MEGSUN Solar Panel Kit 20W 12V Waterproof Solar Battery Trickle Charger Maintainer + Upgraded 12A Intelligent Charge Controller + Adjustable Mount Bracket for Car, Motorcycle, Boat, Marine, RV

This 20w solar panel with charge controller and cables is very compact and provides everything you need to add solar battery maintenance to your RV, boat, tractor, or to power small devices at remote locations. I think the best application for this is a battery maintainer for an infrequently used vehicle rather than as a source of power for remote loads, though it can do either.It comes with a bracket for properly angling the solar panel. The panel appears to be well made. The charge controller is small but seems to work properly. It comes with two sets of power cables, one for permanent mounting and the other with clips for temporary installations. It has hardware to mount the charge controller.If you are just looking for a trickle charger for a single lead acid battery, you can stop here. It looks like a good product and I would buy it for that purpose. If you are looking at a solar panel for powering a remote load of some kind, this is still a good product. But it may not be a big enough product. Unless your load is very small and/or very intermittent it won't have much safety margin and you might end up unhappy by the end of January.If you mount this panel exactly right, it will probably average about 80 watt-hours of power per day. That depends on where you are, shade, and other factors, but it's a reasonable starting point. With battery and charger efficiency factored in, call it 65 watt-hours per day of available power. Again, that's average, so you might have some days where you get 85 and others where you get 5, but in general your battery tend to fill and stay on the upper end of the charge range as long as you stay below a 2.7 watt continuous load.The good news is that there are quite a few devices that can run on an average of 2.7 watts. Small computers such as the Raspberry Pi, GPS trackers, motion detection lights and other small intermittent loads.The bad news is that 65 watt-hour budget is the average for a year, and when you look just at specific times of year you can easily have 60-90 day periods that will average 24 watt-hours per day of power. And that budget will go down if you for example have a larger bank of batteries, or the panel gets dirty, or a cat decides to take a nap on it. Unless you are 100% sure that your load is in the 1 watt continuous (24 watt hours per day) range and that your panel is going to be well aimed, your weather and general shade conditions are going to be good, etc., you may find yourself running out of power from time to time even though on paper it looked like a 20w panel was enough. And battery capacity gets very expensive for covering long term shortfalls. To get through a potential 100 day 2.5 watt deficit of power you are probably looking at an 8D battery that costs $250+ (plus core) weighs 130lbs and would normally be found on a big truck.None of this means this is a bad product. But, as someone who has done math, set up a test, and finally deployed a solar powered remote device only to have the battery slowly cycle down to zero in the winter when my power budget dropped to 40% of the summer budget, I am a big believer in having extra margin on the panels. A 20w solar panel only gives extra margin for very small loads, and often going to a 100w panel even if it is complete overkill 9 months out of the year is going to be less expensive than sizing the battery etc. to cover the shortfall during winter months.

The MEGSUN Solar Panel Kit is an outstanding product! I use it to maintain my snowmobile battery, and it works flawlessly. The 20W solar panel provides reliable charging, even on cloudy days, and the upgraded 12A intelligent charge controller ensures my battery is never overcharged. It’s waterproof and durable, which is perfect for outdoor use on my RV and boat as well. The adjustable mounting bracket makes installation easy, allowing me to position it for maximum sun exposure. This kit has saved me from countless dead batteries, and it’s been great for keeping my vehicles and equipment powered. Highly recommend!

The charger works to keep batteries topped off. The charger recovered a dead battery after only 2 days of sunlight exposure.The only problem that I noticed is that the cables are bleaching in the sunlight. I would have expected that the cables connecting to the solar panel would be UV stable because obviously there would be some UV ray exposure.The build quality on the charger feels a bit cheap, but it obviously works and that is all that matters. I would suggest making the cables longer.Overall, it works well, and lightweight for use in lots of situations.

I have a gas golf cart and I have recently installed some extra lights and a radio that doesn't always get shut off. This little trickle solar charger will do the trick it was very simple to hook up and it will charge my golf cart battery from the Sun. It is not an electric car it's a gas cart but it still has a battery that can be charged from the small solar panel. Velcro will hold it in place and it uses SAE connections is a 12 amp charge controller. It comes with a mounting kit but I just used a couple strips of velcro to hang it on the roof of the golf cart.

I don't have any experience with comparing these to other similar models however, I have a bunch of experience building home solar systems with various parts that don't go together.My idea for this is to put it in a window of a vehicle that is just sitting there for months and the battery always goes bad.Pros=under $100=50 watt instead of the small 20 watt ones=battery attachments=solar charge controller included=actually includes mounting hardwareNo complaints but this is based on looking at just this one unit of this type.