Rolls-Surrette S2-1275AGM

Rolls Surrette has built a solid reputation over the years as one of the best, if not THE best, sources of deep-cycle batteries. Their sealed AGM batteries feature a high cycle life without the need for maintenance. The AGM technology (Absorbed Glass Mat) keeps the electrolyte (acid) contained in the sponge-like glass mats allowing Surrette AGM batteries to not expel any liquids even under severe overcharge. AGM batteries are non-hazardous, resulting in lower shipping costs and they can also be shipped via air. AGM batteries have a very low self-discharge rate, and can handle higher charge currents vs. regular flooded lead-acid batteries.

The AGM line batteries are designed for a variety of maintenance free applications and come with a solid 3 years full warranty. Sealed AGM batteries can be placed anywhere without having to worry about fumes. They are also somewhat more suitable for cold places as they are more frost-proof than regular flooded lead-acid batteries.

Adding batteries in series increases the Voltage, while keeping the Amp-hour size the same. Adding batteries in parallel keeps the Voltage the same, while increasing the Amp-hour size of the battery bank. For example, six S2-1180AGM batteries  (1100 Ah each) in series makes for a 12 Volt / 1100 Ah battery bank. Adding another string of six S2-1180AGM batteries in parallel to these will increase the bank size to 12 Volt / 2200 Ah.

Recommended Charge Settings (at 25C)

Equalize: Do not equalize AGM batteries (or set the equalize Voltage equal to the absorb Voltage)

Absorb time: 0.42 x C / I, where C is the 20-hour battery bank capacity and I is the real-world charge current

For example, a 48 Volt bank of six S2-1180AGM batteries, 1100Ah battery bank, with 10,000 Watt in solar PV would have a realistic charge current of around 150 Amp in full sun. That makes for an absorb time of 0.42 x 1100 / 150 = 3.1 hours = 3 hours 5 minutes

End Amps: If instead of time the current is used to determine the end of the absorb cycle, usually called ‘End Amps’, set it to around 2% of C20 (ie. for a 1100 Ah battery bank that would be 22 Amp as the End Amps setting, when the current falls below this value the batteries are full)

Maximum charge current: 25% of 20-hour battery bank capacity recommended (ie. 0.25 x 1180 = 295A for an S2-1180AGM battery for example), never more than 35%

Low-Voltage cut-off: 11.1 / 22.2 / 44.3 Volt (corresponds to about 80% Depth-Of-Discharge)

Features

• 2 Volt maintenance-free VRLA Absorbed Glass Matt battery
• 1150 Ah at 20 hours, 1175 Ah at 100 hours discharge rate
• M10 threaded terminals
• Reliable and dependable in an impact resistant plastic housing
• Rope and molded plastic handle!
• Three (3) years warranty