I leave my boat at the shed at the lake sometimes for a month or so at a time without using it. It has two deep cycle marine batteries that when I get on the lake are usually about 50 percent or so used up. I live an hour an a half away so I need a battery charger that will charge those rascals up and be able to stay hooked up for long periods of time to keep it ready to use when I finally get a chance to go fishin'. I bought a Vector Smart Battery Charger about two years ago and it has been messin' up. It shows that the battery is not chargeable when it is a new battery and won't charge it. (not so "smart") It did this while I was gone and let two one-year old batteries sit dead for 3 months. Am sure the new batteries are good as I put them on another charger and charged them up fine. That charger isn't one that you can leave on it for a long time though. Anyone know of another charger that will work good. thanks.

You can get either the Minn Kota or Dual Pro on-board bank charger (both are top quality Minn Kota's warranty advantage) and also get a plug in cycle timer and set it to come one for 2 hours every day and that should keep them fully charged just don't run off and leave them for more than a couple of weeks without checking the water level. In fact it would be best to check and fill the water level once you put it up. Charging for extended periods of time will boil off the water and burn the batteries up if neglected.

The newer chargers reduce their output as the battery charges thereby allowing you to leave them on for extended periods of time without harming your batteries. I leave mine on for weeks at a time and have been getting 3 or more years life cycle out of them. Before getting one of the new chargers I could maybe get one year per battery, maybe slightly longer but, never even two years. Now 3 years and I'm actually working on two trolling motor batteries for the 4th year now.
I have had to replace the charger once so nothing is perfect!
Okie Bob

Thanks. What charger do you use? I have been looking at Cabela's Advanced Anglers ProSport II. The 2 bank 8 amp one. Is this the new kind that you are referring to? Cabela's charger

I don't know anything about the Cabelas units but, suspect they are good. Battery chargers are not rocket science~ I have used Minn Kota and the ones by BassPRo. Read the specs on them and get one that says it decreases the charging rate as the battery charges and they say you can leave them on for extended time.
I suspect all the better (more expensive) ones do this now.
If they charge using a pulse that is even better!
There is one at Battery Plus that uses a little solar panel you can lay over your motor cover, it pusles too. Very slow charge rate. From what you said in the beginning post, you don't fish several days in a row, just one day now and maybe another day next week? If so a 2 amp per bank charger would probably work for you. If on the other hand you go all day today and then plan to get up and go again the next day, you need at least a 10 amp per bank charger. See where this is going? And if you have three batteries you need three banks.
Hope this helps.

Thanks for the info OkieBob. I got a MinnKota 6 amp charger today at Academy. Directions say it'll charge two batteries hooked up parallel which they are. I'm takin' my old reliable 10 amp Schumacker to the shed for a backup and in case I decide to stay and fish a second day. Hope to get the MinnKota installed tomorrow. Thanks again!

I have a timer set on mine for 4 hours a night after I get it fully charged.