Signs of a bad on board charger?

[dmc575]

So planning to hit the lake this weekend. Just went out to top off my TM batteries and plug them into the charger for my road trip this weekend. I charge my batteries 2-4 hours after a fishing trip (sometimes longer/the next morning) since its a 2 hour trip. After fully charged I unplug the charger. If I dont fish for a few weeks Ill plug the charger back in to top off the batteries from sitting every 2 weeks or so.

Ive recently gotten in the habit of testing the batteries before plugging in the charger if the batteries have been sitting unused for a while...since my batteries are barely making it 12-13 months, and by my standards I think I "take care of them". Just trying to keep an eye on them better this round. About a week or 2 ago...prolly right in the middle...I plugged my TM batteries into their charger since I hadnt been to the lake in a while, and I wasnt planning a trip so I could top them off. Before I did that charge the batteries read 12.5....which I was worried about, then I googled that and seemed like that was OK since they had been sitting a while. BUT NOW....they read 12.1.....and isnt that getting real close to a bad battery?

These arent lithiums...but theyre from walmart and my old ones were from Sams. Not the highest end stuff...but their both batteries that have had a consistently good track record in boats....and mine just dont seem to be cutting it very long. 1st set couldve been bad luck...but for these to be heading down a similar path....something has to be wrong. My TM is directly wired to my TM batteries, have it on a circuit breaker used the right guage wire (dont remember exactly but went up in size for what was needed per MKs recommendation to make sure there was no loss even though the distance was short). I used to have corrosion problems on my old batteries on ONLY one of the negatives....but I sprayed these with some red spray that was supposed to help and the battery hasnt gotten more corroded so I think its helped.

Aside from the corrosion.....I dont think anything else is wrong. What can be killing my batteries? Is a full charge to 12.1 reading normal after a week or so of just sitting outside and maybe im just over reacting because of my previous battery luck? Dont think it matters...but boat is always covered unless im messing with it. These batteries arent expensive...but I just bought a new graph and an extra few hundred bucks for batteries definitely is not a good thing.

Thanks.

[bobcoy]

If they were charged to 100% they should not be less than 12.5 or 12.6 unless something is draining them. Do you check your fluid and make sure it is not low? Normal lead acid batteries can loose 5% or so in a month. That is about.6 volts.(half of that in 2 weeks) It depends on the health of the batteries. If you don't charge them to 100% right after use every time they can be quite degraded in a year. Probably a good time to get them load tested. Bob

[BoatNoobie]

Just making sure this is clear. So these batteries were put on the charger about 2 weeks ago.

Then you disconnected them. Checked the voltage a week later and they were at 12.5.

Now a week later, it's at 12.1? And this is for both batteries? Or is it 3? Or just 1 battery?

If this is the case, you have a bad battery or a parasite drain. Are you resetting the breaker to kill power completely to the trolling motor?

I've gotten into the habit of using the kill switch and all breakers just in case.

BTW, what charger?

[CatFan]

If they are getting down to 12.1 between charges, you aren’t charging often enough and are killing them.

[billnorman1]

12.1 volts ain't good after a charge no matter how long within reason they sit. Some trolling motors when connected can draw from the batteries even when turned off.

Spray can hide the corrosion but it's still there I'd bet. Smaller than necessary wires won't use more current, it would deliver less power. I fish a lot but I recharge my Everstarts the moment I get back home. Three years, not a drop of water added, and they work just fine.

You should take the time to get your trolling battery situation set right, failure at 13 months might be in the past if everything is put together correctly.

You say you're going on a road trip, can you recharge them while you're on this trip?

[lpugh]

12.1 volts ain't good after a charge no matter how long within reason they sit. Some trolling motors when connected can draw from the batteries even when turned off.

Spray can hide the corrosion but it's still there I'd bet. Smaller than necessary wires won't use more current, it would deliver less power. I fish a lot but I recharge my Everstarts the moment I get back home. Three years, not a drop of water added, and they work just fine.

You should take the time to get your trolling battery situation set right, failure at 13 months might be in the past if everything is put together correctly.

You say you're going on a road trip, can you recharge them while you're on this trip?

