I have been in a maker mood and exploring solar power. I do not really expect to save any money doing this, but I am interested in alternative energy sources and thought building a working system would be a way to explore and comment.
I bought a kit from Renogy (panel, charge controller, cables), a battery appropriate for off-grid projects, and an inverter. You pretty much hook the panel to the controller (which prevents overcharging and some other important functions), the controller to the battery, the battery to the inverter (like the device you might plug into the cigarette lighter outlet in your car), and the inverter to whatever you want to charge/power.
My brother (an engineer) and I could not get it to work. It was very frustrating and I kept staring at the sparse instructions hoping something would make sense and hoping something was not broken so I would have to go through the process of shipping things back without knowing exactly what was wrong.
Finally, I traced the cables back from the controller to the solar panel and thought my brother had made a mistake by reversing the + and – wires going into the controller. This seemed to be the case, but it was unusual he would make such a mistake. Then we looked carefully at the connection between the short cable leading from the panel and the 20 foot cable you use to connect the panel to other parts of the system.
Each of the pairs of cables can be joined in only one way so you would think an error would be unlikely. If you look carefully, you can see the problem. The two ends that snap together are marked – and + (+ and – for the other cable). So depending on which of these markings you happen to focus on, you have a 50/50 chance of reversing the desired connection to the controller. My brother had made the wrong connection, but only because he assumed the + marking on the connecting cable should go to the + connection point on the controller (most of know to look for a similar match when connecting a charger cable to a dead battery).
I thought I would bring this flaw to Renogy’s attention. I send an email with a picture to customer support. The rep responded indicating this was a known problem and the company was working with their manufacturer to address the problem.
What can you say? I can think of about a dozen ways to fix the problem if you want to continue to sell the mismarked product – file off one of the markings, attach a tag to the cable explaining the error, include a page describing the problem with the documentation, etc. Perhaps engineers and marketers just don’t think like psychologists.