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Author Topic:   Batteries are amazing things
David Pendleton posted 05-28-2010 05:38 PM ET (US)   Profile for David Pendleton   Send Email to David Pendleton  
I last used my boat Labor Day weekend 2009.

The boat was winterized and wrapped by my marina several days later and there it sat.

We had a pretty frigid winter this year.

I returned today to cut a hole in the shrink and retrieve the batteries.

When I got them home they tested 12.23 and 12.54 volts.

jimh posted 05-29-2010 08:46 AM ET (US)     Profile for jimh  Send Email to jimh     
I think the cold Minnesota winter temperature helped slow the rate of self-discharge of your batteries over the storage period.
swist posted 06-01-2010 05:22 PM ET (US)     Profile for swist  Send Email to swist     
And you took a real chance leaving the batteries in the boat all winter without periodically charging them (or at least testing them).

If they did discharge enough, for whatever reason, to be susceptible to freezing, you might have a real mess on your hands.

I speak from experience, a few years ago I had forgotten I left a spare battery in a garden shed over the winter. It discharged, froze, cracked, and dumped sulphuric acid all over the place.

David Pendleton posted 06-02-2010 11:17 AM ET (US)     Profile for David Pendleton  Send Email to David Pendleton     
Perhaps, except that I leave my batteries in every winter, and have been doing so for 11 seasons.

I suspect the battery you are referring to was sealed, thus preventing the frozen electrolyte from expanding.

My batteries have always been vented, so it's unlikely the case would crack should the battery freeze.

home Aside posted 06-04-2010 05:17 AM ET (US)     Profile for home Aside  Send Email to home Aside     
I guess I could have left my batteries in the boat which was in heated storage instead of pulling them & putting them in my basement...


davej14 posted 06-08-2010 11:10 AM ET (US)     Profile for davej14  Send Email to davej14     
Vented or unvented, if the electrolyte freezes you risk cracking the case or causing internal damage to the cells. Don't believe it? Freeze an uncovered glass of water and see what happens to the glass. It is best to store your batteries in the basement over the winter months and charge them periodically. If you leave them in the boat be sure they are in a battery box which would contain any leaking acid.
ConB posted 06-08-2010 12:04 PM ET (US)     Profile for ConB  Send Email to ConB     
If a fully charged battery freezes and breaks during the winter it was not a good battery anyhow.

I store mine in the cold garage and try to remember to charge them once during the winter.


David Pendleton posted 06-10-2010 12:30 AM ET (US)     Profile for David Pendleton  Send Email to David Pendleton     
Here's what I know about batteries.

A fully charged battery will not freeze.

As I stated earlier, I leave my batteries in the boat every winter. I've done this for 12 years. I just decided to say something about it, via this forum, this spring.

I don't know if your batteries are vented or sealed. I don't know what their voltage level was at the time of storage or failure.

My original post was an expression of how resilient a battery can be having been exposed to sub-zero temperatures for an extended period of time during a Minnesota winter.

Bella con23 posted 06-10-2010 07:47 AM ET (US)     Profile for Bella con23  Send Email to Bella con23     
Freezing point of lead acid batteries -

Percent Specific Degrees
Charge Gravity Fahrenheit
100 1.265 -75
76 1.225 -35
74 1.200 -17
50 1.150 5
0 1.100 18
<0 1.050 27

I have always left my batteries onboard over the winter months. I use the onboard charger to maintain the charge level of the batteries.

Bella con23 posted 06-10-2010 07:52 AM ET (US)     Profile for Bella con23  Send Email to Bella con23     
Sorry that cut and past didn't work to well. Page 25
swist posted 06-10-2010 08:35 AM ET (US)     Profile for swist  Send Email to swist     
I think there's no reason not to leave batteries in a boat (contrary to what you sometimes hear), but if you do, I would think it common sense to at least check them periodically, given the consequences of failure.
Whaler_bob posted 06-11-2010 10:40 AM ET (US)     Profile for Whaler_bob    
I've been leaving the batteries in my boats for a few years now over the winter- connected full time to the BatteryMINDer device BatteryMINDer-Plus-12-Volt-133-Amp-Charger-Maintainer-Conditio-p-16134. html .
In addition to having no battery freezing problems (NY weather will go to single digits for a couple of days in a row every winter) the batteries always seem to be in top condition in the spring, and no water added over the winter. I now use a BatteryMINDer on my jetski battery and it seemed to work out fine too. The battery had plenty of power when I started it up for the first time two weekends ago.

Along with charging and auto-desulfating, the BatteryMINDer site also states "Allows battery to be stored safely at 0°F to +120°F". It's nice not to have to drag heavy batteries out of the boat every fall now.

moabelite posted 01-21-2014 08:16 PM ET (US)     Profile for moabelite  Send Email to moabelite     
I have a 2007 Montauk 170--my first boat, and I'm one of the "young" boaters folks have been talking about--and stored it for my first time this fall in an unheated garage I rent. My plan was to plug in the charger that is built-in inside the center console once every month to keep the batteries up. I did not disconnect them. I have a motorcycle, and, in years past, this strategy has served me well with the bike. Unfortunately, with the cold winter here in Michigan, my strategy does not seem to be working, and I finally pulled the batteries to bring them home today when I found them dead again and they would not charge.

