4W Poly Crystlline

Great product, even though the first one I bought warped, and died after about two years. Used every day in my truck, as it is parked unless camping or picking up lumber or jerrends like that. I purchased two 8 watt, and they have to be in exactly the right spot to charge, which means you have to keep moving it also and have a meter to check. (Major return problems). That is why I bought this 4 watt again, and is working great.

I love this little thing! It adds just enough to keep my truck charged and ready to go. I generally park with my truck facing away from the sun so I place the solar panel in the rear window and run the wire to the socket on the dash (continuously on) which works perfectly.

Just to note - this seems to fail about every 18 months - I hope this one doesn't do the same again The Sunway Solar Car Battery Trickle Charger & Maintainer is exactly what I needed to keep my 12V car battery charged and maintained. The solar panel is compact and lightweight, making it easy to position on the dashboard or windshield with the included suction cups. It’s super easy to set up—just plug it into the cigarette lighter or connect it directly to the battery with the alligator clips. I’ve been using it for a while now, and it keeps my battery in top shape, even during extended periods of non-use. This is a great solution for maintaining batteries in cars, boats, or RVs. Highly recommend for anyone looking to extend their battery life and avoid unnecessary drains. ⭐⭐⭐⭐⭐

So I bought this Sunway solar Car Battery Trickle Charger to maintain my 12v RV trailer battery's when the trailer is not in use. The trailer is 28ft and has two batteries hooked in parallel that feed the camper. Having battery power is important because it is needed to open the two large slides not to mention powering lights etc. Initially I hooked the solar panel up without removing trailer connections to the batteries and a week later returned to find the batteries totally drained. I knew there must be something drawing power in the trailer and discovered LEDs, a gauge, and a CO2 detector that was drawing power. After recharging the batteries using shore power, I installed a heavy duty switch in-line on the negative lead leading into the camper. I did this by drilling a 2" hole in the battery cover lid and inserted the switch through the lid cover. I ended up with a clean solution. Using the switch I isolate the camper from the battery bank when the camper is not in use and the solar panel keeps the batteries topped up as as designed. When I need to use the camper I simply turn the switch and power is applied to the camper. The output current of this size solar panel is only able to top up batteries. If you want to charge empty batteries to a fully charged state you will need a larger Solar panel. This panel will do what it is designed to do...i.e. top up batteries that do not have a load. The switch can be found at https://www.amazon.com/gp/product/B07MQ54KKH/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Keeps Battery charged on our boat year round.

Nope. This charger is a parasitic drainer. It drained my battery in just two days after connecting the alligator clips to the battery terminals. It has no diode to prevent drain even though it claims to. Do not buy this charger nightmare.

3 star review for the housing breaking apart from heat. Had for less than 2 week and it cracked other than that it charges my vehicle as intended will have to wait to see if it’ll stand the test of time or if the cracked case is due to internal pressure and failure of the product in time.

This solar panel works great.