[Rhodes22-list] Battery Advice

Goodness spreadgoodnews at gmail.com
Wed Apr 4 23:53:23 EDT 2012


As i understand AGM (absorbed glass matt) batteries were originally invented for US fighter jets.  They can spin 360 without spilling acid. (very beneficial for offshore circumnavigators!). Are lighter (yet larger) than equivalent amp/hr lead acid and have a similar lifespan. (thus better for light displacement downwind planing raceboats and catamarans). Turns out they use less lead, but are a little harder to make ($$-??)
They love trickle charging but can still off gas and crack(thus leak and fail) if charged too quickly with high amp chargers.  A regular battery is more resistant to this but only if water levels are maintained.  Either way ventilation for hydrogen gas must still be provided to reduce explosion hazard. (hydrogen high LP gas low)
In summary i dont see the benefit for AGM in the Rhodes except for gee whiz hob snobbery.  If you have the extra money i suggest donation to help promote sailing among kids or you other favorite!


On Apr 3, 2012, at 7:20 PM, Bob Keller <r22yankeeclipper at hotmail.com> wrote:

> 
> I'm sure that AGM batteries are better than the standard lead-acid types but the cost difference is so large that I have never taken the plunge.  I use two of the largest Wal-Mart marine batteries that they sell - I believe they are group 27 - and they cost $85 each.  They last 5 years and you can almost put it on your calendar that they will last 5 years.  Both of mine are in the cabin and I never have to add water, except when they are new.  Can't explain that but I check them every year or even a couple times a year. My batteries are each on solar panels with a charge regulator and I also charge them when my 8hp electric start, 2 stroke Tohatsu is running.  I have more electronics than most and my batteries never run down including: autopilot, GPS, wind instrument, depth & knot meter, stereo, refrigerator/freezer...etc.   When I recently looked at buying AGM batteries for the boat at $230 each, the salesperson said they would last 5 years as did the information I read abo!
> ut them.  Much as I wanted to buy them and have the "best", I could not find a good reason and my cheapness ultimately won out.  I buy Wal-Mart batteries for everything I own - cars and boats.   Regarding Rummy's comments, Sea Doos are totally different animals and it is probably worth the money for those things...Bob K
>> Date: Tue, 3 Apr 2012 10:10:55 -0700
>> From: LKUHN at cnmc.org
>> To: rhodes22-list at rhodes22.org
>> Subject: Re: [Rhodes22-list] Battery Advice
>> 
>> 
>> 
>> Rummy,
>> 
>> Just when I thought I knew more than I needed to know about batteries.
>> 
>> So for my purpose would I best be served getting a dual purpose battery for
>> the one connected to the motor?
>> 
>> I like the idea of AGM long lasting maintenance and spill free--might be
>> worth the extra cost.
>> 
>> The guy at West Marine who knew nothing about batteries did show me a $30
>> solar panel controller.
>> 
>> It's all so confusing that I should probably just take the "What me worry?"
>> attitude and ignore my batteries for another seven years.
>> 
>> Thanks!
>> 
>> Lee
>> 
>> p.s.  Last night I was admiring my neighbor's new $10,000+ canvas job (just
>> the cockpit not sail covers) on his Catalina46 and even though he had three
>> windows in the top I asked if it were difficult to view his sail shape.  He
>> switched on the giant monitor on his helm pedestal and showed me a beautiful
>> view of his deck from the masthead camera.  No problem seeing his sails. 
>> Didn't ask him if he paid extra to get AGM batteries.
>> 
>> ____________________________________________________________
>> Lee,
>> Correction on one point. AGM batteries will last longer than lead acid
>> batteries. They cost more, but I like the maintenance free part. I use only
>> agm  batteries in our SeaDoo and it has more cranking power than a lead acid
>> battery.  I have two deep cycle batteries on Rum Runner and only use shore
>> power for  charging. I know from personal experience that without a charge
>> controller,  solar panels can easily overcharge a battery. You can also buy
>> "dual purpose"  batteries which allow for deep discharge and also give you
>> cranking power for an  electric starter. It all depends on how you use your
>> boats power.
>> 
>> Rummy
>> 
>> 
>> Leland wrote:
>>> 
>>> Rob,
>>> 
>>> Great website with an incredible amount of information.  It's amazing what
>>> I know and don't know about batteries now.  :)
>>> 
>>> Looks like I can forget about checking amps.
>>> 
>>> Looks like my battery gave a "false capacity" because it was dead.
>>> 
>>> To summarize, I should ensure my voltage remains between 12.06 and 12.42,
>>> approximately.
>>> 
>>> Thanks!
>>> 
>>> Lee
>>> 
>>> ___________________________________________________________________________
>>> Lee,
>>> If you had 13.4 volts on a battery not being actively charged, something
>>> doesn't sound right with that battery.  A fully charged battery should be
>>> around 12.7 volts. But then you did say your battery was dead.
>>> 
>>> State of Charge    12 Volt battery    Volts per Cell
>>> 100%            12.7            2.12
>>> 90%            12.5            2.08
>>> 80%            12.42        2.07
>>> 70%            12.32        2.05
>>> 60%            12.20        2.03
>>> 50%            12.06        2.01
>>> 40%            11.9            1.98
>>> 30%            11.75        1.96
>>> 20%            11.58        1.93
>>> 10%            11.31        1.89
>>> 0            10.5            1.75
>>> 
>>> 
>>> Much more on batteries, should you care to read.  I agree a group 27 deep
>>> cycle is appropriate for our boats.  Gel and AGM might require less
>>> maintenance, but they are costly. - rob
>>> 
>>> http://www.windsun.com/Batteries/Battery_FAQ.htm#Top