Wondering what did I do wrong? Once the batteries thaw and if I put them on a tender, do they stand a chance of being useful again? They are deep cycle Marine-RV batteries from Napa that appear to be four-years old. Thanks in advance. I so value all the info I find on this site!

jimh posted 01-22-2014 10:38 AM ET (US)     Profile for jimh  Send Email to jimh     
moabelite--It is impossible to determine from your narrative the exact cause of the two batteries on your boat being deeply discharged in a three or four month period of non-use. We can only impute the most basic causes.

A lead-acid battery will have a self-discharge, but usually the rate of self-discharge is so low that it will not completely discharge a fully-charged battery in a few months. This is particularly true in cold environments, as the rate of self-discharge decreases with temperature. In colder temperatures the self-discharge rate will be lower. It has been established by a great deal of reported experience that a 12-Volt battery with a full charge will not be discharged to a deep discharge state by its own self-discharge in a period of a three to six months.

In a boat there could be some other sources of discharge for a battery. For example, a small lamp could be left on. A radio could be left on. Or some other unnoticed electrical load could be left on. This is the most likely cause of an unanticipated deep discharge of the boat's batteries when not in use.

There could also be a parasitic drain, caused by some unusual path in the wiring, such as a build up of corrosion between a positive conductor and some surface which is bonded to the battery negative. Such a corrosion discharge could even occur at the battery terminals themselves, if there were some build up of a slightly conductive surface between them.

The attachment of a charger to the batteries could also place a very small discharge drain on the batteries when the charger is not powered and charging. It is also possible that there could be a malfunction in the charger, it would appear to be working when charging the batteries, but when powered off the charger could be creating a load on the batteries.

It seems unusual that both batteries would become deeply discharged independently. It is more reasonable to assume they were connected in parallel, had some unanticipated load, causing them to become discharged. It is also possible that one of the batteries developed a shorted cell. If they were in parallel, the bad battery could have discharged the good battery.

jimh posted 01-22-2014 11:47 AM ET (US)     Profile for jimh  Send Email to jimh     
I think Con's observation is quite astute and is worth repeating:

If a fully charged battery freezes and breaks during the winter it was not a good battery anyhow.

You might say the winter lay-up is a battery pass-fail test for next season.

jimh posted 01-22-2014 01:07 PM ET (US)     Profile for jimh  Send Email to jimh     
Actually, you might say that leaving a fully charged battery in the boat for the winter is the acid test.
ConB posted 01-22-2014 03:09 PM ET (US)     Profile for ConB  Send Email to ConB     
I just got home from the gun club where I run a clay target shooting program.

We have 8 traps (clay target flingers) that are powered by 12 volt deep cycle batteries.

It was 2°F and all I can see of a couple of the batteries through the snow is the positive terminal to attach the cable to when in use.

I can't believe the abuse a good battery will take.


moabelite posted 01-22-2014 08:52 PM ET (US)     Profile for moabelite  Send Email to moabelite     
Thanks for the feedback, Jim!

I’m wondering if in fact the battery charger may be causing the drain when not in use. The boat is extremely clean and well-kept (and the batteries and terminals look like they just came off the shelf), so I’m hoping I don’t have some other parasitic drain. I do know that I triple-checked to make sure I didn’t leave anything on, so I’m quite confident in that fact. You are correct in the assumption that they are indeed in parallel, so one shorted cell could have depleted both batteries. I’m trying them both on my battery tender at home, but I’m afraid the results don’t look good. The Acid Test (I did chuckle) will likely seeing me buying a couple of new batteries in the spring. I’ll take any recommendations on make and model that folks can offer accordingly.

Oh, a correction to my earlier post: the Montauk 170 is a 2006.

moabelite posted 01-23-2014 08:12 AM ET (US)     Profile for moabelite  Send Email to moabelite     
Update, after charging both batteries on my battery tender: the first just looks warped (clearly bad) and the second took a charge just like normal. Jim may have called it perfectly. I expect it would still be advised that I replace both?
jimh posted 01-23-2014 11:19 AM ET (US)     Profile for jimh  Send Email to jimh     
If the plastic case of the battery is deformed, the cause could be a build up of internal pressure. Is the battery a sealed battery, also known as a maintenance-free battery? Sealed batteries have a pressure regulator valve that is supposed to vent the battery to the atmosphere to prevent too much build up of internal pressure.

If the battery is a normal vented batttery, and the case is deformed, the damage was probably done by freezing of the electrolyte. That could have occurred because the electrolyte had become more like water than acid, which is likely because it was deeply discharged. I would not count on that battery being usable.

The second battery that seems to have revived with recharging is probably suspect, too. My criteria for the engine cranking battery status is proportional to the ability for the engine to be pull-started with a rope and to be able to run without any battery power. Many modern outboards cannot be pull started and won't be able to start at all if there is not some sort of battery power provided to them. On the other hand, some outboard engines can be started manually rather easily with a pull-rope and are able to run without a battery. You will have to assess your situation, as you have told us nothing about the outboard engine on your boat. If manual starting is an option, then a dead battery can be tolerated for a few moments while out boating. If manual starting is not an option, I recommend having two good batteries on board.

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