I am very disappointed with this charger. After my mechanic diagnosed my 2018 Chevy Silverado with a very low battery drain (he thinks it's computer related and difficult to troubleshoot), he suggested I try a solar charger. I did a lot of research and based on the reviews and the seller's insistence in the Q&A, I settled on not draining the battery. I gave the thing a few chances, tried different connection options and made sure it got plenty of direct sunlight. Well, the good news is that I also bought a jump pack, just in case. The bad news is I've had to use it 3 times already (luckily it works great). I may have a defective one, but I will not order the same one as a replacement. I'll go back and try something different.