Chapter 12.
Maintenance and Troubleshooting
By choosing another power source other than the public utility, you also assume the maintenance responsibilities and responsibility for operating the system correctly. You can no longer call the utility and say, “ My lights went out.” It is up to you.
Maintenance cures a lot of potential problems before they happen. That’s much easier than dealing with problems when they occur.
The meter readings described in the last chapter should be taken and recorded once the system is working properly. They will serve as reference to indicate when something is malfunctioning, or when it fails, of the fault location.
Taking the performance readings is a first step for troubleshooting and the second time is easier.
Troubleshooting
The biggest trouble culprit is the operator. Most of the problems can be traced to operating procedures. In one field it’s called pilot error, hopefully troubles with a PV system may not have the same fatal potential.
1. Ignorance of the system.
A perceived trouble may be that the operator doesn’t fully understand the system’s capabilities and limitations and may be expecting something that the system would never accomplish in the first place. It is important to know what your system will do and what it will not do.
This should be part of your understanding before you hand over those bug bucks in the first place.
2. Misapplication.
This really is part of the above problem, but a system may be applied to a situation for which it is not suitable. Again, learn enough about what you are buying into so this doesn’t come up later.
3. Mis-wiring.
Mis-wiring at the onset may damage or wreck a costly component. Understanding is the key to this problem. If you don’t connect something correctly, it’s your fault.
4. Poor electrical practices.
The importance of a clean, tight electrical connection cannot be overemphasized. A dirty or loose connection creates heat. The heat only serves to oxidize the metal connecting parts and produce more heat. The problem keeps increasing until a failure occurs.
The failure may be as great as an electrical fire, or destruction of the component, or malfunction. The first two are usually visibly obvious, but the last one may be difficult to find and at the very least will result in time lost. Economizing with a smaller gage wire not only leads to possible fire hazards, but it may cause malfunctions as well.
Troubleshooting Process
Whatever the problem, the troubleshooting routine is the same.
++ Isolate the problem.
++ Isolate the faulty component.
++ Substitute a good component for the suspect one. If the system works, you have the culprit. If the system fails to work, start over, you missed something.
++ If you cannot substitute, you must find a way to check the suspect component.
How to test a fuse
With the system energized, measure voltage across a fuse. A good fuse will not show a voltage from one end to the other. If it is open, the line voltage will be indicated across the fuse. At this point, de-energize the circuit: Use your voltmeter to make sure. Remove the fuse and replace it with a good one. ( A good fuse is one you have checked. )
If the fuse in question is out of the circuit, set your meter to ohms and check it. A good fuse will show a short or nearly zero ohms. A bad fuse will either read infinity or the high end of the selected ohms scale. A fuse that reads less than infinity, but higher than zero ohms has something wrong with it. Discard it.
How to test a circuit breaker
Sometimes, a breaker toggle will look okay, when all it needs is to be reset. Throw the toggle to the off position and then back to on and see if it works.
Measuring the voltage across a circuit breaker works here, too. The big problem is getting to the line side of the breaker. Its mounting may not make this side available. Place one meter probe on the circuit side and use the other probe on the panel input terminal. Operate the toggle several times while the meter is in place. (This takes three hands, or two hands and a nose) Again, if the breaker is open or bad, it will show line voltage in the ON position. A good one will read zero volts.
Circuit breakers will either stick open, have too much oxide on the internal contacts to work, or the contacts have burned away. In the extreme case, drill out the rivets holding it together and check the contacts. If they can be cleaned, do it. Reassemble the unit, using small machine screws in place of the rivets.
What it takes
A simple system is always more difficult to work on, because the problem is limited to so few parts, yet the blame thing doesn’t work. It is a task of checking and rechecking until you find the culprit.
The difference between a pro and a beginner is the amount of time to the solution. Don’t give up.
Spare Parts
If you are remotely located or expect to do your own maintenance and repair, plan to buy some duplicate parts so you can more easily accomplish substitution. What parts?
Circuit breakers.
Fuses.
Both of these items must be stocked in the required sizes. The fuses aren’t so much for substitution as the are to be available for replacement. A faulty circuit breaker can be difficult to spot: substitution is the easy way. How many to stock? Depends on how far away the supply is or how long you would have to wait.
When I was training technicians, I had a drawer full of faulty components which somehow would manage to get into a piece of equipment. Nothing trains a troubleshooter like the real thing. Now what kind of an S.... would do a thing like that?
Major components should give a reasonably long life and stocking shouldn’t be necessary. If power is critical to your existence, a spare may be justifiable.
Batteries are checked regularly and you should have ample warning if a battery is going to fail.
Solar Panel problems are most likely to occur in the junction box due to corrosion from moisture. A cracked glass cover or some discoloration around the edge would indicate a leakage problem and a potential failure.
