A very tough panel and waterproof. Lots of connectors. I did notice that the battery clamps were thin metal and corroded when left on a battery for a long period of time. Otherwise just a fantastic productPretty good product. The one on my boat has kept me charged without issues for a year. The one for my lawn tractor failed after 6 months. Since there's a 12 month warranty, I called and emailed the US location for TopSolar but got no response at all. 5 stars for the boat charger, zero for the customer service.So I get a green LED indicating "normal working", and I can reverse connect it, and see the polarity reversal LED works. However there is zero output. Cables are all good.I also bought the Top Solar 100watt portable folding panel, and that one is great!I am a EE, and power supplies are a specialty of mine. So I am technically qualified to say this thing is inert, there is zero output whatsoever. I have some spare charge controllers, I may just swap out the charge controller, or repair it. I see it has a missing diode, d4, but the silk screen doesn't say what kind it is. I may be able to replace that and it might work then... I'll have to see if I can look up the main chip and see if I can find a circuit diagram.A good charge controller costs more than this little panel, and will probably out live the one in the panel, so I'm not sure returning for replacement is worth it, if I will want to replace the charge controller anyway. The output from the panel under a tiny led desk lamp is 13v open circuit(measured internally) which is fine, so for me I'll just put a different charge controller on it and call it a day.But yeah, this slipped right past qc checks. The LED's pass, but the input and output are not connected in the middle somewhere.UPDATEAdded a star back when I got it working...So I added a $1 boost converter to pump the voltage to the nominal value for a pv panel rated for 12v (about 17v) and then fed that to a conventional battery charge controller. I have three different charge controllers I'm trying out, two I bought years ago for my larger panels, and a new one that is programmable for different battery types. I'm going to see which one has the lowest overnight current draw (I think they all take *some*, it just needs to be less than what is pushed into the battery during the day).With me and the wife both working from home, there aren't enough miles put on our vehicles to keep the battery charged.I tried out and returned several brands before keeping this one. The integrated charge controller does exactly what an AC wall powered model does; it applies the correct voltage during the three stages of charging (bulk, absorption, and float).Testing this panel on a fully changed (12.9v) 35 AH lead acid battery with a bluetooth voltmeter the voltage rose to 14.50, held there and dropped off to a 13.20v float charge. That is perfect for lead acid. It only outputs ~0.65 amps best case sunlight so don’t expect to charge a totally dead car battery (maybe a week or two LOL)Pros:- Very durable, you would need to really mistreat/abuse the panel to break it.- Charge controller applies the correct voltage and won’t overcharge.- Has a diode to prevent discharge of battery into the panel in the dark of night.- Should be weather resistant (a light brief sprinkle, not a soaking downpour)- Costs less than other 10 watt panels that lacked said features.Cons:BOTH the panel and the three accessories (clamps, cigarette lighter plug and eyehole bolt wires) have a female receptacle connector. You must use the included cord that has a male plug on each end to connect them.Why?Every DC power supply in existence has a male plug that connects to a female receptacle.. So if you lose/forget or damage the cord with male plugs on both sides you can’t connect the panel directly to the accessories.I took a star off for this break of universal DC connector convention.I have a 12-volt diesel pump with a 100-gallon tank and wanted something to keep the battery fully charged. It's an older deep cycle marine battery so I connected using the included eye-terminals for a positive connection.The solar panel itself has battery charger circuits built in. I had previously owned a similar solar panel but I had to buy a separate battery charger circuit. The four holes in the panel are the perfect size for the wood screws I had. I had thought the holes were too big, but the head doesn't go through and the head sits slightly countersunk in the reinforcement ring. It has been installed for only a few days but the battery voltage was 13.6 volts with the charger installed so my battery should stay full.The only unknown is how long it will last in the semi-desert sun of North Central Washington during the long hot summers. I did mount it on a couple of scrap strips of 3/4 plywood so there is air circulation around it, which should help.It keeps my boat charged and handles rain well. The only thing I'm upset about is the listing was confusing. it was listed with the 20 watt panels. This is only a 10 watt panel.I'd used a battery maintainer ( plugged into a wall ) to keep my bike battery at full charge and the battery lasted a lot longer than normal ( 10 years ). I keep my pickup parked at the curb so the wall plug idea isn't practical. I came across this solar maintainer and thought it should work the same only using solar power instead of PG&E. I have two cigarette lighter plugs in the pickup, one 'constant on' and the other 'ign. on'. I tried the 'constant on' plug first and it ran the battery down overnight (??). I then tried the 'ign. on' plug and it did the same thing. It was sucking power from the battery. I'm not an electrical engineer and had no idea why it would do that. The only thing left meant drilling a hole in the firewall and running the cord straight to the battery. It's been a few months and so far it seems to be working. I need to check the battery voltage. Now, sometimes my remote door lock fob dosen't work. Any electrical engineers out there have a thought?