Conference vicki::boats

    
    Roy, you would be better off getting 2 6 volt Exide"s and tie them
    togehter to make 1 12 volt bank.  They  will run your fridge and
    lights for 24 hours with no problem.   You will need an onboard
    charger to cahrge them during the week.   
    
    
    12 volt batteries just can't handle the abuse.  The large exides
    i'm referring to would  cost about $70 each
    
    JIm.

     I've used the Sears RV batteries in my boat for year and my trailer in
    the woods of N.H. without any problems. There now power anywhere need
    my trailer and the battery is used to turn on the gas heater, power the
    fans for heat circulaion, turn on the gas refrid and power the lights.
    I've spent a 3 day weekend up in the Woods in the late fall and early
    spring without running out of power. These are deep cycle batteries and
    I had great luck with them. The battery for the trailer I bring home
    with me and recharge it every time. The battery for the boat gets
    charged by the engine but it doesn't see the same deep discharges that
    the trailer one does. 
    Jim

re .0:

The answer to your problem is not necessarily as simple as adding 
another battery, despite the last two replies. First, you must estimate 
the number of amp-hours your refrigerator uses during the time between 
batttery recharging. The amp-hours used will depend on, among other 
things, the ambient temperature outside the refrigerator, how often the 
refrigerator door is opened, how much warm stuff (ie, drinks) is put 
into the refrigerator, how full the refrigerator is initially, the 
running current of the compressor, and so on. A refrigerator with a 
front opening door (like a home refrigerator) will lose a lot of cold 
air every time the door is opened. This is why the refrigerators used on 
serious cruising boats have only top opening iceboxes/refrigerators. 

According to one catalog I have, a refrigerator draw as much as 10 
amperes, though 5 amperes looks more typical. On a hot day with 
considerable use, the refrigerator compressor might run 75% of the time. 
So in 24 hours you'll use 90 amp-hours. Battery life is shortened 
significantly by deep discharge. Optimum life is with about 50% 
discharge before recharging. A deep-cycle battery with 200 amp-hr
capacity (be it one 12 volt battery or two 6 volt batteries) is not
cheap, and it is heavy. Also, battery recharging is not 100% efficient. 
You have to put more amp-hrs into the battery than you take out. With a 
20 amp charging current (more than you'll likely get with an OEM 
alternator/regulator) you'd need maybe five hours of engine running 
time to recharge the battery. 

A friend of mine uses a 250 amp-hr battery for his refrigerator in 
Maine. He has chronic problems with keeping the battery charged. For 
your limited use, why not simply take along a cooler with lots of ice 
for drinks, etc? Cooling warm beer and such in a refrigerator takes an 
appalling number of amp-hrs. Put ice in your refrigerator, too. 

Alan

PS If you want to learn the details of marine refrigeration and the 
advantages/disadvantages of the various available systems, see the 
book by Nigel Calder. What you have now is the least efficient, 
unfortunately. 

Also, there is a long discussion of refrigeration in note 1796 in the 
SAILING notes conference (UNIFIX::SAILING). There are also several notes 
in SAILING about battery charging and monitoring systems (on which you 
could easily spend $2000). 

    
    Alan makes some very good points.  The comments on conditions
    are important. And you alternator will have a hard time keeping
    up with charging if you were to stay put for 2-3 days.
    
    I have a larger boat, i have 2 refrigerators. the standard 
    front door type, (which is opened seldom, except at meal times)
    and a top loading 3 cu. ft. which can be open frequently.
    
    the temp of the items going in there make a big difference,
    as of course they will take longer to cool down, and will reuire
    more amps to do it.
    
    the cooler is definitely recommended in your case, for drinks.
    To make your ice last longer, put drinks in first, and cover with 
    the ice. Go one step further, put a small piece of canvas over
    the ice, put on the lid. 
    
    When you access the cooler, lift one corner of the canvas to get
    what you need, and close the lid.  Obviously don't put it in the
    sun, self defeating.
    
    I have 2 6 volt batteries for house power, also 2 engines,
    on a week-end i can do well with no recharging.
    I also have a generator (portable 1000w) which can run
    the on-board battery charger if needed.
    
    
    On a 26' powerboat, i doubt your amperage use is that great,
    refrigerator and lights, unless there are other appliances
    you didn't mention.
    
    Its all in managing your use, not being careless. When you open 
    the refrigerator, you can't fool around looking for things
    like you can at home. Cold air falls out and downward.
    
    The other factor is what you do with the boat, are you running a lot
    and then pull in for the night, or do you go somehwere and anchor
    get a mooring. Staying put without running will take its toll.
    
    A marine refrigerator will usually use 5 amps per hour, but will
    usually run at half cycle. So in 24 hrs, 5x24=120 div. by 2=60.
    If you anchor or moor for 12 hrs. each day, then you would need
    about 30 amps each night to run the refer.  
    
