SUNER POWER Waterproof 12W 12V Solar Battery Charger & Maintainer Pro, Built-in UltraSmart MPPT Charge Controller, 12 Volt Solar Panel Trickle Charging Kits for Car Automotive Boat Marine RV Trailer

UPDATE: My initial review of this Suner Power BC-12W-Pro solar battery charger was one star, because it just sat there and did nothing and neither I nor Amazon could get any response from Suner. I suspect that Amazon didn’t really contact Suner, because once Suner saw my review they contacted me and have been VERY responsive, even on nights and weekends. Mason of Suner Power walked me through some very simple tests requiring nothing more than a digital voltmeter and some sunshine and explained where I had erred. His diligence, my patience, the tests, and my better understanding of how to use and what to expect from a small solar panel resolved every issue efficiently and gave me faith in the company and its products.The initial problem with the panel was that it refused to even detect any of four automotive batteries I hooked it directly to via Suner’s battery clamps. Their instructions didn’t make it clear that the panel must be in sunshine just to detect a battery. Once Mason explained that to me, the panel came alive in the sun as verified by its informative brightly blinking LED.The next problem was that the panel still couldn’t detect a fully charged battery, let alone a marginally charged one. The third and most frustrating problem was that I could not contact Suner Power. The support and technical email links on their website did not work and Amazon’s call to Suner on my behalf got no response in more than a week. When frustration morphed into anger, I ripped Suner Power a new one in a one-star review here. THAT got immediate, clear, very helpful, and ultimately very effective responses from Suner. That bumped my rating to two stars, but I still couldn’t get any … you know … CHARGING from my charger.Suner/Mason then very generously sent me a pre-tested replacement and has continued to work closely with me to perform simple, sensible performance tests on both the original and replacement panels. Still, many hours of comparison on multiple vehicles in various stages of charge in various lighting conditions produced negligible charging.I have graduate degrees in engineering including many courses in electronics. I’ve been an avid automotive DIYer for many decades. I've installed big rooftop solar systems on two RVs and fixed automotive electrical problems that left me stranded and subsequently stumped dealers and independent garages. Yet this time I was stumped. Where does that leave the average consumer?I finally found the “secret” to making the panels work: Hook them up and let them sit in blazing sun for half an hour. Only then did the voltage start to climb, ultimately to a reassuring 13V or so. Once that happened, I switched panels and the second one, the one that initially couldn’t detect a battery, quickly detected the battery and hit 13V. I anticipate that the Suner Power 12W panel will work even better on the small 18aH jet ski battery mine is intended for.At this point I suggested to Mason that adding comments addressing these three additional caveats in their otherwise thorough instructions might save him and his customers a lot of time and angst:1. Even for a panel to simply detect a battery, the panel must be in sunshine.2. A quick operational test is insufficient. It may take up to an hour for a panel to boost a fully operational but marginally charged automotive battery’s voltage to 13 volts, even in bright sunshine.3. To contact Suner Power, customers must manually type [email protected] or [email protected] into an email address window. Clicking on those links on the Suner Power website does not work.My only remaining dilemma was how many stars Suner has earned at this point. Just 3, because even though the panel works fine now, an initial glitch and shortcomings in the instructions thwarted the anticipated no-brainer plug and play? Naah … maybe 4 because it now works due to my better understanding? OTOH, how about 5 because of Mason’s outstanding, and these days rare, support? Yeah, let’s do 5, and hope that Suner Power adds a couple of comments to their instructions. That’s a cheap and hopefully helpful fix.

I didn't know what to think about this and if it would work for my situation, but the price was right so I went ahead and ordered it. I have a car that doesn't get driven enough and it sits in my driveway. The battery ends up dying and that ends up being a big pain getting it jumped or recharged or replaced. So, I picked this up thinking I didn't have anything to lose. I tried using it with the cigarette lighter attachment, but that doesn't work in my car if the car isn't running. So, I ran the included alligator clips to the battery through the door and hood, and...it works! If I'm not going to be using the car I just hook it up, put it on the dash, and I'm good to go. My battery stays charged with no work on my end. Glad I bought it.

It keeps the battery charged, even in cold weather and the vehicle we have it on does not get driven very much, maybe once a month.

I like that the size is not overly obtrusive, and it's got plenty of length in the cords which is a huge plus for me as it doesn't limit where and how I decide to connect the solar panel to my battery. That being said, I have an older 2000 Toyota 4Runner and it's one of the models that does not work with the cigarette lighter which my sister said to use. Her husband used to have a collection of cars including Ferraris and $400,000 Porsches etc. all on trickle chargers but unfortunately I tried that mode and it will only connect while the engine is running which defeats the purpose! The small clamps are covered in cheap plastic and just barely fit around my battery terminals but they seem to work and send a signal. The third option doesn't look like it goes with my traditional type of (EFB) battery even if I unscrew the bolts and put it underneath. I'm not sure so I'm going to have to ask my mechanic because the kind that could just attach to your terminals without clamps. I could leave on and just disconnect and connect at will. The photos show a different type of battery for that straight wire connection so it looks like I am stuck with the clamps. I bought a 4 pack of round Dyi...?(you can find it by searching rubber coated magnets ) that won't rust or hurt my car and actually attach strongly to car. I read a lot of reviews on a lot of different magnets and many of these magnets won't even stick to stainless steel. You can't really attach them to this all on their own so what I did was I glued two of the magnets that are the exact size of the suction cups and added them to one end/side of the back of the board. This magnetized the board very strongly to the top of my roof and I was able to put up an angle on my roof rack. (See pictures ) It's not going anywhere! I don't know if I would want to attach it to my window as I'm not a big believer in suction cups holding in extreme circumstances like the magnets would . I have every confidence that these magnets will work through my car cover when I put that on. I sure wish I could've used the cigarette lighter but cannot so don't expect it to necessarily work on your car or think that it's defective because it doesn't light up on your model. It's charging right now so I will get back in a week or two to see if it stays fully charged. I know some people are recommending that you buy a battery status contraption for another 40+ dollars that if you get Bluetooth and you stand within 30 feet of your car it will give you the status of your battery health. I don't know if I need to go to that extreme. It's for a car that I don't drive that often, either of them that often, so I always have to worry about the battery. I sure hope for the price that this last for a while and from some reviews it seems to kind of be hit or miss so check the status light fairly frequently.

I was very pleasantly surprised with this product, I used it for three months, 90 days, as a snowbird and it worked great, when we returned ,the car started with no problem. Highly recommend.

charging truck .it sets a and all the electronics like any car truck auto will eventually drain down the battery i don't drive it often so wanted something to keep electronics from draining battery seems to be working just fine 2 weeks and still good start up on truck , attachments are nice to have also .i would buy again and recommend for that not being used car or boat or just to keep up to peak .takes a while to get to full depending on amp hr and size of battery but will work as long as sun is out .

Works great! Keeps battery charged even in grey, cloudy conditions.

Use to charge my battery on dump trailer. Works excellent