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post #21 of 25 Old 03-23-2013
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Re: AGM batteries

I agree but I hauled them into Interstate Batteries and watched them check each battery with a Midtronics tester. I still have the print out.

Originally Posted by hellosailor View Post
md, even a nuclear pile loses some capacity over seven years. So if someone tested your Optimas and found them above rated capacity after seven years, I'd say they are in great shape--but the test may have been done wrong, one way or another. Even if you never used them and simply kept them on a float charge...after seven years...most unusual.
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post #22 of 25 Old 03-23-2013
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Re: AGM batteries

Originally Posted by kellysails View Post
Chef & Maine, you guys really make this forum the best, thank you! Yet another interesting topic.

Once the admiral and I finally cast off our lines I was planning to replace all the wet cells with AGM's. I have been following AGM for a number of years and while hearing all sorts of positive remarks, occasionally I would hear about the consistent need of equalizing the batteries. It seemed anytime Lifeline received an issue from a customer their response was, equalize. I did make sure my regulators for my 100amp charger and 210 Balmar supported equalization. But more recently I have been put off by this idea. What am I to do when laying off of Dominica with my AGM's in need of an equalization treatment? I have felt recently that I need to re-examine this approach. This thread pushed me over the edge.

While looking at the Rolls website the other day they noted their AGM's do not need equalization ever. WTF? They note the use of Pure Lead which gets into the new Marketization term of "TPPL" (thin plate pure lead). Is this the resolution to this AGM issue? Or yet another marketing ploy to lead me astray. This is very frustrating trying to get past all the BS.

With a use budget of 200-250 amps per day, (2) D400's and a 10amp solar panel and the above mentioned charger/alternator which way should I go? I was thinking a 600a/h house system. We are not dock marina people, laying on anchor is what we prefer.
For me the jury is still out on the new Roll's AGM's. Rolls is not making these like they do their wet cells. They are a Chinese made AGM. I stil think if you go AGM you go Odyssey or Lifeline with Lifeline having a lead due to the ability to equalize them.

That said I think you would be much better off with a GEL battery than an AGM. Provided they are properly charged they will accept more current than flooded batts and are not nearly as finicky about getting back to full. When properly charged they are some of the longest lasting batteries out there.

If you are still considering AGM technology you owe it to yourself to read John Harries multiple article work on AGM's and how they've learned to manage them on a full time cruising boat.

AGM Battery Care / Morgan's Cloud

What John says is all stuff I have been saying for many years. AGM's certainly can work but they are anything but "maintenance free" and require PROPER care to get them to last.... Still as of Jan 2012 he was at 90% of new with only about 400 cycles to 50% and a 180 very shallow cycles all this over 18 months. A battery is considered failed at 80% of new capacity. I will be surprised to see John break much over two years, even with exemplary care ...
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post #23 of 25 Old 03-26-2013
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Re: AGM batteries

Originally Posted by Maine Sail View Post
Wow, that was eye opening. Monthly equalization? Yikes. That was downright depressing. I expect that we will be doing six month cruises and will be very hard on the batteries. It seems AGM is really out of the question. Back to square one on a battery solution. Whew! Thanks for the info. We have a couple of years to figure this out but thankfully down to a reasonable short list with AGM off the list.
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post #24 of 25 Old 03-26-2013
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Re: AGM batteries


Batteries are the least taken care of piece of equipment most peoples boats IMHO and it suprising how little the average sailor knows or pays attention to them, unless of course they dont work, they quit after a year or two, or they spend a lot of money on them.

Morgans Cloud is an example of someone who didnt do enough research and also mismatched his system to his actually maintainence so it cost him dearly, which is why I am sure he posted so other wouldnt fall into the same trap. 3 battery banks in 4 years is
operator error.

For our type of sailing and the battery banks inaccesable location the Lifeline 6- 6 Volt AGMS have been a good decision. We can bring them up to 100% as we have a slip in a marina like many other boaters do who post one here and have a three stage charger. After reading extensively and consulting a well qualified marine electrician in our area who knows how we use our boat, we have concluded that this is the way to go for us. We also have a large enough battery bank that one day does not bring us down to the 85% of capacity mark. We also have been equalizing them as necessary. So far we have gotten 4 solid years out of them with no drop off noted. As long as we follow our current treatment of them there is no reason to beleive that I am at about half their life span, with little maintaince as possible but lots of monitoring.

Sailnet has many different types of sailors from weekend to weekend plus cruises, to liveaboards, to cruisers. We all keep our boats differently. On the Chesapeake and in Florida, the majority have shore power and marinas. In LI Sound and New England its mostly moorings. This also leads to different "expert advices" on how to keep your boat as well as what battery systems work best. You have to educate yourself as best as possible using all the experts and figure out what works best in your situation for you boat and how you use it. Taking battery advice from a cruiser when you dont cruise may not be the best advice for you. Taking battery advice from a person who has access to a 3 stage charger every week may not be the best advice for you.

MaineSail always gives great advice and I have followed him reverentially. He has helped educate me in many ways concerninig electrical and electronics. He has also saved me headache and money in making sure that I matched all the componets of my system. He is n ot a big fan of AGMs unless used in the right apllication and has helped guide me in my use of mine

If I was to keep this boat and cruise it I would certainly think about having a solar array to really keep the batteries bank in the 90% charged range all the time even when away from the dock. If I cruised Id probably go to gels and even when this bank goes away may do that, but alwasy will be 6 volters

The more I read the more I am convinced that the way to go no matter what type battery you are using is to make sure you have a large enough bank to start with. The old school reasoning of having a couple of house banks has now given way to the efficiencies in charging, cycling, of the 1 large house bank. The less deeply you discharge it % wise the great number of cycles you get from it.

Figure out you needs and install what works best for you. If you are a cruiser...find some good way of charging the bank and make sure you have a large enough bank. Using an engine/ generator to drive in the last 15% of battery a charge is linited by acceptance is proably not cost effective as say solar would be. If you can manage wet cells...go for it, Desulfating through equalization is the key.

I am not an expert at al and can only speak to what has worked for me in my application
Figure out what yours is and what you need.
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post #25 of 25 Old 03-26-2013
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Re: AGM batteries

More great advice, thanks Chef!

Once we cast off our lines our biggest issue will be "very little time in a marina with reliable power". That is the design principal of the solution that I will need. I might be leaning towards Gel at this point but really I have a couple years to mull this over. I will likely change my mind a dozen times between now and then. And I will watch SN like a hawk for more great advice.
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