Frozen Batteries

[KevinWI]

So I left my boat up North at the end of October thinking I'd be back up to use it at the end of November. Batteries were charged, left it on the trailer. When I couldn't make it back up, Dad tarped it for me.
Well, end of Dec I was able to pick it up and bring it home finally. Had been cold up there. Parked it in the garage.
1st thing I did was plug in the on-board Minn Kota 210D on-board charger. Both registered red lights on the charger...which means bad connection or check connections. I did and everything checked out fine...I found that extremely odd. I tested the Trolling motor, lights, etc...everything was dead. I left the charger plugged in for a few days.....still red. Pulled both batteries and took them inside. could here sloshing in them. Took the voltage tester to test the charger, which appeared fine.
Let them warm up for a day and put a charge on each..both took a good charge. Put them back on the boat connected the charger and no problem...charger charging both just fine.

Wondering how both batteries apparently drained down to under 4v and whether I will probably need to replace them both now? Also wondering if I should just leave the batteries plugged in all winter or just remove both and leave in the house?

 

[redbug]

I leave my agm batteries plugged in all winter

 

[gillhunter]

I have always left mine plugged in all winter, in fact I leave mine plugged in whenever the boat isn't in the water.

 

[tnriverluver]

If your batteries were actually frozen then you most likely have damaged plates inside and they should be replaced. Not sure from your post if the batteries froze or if they had just somehow been discharged to low.

 

[KevinWI]

Thanks for the input...I put them both back in the boat and plugged them in. Started with flashing yellow and now both flashing green which indicates all is well. I will leave them plugged in all winter then.
It does appear that they were just drained low rather than froze...still could have done damage....will see come spring.

 

[fish devil]

:twisted: LOAD test each battery individually. Just because the lights are green does not mean there is a problem.

 

[tnriverluver]

Just a word of caution on your batteries. Again not knowing if they actually froze or not. If you have a broken plate in a battery, they can dislodge and sometimes cause an internal short which can cause a battery to explode. Working as an auto mechanic I saw this first hand on more than one occasion. Use caution and wear eye protection when handling these batteries until you determine their condition. And as suggested above have them load tested!!!!

 

[KevinWI]

Friend who is a mechanic has a load tester, but said you can't load test a deep cycle marine battery like you test a normal battery...there is a lot more to it....meant for regular car batteries, etc. At least from what he understands about them.

 

[russ010]

turn your trolling motor on and let it run for a while... check the voltage drop when it comes on and go back and check it again in about 15 min with the motor on or off. You'll know if your batteries will hold a charge or if they are dead.

I run long distances with just trolling motors on electric lakes. I start the day out at 13.2, and after about a 30min ride on high speed, the voltage still sits at 13.0-13.1 depending on the outside temperatures.

Is it possible you had a loose connection somewhere that was draining the batteries, or possibly left a light or something on?

 

[KevinWI]

Well, I ordered a new digital multimeter...arrives tomorrow and I will test it then

 

[KevinWI]

Today I did the test.
1. unplugged the charger
2. tested voltage right way and it was at 12.69v on one and 12.99v on the other.
3. decided only to test the one hooked up to the TM.
4. Waited 2 hours for surface charge to dissipate.
4a. Tested battery #1 and it was at 12.67v
5. Ran TM for 10 minutes...while running voltage dropped down to around 11.95
6. Shut off TM, waited 10 minutes and Voltage read 12.59
7. Temperature outside was at 29 degrees, so I'm sure that has a bit to do with it as well.

 

[tnriverluver]

Fully charged your batteries should be reading 13.2 volts. Sounds to me like your batteries are toast and it is time to replace. Your batteries should be reading 14-15 or even 16 volts immediately after unplugging the charger.

 

[tnriverluver]

Leave the batteries off the charger and recheck the voltage tomorrow. If any noticeable drop they are definitely bad. Sounds like the extreme cold has done your batteries in which is very common. Extreme hot weather will do the same.

 

[KevinWI]

this is disheartening. will have to wait a bit to do the overnight check....very cold here now....below 0 degrees

 

[redbug]

how old are the batteries we are talking about? if they are over 2 years old I would start to think abut replacing them
i have been stuck on the water with a dead battery and it wont happen again if i can help it.

 

[KevinWI]

Not sure...the batteries came with the boat and I have owned the boat since Sept 2011.
I will probably wait to buy batteries in the spring.

 

[KevinWI]

Both Batteries are series 24DC Brite Start from Fleet Farm....both marked as purchased in July 2006, so yeah....it's about time. 6 years is not bad.
Replacements looking at $80ea.

 

[redbug]

yeah at that age it is time to replace them... they have lasted that long it is good

 

[tnriverluver]

If you have room, look into Walmarts group 27 or 29 for about $80-85. They will not run down nearly as fast as the 24's.

 

[KevinWI]

Are they taller or wider? I have room for wider, but no room for taller.