PV array output

Masterjoe · July 2019

Question. Electric company and solar installers come down to look at the system. The net meter works fine and the array is producing 305v. Problem is non of that power is reaching the house as far as our usage is concerned. Our power is being delivered to our house everyday. The array produces less than 1kw each day. Most of the day we are less than 500watts of usage. prior to Aug 2018 the system produced from 125-280KW each month depending on the month. Sometime around August the only house above our power lines is put in. Since then our production each month has dropped off to the point now we are consistently below 50kw per month for a 4.5kw hybrid system with battery backup. Why is this?

mike95490 · July 2019

If your array is only producing 305 (watts?) that's not much. Making sure the units of measurement you are stating is crucial to getting help.

Can you tell us more about your PV, inverter & battery ?

Another thing that happens is "User Bias" we have free electricity, I'll leave this heater (light, fan, TV....) on and i'll be back in an hour. I've seen overall usage and bills go UP after installing solar PV because of this.

Masterjoe · July 2019

No it is 305 volts which equates to 18,600 watts. Problem is where is it going? Our energy usage is no different now than is was last year or the year before etc. etc. Yet our production was over 1100Kw for the year last year and now we dont even top 200. Solar installer measured the voltage coming off the array, so if that is true and the electric company is seeing my meter reading delivered something is going on within 100 feet from the array to the house. Every once in a blue moon the array will start to produce and we'll produce a few KW of eelctricity on a good day so I know something is wrong because im not getting that every day and we are using anything else than we normally do. The installers cant tell me where it is going nor the installers except its either going to the batteries or the sub-panel is using it. Both of which arent true, our power is always being delivered from the power company and the batteries are always full above 25v. Like i said before this freaking house came in we were producing now we cant even get 50kw a month. We can produce 18kw a day. Solar installer wants to give me 6 more 250w panels and take out the battery backup system and wants me to believe thats going to show me 75% savings off my bill. Giving me 1.5KW more isnt going to do jack if it aint getting to the house. Getting to the house meaning my Solar Control Panel on the wall is not showing the array has harvested any KW.

Estragon · July 2019

If the problem started when a new house was added to your grid service, I wonder if its demand is causing grid power to go out of the GT inverter spec, causing it to cease selling. The problem might be sporadic depending on loads at the new house. If not selling to grid, the array would only produce enough for your loads. I would think this should be logged if it's happening though, which would help if you need to adjust settings and/or get the utility to solve the problem.

I assume the new house "above" yours isn't causing shading issues, and if it potentially could, the solar installer would have noticed.

Masterjoe · July 2019

No shading on that house its a good 2 football fields away. But before that house went in

Jan 18 46kwh
Feb 18 33.73kwh
Mar 18 78kwh
Apr 18 57.66kwh
May 18 25.34kwh
Jun 18 8.06kwh House goes in
Jul 18 6.27kwh
Aug 18 4.63kwh

By Jan 2019 we are less than 1kwh per month and its been the same since.

Estragon · July 2019

Assuming you're in a rural area? It may be that the added current going to service the new house has loaded the local grid spur or other infrastructure to the point voltage is going out of spec. AFAIK, most grid tied gear tracks grid voltage and hz, and has a settings for "acceptible" values. They likely log out-of-range exceptions, probably along with values causing the exception.

Local utilities sometimes increase voltage on spurs as more customers are added to offset increased line loss, but this has limits, and can cause problems with too high or low voltage depending on demand at a given time, and where you are on the spur. There may be a set range of values the utility is supposed to provide, which may vary by type of customer (eg wider for rural residential that urban). If the actual value(s) are wider/different than what is supposed to be provided, the utility may (or may not) be willing/able to correct it.

Your GT gear may be able to handle a wider range, but be set to a default more applicable to an urban area, which you may be able to widen.

In any case, it would be useful to see if the exceptions/values are being logged. Without this, it's hard to say if this actually is the problem, and if so, what to do about it. I'd start with getting the logging, and seeing if the GT gear settings can be changed. I'd avoid getting the utility involved at this stage, as they could claim your gear is actually causing the problems, and you'll want to be able to refute (or remediate) this.

mcgivor · July 2019

To find out what's going on will require test equipment such as a power quality analyzer which records all parameters, voltage, current, frequency and so forth. Before that it would be wise to remove the batteries to see if that is a factor, check each PV string current as a failed MC4 connector would result in lost output, a process of elimination.

The new house probably has nothing to do with output but rather a coincidence, it is more than likely that the grid cannot accept more input, or there is an equipment problem on either side of the demarcation.

Masterjoe · July 2019

Thanks for the help i'll give this a try. The installers will be out in a month or so to take out the batteries. I'll keep you posted.

PV array output

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