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

5-Star Review: ⭐⭐⭐⭐⭐ Best Solar Battery Maintainer I’ve Ever Used – Truly Set It and Forget It! I picked up this SUNER POWER 12V solar charger maintainer for my car battery here in Pennsylvania, and it has been outstanding. The plug-and-play setup was ridiculously easy — multiple connectors included, suction cups for quick mounting, and it started charging the moment I hooked it up. No complicated wiring or settings required. The Ultra-Smart MPPT technology really delivers. Even on our cloudy and rainy days it keeps producing power, and it charges year-round without any issues. The 3-stage charging (Bulk, Absorption, Float) is smart — it tops the batteries off perfectly and then switches to maintenance mode so there’s zero risk of overcharging. My batteries have stayed at full voltage for months now with basically no effort on my part. Tips I’ve learned for maximum effectiveness: • I mounted mine south-facing with a slight tilt (around 35-45 degrees) and it gets great sun exposure. I wipe it clean every couple of weeks to keep the high-efficiency solar cells performing at their best. • Connecting directly to the battery terminals gives the strongest charge. I leave it on my boat and RV all season — rain, snow, or shine — and it just works. • For winter storage or vehicles that sit a lot, this thing is perfect. It automatically stops when the battery is full and resumes when needed. True maintenance-free operation. How I test it with my multimeter (super easy): I check it every few weeks to confirm it’s working great. Set my multimeter to DC Volts and measure across the battery terminals — a healthy battery sits at 12.6–12.8V when fully charged. After the maintainer has been on for a bit in the sun, I see it climb and then stabilize nicely in the 13.2–13.8V range on float. For current, I switch to DC Amps (10A setting), put the meter in-line on the negative side, and in good sunlight I usually see 0.2+ amps flowing in. Even on overcast days I still get a useful trickle. If you’re getting near zero in bright sun, just double-check your connections and panel angle. This maintainer works with everything — flooded, AGM, gel, and LiFePO4 batteries. The build quality is solid, the safety protections are comprehensive, and it’s survived everything Pennsylvania weather has thrown at it so far. If you hate dealing with dead batteries or constantly dragging out a charger, get this. It’s been one of the smartest and most useful purchases I’ve made for my vehicle. Worth every penny — highly recommended!

I have a late model 5th gen 4Runner, purchased new. It isn't driven very often: after two years, it has amassed a whopping 3000 miles :) Great vehicle for me, but unfortunately, the telematics on this vehicle (SOS button, auto dial in the event of a serious crash, etc.) pre-dispose it to parasitic battery drain. This is a common problem for these vehicles if driven infrequently, a Toyota problem; my 15 yr old Ford P/U has similar telematic features but cranks without fail, even though it gets the same intermittent use. After replacing the battery twice on a virtually new car, I tried this solar charger. I've had it going on three months now. I leave it connected to the terminals and disconnect it quickly, using the quick disconnect lead included by the manufacturer. It stores easily in the seat pocket behind the driver seat. Compact, weatherproof and durable with nothing to switch on/off, it comes with an led indicator to show what it's doing once connected. Blinking green shows 'ready' and blinking red indicates current is flowing to the battery. Circuitry prevents over charging. As simple as that to use. I monitor the charging performance and battery state using an Ancel BM300 Bluetooth Battery Monitor ($35 on Amazon) which sends info to my cell phone at designated intervals or on demand. The battery is always topped off and ready to go. Problem solved. The Amazon listing shows suction cups that permit sticking the panel to a suitable surface while in use. I didn't receive suction cups with my charger (an omission, I believe) but that's not a problem. I affixed four coin-sized magnets to the reverse side which secures it to the hood or roof when in my driveway. If using it in a less secure location, I would keep it inside the vehicle, flat on the dash. The harness has a generous length, making routing to different spots simple. Would I purchase this again? Yes. 5 stars for simplicity, performance and ease of use.

*** update*** one of my best purchases! Changed it from four stars to five because I had not had it very long. This thing is fantastic! I have an older 2000 4 Runner where if I don't have a stronger battery like an AMD or EFG the battery is dead in three days without driving. There's a constant known drain on these Toyota's. The stronger batteries last about three weeks before they start to slowly disintegrate in charging. After having to get a second EFG battery the mechanic down the street told me to get a solar charger. I read lots of reviews and this is the one that I decided on. I had my portable jumper with me today prepared for the battery to not be working because I literally have not driven it in at least three months! I thought no way!?? But yes, it started up like a perfect brand new battery. I brought the charger on my errands because I thought maybe when I stopped it will discharge but no, it started right up again! I love this thing! Remember if you're gonna let your car sit to have a full tank of gas for the Health of the tank*****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.

This thing is pretty sick. I had a car that sat for about 2 years and was jumped started and ran maybe twice, needless to say the battery was dead. I actually bought this with the intention of using is for a winch setup that I haven't gotten around to, but I threw it on that car battery expecting it to fail, it did not. It was one of those random thoughts that popped into my head, I put it on later in the evening with only a few hours of sunlight left and went out and started it around noon the next day and it fired right up. I've been able to place it on a battery and fire up the vehicle in a matter of hours. I'm not necessarily saying it's a permanent fix, but after consistently keeping it on the dead car for about a week, I've been able to drive it for months now without it needing to be hooked up. The only real negative I have is that the build quality isn't the best. I've had the casing pop open on me a few times when I'm removing the suction cups, it's not a huge deal, it snaps back together, but it happens consistently, which can be annoying for daily use.

Works great for my parked car at my second home. Keeps the battery charged. One potential concern. The unit does get warm. I purchased a silicon mat to place under it vs potentially damaging the dashboard.

I was rarely using an old BMW and was always confronted to a dead battery on the rare occasions where we needed a second car. This solved the problem. Very easy to install on the windshield and it connects to the cigarette lighter. Considering a dead battery costs you $200 to 300 to replace, it definitely is worth investing in this device.

Keeps my 2500 GMC truck battery fully charged

Five stars to get high on the list. In reality, zero stars. Regardless of what the flashy lights tell you, the two chargers I purchased wouldn't charge a double A battery let alone a 12v automotive battery. In full sun, all the blinky lights show red (charging) batteries started at 12.7v and 12.1v one week later batteries are 12.6v and 12.1v. No chargy

I've had it for 2 years and its saved dead batterys and brought many things back to life lol I want another its been sitting in the snow and rain and sun and still works great

Using to keep our generator battery charged. Working well as needing to run the generator at the moment.

Bateau sans « shorepower ». Super 👍👍👍

Even though the flashing green lights indicates it’s charging I didn’t verify output when installed. I went to start my boat the the battery was dead. After putting a meter on it was reading -5 to + 6 resulting in draining my battery. Unfortunately I can’t return.