigo TS4 optimizers, at least initially. The inverter installation manual has a lot of stuff about connecting it to your network, but little about what you can actually do once connected. Is there any hope of simply monitoring my instantaneous and cumulative solar power production, without installing TS4's on every panel ? If so, which of the various SMA/Tigo accessories do I need to purchase ? Would I be better off simply adding a meter to the inverter's AC output ?
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You can monitor instantaneous power as well as energy production on SMAs sunny portal. It works great. Locally you can also log into your inverter via WAN and see each MPPT channel voltage and current as well as grid voltage and frequency.
.... I don't see any real benefit or need to add another meter. -
You have the -41; I have a 7.7 -40 so I am not entirely sure all the screens are the same, but I will give you some info for reference. I have my system set up with a hard wired ethernet connection and set the IP address to a known value at my router.
When you type in your IP address in your browser, a default home screen comes up whether or not you are logged onto your inverter. This shows a rolling 24 hr snap shot. Not much good for anything except determining that your inverter is on line and producing power.
Since you are doing DIY, you can log into the inverter as the installer to get the installer screen. I'm sure you know what this looks like since you will be commissioning your own system. The screen shot can be seen on youtube if you search for "Commissioning an Inverter via the Intuitive Webserver". You can see instantaneous values by string, daily output, monthly output, etc. One thing to note is that the inverter only saves so much daily output data. If you want to look at the daily output snapshot of October 1, 2019, you are out of luck. You can get the value for the day, but not the output every 5 minutes. If you set up Sunny Portal, all the data is pushed to the portal.
You can use Sunny Portal to look at daily output graphs from the date of inverter commissioning. That is one benefit of Sunny Portal. If you ever need service, SMA will want to have data that would be pushed to Sunny Portal. This includes error logs, etc.
Two other side comments: 1) I would put an AC shutoff near your ground mount array for easy troubleshooting since the SMA inverter doesn't have a built in AC shut off like alot of other inverters.
2) If you aren't going to use the inverter wifi, turn the function off. You can read many articles on people trying to gain access to home networks via inverters and other appliances.
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OK, I'm a mechanical person. Fronius has AC fusing that you can disconnect when troubleshooting.Comment
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It looks like my frame of reference is old. New models don't have integrated AC disconnects. Sorry for any confusion.
From July 2014 "SolarEdge will also begin shipping inverters with Safety Switches that disconnect the DC only. These switches replace the AC/DC Safety Switches that have been supplied in the past, and remove the AC disconnection redundancy at the AC breaker and at the Safety Switch."
Discontinued 2015 Fronius IG: "Standard Code Compliant DC & AC disconnects"
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Thanks for the explanation of the monitoring.
My POCO requires an AC shutoff near the meter (at least that's how I decipher "The switch must be in close proximity to, and on the Interconnection Member’s side of the point of electrical interconnection with, the Cooperative's System"). So that'd be two AC shutoffs. No harm I guess. But they'd only be about 20ft apart and visible from each other.
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I've never found much benefit in remotely mounted disconnects. It's not as if there's regular maintenance that requires isolating these systems that would make the convenience even remotely worth the cost. IMO it's just another point of failure. Australia is really suffering from this since someone thought it would be a good idea to require DC disconnects on the roof... and now a lot of them are causing fires.
Another option would be to mount your inverter near the meter and it would be next to your AC disconnect anyway.Last edited by nwdiver; 12-18-2019, 03:09 AM.Comment
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Got it. I was mainly thinking to put inverter at ground-mount because if I put it by main panel (in house) I'd have to deal with the issue of limiting the DC wiring within the house to 5ft (since I'm trying to avoid rapid-shutdown). But since the inverter apparently is ok mounted outdoors, I could put it next to the meter, as you suggest. I'm gonna have two strings, so I guess that's 4 conductors plus a ground, but since my panels have a short-circuit current less than 10 amps, I suppose it can be pretty light-gauge THWN (as opposed to 3 heavier conductors plus ground). Also leaves more options as far as upgrading to a DC-coupled multi-mode system later.
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