I don't know a whole lot about charging batteries
within a boat, but I do know that I have to do it often for the trolling motor battery in my garage. Is there a way to just charge it from my main motor while it's running? If so, what are the proceedures? I have been looking at the onboard type chargers, but notice that they all have the A/C power plug (I don't understand that)
I don't have any kind of plug, and was only wondering if anyone knows if it's feasible to hook the battery inline with the main motor to charge it while fishing.

Search some of the recent posts. I think I saw something about this a few weeks ago and I could be wrong but I think they were saying that the alternator on the motor did not have enough output to do much good. But like I said look it up because I did not pay much attention to that one so I could be wrong.

Two ways to charge the batteries -- at home using an on-board AC charger that is mounted on the boat or the on-board DC chrger that uses alternator power as the big motor runs.

Most guys use the AC chargers adn just pull the cord out and plug in the boat after the fishing trip.

I have some striper fishing buds that have installed the DC chargers so they charge while running. Most bass boaters do not run the big engine long enough to do any good, but the striper guys use a run and gun method of fishing that runs the big motor a lot.

Do a search on the TFF as suggested or hit the Guest Battery charger site to learn more -- both are easy installs.

Actually, bass boaters do run long enough. An alternator will charge a battery much quicker than an AC charger. Two run down trolling batteries will get a very good hit from just a five minute ride. I have the Stay 'n Charge which charges while you tow your boat. It has a 30 amp breaker so it won't draw more than that from the alternator. From a rough, windy, full day on Benbrook, the 15 minute ride home was enough to fully charge all the batteries. My AC charger immediately went into float when I plugged it in.