Installed this under the hood of my 2003 GMC 2500HD to keep the battery charged. Truck kills batteries in 5-7 days since new. Dealer and GM could not find of fix this trouble and told me to "drive it more often." This is my last GM product! Charger is easy to install and I ran the cord out of the grill so no need to open the hood every time I use it. NOw I have a fully charged battery no matter how often I drive the truck. Best $20 I have spent in a long time.