    The one thing you do need is shore power during the week.
    
    I have forgotten to turn on my charger when i left the boat,
    its a case of diminishing returns. If not that week-end
    the following week-end i'll find the batteries so low,
    that they cannot keep-up with the load..
    
    JIm.

    .3 Summed things up very well!  I agree with his points completely.
    Your going to have to spend ALOT of money to get the battery capacity
    you need for refrigeration... and suffer the weight penalty (heavy
    batteries) on the boat too.  As other noter have said there are more
    efficent ways to keep your food cold.  I read THIS MORNING in an
    electrical eng. book on batteries that deep cycle batteries will last
    far longer if one avoids cycling them more than 50 % of their amp hour
    rating.  If you are determined to have electric refrigeration powered
    essentially by batteries then you must figure out your average current
    consumption... then buy deep cycle batteries with twice the amp hour
    rating of your average consumption.  It doesn't matter whether you 
    parallel 2 6 volt batteries or buy 1 twelve volt battery EXCEPT for
    considering the overall application: Physical space for the batteries,
    price per amp hour for 2 6's vs. 1 12 volt batt.... etc.  You will
    find 2 sixes more expensive than 1 12 volt batt amp hour for amp hour. 
    With 2 sixes if one batt fails then you only have to replace one
    battery (for a while).
    
    I urge you to find an alternative to electric refrigeration.  Look at
    the worry your already under trying to figure out whether the engine
    will start.  
    
    Jeff

re .0: again ......

If, after only four hours at anchor your battery is so discharged that it
won't start the engine, it seems to me that unless your battery's
capacity has seriously diminished with age and/or has been damaged by
excessive disharging, it is likely that your refrigerator has a high 
running current. If you assume that your battery has only a 48 amp-hr 
capacity (small), then the average running current is around 12 amperes. 

If you're using 48 amp-hrs in 4 hours, in 24 hours you'll use around 288 
amp-hrs. If you follow the 50% discharge rule, you'll need 576 amp-hrs 
of battery capacity plus a huge alternator to recharge the batteries in 
any reasonably short time. Assuming your present battery has a capacity 
of more than 48 amp-hrs only makes these numbers worse. Other than 
replacing your refrigerator with a much, much more efficient one, it 
does sound like block ice is the best alternative. 

    One thing i forgot to ask, is the refer in question in good
    condition,,,,   i.e. not in need of a charge. your consumption
    is quite high.
    
    Something does't add up.  Or is the battery your using 
    older.
    
    One other thing, unless you make the ice yourself, your gonna
    find that ice bought on or near the waterfront will in time
    cost far more than a good battery.
    
    JIm

    			MAKE YOUR OWN ICE!
    
    Try filling gallon milk jugs with good drinking water and freeze
    during the week. You can drink the water as the jugs thaw. You can
    either use a good large cooler or even put a few in your frig. When
    I do this the jugs stay frozen for two to four days!

    Something is out of whack. What size fridge does your 26 footer have?
    
    A Norcold 2.9 Cu ft. which is a big under the counter model only draws
    3.5 amps on DC. The big, full size (for a boat) is 6.2 cu ft and draws
    6 amps on DC. I run a 2.9 over night all the time on a single 100 amp
    battery and have no problems. I have two accessory batteries with a
    switch so I don't care if one runs out. However, that has not happened.
    I have even lasted over two days at anchor aboard my 32 footer with no
    problems. It doesn't run all the time, so 3.5 amps on a 100 amp battery
    should last a lot of clock time.

    I suggest you NOT run either of your batteries down below 50 % of amp
    hour rating.  At least don't do it on a regular basis.  If you do you
    will dramatically shorten the life of the batteries.  Ref: Storage
    Batteries by George Vinal.
    
    Jeff

    I forgot to say.  If one is going to beat on ones' batteries by
    frequent very deep cycling you might be better with NICADS.  They
    are about twice as expensive as comporable amp hour lead/acids but
    they can withstand unbelievable abuse without damage, AND they will
    LAST up to 20 years!
    
    Jeff

    A couple of other thoughs on the battery life.  Check the air
    circulation around the back of the fridge.  Most boat mfgs just cut a
    hole in a cabinet and put in in.  No place for the heat to go.  If
    possible add a small fan to the cabinet to exaust the hot air from the
    back of the fridge.  (small 12v fan takes .08 a to .32 amps.  go for the
    small one).  
    
    The other thing.  You did not say where you kept the boat.  Mooring or
    slip with AC power.  If it is at a slip the batteries may not be at
    full charge when you stsart out.  
    
    Ihave tested the battery on mine by turning off the charger when we where
    at the slip and did not do out for two days.  One group 27 battery
    worked fine for the cabin lights and fridge.  We did all the things the
    previous noters said.  Don't make ice, start with only prechilled items
    and keep the beer and soda's in a seperate cooler with ice.  
    
