I'm battery dumb no doubt, I do charge trolling batteries as soon as I come off the water, and do pretty good through the summer because I use the boat a lot.
This year I have my boat stored in a rental storgage facility, and I have put a charger timer on the trolling motor batteries. It charges the batteries for 18 hours every Friday. So far this has worked great. One thing I was told is never charge your batteries with the access door closed down. The fumes are very
toxic and over time can damage tubing and wiring, so I always leave it open. I also turn off the trolling motor power and the main power switches,...
so far so good.

I learned a hard lesson when I failed to check the water levels in my batteries. Had one blow up while I was out alone and it scared me to death when the smoke poured out of the compartment. I gingerly went home and opened up the compartment to find anbusted opened battery and acid burned some of my wiring. The cost of that little lesson was enough for me to check levels every other time I go out.

I keep the charger plugged in until I take it out and then plug it back in as soon as I get back in.

I keep a check on the water and when needed use only distilled water to refill. Plug the charger up as soon as I get off the water. And if the boat sits for a while I plug the charger up ever few weeks just to top them off.
I have not had the boat out since the end of Oct. And have plug the charger up ever now and then. Went out today and plugged up the charger and went back and looked at it in ten minutes and all the batteries were saying they were fully charged.
My last starting battery lasted six years. And usually get three years out of trolling motor batteries

This is the only thing I disagree with in your post. For the life of me I can't find the source where I found this information, mostly because it was some 7 years ago when I started in the battery industry. The basics of it was that every battery has only so many cycle lives, so draining from 100% to 0% is one cycle, same goes for draining the battery to 50% and recharging twice. There was some good reading on this, maybe I can find it tomorrow while I'm at work.

Chad,

Let me explain the reason for my simplified statement, and then I'll give you some info from Trojan that backs up what I said.

Let's agree that we're discussing traditional flooded wet cell batteries and that all have a "discharge profile" engineered into the design depending on the intended service. This is set in the specifications and will vary by battery model and by manufacturer. "Discharged" doesn't mean dead, as in nearly 0 volts, of course. I have seen manufacturer recommendations that encourage discharge to not less than the 50% charge level, but any specification assigned for a battery is whatever it is - but it should be heeded. It's not uncommon to see a notice such as "discharge beyond xx% is not recommended and will result in irreversible damage".

We have two identical boats with identical loads and trolling motors. One boat has two batteries with 205 Reserve Minutes each, and the other boat has two batteries with 150 Reserve Minutes each. The batteries are from the same manufacturer and product family - their only difference is Reserve Capacity. The TM on each boat gets run for the exact length of time. Each motor burns exactly xxx watt-hours of energy in the course of the trial.

At the end of the trial, each battery is properly measured. The boat with the higher capacity batteries discharged to a remaining charge level of 65%. This is noted as being within the manufacturer's recommended range. The boat with the lower capacity batteries burned the same number of watt-hours of energy, but there was less stored energy to draw from. Those two batteries are found to have a remaining charge of 30%, meaning they were 70% discharged.

Our example manufacturer recommends that batteries not be discharged beyond 50%. Repeat the above example once each weekend. Which set of batteries is going to need replacement first?

Now, here's some of what Trojan says:

Shallow discharges will result in a longer battery life.
50% (or less) discharges are recommended.
80% discharge is the maximum safe discharge.
Do not fully discharge flooded batteries (80% or more). This will damage (or kill) the battery.
Many experts recommend operating batteries only between the 50% to 85% of full charge range. A periodic equalization charge is a must when using this practice.
Do not leave batteries deeply discharged for any length of time.
Lead acid batteries do not develop a memory and do not need to be fully discharged before recharging.
Batteries should be charged after each period of use.

Please note that I was not aware of this info published by Trojan when I wrote the prior posts; I found it only tonight when searching for info to share in support of my own recommendations.

Man just put a T-H Alarm on your boat problem solved trust me your not taking power poles off without it going off lol

Flippin,
After reading your second post and rereading both mine and your original, I think we're saying the same thing but in a different way.

I did that too! ....The boat already had a locker-bar with the alarm lock. I've seen LOTS of stuff stolen over my lifetime of fishing. I know I won't stop it if they truly intend to take it. But, I can make it inconvenient as all get-out, and slow them down to the point that someone may come along and spook them away. I might come by to say howdy too....

+1

I have them on a timer. Every morning it turns on for 45 minutes, then turns off and that way, they're always topped off. No problems with them overheating this way. Of course, I always charge them when I get back from fishing.

You are....

If he only charges the day before he uses the boat he is shortening the life of his batteries. His batteries are sitting in a discharged state and that is not good for a battery.

I guess at this point I'm wondering: who does not have a "quality AUTOMATIC battery charger"? While small changes to this industry still occur automatic chargers that monitor the state of the battery charge have been around for a long, long time. If you are still using an old automotive charger that simply cranks out the factory set amps until you unplug it you are wasting your time...and batteries. Even if a high-end $800 built-in 4-bank charger is not in your budget there are lots of cheaper battery chargers, even portable ones that are "automatic". Plug it in and forget it.