Edd;
Like several others, I would endorse the choice of going with golf cart batteries (I'd use GC5s, not GC2s, but I'd have flooded golf cart batteries in my boats if there was enough room in the locker that the batteries are housed in to accommodate the height of the batteries. You have raised the question of the batteries freezing. A fully charged wet cell battery has a freezing temperature of 76 degrees below zero Fahrenheit. It is true that the liquid in a flooded battery that is fully discharged is around 30 degrees, since the liquid is almost 100% distilled water. But I don't think I've ever seen a frozen battery - even is a winter stint at the GM Arctic Proving Grounds years ago. Unless New Jersey is expecting an Ice Age, I wouldn't worry. Storage on the boat over the winter is also not a real problem - although there are a lot of old wives' tales about taking batteries home for storage and not setting them on concrete floors, and so forth. The accepted self-discharge rate for a lead-acid battery is between 1.5 and 3% per month, depending on storage conditions. The rate gets higher as the storage temperature gets higher, but isn't really very high until you get over 100 degrees. AGM batteries are a bit less, but the chemistry is almost the same and the lower rate for an AGM battery has more to do with the fact that the AGM has less plate surface area in contact with the electrolyte mat, so the reaction is slower. You may want to think about how you use your boat when you make the decision about batteries. You mention wanting 4 to 6 T-105 batteries in your house bank. That's 450 to 675 AH in a 12 volt configuration, and that gives you a lot of live aboard time. My 460 AH house bank will power my 38 for 2 to 3 days on the hook without recharging. (My biggest draw is for refrigeration and that is more than half of the total.) But if I recall you mostly daysail and race, so what impact will 400 pounds of batteries have on trim and performance? Do you need that much endurance? Also, you say you only charge with your engine alternator. A 675 AH bank is going to need a 75 amp (or more) alternator and a smart voltage regulator to recharge it in any manageable amount of time, and at least a 60 amp charger if you plug into shore power. I have many years of experience in the marketing of batteries for industrial vehicle, and I have an aversion to AGM batteries, so I'd recommend not using them. YMMV. Sure, you can lay them on their side. But laying your sailboat on its side is slow, and flooded batteries - particularly the maintenance free versions - don't generally leak liquid at normal angles of heel for reasonable lengths of time. AGM batteries are more demanding about proper charging voltages (the regulator in your boat is almost certainly designed for flooded cells, not AGMs, and will need to be replaced) and less forgiving about being stored when partially discharged than flooded cells. And AGM batteries have a significantly shorter service life - in terms of charge/discharge cycles - than do flooded batteries. Plus they are a lot more expensive. I looked at the AGM batteries in your post. Trojan T125s from the same supplier would have 15% more capacity and cost 15% less than the AGM. Two Exide or Interstate 27 deep cycle batteries in parallel would have the same capacity as two of these AGM GC2s wired in series and cost about half as much. These particular AGM batteries don't look like a particularly good value to me. Good luck making your decision Rick Brass From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Edd Schillay via CnC-List Sent: Wednesday, February 25, 2015 12:16 PM To: C&C List Subject: Re: Stus-List Batteries -- Flooded, Sealed or AGM? Josh, I'm leaning towards 4 to 6 (depending on the space available) Trojan T-105s, but am concerned about the maintenance, especially since I'm kinda cut off from the boat all winter long. Alternatively, I was looking at these AGMs: http://www.atbatt.com/amstron-gc2-6v-agm-deep-cycle-battery.asp?utm_content= Amstron-AP-GC2 <http://www.atbatt.com/amstron-gc2-6v-agm-deep-cycle-battery.asp?utm_content =Amstron-AP-GC2&utm_term=AP-GC2&utm_category=Sealed-Lead-Acid&gclid=CLy95KfH _cMCFXBp7Aod2WkA2g> &utm_term=AP-GC2&utm_category=Sealed-Lead-Acid&gclid=CLy95KfH_cMCFXBp7Aod2Wk A2g, but won't bother if AGMs are only going to last a few years. My charging system is the alternator, since the Enterprise lives on a mooring during the season (yes - we call that "standard orbit"). I only hook up to shore power a few times a year when cruising. The new system will connect the alternator to the house bank and use a Blue Seas ACR (https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_ 24V_DC_120A) to also charge the starting battery. That means I'll have a New-In-Box Echo Charger to sell this Spring. All the best, Edd Edd M. Schillay Starship Enterprise C&C 37+ | Sail No: NCC-1701-B City Island, NY Starship Enterprise's Captain's Log <http://enterpriseb.blogspot.com/> On Feb 25, 2015, at 11:53 AM, Josh Muckley <muckl...@gmail.com <mailto:muckl...@gmail.com> > wrote: I was at a point of extremes when I bought 5 AutoZone marine/deep cycle for a total of about $600 and 500Ahrs (~250Ahrs usable without damage). They are the standard maintenance free auto style which can be but are not intended to be watered. For me they were relatively cheap, readily available, easy to claim warranty, light enough to move/install/uninstall. They are also the easiest to charge and discharge since it is such a long standing standard. There are certainly advantages to other technologies and disadvantages to wet cells but for now this solution has met my needs very comfortably. T-105 golf cart batteries would really be my only other concideration but availability, movability, and warranty claimability are hold backs. You also have to consider the charging system when choosing batteries. I have a 100amp balmer alternator with external charge controller and a ProMariner P Nautic 60-12 charger/maintainer. There are disadvantages to staying on shore power 24/7 but it is working for me right now. Maybe I'll change that practice in the future. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Feb 25, 2015 11:17 AM, "Edd Schillay via CnC-List" <cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> > wrote: Listers, As you know, I'm redoing the electrical systems on the Enterprise (thanks to all for diagrams and advice). So now comes the question of what type of battery to use in my house bank - Flooded, Sealed or AGM? What do you have on your C&C and why do you prefer it? And, if you have flooded, how often do you top them off with distilled water? The countdown has begun! http://enterpriseb.blogspot.com/2015/02/launch-of-enterprise-countdown.html All the best, Edd Edd M. Schillay Starship Enterprise C&C 37+ | Sail No: NCC-1701-B City Island, NY Starship Enterprise's Captain's Log <http://enterpriseb.blogspot.com/> _______________________________________________ Email address: CnC-List@cnc-list.com <mailto:CnC-List@cnc-list.com> To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
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