Same for me including no water added in three years, if my boats in the garage it on the charger 24/7, as good as they test now and no water loss, I think another year or more before replacement. Typical for me at 3-4 year replacement's for conventional lead acid batteries
Napa commercial for cranking and everstart grp 29 for TM

[dmc575]

If they were charged to 100% they should not be less than 12.5 or 12.6 unless something is draining them. Do you check your fluid and make sure it is not low? Normal lead acid batteries can loose 5% or so in a month. That is about.6 volts.(half of that in 2 weeks) It depends on the health of the batteries. If you don't charge them to 100% right after use every time they can be quite degraded in a year. Probably a good time to get them load tested. Bob

It takes me 2 hours to drive home from the lake. After I get home I plug in the batteries. Ill leave them plugged in at least a day, but sometimes 2 and 3 days....but they get charged to 100% and are never unplugged unless the charger is displaying a full charge. They were fully charged less than 2 weeks ago. Didnt check the fluid yesterday, but did a couple weeks ago and it looked ok.

Just making sure this is clear. So these batteries were put on the charger about 2 weeks ago
A little under 2 weeks ago.

Then you disconnected them. Checked the voltage a week later and they were at 12.5
No. They measured 12.5 a couple weeks ago PRIOR to charging. Did that check kinda as a health check on it.

Now a week later, it's at 12.1? And this is for both batteries? Or is it 3? Or just 1 battery?
So I charged the batteries about 2 weeks ago, like i mentioned above. Im going fishing tomorrow so I plugged in my TM batteries yesterday to "top them off" prior to this weekends trip. Before I plugged them in, I did another voltage check just to see the current level and have it act like a health check. I was hoping for above 12.5 (reading I got last time before plugging in) since it was a little under 2 weeks ago that I was plugged in...but it read 12.1.

24v system wired directly from TM to batteries. Both batteries read the same readings both times.

If this is the case, you have a bad battery or a parasite drain. Are you resetting the breaker to kill power completely to the trolling motor?
Both batteries read the same. I am not resetting or unplugging the TM at all. Just get off the water, drive home and plug in. Should I get in the habit of unplugging my TM after fishing trips? Ive got one of those 3 prong plugs on my TM so thats an easy fix to do if it will help.

I've gotten into the habit of using the kill switch and all breakers just in case.

BTW, what charger?
MK 210D

If they are getting down to 12.1 between charges, you aren’t charging often enough and are killing them.

With them reading that, I dont disagree with you.

So how should I charge them or what habits do I need to enact to prolong their lives? Do I just always leave them plugged in? I did that with the last set of batteries and they only lasted me 13 (literally) months. so I decided to go plug, unplug after full charge and top off every couple weeks if there are no fishing trips...so basically either I hit the water, and they get plugged in day before or if I stay home a couple/few weeks with no fishing, I will plug in to top them back off....since its my understanding you want DC batteries to stay as close to a full charge as possible as much as possible to help prolong life. Thats also the reason I left them plugged in 24/7 on the last set of batteries, made sense to leave plugged in so it was always maintained at near full/full levels....but those batteries didnt last so I told myself that was the wrong way to do it and decided to go the "top off route" I go now.

So with that being said...what do i do??? This sucks buying batteries yearly...last one really stung because they were both on their 13th month and the sams warranty was 12 months. I think im under warranty still, so I might be good if theyve already gone bad.....but if theyve already gone bad thats 2 sets of batteries that went south too quick...so theres gotta be a problem.

Another thing....that doesnt make sense. So LAST time I charged (when it read 12.5 a little under 2 weeks ago) it was for sure 2 weeks between plug ins. yesterdays charge (where it read 12.1) was for sure less than 2 weeks ago. So less time lapsed between charges....but the voltage dropped a ton more.

12.1 volts ain't good after a charge no matter how long within reason they sit. Some trolling motors when connected can draw from the batteries even when turned off.

I think unplugging my TM is my only option at this point...because I think im doing it right.
Spray can hide the corrosion but it's still there I'd bet. Smaller than necessary wires won't use more current, it would deliver less power. I fish a lot but I recharge my Everstarts the moment I get back home. Three years, not a drop of water added, and they work just fine.

Might be right about corrosion but I couldnt see any when I poked around. Cant tell you the exact guage cuz it was a while ago....but I got the right guage wire, if not a little more than needed. I called MK and told them what I was doing and what size they recommended. They gave me 2 options, minimum needed and then next size up and I chose the bigger one just as extra insurance. They wires are also only run about 10 feet...and its prolly 6 or 7 feet if I remember.

