Sealed AGM Batteries are the work-horse of the battery world. Their construction and design allow them to have low to medium current drawn out of them, over a long period. This is because an AGM Battery is still a lead-acid battery but in between the lead plates is a thin sheet of Boron-Silicate glass mat. This glass mat is what the electrolyte (acid) of the battery rests in, rather than being free flowing like a wet-cell battery. This design feature makes an AGM Deep Cycle Batteries “unspillable” as the acid is contained by the glass mat and therefore won’t leak even if tipped on its sides. This characteristic, as well as not producing gases while they charge, makes Deep Cycle AGM batteries perfect for use in getting power from off grid applications including; camping, caravans, boats, RV’s or as a second battery in a dual battery system.
AGM batteries when used as power for camping, caravans, camper trailers, motor homes and off grid solar charge faster and deeper than lead acids, and they are more rugged mechanically and electrically. They also have far less internal discharge. If initially fully charged, they will often retain 60% or more for over 12 months (except in very hot areas). AGM batteries can also endure deeper discharges with less damage than their lead acid counterparts. Their lifespan, however, is still related to the frequency and depth of discharge. For example, the chart below shows how Giant Power AGM Deep Cycle Batteries typically withstand 1600 charge/discharge cycles if routinely discharged by 30% (i.e. 70% remaining), with a Deep Cycle AGM Battery, in essence, you are buying the usable amp hours.
Things to consider when choosing an AGM Battery include the weight and battery life cycle.
Traditionally, it was considered that an AGM battery weighs about 3kg per amp hour. With the increase in manufacturing technology, and substantial variances in products available in the market - including lead purity, density, footprint and lifespan - the weight is no longer a relevant metric to reflect a battery's capabilities. The main benefit of choosing to use a high-quality Deep Cycle AGM battery is that it has low internal resistance and low self-discharge rates, enabling faster recharge and a longer overall battery life. This means that when they are fully charged, they can be stored for extended periods of time and conveniently recharged using a range of AGM Battery Chargers.
Things to remember, AGM batteries are not intended to be cranking batteries, however using them as a cold cranking occasionally will not affect their overall service life. The draw needed at start up is too high to be sustained by the battery and continued use in a cranking state or a situation with a high draw out of the battery will affect service life. AGM and Gel batteries are also sensitive to heat and are not suited to be mounted under bonnets of vehicles unless they are in an insulated covering.
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