12V 20 Watt Solar Trickle Charger Maintainer with MPPT Controller - Portable Waterproof Solar Powered Battery Charger - Solar Panel Kit for Car Rv Trailer Truck Boat Automotive Marine

Build quality:Seams to be sturdy. Had to make a frame for it for my application but handles the elements. Charging speed:Definitely works. Keeps my troller battery fresh!Ease of installation:plug n play. For most applications. Be great for car, comes with window suction cups.

My experience with solar chargers started about a year ago. I had a 5 watt charger that a friend had given me for my generator battery. I never used it for that.Fast forward one year later - I have since retired and my truck sits in my driveway a lot more than it used to.My battery kept going dead so I tried the 5 watt charger and waited a week to see if it either worked or if my battery was dead again.To my surprise it worked! My truck started right up but the problem was that the old battery was 4 years old at that point and I knew that this was going to keep happening unless I either went back to work or I was going to keep the solar charger on my truck battery.The sun and the heat warped my 5 watt charger so I needed a new one. I saw this one and it was on sale at the moment I purchased it here on Amazon. You should know that any solar charger you buy will be subjected to extreme heat and light so please keep that in mind when you buy one of these things. I recently went to remove mine during a hot afternoon and nearly burnt myself because the unit was so hot after being on my dashboard in the midday sun in front of my dashboard heat shield (see pic).20 watts seems to be the limit for a solar charger before it needs a separate controller to regulate the flow of power to what whatever it is you're charging.Also for those who care at 20 watts the charger is putting out about one amp of DC electricity which would be the equivalent of a trickle charger output from a battery tender.I like this unit because the solar panel is flexible instead of being rigid or made from hard plastic like my 5 watt charger. The holes in each corner give you the flexibility on how you want to position for maximum sunlight exposure. In my case I laid the panel down on my dashboard and put my big sunshade behind it to protect the dashboard and interior of the truck from the heat and sun fade. The sunshade keeps the panel propped up for best sun exposure.I didn't write the review until I tested it out the same way I tested the 5 watt panel, by waiting a week to see if my new battery (Northstar AGM- NOT RECOMMENDED due to it going dead within 10 days of inactivity and VERY poor warranty support-see my review) would be able to start my truck (Nissan Murano). The Murano has a 3.5 liter engine, not a big engine by any standard yet I have to keep a solar charger on it in order to prevent the battery from draining on me.The charger has been on my truck for about 3 weeks now and whenever I decide to go for a drive my truck starts right up with no issues. I disconnect the charger before I start the truck and when I come home I reconnect it. A bit of a pain in the neck but it guarantees that my truck will always start no matter how long it sits in my drivewayI can see this charger might have other uses too. It could be used in a camping situation to charge battery packs or an emergency situation as well.The only minor quibble I have is that the panel does come with a small controller attached to the back to let you know that the charger is charging. There are 3 lights on this little controller. One to let you know that it's receiving sunlight so that it can function. Another LED to let you know that it's charging whatever battery you have it attached to. Then there is a third LED, a green one. Once an item is fully charged the green light is supposed to come on. I have yet to see this green light come on but the charger does work as it's intended.Update 5-29-21- The green light on the controller does appear to function! I noticed the other day after having my truck sitting with the charger attached the green light on the back of the solar panel was on! Apparently my battery must have been low and it took time for the charger to top off the battery.Highly recommended--------------------------------------------------------------------------------------------------------------------------I rely heavily on reviews when I make purchases so I put some time into reviewing everything I buy on Amazon for personal or business use so I can help other people considering that item. If you found my review helpful, please consider hitting the "helpful" button below when it asks if the review is helpful. Thank you!

I haven't had it that long, but It seems to be working fine. Don't expect the suction cups to work. I can't get them to stick to any smooth surface. I bought better ones. Another issue is there is no setting for a lead acid battery.

It works wellI've had this panel for a little over a year now, the 20 watt version.I keep it hooked up to a truck that doesn't get driven as often as it should. It's got some small parasitic loads, like a dash cam and remote start system.The truck will kill the battery if it isn't started once every couple of weeks or so. This panel stuck to the south facing windshield and plugged into the cigarette lighter works great. I could probably hook it directly to the battery but this is easier to use that way. Just unplug it and take it in the cab with me. The suction cups hold on well if you get them wet first.It does have to be on the outside of the window to do any good. Windshields block UVNo complaints at all from me. Still works well and my remote start says my battery is sitting at 12.8 volts as I type this. It certainly won't charge a dead battery, not very fast anyway. But it will keep it full.

This 20W solar panel has proven to be a reliable power source for my Meshtastic node. The built-in charge controller is particularly valuable for this application, preventing overcharging of the battery without needing additional components. I'm getting consistent power output even in partial shade, which is crucial for maintaining node uptime in less-than-ideal locations.The panel's physical construction is appropriately weatherproof - I've had it outdoors through several rainstorms without issues. The included mounting O-rings are sturdy and make it easy to secure the panel to poles or other structures. While the cigarette lighter adapter isn't particularly useful for Meshtastic applications, the alligator clips work well for connecting to standard battery terminals.For Meshtastic users specifically, I found the voltage output to be very stable, which helps prevent node resets. The 20W capacity is actually more than needed for a basic node setup, but this overhead is helpful on cloudy days or when running additional sensors. You'll want to add appropriate connectors for your specific battery setup, but the included wiring is of good quality and easily adaptable.One minor consideration is the somewhat limited length of the included cables, so factor in some extension wires if you're planning to mount the panel any significant distance from your node. Also, while the frame is sturdy, you might want to add additional UV-resistant coating if deploying in extremely sunny locations for long-term installation.​​​​​​​​​​​​​​​​

Excellent product. Charged car battery even in partial Sun under my carport. Best used as maintenance charger.