>>> 
>>> 
>>> 
>>> Leland wrote:
>>>> 
>>>> David and Geoff,
>>>> 
>>>> Went to West Marine and Western Auto yesterday.  I guess it depends on
>>>> the individual sales/service person, but the Western Auto staff seem to
>>>> know far more about boat mechanics.  We live in a fishing community so I
>>>> guess West Marine is for recreational boaters and Western Auto is for
>>>> working boaters.  Last month West Marine couldn't figure out what size
>>>> spark plug wrench I needed (18mm).  Last night they checked the volts but
>>>> not the amps on my dead battery and declared it was a connection problem. 
>>>> Sounds like something I would do.
>>>> 
>>>> Anyway if you have a 9.9, 4-stroke Mercury you'll need a 12V deep cell
>>>> with about 465 amps of marine cranking and 350 amps of cold cranking.  A
>>>> starting battery might be better for your electric-start outboard but not
>>>> for your motor lift.  Very important is the group size which tells
>>>> nothing more than the physical size of your battery.  You want to ensure
>>>> it fits in the tray that Stan installed.  Mine was a group 27 (27G).
>>>> 
>>>> 
>>>> http://www.mercurymarine.com/service-and-support/storage-and-maintenance/faqs/outboards/?category=electrical
>>>> http://www.mercurymarine.com/service-and-support/storage-and-maintenance/faqs/outboards/?category=electrical 
>>>> 
>>>> I basically bought the same battery that Stan gave me.  The Western Auto
>>>> mechanic told me that if it lasted seven years without maintenance then
>>>> it was the right battery.  Like Geoff he said to check the battery
>>>> acid/distilled water level once a year.  He said it was impossible to
>>>> overcharge the battery with the outboard or solar panels.  If you use a
>>>> charger without an automatic cut-off you could overcharge the battery
>>>> (boils the acid/water).  Charging the battery if needed is a good idea,
>>>> but you need to check the volts and the amps.  My dead battery had 13.4
>>>> volts but hardly any amperage.
>>>> 
>>>> Gel and AGM batteries cost more and may not last as long.  Big advantage
>>>> is that they're maintenance-free and won't leak.  Just ensure your
>>>> fluid-filled battery covers are on tight for those bury-the-rail heels.
>>>> 
>>>> Good luck!
>>>> 
>>>> Lee
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> _________________________________________________________________________________
>>>> I'd be interested in the same.  Original GBI batteries going into their
>>>> seventh year, and the boat has been out of the water for almost two
>>>> years.
>>>> I'll pull the plastic shrink wrap off next weekend and see if the motor
>>>> will turn over...
>>>> 
>>>> David
>>>> 
>>>> 
>>>> 
>>>> 
>>>> On Mon, Apr 2, 2012 at 11:35 AM, Geoff Farrell
>>>> <geoffreylfarrell at gmail.com>wrote:
>>>> 
>>>>> I have the same setup as you do. My batteries stay charged with the 
>>>>> solar panels. It's interesting to note that although I stored my boat 
>>>>> under a roof from April 15 through Dec 1 my batteries were fully 
>>>>> charged when I got the boat out of storage. Seems the ambient light 
>>>>> was enough to keep them topped off.
>>>>> 
>>>>> I do notice that my batteries use a lot of water, perhaps because they 
>>>>> are constantly being charged by the panels. I was warned by an old 
>>>>> salt to check the fluid often, and he was right.
>>>>> 
>>>>> Recently, I purchased a battery meter that simply plugs into the 12V 
>>>>> outlet over the galley. It monitors the batteries during charging and 
>>>>> also while they are being used, and seems to work great. I can measure 
>>>>> voltage drop while using various combinations of equipment (radio, nav 
>>>>> lights, etc.). I have been very pleased that on bright sunny days I 
>>>>> can use the VHF radio and my Ipod (for navigation and music) and 
>>>>> charge an external portable speaker without any battery drain.
>>>>> 
>>>>> My motor is hard wired to battery 2. When cruising I set my battery 
>>>>> switch to battery 1 to keep battery 2 fully charged for restarting the 
>>>>> engine. I haven't, however, done any overnighters so my battery use is
>>>>> minimal.
>>>>> 
>>>>> I still have Stan's original batteries and so I would also be 
>>>>> interested in what the best replacement batteries are for when mine die.
>>>> 
>>>> Leland wrote:
>>>>> 
>>>>> Need some battery advice.  
>>>>> 
>>>>> Probably should have replaced my battery long ago.  When I need to
>>>>> pull-start my outboard in the marina it usually recharges the battery
>>>>> enough that I can use the electric start when I'm ready to come in. 
>>>>> Didn't happen yesterday.  By the time I unscrewed everything to get to
>>>>> the flywheel I was dangerously close to running into the causeway
>>>>> rip-rap.
>>>>> 
>>>>> Easy answer would be to replace the battery with the one Stan put in. 
>>>>> Wasn't sure if there was something better out there now.  I've got the
>>>>> electric motor winch which I assume uses a ridiculous amount of juice. 
>>>>> I have one battery hardwired to the motor which is linked to a second
>>>>> house battery.  Both batteries are linked to two solar panels.
>>>>> 
>>>>> I've taken zero care of the batteries since I bought the boat seven
>>>>> years ago.
>>>>> 
>>>>> Should I be concerned about the solar panels overcharging the batteries?
>>>>> 
>>>>> Should I periodically charge the batteries to full capacity?
>>>>> 
>>>>> Any advice on what battery would be best and what care it needs?
>>>>> 
>>>>> Thanks!
>>>>> 
>>>>> Lee
>>>>> 1986 Rhodes22  AT EASE
>>>>> Kent Island, MD
>>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> -- 
>> View this message in context: http://old.nabble.com/Battery-Advice-tp33544997p33545034.html
>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>> 
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