Electronic Components are likely to smell like burned insulation before they fail. One sure indication is smoke pouring from a failing component. Transformers often smell bad before they fail. Fuses should protect a unit, but the unit may have internal problems before the fuse can act.
Visual observation can often identify the blackened component. Bad news.
With the power turned off, touching individual components or a transformer (You will know when you reach the hot one) is a good procedure. A burned resistor will have three black rings where the color code rings should be. Feel wires after first turning off a suspected unit.
In more sophisticated and complicated equipment, temperature sensing is common practice, even to having an infra red scanner that shows the hot spots on a video screen.
Around terminals, look for signs of melted solder. A dark or black connector, it should be shiny metal, is another indicator. Lugs overheat when they have become loose, wires do, too.
Many simple problems can be corrected before you ship off the unit and go back to candles. Don’t give up easily.
Maintenance
Solar Array: Keeping the glass clean is about the only maintenance problem. Dust may accumulate on the glass surface and reduce output. Snow will do the same thing. A tree or trees may grow into the field of view and reduce output, too.
Wiring: The most likely problem wiring will be outside, and that will be a long time in occurring if sealed, weatherproof boxes are used. However, heat, moisture, and dust, will work on connections. It is unfortunate that the very metals that conduct best are also among the most active and are subject to oxidation. After a year, open an outside terminal box and closely inspect the connecting points for oxidation, even to the point of removing a wire to really see it.
The cables in the battery location are most likely to be wiring trouble spots. Acid will work on exposed metals and a corroded connection will be an indication of an electrical-problem connection. There are compounds that may be spread or sprayed on the exposed metal parts to keep the corrosion in check. Petroleum jelly, available at drug stores is a good choice, although it tends to run if the location is warm, and certainly it will run if the location is hot.
Electronics, especially printed circuit cards, are doomed in the presence of acid fumes. I recommend never placing electronic devices in the same location with batteries. The same goes for meters, any kind of meters. Battery fumes are also a sure way to antique your tools.
Door hinges and nail or screw heads will also suffer from long term exposure in a battery location. Be sure to use a good grade of paint, and certainly use galvanized nails and screws.
If your wiring uses aluminum conductors, all of the exposed wire ends should have been dipped into a deoxidant before they were connected.
If your situation is especially harmful to ,metals, such as a seaside location, you will already have the problem.
We lived a half mile from the beach for almost 20 years. I had to spray all exposed metal on machinery and tools once a month to keep them rust free. It was either that or paint them. That was a special problem in our print shop; oil and paper are not compatible.
A spray galvanize compound was used on all metal surfaces outside. It’s the same stuff I used on the tracker platform with this solar system: an epoxy based spray containing 97% zinc.
Batteries: The connections on batteries are especially subject to corrosion and will need cleaning more often. Be sure to neutralize any spilled electrolyte after testing batteries. A drop of electrolyte will have the water evaporate from it and it becomes more concentrated and more corrosive.
Probably whatever floor the batteries rest on should be sprinkled with soda to neutralize any spills. Of course, we would not place batteries on a concrete floor. The colder concrete causes a temperature imbalance within the battery cells- top to bottom, and degrades its performance, besides, acid spilled on concrete would turn it into dust- sooner than later.
Rigid-foam insulation is usually covered with aluminum foil to enhance its R value. Plan on the aluminum corroding in the presence of battery fumes. I am uncertain of the effects of battery fumes on urethane foam, but I will find out in due time. I could have used polystyrene foam sheets, but they are not as strong and besides, I don’t know how much they are affected by acid, either.
This is when time caught up with me. I had just completed construction of the battery box when the batteries arrived and we placed them right in the box. If there had been any time with the box empty, I would have coated the exposed foil with spray galvanize.
Just as I mentioned with handling gasolene, cover up when you work with batteries, and be sure they are old clothes. The acid will do wonders on any kind of fabric. Eye protection, and even a face shield are absolutely necessary. Have soda, water bucket, and fire extinguisher nearby, too.
Overcautious? Overprotection? It’s only overprotection if something doesn’t happen. If something does happen, you would give anything to have been properly protected.
I went to visit another art foundry. ( Our studio cast bronze, too.) You know, just to see how someone else does it. I saw a guy pouring bronze with his shirt off, and he was barefoot! If you don’t know, almost anything, like a moth flying into the crucible, or a drop of sweat, can cause molten metal to scatter in every direction- like buckshot. Sure it was hot in there, but stupid is stupid, whatever the temperature. Talk about tempting fate.
I didn’t stay to watch a potential tragedy.
Conclusion
Having built the system, you should know where everything is and you should be able to spot the problems. It is much easier to work on a system with which you are familiar. You pay a repair person for the time it takes them to find everything and to learn how it was connected.
End of Excerpt