Deep-cycle battery

deep-cycle battery is a battery designed to be regularly deeply discharged using most of its capacity. The term is traditionally mainly used for lead–acid batteries in the same form factor as automotive batteries; and contrasted with starter or ‘cranking’ automotive batteries designed to deliver only a small part of their capacity in a short, high-current burst for cranking the engine.

For lead-acid deep-cycle batteries there is an inverse correlation between the depth of discharge (DOD) of the battery and the number of charge and discharge cycles it can perform; with an average “depth of discharge” of around 50% suggested as the best for storage vs cost.

While the main focus of this article is on traditional lead-acid, newer technologies, such as lithium-ion batteries – already commonplace in smaller sizes – are beginning to become common in this same form factor; although still at a large price premium.

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