Proper battery charging protocol

What is the proper way to charge your batteries. I leave mine on the charger until I use my boat next. That might be one week to one month. Is that bad for the batteries? Friend of mine only charges his the day before he goes. Who's right?

I top mine off when I get home and unplug after they charge. The day before I go back I plug them back in until the morning I leave batteries last along time for me never a problem.

I leave mine plugged in anytime it is at the house. The onboard charger I have fast charges, then floats and maintains them until the next time they are used. The charger is designed to be left on as often as possible.

Depends on quality of your onboard charger. I was just checking out the operating instructions on the dual pro I have and it actually states " We recommend that you leave your system plugged in. This will reduce sulfation on the lead plates of the batteries and allow your PCS charging system to keep your batteries fully maintained and ready to perform at their best."
I personally didn't know this and unplug my charger after they are fully charged.I also plug them in the night before a trip just to ensure full charge. This method has served me well for about 18 years.

Open beer, take a drink, plug in the charger and back to the beer. Works every time.

A big opinion discussion often ensues when discussing battery charging as there are opinions in several camps. One thing that no battery-knowledgeable person would ever do that's quoted about the friend above is: Leave the batteries in a discharged state for any length of time.

For sure:
1. Discharging a battery takes a toll on it, which is why they don't last forever.
2. The deeper a battery is discharged, the shorter its service life will be. This is why higher capacity batteries last longer, assuming all other characteristics are fairly equal.
3. The LONGER a battery stays in a discharged state, the more pronounced the impact of that discharge cycle will be.
4. You give a battery the best chance for a longer service life if you recharge it ASAP after any discharge cycle.

So, the buddy who doesn't charge his batteries until he's ready to fish again is killing those batteries faster. Today's high tech smart chargers have a microprocessor controlled profile that includes a high-frequency desulfation cycle that can help extend battery service. They also have a smart float mode that avoids evaporating excessive amounts of water from the electrolyte. This "boil-off" was a reason that chargers were once not left connected.

I vote for the following with respect to conventional lead-acid batteries:
1. Charge ASAP with a good smart charger.
2. Leave it connected, but keep an eye on it and the condition of the batteries.
3. Check electrolyte level after charging at proper intervals for your level of use; fill properly using only distilled water. You'll have to learn by experience how often your batteries need water replenished.
4. Use a battery cut-off switch for the main battery.
5. Be sure to flip the TM breaker or unplug the TM. (Read TM manual to discover you should do this.)
6. Use an AC supply surge protector with your charger. This step is cheap insurance.

I bought a small 2 outlet surge protector made as a small box. It isn't waterproof, but I can protect it under the deck in a place where rain doesn't get to it if charging outdoors on a trip. IF something funky happens on the AC line, the surge protector makes it less likely that my expensive charger will get fried.

Ever had an extension cord stolen? Use a small shackle padlock to secure the cord to a transom eye of your boat. The padlock lets the cord pass through, but the plug and receptacle on the ends are too large to do so. Stealing the cord would require cutting the lock or cutting the extension cord itself. This could be an adequate deterrent.

For sure:
1. Discharging a battery takes a toll on it, which is why they don't last forever.
2. The deeper a battery is discharged, the shorter its service life will be. This is why higher capacity batteries last longer, assuming all other characteristics are fairly equal.
3. The LONGER a battery stays in a discharged state, the more pronounced the impact of that discharge cycle will be.
4. You give a battery the best chance for a longer service life if you recharge it ASAP after any discharge cycle.

From being in the golf business, dealing with golf car batteries, for the last 40 years, take these statements as battery gospel.

SE Kansas grass grower

I agree with all said here. Also like the pad lock idea.

Thank you for your in depth responses. I have believe my charger has the cut off sensor on them so I should be good leaving them plugged. I love TFF and people who share their insight. Has helped me tremendously over the years.

I was one that left mine connected all the time until I had a battery blow up in my boat. My charger failed and supplied 14 volts to the battery non stop. So make sure you check your batteries often.

You are correct about due care, hence my statement:

2. Leave it connected, but keep an eye on it and the condition of the batteries.

Quite often I take a peek into the battery compartment. I put the back of my hand on the side of the batteries to feel for heat. If overly warm long after the charge cycle should have completed, I worry about a shorted cell prompting the battery to attempt to pull it up, or about a failed charger itself.

A few years ago I had a very catastrophic battery failure in a truck I was starting. The belief is that a plate warped when the high current surge for the starter initiated. This resulted in a significant and rapid "expansion" of the entire case. The terminal posts were blown off and very little of the case sides remained. The top was in several pieces. I think a person a half mile away would have heard it. Being that I was sitting in the driver's seat in silence when I turned the key, it took me quite some time to regain my composure after that event!

Thank you. The padlock idea is my own original idea. I have a couple of epic trips in the works and have been thinking through how to slow down some of the separation of me and my stuff - or at least make it less convenient to take.

My power-poles mount to a plate sandwiched against the transom, so taking the bracket is difficult. But, Power-Pole theft = 4 bolts and snip snip to the hydraulic tubing. I've seen a $100+ solution per pole that's nice but a bit much! I am still working on ideas to slow them down or cause a thief to decide it's too much trouble. One is to add an appropriate hole to the square mounting plate near the edge. Use a good quality armored shackle lock on it (if that fits, need to check). Another is use a proper length "bolt style" trailer coupler latch lock on a hole added to the PP/bracket. The locks can easily be removed before launching for a day of fishing.

Yes this for sure and if you don't have built in battery chargers I HIGHLY suggest charging all batteries equally at the same time. Also on boats I've owned where there was a 24 volt system for the TM and same for the 36 volt systems, I found my batteries lasted longer if I ran the TM using all the batteries and adjusted the speed accordingly. I found if I ran on 12 volt and 24 volt in high stress situations the battery that was taking all the load in the 12 volt mode give up a lot sooner than the others......discharging them evenly really seemed to help with battery life...........

After working 11 years for a battery factory I can tell you that you need to get them on charge as fast as you can or they will develop memory and will show a full charge but will not be at full capacity (this a for the conventional type battery there are a few new styles of batteries out now that I am not familiar with). Also it is not a good idea to leave them on charge very long after they are fully charged unless you have a battery maintainer charging system. And yes you should recharge them the night before you fish just to ensure that there was no kind of discharge which is common with batteries while your boat is sitting in idle. Good luck

This is what I wonder about. I have heard you shouldn't keep the on-board charger plugged in for extended periods but I am guessing there are some 'smart' ones where this is OK to do. My charger is an old Guess 2-bank charger and I think I would be concerned to leave it plugged in for a month or two if I wasn't able to use the boat for a while.

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.