I bought two of the 70 watt panels for my teardrop trailer. They have a surprisingly high level of tension. Even under load (charging the battery, running lights, 12 volt refrigerator) I get about 31 volts. Is this normal for panels under load? I wanted to run them in series (to take full advantage of my MPPT charge controller) but that overloaded my controller (can only handle 60 volts). In the end I just let them run in parallel and my controller is very happy. We just finished a 6 day trip and the panels supported my 100Ah battery with no issues (working 12v fridge, lights, charging phones etc).