My boat is in a slip this month at a private marina and taking my 2/10/50 amp charger down there is a pain.

I know that some cheap chargers will RUIN a battery in a heartbeat by not shutting off when they should ...thus overcharging. ( had one do it)

Who makes a cheap onboard two bank charger that's KNOWN to be reliable?

This marina is a long drive from my place and I want to be able to leave it on all the time without worrying about it. Not crazy about buying two new trolling motor batteries due to a bad charger....but I dont want to spend a ton on one either.

2-4 amps per battery will be fine, since it will charge at least 24 hours before I use it again.

There's a Bass Pro here in town, but I didnt see much on the website.

Depends on what cheap is. To the best of my recollection, Academy has a 2 amp Minnkota on board "maintainer" for $89.00.

You can always do what I did. Get you a good heavy duty timer (outdoor light) and just set it to run for an hour a day with the battery charger plugged to it.

Go with a Pro-Mariner Generation 2 Charger, 2 bank 12 amp. It will bring your batteries up fast if you need them quicker plus it is only about $139.99. It is more than the 2 am maintainer, but you have to remember, the maintainer is just that, it really isn't a charger. If you burn those batteries down hard, the maintainer may not ever bring them up.

I Haven't had any luck with any I have had not burning up the batteries quickly. I installed a Stayncharge system. I know this does not meet what you need. The best I have used is the Dual Pro.

http://www.dualpro.com/