Batteries (Winterizing)

[andyfender]

Since it’s a PITA to take out all the batteries,  I plan on using this procedure. Thoughts?

It’s time to start the process of putting the boat until Spring.  I have four batteries in my boat.
1)   AGM Cranking
2)   2 Trolling Motor batteries
3)   1 House Battery that runs all the accessories


The trolling motors batteries and house battery are connected to a 3 bank dual pro charger. The AGM cranking battery is not connected to any charger.

I plan on keeping all the batteries in the boat over the winter and once a month I will plug the charger in just to keep the batteries at a full charge. The cranking battery I will just disconnect and forget about it.

[frugalangler]

I'd recommend obtaining a small (good quality, not a 'float' charger, but a good micro-controlled one - Battery-Minder/Tender or equiv.) 1.5A charger for the AGM and not leaving it disconnected for extended period. Technically, the Dual-Pro can be left plugged in all winter, but your procedure is acceptable. In any case, don't let any of them fall below about 11.8V open circuit voltage before replenishment lest sulfation will begin to deteriorate them, especially the lead acid variety. Sulfation destroys more batteries than other failures, and is precipitated by extended periods of LESS THAN full charge storage. Even slightly discharged batteries begin to sulfate, hence why my recommendation to leave the charger connected, it's better to add water periodically if needed than to allow sulfation. Once a month should be frequent enough to check water level and add if necessary.

My results, I've had some occasional use lead acid marine batteries last 8 years using that procedure.

[Curt]

@andyfender  Not sure if this is an option, or even necessary for you, but here's something else to consider.

If you live in an area that drops well below freezing for extended periods of time, it is possible to freeze a battery. Especially standard lead-acid batteries. A frozen battery is usually toast and ready to be recycled.

My boat is stored inside my garage, so I have the privilege of leaving it uncovered all winter. But my garage is not heated or insulated (yet), so it does still get pretty cold during January & February.

What I do to aid with keeping the batteries from dropping too far below freezing for too long is to place an older style electric heating pad (one of those made for sore muscles) on top of them and turn it on high, and then close the bilge lid to retain the heat. I've been doing this for several years now and I still have the same AGM batteries that I bought back in 2010.

I turn it on when I know the temps are going to be severely cold and it seems to have helped me.

[frugalangler]

Another option for an UN-attended warmer - a plumbing heat tape wrapped around the batteries, they usually have a thermostat on them to only activate below about 20*F IIRC, wouldn't take a very long one but.......

in most climates except those that go sub-minus about -15*F for extended periods a fully charged battery will not freeze, the electrolyte specific gravity is such that it won't freeze at that temp. Go below about -25F* (like mid/northern Canada/Alaska and it becomes a problem, not so much from freezing but thickening of the electrolyte that the capacity of the battery id severely degraded (reason for slow crank in cold weather climates). They do actually make battery blankets for those climates, but that is extreme for where most all of us are.

Here's a table of Specific Gravity to freeze point:

1.000	+32F
1.100	+19F
1.150	+5F
1.200	-16F
1.250	-62F
1.280	-90F

For reference, a fully charged battery will have a Specific Gravity around 1.275 or so, depending on what is considered 'fully charged' state.

[Curt]

@frugalangler Awesome info! Thanks for sharing 

[bullet20dc]

if you have a power company like mine that gets a ridiculous amount of money each month that heating blanket will run ya some bucks to run.  If ya wanna try something a little cheaper to run and just as effective  take a 40watt incandescent light bulb and leave it in the bilge area ON  you will be surprised at how much heat that will put out in an enclosed space     
  Andy  you've seen my setup on my batteries   the only time my batteries arent on my charger is when I fishing.   That charger u have will monitor the state and keep em up    I have been leaving the charger connected for more years then I wanna admit to
 BYW Andy we havent winterized it yet or did I teach you too much and you did it yaself.   

[andyfender]

Charlie, 

You have thought me very well!!! I was planning on winterizing the boat on Sat, if you are free  maybe we can do it together? Let me know. 

Did you move your boat down to your other garage? If so, the space where you keep you boat is available? I would pay you to rent it for the winter for my boat?

[Jig Man]

Before you plug that charger in and leave it unattended for an extended period, call Dual Pro.  I was going to be gone for about 5 weeks so I called them and asked about my specific Dual Pro.  They told me DON'T DO IT.  So I didn't.

I now have a Genesis charger.  When I called them about leaving it plugged in to my AGM batteries they also told me  DON'T DO IT.

[andyfender]

Yes I did that when I first got the charger, here is his reply:

We normally recommend to leave the charger plugged in, it goes into a
maintenance mode once it reaches a full charge. The only thing is we
recommend to check the batteries every month or so if the batteries are
wet cell. Hopefully this will help but if any questions just let us know.
Thanks have a great weekend.



Josh Dodson

Pro Charging Systems

[Curt]

@bullet20dc The heating pad I use is one of the small ones used for sore or aching muscles. Maybe 12 x 20 inches or so? Did you think I was referring to something bigger than that?

But your suggestion about a small light bulb is also a good one, provided there is room to put it in there without it touching or hitting anything that can melt or catch on fire. 

[bullet20dc]

Before you plug that charger in and leave it unattended for an extended period, call Dual Pro.  I was going to be gone for about 5 weeks so I called them and asked about my specific Dual Pro.  They told me DON'T DO IT.  So I didn't.

I now have a Genesis charger.  When I called them about leaving it plugged in to my AGM batteries they also told me  DON'T DO IT.

I have 2 csi dual pro 3 bank chargers  Have been leaving them connected 24/7 365 for over 15 years except when fishng never had one problem with them.  I also have a genisis 3 bank that i keep batteries on he shelf  for shop use  charged   You're right tho You have to keep an eye on flooded batteries.  Some cheap ones will boil out over time