Adapting a suitcase panel to your existing solar setup

Sometimes, one panel just ain’t enough. Poorly lit conditions or high energy usage can sometimes be more than one 100W panel can keep up with. Suitcase panels can be a great option for getting that extra charging capacity with more versatility of placement.

We purchased a 100W Thunderbolt Solar Suitcase to supplement our Renogy System. The suitcase came with an SAE connector and an 8mm adapter. Neither of which do us any good, since our system uses MC-4 connectors and our camper is not pre-wired with a zamp port. Still, I wanted to run our panels in parallel… off to the google!

Adapting your kit is not difficult, but there are some steps you must take and things you must buy to make sure you make proper connections. First off, make sure your charge controller can handle another panel. If you have a PWM like we do, run them in parallel so that you are sure not to exceed the voltage rating on your controller. Excess watts are not recommended either, though less catastrophic for your system than excess voltage. We have a 30amp controller, so how do I know our wattage capacity? 30amps X 12v = 360watts. We could probably get away with four 100W panels, but I’m sticking to the conservative side of things and don’t plan on exceeding three.

Running panels in parallel means you are running panel wires negative to negative and positive to positive into a Y-adapter, which then runs into your charge controller. So, you will need an SAE to MC-4 adapter to make the connection to your y-adapter. The kit referenced here comes with a reverse polarity adapter, which you may need. If the MC-4 red and black wires are not matching up to the same polarity on the SAE connector coming from the suitcase, you will need to use the reverse polarity adapter to correct for this.

As for the Y-adapter, I purchased this entire kit, which came with 20ft lengths of panel wire. You can see how it all connects in this diagram from the Renogy website.

The bottom line about all this solar business is that you’ve got to make it work for you. Acquire only what your rig and your camping style need and make sure your components are versatile enough to be used in different conditions. You can have six fixed panels and a big lithium battery bank, but if you’re not drawing the amps, what’s the point?