50 Watt Flexible Monocrystalline High Efficiency Solar Panel

This is a pretty good fit on the back of my new grocery getter ebike. Wired to an Elejoy MPPT step-up charger, this provides a steady recharge whenever it's parked under the sun. It even reduces voltage sag while throttling the ebike.I did catch some flak on social media because 50 watts isn't enough to quickly recharge a fully depleted battery, but those people are missing the point. The battery is rarely depleted because it's charging when I'm eating lunch, it's charging when I'm shopping, it's even charging when I ease off the throttle. But yeah, I do carry folding panels on longer rides, and I do plug it into a 300 watt solar array at home, so they are technically correct, 50w is not the fastest way to recharge.

This cell is a beast. With a brand new cell (Boston area) I measured about 43w at about 330pm in late June using an omnicharge 20+ (note: the omni20 maxes at about 45w). I saw 34w with a renogy powerbank (its charge controller isn't as capable as the omnicharge, and doesn't handle voltages below 18v well). Want to add a kudos to the vendor, my first cell arrived damaged (a crease with cell cracks) from shipping and wasn't producing full power. They were very nice and sent me a new one after we verified power output from the cell against what I should have been seeing, as it was only producing about 2/3 of expected output (~27-29w via my omnicharge). I wasn't asked to return the damaged cell.I use the sunpower quite often to work at parks with my laptop and an omnicharge or enginstar power bank. It cranks in the watts and is actually pretty good even in imperfect conditions. Strongly recommended for folks looking for a good solar cell to use in pleasant conditions.Fast forward a few months. I recently went on a white water canoe trip to northern Maine. Since I have a CPAP, I needed power. I knew it was going to be a brutal trip on the solar cell, and i did my math and only needed 12w for a couple of 4 hour afternoon/evening stretches and producing "some power" during flatwater paddling to make my battery last. Because I'm a pack rat, I never threw out the damaged cell. I decided to take it since I knew it would be a rough trip on my gear. That cell suffered every possible indignity for over a week. I often had it underneath my gear on a canoe during rapids. I managed to (sigh) flip my boat multiple times, hit lots of rocks, scraped up the cell, and flexed it and the boat quite a bit when pinned on a rock. It also got banged around on portages and sometimes in camp, I tried to be careful, but... things happen. The Sunpower cell exceeded my expectations, even with all its wounds. I was able to finish the trip with my batteries nearly full, and was able to charge other people's equipment, in addition to running my CPAP, which was a bonus.After the trip, I set it up and was still cranking in the high teens of watts on my renogy and 26w using my omnicharge, voltage seemed down 1-2v from before, but otherwise looking surprisingly good. Having that panel with me let me charge my batteries and run my CPAP while I dried everything out several afternoons. I'll bet if I polish out some of the scratches and scuffs I'll be able to get back into the mid to high 20's for watts on it with the renogy -- in line with where it was before I started. I've included a photo showing the cell which had been previously damaged (see crease w/cell cracks) before going into the field, plus all of the scuff marks, with a brand new cell.If you can handle the dimensions and the weight (which is reasonable for its size), it is a good friend for those who need power where the mains don't go.

Came as expected in original packaging

I purchased this panel to maintain auxiliary battery charge in my SUV during camping trips. It fits nicely in the center of the roof, secured to the rails with paracord at the front corners and bungee lines at the rear. To keep it from flapping, I attached twelve 60 x 10 x 3 mm LOVIMAG Rare Earth Bar Magnets to the bottom edges with the supplied double-stick tape, and put a strip of white electrical tape over each magnet to help protect the roof paint from scratches. It stays right in place at speeds exceeding 75 mph. Output cables are connected to a short 12 gauge jumper that terminates in an Anderson PowerPole connector, which in turn plugs into a cable running from the liftgate to a PWM buck converter (XINGYHENG 15A Dc-Dc Adjustable Module) to drop the voltage from 17-18 V to 14.5 V. I use a West Mountain Radio PG40S "PWRgate" and four paralleled 12 amp-hour AGMs under the driver seat for the auxiliary battery system. A 40 amp relay sends current from the vehicle's alternator to the PWRgate input when the ignition switch is on -- but when the engine is off, the solar panel feeds the input, charges the aux battery and helps to power any load. During camping adventures, this load is primarily a small refrigerator that consumes about 38 watts (3.0 amps at 12.6 volts) when the compressor is running. In bright mid-day sunlight, the panel provides enough current to run the fridge by itself, however, earlier/ later in the day or in overcast conditions, the battery makes up the difference.In my initial tests of the panel, I measured output voltage and current into a 6 ohm resistor and saw as much as 2.9 amps at 17 volts, although the efficiency drops slightly as it warms up. The panel's flexibility easily allows a snug fit to the roof, and it's easy to remove when not in use, or to protect against hailstone damage or theft.UPDATE: In September 2022, I took a 6800 mile round trip from eastern PA to several National Parks in CO, UT, and AZ. During the day when my vehicle was parked in sun, the panel supplied nearly all of the power demand of my 12 volt refrigerator. The "LOVIMAG" rare earth bar magnets held the panel tightly to the roof (even at speeds exceeding 80 mph on western Interstates) until I reached eastern Indiana on the return home, when high crosswinds caused the right rear corner to lift and begin slamming down. Hard impact caused severe damage to some of the fragile magnets, so I had to remove the panel on the final day of the journey. I've since replaced those adhesive magnets with "TRYMAG" heavy duty rectangular pot magnets, three on each side of the panel, fastened 1/2" in from the edge with stainless flat head M3 screws, flat washers, and nylock nuts. They're more expensive, but the fragile neodymium material is protected within a rigid steel capsule. Fortunately, the Sunpower panel itself showed no damage and continues to meet specifications.

I bought two of these. The first came in original packaging and works as expected. I ordered a second one and received it yesterday. The manufacturer's packaging had been previously opened and the panel looks as though it has already been (ab)used: it is scratched (the manual is very clear about the need to avoid scratching the surface and the first panel came with a protective sheet) and there is discoloration in the plastic near electric pathways (due to overheating?). Yet the box has a sticker declaring it a "new item". I expected better from Sunpowered Yachts. Returning that panel today and giving alternative brands a shot.