It takes me 2 hours to drive home from the lake. I unhook the boat, and plug in. I got in late once and was tired as hell and plugged in the morning after....but I about always plug in right when I get home. I dont have a ton of money like some, so buying batteries yearly isnt cool....so I try to be very cognizant of my battery care after the last set. Done research on it too, and why i think im doing it right....but clearly not.

You should take the time to get your trolling battery situation set right, failure at 13 months might be in the past if everything is put together correctly.
What does that mean? How do you get them set right? Directly wired to MK circuit breaker, which is connected to MK 3 prong plug receptor, then I have TM plugged in via 3 prong connector. Batteries are sitting in battery trays strapped down. What needs adjusting, so I can do it?

You say you're going on a road trip, can you recharge them while you're on this trip?
Theres only been 1 trip they werent plugged in to charge as soon as I got to my hotel, and thats cuz the hotel manager was a dick....and now I also never stay at that hotel because they gave me trouble that one time...and I know how important charging is. Plus my lakes windy as heck so I always like to have as much power as possible, so plugging in right away is big for me.

[billnorman1]

When I say put together correctly I mean all the terminals are properly installed, stainless lock washers under a stainless steel nut properly tightened, no corrosion at all. The lock washer is something I do to make absolutely sure you're getting a solid connection.
I don't recommend 24/7 charging, but that's just me. I fish almost all the time, and I don't plug mine in for a top off, but it shouldn't hurt to do so.
How long do you fish, and is there a lot of current? Did I miss the size of your batteries? Bigger is always better. If you run them down to the point they drop below, say, 10 volts each, they can become damaged and not recover.

[yupitsme]

Plate sulfation begins @ 12.3v and continues until the voltage is above 12.3v. A good charger that has a desulfation mode is a good thing. The Stealth 1 charger has the desulfation mode for the trolling batteries but not the cranking battery - according to Danny....

[dmc575]

I dont know what the hecks going on....but its ok at the moment.

Been about 2 weeks since I been on the water (15 days technically since i kept track this time) so wanted to plug batteries in to top off. Tested before plugging in and the both read at 12.6. No idea how I ended up at 12.1....especially since it was a shorter time frame between charges that last time.

I think im stuck just doing things the way I been doing them and just hoping they last me more than 13 months this time.

[lpugh]

24/7 on the charger, no wing nuts, no lock washer, nylocks and I recomend flange lock nuts due to the fact the contact area is larger than any other method. Flange locks will never loose. Stainless has pluses and minus as well. Nothing works as good as a quality flange lock

[Lou r Pitcher]

A personal preference for ny-locks used/not used on a battery terminal.

I avoid because I went to the trouble of looking up the battery manufacturer's recommended max torque spec on the nut and using a torque wrench found that the max torque could have to be exceeded to simply get a brand new ny-lock to tighten down fully.

Over tightening a terminal nut can break/fracture the battery terminal internally ruining the battery.

------

And though I don't necessarily recommend charging 24/7, I leave my smart charger plugged in and connected 24/7...it takes care of optimally applying the charge.

[dmc575]

24/7 on the charger, no wing nuts, no lock washer, nylocks and I recomend flange lock nuts due to the fact the contact area is larger than any other method. Flange locks will never loose. Stainless has pluses and minus as well. Nothing works as a quality flange lock

went 24/7 last battery and they crapped out on month 13. so trying the top off method this time around. Starting to unplug the TM when not in use....not sure if that makes a difference.

A personal preference for ny-locks used/not used on a battery terminal.

I avoid because I went to the trouble of looking up the battery manufacturer's recommended max torque spec on the nut and using a torque wrench found that the max torque could have to be exceeded to simply get a brand new ny-lock to tighten down fully.

Over tightening a terminal nut can break/fracture the battery terminal internally ruining the battery.

Connections have never felt loose....not that I have it right, but I dont think loose connections are my issue.

[Lou r Pitcher]

Wasn't suggesting a loose connection problem....but if ny-loks are used or a torque wrench is not used, can be easy to overtighten and damage (fracture) a battery terminal and installer would not even know other than battery soon fails.

Max allowed torque tightening a battery terminal connection is less ( for some batteries a lot less) than many boaters would use.