Other options are nice, pricey, and really don't offer that much for the cost.
I respectfully disagree with this statement BryanL.
AGM (Absorption Glass Mat) sealed battery technology was originally developed in 1985 for military aircraft where power, weight, safety, and reliability were paramount considerations.
AGM battery technology has continued to develop and offer improvements over other sealed battery technologies. AGM technology has become the next step in the evolution of both starting and deep cycle sealed batteries for marine, RV, and aviation applications. This "next generation" technology delivers increased safety, performance, and service life over all other existing sealed battery types, including gel technology.
AGM BATTERIES FEATURES:
" Aircraft class cell construction:
- Lowers internal resistance for high repeated engine start current.
- Withstands shock and vibration much better than flooded or gelled electrolyte designs.
"
Twice as many discharge/charge cycles as the leading gel battery.
"
Faster recharge; no current limitations with voltage regulated recharging.
" Sealed construction with absorbed electrolyte - no shipment restrictions; submersible without damage; install in any position;
no need for watering; no corrosion on terminals.
" Cell safety vent valves - pressure regulated, nonremovable.
"
Safety - even during severe overcharge the LIFELINE AGM battery produces less than 2% hydrogen gas(4.1% is required for flammability in air).
"
FAA and Military approved; Manufactured to DOD military specifications; "
Lowest discharge rates (Less that 3 percent per month unattended)
In AGM sealed batteries, the acid is absorbed between the plates and immobilized by a very fine fiberglass mat. No silica gel is necessary. This glass mat absorbs and immobilizes the acid while still keeping the acid available to the plates. This allows a fast reaction between acid and plate material.
The AGM battery has an extremely low internal electrical resistance. This, combined with faster acid migration, allows the AGM batteries to
deliver and absorb higher rates of amperage than other sealed batteries during discharging and charging. In addition, AGM technology batteries can be charged at normal lead-acid regulated charging voltages, therefore, it is not necessary to recalibrate charging systems or purchase special chargers.
Unlike other sealed battery technologies, the AGM battery technology allows for more positive plate material in its cell construction. Therefore, there is an
increase in Amp Hours, Reserve Capacity, depth of cycle, cycle life and a reduction of internal self discharge over other sealed batteries.
This increased performance have made LifeLine AGMs original equipment on many high quality commercial ships and pleasure craft including Lazarra Yachts, Island Packet, Pacific Seacraft, Viking Yachts, Elco Electric Boats, San Juan Yachts, Alden Yachts, Hinckley Yachts, Santa Cruz Yachts, Christensen Shipyards, Blue Water Yachts, and Broward Marine.
In addition, Lifeline AGMs are original equipment on Airstream, American Carriage, American Coach Works, ARI, Coaches by Dare, Country Coach, Creative Mobile Interiors, Dynamax, Earth Roamer, Executive Coach, Four Winds, Featherlite, Fleetwood Motor Homes, Four Winds Intl Inc., Gulf Stream Bus, Hoffman Coach, Integrity Motor Coach, Innovative Coach Works, LDV, Mattman Company, Millennium Luxury Coach, Mirage Mfg Co., Marathon Coach Inc, Monaco Coach, New Horizons, Newmar, NRC, Newell Coach, Outlaw Conversions, Pace American, Parliament Coach, Sports Mobile, Thompson Coach, Travel Supreme, Renegade, Royale Coach, Vantare, and Premier Motor Coach.
Check this link
http://www.dcbattery.com/lifeline_ag...ycle_comp.html for a comparison of AGM Vs leading GEL battery life cycles. Based on this, the leading GEL deep cycles live cycle is 400 cycles @ 50% - LifeLine AGMs are 1000 cycles at 50% (2 more life cycles.)
In addition, these batteries have a 5 year warranty Vs a standard 3 year for most other deep cycle batteries.
I for one see little "value" in spending my time checking specific gravity levels and adding water to batteries.
So, while admittedly "pricy," I believe, for all the reasons cited above, I am getting a lot of "value" for the additional cost.