SUNAPEX 20W Flexible Solar Panel with MPPT Charge Controller, Solar Battery Charger Maintainer, 12V Waterproof Solar Trickle Charger for Car, Motorcycle, Boat, Marine, RV, Trailer, Tractor,Truck, etc

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.

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 had a 10w unit that never gave full charge, neither did the 20w alone, but together they achieved full charge. I recommend a 30-50w unit, especially with newer model vehicles loaded with electronics. Cloudy winter days limit changing as well.

I bought 1 to try out on my SxS for a trip to Arizona. Unfortunately for me, this one was working so well recharging my marine battery backup (I have 2 of these batteries for my lights) I purchased another 1 and hooked it up to the other battery. Now both batteries are charging at the same time when I am running around in the desert (and at home) and at night (depending upon how many lights I have on, the SxS headlights are separate from the other lights) I will have between 4 to 8 hours of battery usage longer if I use only 1. Then during the day, they are recharging. They are completely waterproof which is good because I did buy 1 and it was water resistant (not the same thing, it did stop working won't mention the product). I found out because I wanted to know how water resistant it was, so I left it outside during some local rain storms we had before going on my trip and that's how I found out the difference between water resistant to waterproof. I did the same thing with these and I had no issues yet. While on my trip we had very good and hard downpours. However I did bring my battery chargers (just in case) to help out if I had problems with the panels. During this part we had a storm move in and it was agully washer of a storm. The storm lasted 2 days and at times it was pretty dark during the day so charging was hampered. If you ask me would I get another 1, "YES" would be my answer even as a gift. I hope this helps you, I am always trying to find ways to just get another panel but the 2 I have are doing the job. No regrets

I purchased this solar panel kit after I found out my car battery was draining because I wasn't driving enough. I was a little skeptical at first but ready many reviews. I put this in the back driver side window as my house faces north east. It gets great sun and tops off my battery. Now my car starts right away and strongly! Nice design with suction cups to mount to your windows and I only had to wait 1 day to see a difference in the way my car started! Decent charge speed, basically trickle charge. Easy easy easy to use. Just find an outlet that is always on and plug it in.

I'm happy with the product I'm just not happy with the delivery company the digital delivery because the first one got lost in their hands and I and I had to get it reordered I got a reorder I got it yesterday and I made sure it's working so other than that I'm thankful and thanks you guys for pushing issue of refunding my money and sending me the new solar panel thank you

Very useful for keeping full start battery charge in a vehicle that has power draw all the time but is not used daily. Set on dash and plug into cig. lighter outlet.

High quality item