    
    Ken Chester

    This is a little off the track of the original note.
    While looking at boats at the boat show (offshore fisherman type boats)
    I notices that most had no fridge but had icemakers usually on deck.
    would an icemaker be more efficient that a fridge.  Just put the ice in
    a cooler.
    
    Could wire the icemaker so that it only worked when the engine was
    running.
    
    Gordon

re -.1:

Well, it would depend on the icemaker and how the refrigeration 
compressor is driven (eg, by an electrical motor or directly off the 
engine via V-belt).

Making one pound of ice requires removal of 144 BTUs of heat from the 
icemaker. An Adler-Barbour Cold Machine (small refrigeration unit for 
built-in iceboxes) removes 225 BTUs per hour with the electrically 
driven compressor drawing 5 amperes. That's 1.6 pounds of ice per hour. 
In a well-insulated top-opening icebox (4 inches or more of insulation
on all sides) used only to keep previously chilled things cold some 10
to 15 pounds of ice per day might melt in hot weather. 

The implication of this is that a icemaker big enough to make a 
significant amount of ice in a short time is going to be expensive. A 
Cold Frost engine-driven refrigeration unit  will make the equivalent of
10 to 15 pounds of ice in about half an hour of running time. Cost of 
just the compressor, holding plate, and various other bits is $1800 to 
$2000. Icebox and installation (all custom) is extra. 

    Has anyone ever had a battery post repaired, is so where?
    The post is the marine type with the wingnut.  The post became
    disconnected from the battery when I tried to unscrew the wingnut.  If
    I had the equipment I believe that I could do it myself, I certainly
    don't want to use a propane torch, but a large soldering iron might do
    the trick.
    
    I thought I read somewhere that you could get a new post "poured".
    
    The battery is two seasons old and I had pland to buy a new one and use
    this as a spare.  I really don't want to buy two new ones if this one
    can be repaired.  And I definitely don't want to go out with without a
    spare -- Pull starting a 150 hp o/b isn't my idea of a good time.
    
    Gordon
    

    Why not ask Battery Shop of New England, they are out of Lowell, Mass.
    They work on commercial size batteries so I doubt they would repair a
    small marine battery but why not ask.
    
    You don't say HOW FAR down into the cell the post is broken off.
    Is it broke ABOVE the flat cell top sheet, or down into it.  If its
    down INTO the cell cover I suspect your battery is history.
    
    Jeff

    The terminal is soldered onto a 3/8 inch high post which goes into the
    battrery cell.  I believe that if I had a large electric soldering
    iron, I could repair it myself.  The post into the battery is still
    good, just the terminal post has come off.
    
    Gordon

    Once you melt the post lead UNDER the terminal you wish to re-attach
    I think you will find the post collapses when it gets to soldering
    temp. and will be ruined.  Also, the plastic battery case top may 
    melt at the edges of the post.  This is a tricky repair I think.
    But if the battery is trash without a good terminal you have nothing
    to loose by trying the repair.  If you use a flame for soldering 
    you MUST WATCH OUT FOR HYDROGEN at the top of the battery.  To
    try flame soldering I would make sure the battery sat unused (not
    charged nor a discharge load) overnight,  this is to reduce gassing
    hydrogen formation as much as possible, then gently blow each cell
    out with a GENTLE blast of air, then cover the cell tops with a wet
    rag.  Then using safety glasses I would dare try the flame torch.
    
    Have you called Battery Shop of N.E. in Lowell?  Ask them what to do.
    
    Jeff

    We'll I think I have repaired it, at least the terminal is attached
    securely to the post.  I borrowed an old electric soldering iron and
    soldered the terminal to the post.  It took a long time to heat it up
    enough and I'm sure that it's only soldered half way down.  However,
    it's on tight and good enough for a backup.  we'll see if it's still
    together at the end of a season exposed to the saltwater elements.
    
    I agree with the last couple -- NEVER put an open flame near a battery. 
    I too have seen a couple blow up, not a pretty sight.
    
    In retrospec, I think there was probably enough of the post sticking up
    to put one of those marine clamps on it with the wingnut post on top.
    
    Thanks for all your replys.
    
    Gordon

    I work at DEC in an area where electric trucks are used.  I once
    watched a guy from an area battery shop do electric arc lead burning
    on the posts of a 36 volt 1000 Amp Hour industrial lead/acid battery.
    I though he was NUTS.  But he said he did it all the time with no
    problem as long as the battery did not just come off charge.  He
    did not use the wet cloths or anything... not even goggles... he
    was NUTS I thought... and this was a pro following their standard
    shop practice.
    
    You wouldn't catch me doing it that way.
    
    Jeff

    One more thing.... he used the cell he was welding on to supply the
    current for his lead burning... the load would produce gassing.
    
    Jeff