The Longest Night

Turns out you were on the right track in a roundabout way. Panels are currently feeding 47 volts. I have a problem up on the roof somewhere. The panels normally feed about 80-85 volts. Too bad the wind is now gusting over 30 mph. Less than ideal for roof work. 

I just don't know what would cause a 47 volt panel feed. I've never seen 47 volts from a single panel - as I recollect. 

Completely wrong wiring can throw off weird voltage. But that seems pretty well impossible considering the connections are in watertight boxes. I guess looking at fuses is next. Perhaps something blew some fuses. 

Problem solved - more or less. One of the four combiner boxes was putting out about 41 volts. The other three - 82 volts. 

Simply by disconnecting the problematic source feeding 41 volts - the CC is now feeding my banks. Cloudy now but it is working. 

Lesson - get yourself a BMS (Battery Monitor System) and maybe place the readout on the television or computer or ......

Pretty delicate system. Lost a little something somewhere that effectively took down all the panels to 47-48 volts. That from 80-85 volt strings. 

^^^Got a lot of emergencies going on right now. No way do I think about anything that hooks my stem up to the hackers highway, I mean the internet. No way. 

My question now is; How did proper wiring transform into improper wiring? Easy to fix. Diagnosing? That took some time. 

I must have miswired the array when checking things last time. Surprised it lasted that long. 

FWIW - They were being charged with 52 volts at 9:30am. Four hours later and the batteries finally have 52 volts/bank. May take a couple days to get to a full absorb cycle. 

mike95490 said:

softdown said:

I must have miswired the array when checking things last time. Surprised it lasted that long. 

So you had one string of poor panels pulling several strings of good panels down ?   I suggest taking a close look at all the panels in that dud string, one may have a short or bad spot and a corresponding burn mark on a cell.  It wasn't enough to pop a fuse, but something was not happy.  At least the batteries are recovering

I had two panels that were not wired in serial. One was somehow hooked up to itself. The other one fed into one of four combiner boxes. It is hard to believe that I rewired it improperly when checking things a couple weeks ago. It is harder to believe that somebody else went to the trouble of doing it. Though I do wonder why those two panels were the only ones to yield a 0 reading on the clamp meter - which I used prior to checking individual voltage. The whole thing is on the strange side. 

Still incredulous that one 42 volt feed pulled the entire array down to a 47 volt feed. Yet all 16 panels were reading 42 volts a couple days ago. They were yielding 37 amps of power at 9:30am yesterday. That sounds about right. I need to check the output at closer to high noon. 

The battery bank did not get to 100% SOC yesterday. The bank is probably on the large side. Too bad that batteries can not be stored in a satisfactory manner. I'll bet a battery manufacturer could do well selling dry batteries, without electrolyte, that can be stored until needed. 

I suspect the EPA put a few manufacturers down. We only have a couple left with Johnson Controls being completely Mexican mfg. I think. - even their previously esteemed Optima line. Lack of competition always has horrific consequences. 

Dave Angelini said:

Keep in mind that solar array problems can take alot of time. The many that I have had to repair that others did often start out with my troubleshooting taking me one way. I often get into it and start getting conflicting data. 

In the end it often ends up an intermittent internal connection inside a panel. Total PITA and travel time up the ying yang !! 
Hint  I see you have BP panels. They (the ones in the suit) are one of the prime sources of this kind of failure. They should be scrapped.

Grape Solar panels. I have BP panels for experiments and they have been less than stellar. "First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter."

Two of the panels were incorrectly wired. Pretty concrete finding. It isn't necessarily over but it "might be". 

My dad was a medical electrician for four decades. He always said that intermittent problems are the worst. 

My gut feeling is that I have at least a 50/50 chance of having the issue resolved. Really going out on a limb with that prognostication. 

Hard to determine with weather like this: https://weather.com/weather/hourbyhour/l/874b2d082ff2caeaf5d18b4a92a3b4f15c739702c08833b3547c3554ef50d9af

Lets relax for a day or two? I just found two panels that were wired incorrectly and apparently throwing everything off. I'll go check right now but clouds are intervening significantly. 

Photowhit said:

Still feel your grape panels are too low a voltage to use with an FM80 with just 4 in series. I read you see 80 volts input, but feel that must be during sweeps and not under load since the VMP is <20 volts per panel...

I'm uncertain what you are thinking. Four in series would easily yield voltage of 180. I believe the FM80 is programmed to shut down around 140 volts. "HyperVOC" strikes in the cold early morning before the charge controller wakens and draws down the voltage level via feeding current to the battery bank. "HyperVOC" still strikes me as "witchcraft" but I don't want to send my controller interstellar. It must have occurred enough times to earn its place in solar lore. 

Things look better all the time. Approx. high noon readings: 75 incoming volts - 55 charging volts - 42 amps. Feel like a celebratory beer is in order. Doesn't take much to make me feel like celebrating. Waking up? Good enough reason. 

Photowhit said:

I think the FM80 will still function, but you are likely losing some of the positive aspects of the MPPT type charge controller.

I've never dropped acid but some thoughts make me feel like I did. I'll have over 80 incoming volts soon enough. I think that may be in the "ideal range". 125 volts becomes a Hyper VOC risk if the temp drops below ~ neg. 30F. Which it does here from time to time.