I was wondering how everyone charges/maintains there 12v battery's for their trolling motors. I don't have an onboard battery charger and have read about battery maintainers that trickle and turn on and off to keep your deep cycle battery's charged. Are these maintainers a fire hazard? I get concerned leaving these on all the time. 

You have boat insurance id assume? Thats essentially what an onboard charger does as well. It charges then switches into a maintenance mode similar to a maintainer.

I pulled mine out due to the cold.  Keep them in the garage (while not exactly "warm" it is warmer than the single digits outside).

Put them on the charger every other week or so to keep them up.  You can keep them hooked up in the boat as long as there is adequate ventilation so any gases don't build up due to charging.  Just make sure the charger has a float or maintenance mode and doesn't supply full amperage all the time.  That could destroy a battery as well as create a big mess in the boat.

I do have boat insurance but I leave my boat far away at a vacation house. And I don't have a on board charger because I leave it moored all summer long and there is no power at my slip 

Well it may seem like a pain, but I would pull the batteries take them with you and do what was said above. I got a decent charger maintainer from Wal-Mart for around $20-30 dollars. With safety mechanisms on these chargers, if there is a problem, they cut off. 

OR

Find a better dock slip with power.

OR

Get some cash ready to buy new batteries.

Yea I am going to get 2 cheap battery trickle charger/maintainers and keep the battery's in my house. I'm looking at either battery tenders or black&decker.  What brand do you use and do you like it?

My slip is Free so I can't complain! ?

I'm using a couple of old Battery Tenders that were laying around the shop.  We upgrade them every couple of years.  A couple had chewed up cables that had been thrown away.  I repaired the cables and they work fine.  Any brand will work as long as it has a stepped charging system where it goes into a maintenance mode after fully charging the battery.  Make sure the charger matches the type of batteries you have, i.e. flooded, AGM, Lithium, etc.  Chargers that work for the flooded type may not be adequate for the higher end batteries.

Schumacher XC10 10/6/2-Amp Battery Charger

I had different "toys" with different batteries so this multiple Amp one works good for me. It also auto senses the type of battery.

I got a battery charger from bass pro for 12/24v two bank its made by promariner

I use three Schumacher SC-1200A/CA SpeedCharge 3/6/12 Amp Charger/Maintainer/Testers.

Work very well as an out of boat / portable charger, maintainer & tester. 

 Compatible with both 6 & 12 volt batteries.  So it pulls double duty for use on the tractor, lawn & garden as well as snow removal equipment.

One baby sits the GTO all winter for me as well.

A-Jay

I have the Schumacher 10/6/2 charger but I didn't realize that it is a maintainer also... I thought it would continually supply 2A at a minimum. Does it ever turn off "float" and turn back on when the battery loses some charge?  I do like this charger however I did find it can be loud. Are all chargers this loud? 

Where I live the temps can dip into the -20 over winter. I pull the battery's in the fall, put the battery in the basement and hook the batteries up a few times over the winter to keep them at full charge. No need to leave a battery charger hooked up to them all winter.

Edited January 9, 201610 yr by IntroC
just cause

I have the Schumacher stated above. 2015 model.  Great unit.  I also have a 1969 Schumacher trickle charge.  Still works.  

Battery sits out in the garage.  About once a month a put the charger on it for a few hours.

Mine are in my basement on these

http://www.amazon.com/Extreme-Max-1229-4000-Intelligent-Maintainer/dp/B00K72C1T4/ref=sr_1_3?ie=UTF8&qid=1454249751&sr=8-3&keywords=battery+maintainer