Protocol for Dismantling (Disconnecting) Portable Solar Panels?

johnfconway

Warnings from Renogy and folks who sell MC4 connectors about disconnecting give pause. "Please remember never disconnect the connectors when the sun is on your solar panels or they are connected to a battery, or you may be injured by your free green energy".

While we won't have circuit breakers between panel and controller and controller and batteries, there will be a 20A and 30A fuse respectively.

Do you close up panels so no sun is on them while cables are still connected, then disconnect from battery end first and then solar panel end?

Also, looks like you need the tool to get MC4 connectors apart, correct?

Thanks, as always for sharing experience!

pthomas745

The only MC4 connectors I still have are the ones that come from my panel to the solar cable that runs to the controller.  I bought several of those little plastic "tools"....and every one of them broke first try.  Never found a metal one, or a tool that would compress the little tabs enough to disconnect them.  So, I filed down the little tabs, and now I can pull them apart if I want.

Used to just run the solar cables directly into the controller, but now I use SAE plugs for that connection.  Out to the battery, the same thing: a properly wired SAE cable from the controller to the SAE port on the trailer.  With the SAE at all points covering the "hot" wires, I can disconnect in any way I want.

But, normally...I connect the SAE to the trailer first, let the solar controller read the battery, and then connect the panels.  I seem to remember in the distant past a hint to plug in the controller first. 

Basil48192

I have a Renogy 200W suitcase model.  I added a bulk-head connection port (with MC4 connectors) to the side of my battery/propane tub which I use to connect/disconnect at site.  I simply cover the panel with the carrying case when I connect and disconnect.  Since my controller is hard-wired to my battery, I don't disconnect that...maybe I should?

johnfconway

Basil48192 said:

I have a Renogy 200W suitcase model.  I added a bulk-head connection port (with MC4 connectors) to the side of my battery/propane tub which I use to connect/disconnect at site.  I simply cover the panel with the carrying case when I connect and disconnect.  Since my controller is hard-wired to my battery, I don't disconnect that...maybe I should?

I think what they warn about is forgetting to somehow cut off the sun energy source before disconnecting. Our setup will be similar to yours. For no particular reason, will disconnect cables at storage locker first (MC4 connectors wired back to controller), then up at panels.

ScottG

I use Renogy MC4 connectors for my "modular" solar controller, as well as for my external auxiliary battery connection. I routinely connect and disconnect these without any need for the special tool. In fact, I'm a little surprised they don't put up more resistance to being pulled apart, but it works for me so I don't ask too many questions.  ;-)  

Like @pthomas745, my understanding is that the controller should be hooked to the battery before hooking panels to the controller. I also vaguely recall advice to cover the panels before hooking them to the controller, but don't typically do this as it is a bit awkward. Maybe I should? I'm interested in others opinions on the matter. 

pthomas745

I have made every stupid electrical mistake around the trailer.  When I first started wiring an SAE cable into the port and used a "bare wire" to attach the solar controller.....several times I unscrewed the "bare" wires from the controller before pulling the SAE plug from the trailer port.  Sparks and melted cables ensued.  Luckily, only 12V, but..dumb as a rock.  Once I learned just leave the cables attached to the controller when packing up, I just pull the plug from the SAE port.  Now that I have the SAE cables "hard wired" to the controller, I am protected from my own stupidity by the design of the SAE cables. But, I now do it by habit: attach the solar controller to the trailer first.  Then the panel to the controller.

I used "bare wire" ends into the controller from the panel until just recently.  I never covered the panels.  Pull out the cable, roll up the wiring.  Never had a spark or any other reaction in the 8 years of operating like that.  Not that I didn't realize that there was probably some current coming from the panel...but it never happened.

I don't know why a wire from a 12V battery will spark and ground itself, but a wire from a solar panel that might be putting out more voltage never has.

But, now that I have the connectors crimped onto the solar cables, this is no longer an issue.  Unless I think of some other dumb thing.