Uncertain Beginning

[jdfnnl]

I am currently working on a pickup truck camper setup and just finished mounting (2) 100W Renogy panels on the shell. To keep the cables in place, I quickly but naively snapped them together in a closed circuit. A couple weeks later I glanced at the situation and saw how this is a terrible oversight electrically. Hopefully the panels have exactly canceled each other during this time, but of course concerned about damage incurred. Would anyone advise about the certainty of irrecoverable harm or the best method to test the panels for viability? Would it be as simple as open circuit voltage or could there be other problems?

 

[timselectric]

Test open circuit voltage.
They should be fine.

 

[timselectric]

Hopefully the panels have exactly canceled each other during this time,

They don't cancel each other out. They power each other at full production. As long as one isn't shaded, while the other is in full sun. There shouldn't be any damage.
But I wouldn't recommend doing it, again.

 

[n2aws]

Also,
I'd shade the panels or wait until nightfall to disconnect them.

Otherwise, you may see some plasma balls!

 

[Whats_per_question]

Remember that during the commissioning phase of your installation, you will be directly shorting out the panels to test the current (i.e making sure the panel array is generating the expected current), and this won't harm the panels.
Also, your panel's Isc (short circuit current, the current that has been flowing through your panels due to you clicking those MC4 together) will be very close (but slightly higher) than its Imp (maximum power point current), which the panels are required to handle all their life, so as mentioned above by @timselectric, provided they are not shaded, there should never be an issue.

Partially shaded panels, and what happens internally to them, is another art altogether and probably belongs in its own thread.

 

[MisterSandals]

Otherwise, you may see some plasma balls!

That current can flow quite a ways down from your hands!

 

[timselectric]

Keep it away from the non plasma balls.

 

[jdfnnl]

lol, great advice