Well this is just what I know about onboard chargers. 1. It is really the only way to go, they are a plug it up and forget about it till you go fishing item. 2. they are great for maintaining a battery, if you use the old style of batteries that you have to add water to, you have to check them more often to keep them from going dry. 3. Onboard chargers only charge to 85% of capacity, so if you want a 100% charge you still need to top the batteries off with a regular charger, I learned this the hard way during a couple of bass tournaments when I ran the batteries dead knowing that they showed a full green light charge. I actually called the manufacter to get the info. They said that at 85% the chargers show full charge and go into a maintanace mode. 4. If you are out fishing and are staying in motels they are nice because they aint easily picked up and walked away with, and it is one less peice of equipment to pack, store, and repack at the end of the trip. 5. They are easy to install, and depending on the number of batteries you have, you can get chargers with multiple charging banks in them so this means you can get multi battery charging from one small unit.Thumbs Up Thumbs Up