Winter Battery Storage

[Kyle Ewing]

I bought new 6 volt golf cart batteries this year and want to treat them right.  Other than freezing (no risk as long as they're charged), will storing them in the boat over the winter damage them?  I figure I'll top them off periodically (can only charge while I'm visiting the boat) but self discharge will be slower than in my basement.  In the boat they'll be charged with my Truecharge 40.

If I bring them home they'll discharge faster in my basement but I can more frequently hook up a charger (automotive charger), but have the hassle of moving 280 lbs of batteries.  I don't want to leave them on a charger continuously for fear of losing electrolyte.  I've always considered moving batteries to be tough on them (no facts to back it up, just a feeling).

On this board and others, preferences seem mixed.  Is there a concensus on what's best for batteries?

[Stu Jackson]

No consensus anywhere.  One theory is that your back will not get hurt by moving batteries!

The very best thing you can do is to charge them and leave them  John Nixon has written here on this board about the downside of constant trickle charging:  sulfation.

If it was my boat, I'd completely charge them, and either leave them alone or have a small solar charger thru a controller keep them topped up.

You might consider reading the Ample Power Primer at www.amplepower.com, Tech Tab.  They also discuss "breaking in" new batteries.

[RV61]

Kyle,
I have the wet flooded batteries and have topped off and left in the boat for 8 years now. 2 of my four batteries are 6 years old and going strong. The other two are newer as I beefed up the house bank. Each spring I always wonder how the batteries did over winter and each spring when I connect them back up they are fine.
Rick

[Ken Heyman]

Kyle,

I have four T105s. The last four seasons I have left them on the boat while attached to a solar panel. The panel(22.5 watts) provides enough trickle to keep the batteries at say 80% capacity by spring, The last couple of seasons I didn't bother with a mid winter charge. Of course make sure that your electrolyte is above the plates and you should be ok for a midwestern winter. Both my back and my batteries are fairing well.

Ken

[lazybone]

I've had T105's for the last 14 yrs.  My first set were replaced after 6 yrs because I was told it was "time".  The set I have on the boat now are about 8 yrs old and are still strong.
I never remove them during the winter.  I top up with distilled water at the end of the year and recharge once a month during the winter.  No need to disconnect anything.

[Ken Juul]

When a battery will freeze is determined by the specific gravity of the electrolyte.  Found the following chart on the web.

SPECIFIC GRAVITY VALUE   OPEN CIRCUIT VOLTAGE   STATE OF CHARGE      FREEZE POINT C/F
1.265                                  12.60                     100 %      
1.245                                  12.57                       90 %      
1.230                                  12.54                       80 %           -32/-26
1.216                                  12.45                       70 %      
1.202                                  12.36                       60 %      
1.190                                  12.27                       50 %            -24/-11
1.175                                  12.18                       40 %      
1.160                                  12.09                       30 %             -16/+3
1.148                                  12.00                       20 %      
1.120                                  11.70                      DEAD              -8/+18

It has to be awful cold to freeze a battery, even one partially discharged.  I go with the make sure the electrolyte is full and charge once a month plan.  Maybe after I get my davits on, I'll add a solar panel too. 

[Ron Hill]

Kyle : For the past 22 years I've left the batteries on the boat.  I wouldn't use a small solar panel to trickle charge, as that's what John is saying about sulfating of a flooded battery.  Just give them a shot of charge when you check the boat every month.

Ken : Your chart is very interesting.  In the Mainsheet I published a similar chart from Practical Sailor (15 years ago??)  Your and my charts agree on the % charge for specific gravity, but differ on the voltage state of charge %. 
My 100% is 12.75V and 50% is 12.25V    Interesting!!!   

[tonywright]

I follow the advice given on the Surrette winter storage page:

http://www.surrette.com/content/winter-storage-506?phpMyAdmin=0610e516bf803196b5feee0b1ad65c08&phpMyAdmin=3jSJ-jdC5E7b53DHgV8TGvpSCF6

I spoke to the Surrette/Rolls reps at the Toronto boat show before deciding to leave the batteries on the boat. Their advice is: as long as the batteries are in good condition, fully charged, and completely disconnected from any boat systems, they are better on the boat than in a warmer location.  Reason: they will discharge much more slowly thanm when warmer. But the caveats are very important.

Tony

[Ron Hill]

Guys : I have professed that one of the most important electrical gages on your boat is the battery monitor!!  When you get ready to leave the boat I always check BATT 1 and then BATT 2 and make sure I see 0.00 amps.  That means nothing is ON and drawing current from the battery bank/s. 
I've never disconnected any battery (boat on the hard) in the past 20 years and have never had a problem with winter battery storage!
A thought

[Bobg]

Very timley thread, heading to the boat for the final winterizng, was wondering about by new T105's, Does anyone recommend a decent specific gravity tester?  The ones I find are in the hardware or automotive stores and are cheap, floating balls, or that rocker one, by going by Kens chart, I would think a more trustworthy accurate one would be best.

[tonywright]

Re Hydrometer: I use one like this:

http://www.diseno-art.com/products/tools/battery_hydrometer.html

Ron: I disconnected my battery monitor earlier this year, after I discovered that it was responsible for running my batteries down to 11 volts after leaving the boat for 3 weeks. Maybe it is defective?

[David Comando]

After 7 seasons using my 4-six volt battery house bank, they seem unable to maintain a charge. I have a rocker style electrolyte tester, but it hasn't made it from my truck to the boat. Is there a recommended location to purchase new 6 volt golf cart batteries here in NY? I will be replacing the old ones shortly.
P.S. My back and I are very happy to leave the batteries in all winter with nothing hooked up.

[Ted Pounds]

I always found the best deal at Sam's Club.  Make sure you check the date code on them and buy the newest ones.

[Mike and Joanne Stimmler]

Costco is another thought, depending on where you have a membership.

[Stephen Butler]

We purchased 4, InterState 6 volt deep cycle golf cart batteries from Costco this summer, for $73 each (including sales tax).  Sam's Club was pretty much the same price, but for an unknown brand (atleast for us).  Easy decision given the $130 cost per battery to replace each of our group 27 batteries.