Lazy Daze Owners' Group

For what it's worth, I've been using portable panels for years to provide supplemental power in wintertime and in shaded locations. I haven't had one stolen yet, but maybe I've just been lucky. For the most part I've used "just plain" (no built-in controller) panels such as inexpensive Renogy 100-watters, propping them up with a cheap folding stool to get a better angle. I feed the output into my rig's solar controller in parallel with my roof panels (matching voltage, of course).

With my Airstream I carry two cables: a 25' one and a 10' one, made from Ancor 10/2 (AWG 10) marine cable. When feasible, I use the shorter cable, which minimizes voltage drop, but if necessary I use the longer one or even (rarely) both. I've even connected two 100 W panels this way, paralleling them at the panel end with MC4 Y-cables.

With my Subaru Outback (which has a solar-powered refrigerator), I have a 45 W panel mounted on top of my rooftop storage box--it was the largest I could fit there--and use a 50 W Renogy controller-less portable panel with a folding support frame to provide supplemental power if parking the car in the shade. (Both feed into a Victron solar controller, which charges a group 27 AGM battery.)

For that portable panel, because the 2.7 amp current is so low that I don't worry too much about voltage drop (1.6% at max current), I use a cable made from an off-the-shelf 25' 12-gauge outdoor extension cord. I just cut off the plug and outlet ends and crimped on MC4 connectors. For higher panel wattages, though, the 12-gauge extension cord would impose more voltage drop than I'd be comfortable with.

For what it's worth, I've been using portable panels for years to provide supplemental power in wintertime and in shaded locations. I haven't had one stolen yet, but maybe I've just been lucky. For the most part I've used "just plain" (no built-in controller) panels such as inexpensive Renogy 100-watters, propping them up with a cheap folding stool to get a better angle. I feed the output into my rig's solar controller in parallel with my roof panels (matching voltage, of course).

With my Airstream I carry two cables: a 25' one and a 10' one, made from Ancor 10/2 (AWG 10) marine cable. When feasible, I use the shorter cable, which minimizes voltage drop, but if necessary I use the longer one or even (rarely) both. I've even connected two 100 W panels this way, paralleling them at the panel end with MC4 Y-cables.

With my Subaru Outback (which has a solar-powered refrigerator), I have a 45 W panel mounted on top of my rooftop storage box--it was the largest I could fit there--and use a 50 W Renogy controller-less portable panel with a folding support frame to provide supplemental power if parking the car in the shade. (Both feed into a Victron solar controller, which charges a group 27 AGM battery.)

For that portable panel, because the 2.7 amp current is so low that I don't worry too much about voltage drop (1.6% at max current), I use a cable made from an off-the-shelf 25' 12-gauge outdoor extension cord. I just cut off the plug and outlet ends and crimped on MC4 connectors. For higher panel wattages, though, the 12-gauge extension cord would impose more voltage drop than I'd be comfortable with.

"could you explain this process a bit more thoroughly...?"

Sure! Power from the roof panels comes down into the compartment where I have the solar controller mounted, and connects with ring terminals to a pair of PowerPosts. From there, wires to the positive and negative "PV" inputs of my solar controller. Another cable goes from the PowerPosts to a short lead dangling outside the RV, ending in MC4 connectors--the kind used to connect most solar panels. From there, the MC4 extension cords I made up go to the panel or panels on the ground.

"matching voltage, of course"

To clarify: with my Lazy Daze and my 27' Airstream, I had the roof panels wired in series pairs, so the voltage into the solar charging controller was about 18 V + 18 V = 36 V. Thus, when using additional panels on the ground, I used a pair of panels wired in series to match the 36 V from the roof panels.

In other words, when using both roof panels and ground panels, whatever the voltages are must match, because the two sets of panels are connected in parallel at the PowerPosts.

If I had my roof panels wired in parallel with each other for 18 V, as many RVers do, then a single 18 V panel on the ground would have been a good voltage match. If I needed more power and wanted to use two ground panels along with the parallel-connected roof panels, then an MC4 "Y" connector would let me connect my ground panels in parallel with each other, thus matching the 18 V from the roof panels but adding extra amps.