Battery Winter Storage

[bjoc2314]

What do I do with the batteries on my Catalina 310 for the winter? I assume I take them off and store them inside to prevent freezing. Do they need to be periodically charged and if so, how do I do that?

Thanks in advance.

[Sailmc]

Save your back and leave them on the boat. Only a discharged battery will freeze. If your batteries are in good shape charge them fully before storage and either turn them off or disconnect them if you feel you might have some drain. If possible come back once during the winter and plug your boat in to give then a charge for an hour or so. Don''t forget to disconnect the bilge pump, they are sometimes wired directly to the battery in Catalinas. I used to remove my batteries until I saw a couple of well respected yards store peoples batteries in an unheated shed.

[DuaneIsing]

Until I started reading about the care and feeding of batteries in marine usage, I knew very little of the details. Keeping it fairly generic and simple:

It turns out that all batteries will self-discharge even if all external loads are removed. The rate of discharge depends on lots of factors, but the bottom line is that you cannot expect to leave any battery for long periods without taking care that they remain reasonably well charged.

The longer a battery stays below its optimal charged state, the more the process of sulfation can occur. Left too long in a partially drained state, the battery is permanently "robbed" of some of its original capacity.

It sounds like a lot of extra expense and effort to ensure that your batteries are always clean and properly charged at the appropriate voltage levels, but the experts in the field say the payback in battery reliability and life is worth it. Some recommend an appropriately sized solar panel to keep them topped off with no risk of overcharging.

I''m not trying to say that Sailmc''s methods are ill-advised. Those batteries may be coming through a winter OK. I''m merely summarizing what the experts are saying.

Good luck.

Duane

[Sailmc]

If you recall I did recomend a charge or two during the winter but more than that has never been necesary for me. My batteries will maintain 12.75 volts all winter. This is considered a full no load charge. I have not experienced any self discharge that could not be attributed to an electrical problem. I live in Winconsin where sub zero winters are the norm and have never experienced a problem with in boat storage. I also replace my batteries every 5 seasons whether they need it or not. I''m sure I could go longer but I want to avoid that one day they fail. I agree that leaving a battery in a discharged state will shorten it''s life but we are talking a significant discharge of 40% or more. This will not occur unless you are draing power somewhere.

[DuaneIsing]

Hi, Sailmc.

I wasn''t trying to dispute anything you said. I was just regurgitating (in summary form) what the marine industry battery experts seem to be saying. I don''t have any of my references in front of me, but it may be that cold temps actually slow the rate of self-discharge (because it is a chemical reaction after all).

In my winter storage of batteries (tractor, motorcycles, etc.) in my basement at 50F, I have absolutely noticed a marked discharge over time, although now I don''t let it get down very far before I bring them back to full charge.

I''m glad to hear you have been having success in your situation. If it''s working, don''t change it.

Fair winds,
Duane

[dhartdallas]

Ahoy, Duane. You are right about the impact of cold on batteries. That is why battery makers make so much ado about "cold cranking amps". It is heat that is death to batteries. Cold does slow reactions. At absolute zero all chemical and electrical activity stop. If your battery is weak, it will show up when winter hits and when hot weather arrives. But, the biggest problem that boat people have with batteries, especially deep cycle batteries is that they run them too far down before they recharge. The farther you discharge, the more damage you do. It is amazing how fast some people go through batteries. It is recommended that you have twice the capacity required by the electrical equipment you are running. Check the water every 30 days, add distilled water when needed. Keep the posts free of corrosion, and don''t run them too far down and batteries should be the least of your worries.

[DuaneIsing]

Hi, Dean.

Thanks for the hail.

I was thinking some more about this topic this morning and did a quick web search. This site (see URL below) does a pretty good job of explaining things.
http://www.progressivedyn.com/service_battery_basics.html

[dlahlers]

I pull all 4 batteries out and store in my basement. A battery loses 1% charge a day just sitting w/ no drain. So unless you have a 3 stage charger that fully charges batteries you should charge them during the winter once or twice. If you use an inexpensive charger (ferro resonant/hardware store type)you never get them completely charged anyway and may experience problems. A discharged battery can freeze. Get a good hydrometer and test each cell, you may be suprised.

[windship2]

Somtething else,
Batts that are fully discharged will freeze at about seventeen degrees. Batts that are fully charged won''t freeze until minus seventy-two degrees. And, the plates in your batts get a build up of PBSO4 that can be converted back through equalization. If there is no equalization done this build up gets knocked off the batt plates and piles up on the bottom of the cells.This can cause shorting of the cells and shortens batt life.Moving batts is not good for them.
I used to remove my batts every off season but now keeping the formentioned facts(and the fact that I have seven batts)I leave them right where they are but I keep them fully charged with my turbine.

Dennis

[Elie]

A neat trick is to install one or two small(5 watts)solar panels wired to the batteries without any charge controller, but fused. The panels are fixed on a broom handle verticaly (to avoid snow accumulation) and oriented due south in a spot with no shadow interference. It works well in keeping the batteries charged all winter.