The battery sizing calculator can be found here.

Trojan’s calculator is designed to simplify the task of properly sizing a battery bank for off-grid renewable energy systems. A battery bank is a vital component of a system, so careful attention must be paid to battery sizing to ensure maximum battery performance and longevity. According to Trojan Battery, three factors must be considered when sizing battery banks for renewable energy systems: the electrical power required, or load, of a particular application; the maximum depth of discharge (DOD) the battery will be allowed to go down to; and the autonomy desired, or the number of days the battery will be used to power the loads.

“Failing to properly design the system to meet specific load requirements, leads to improper sizing of the batteries which can reduce the life of the battery bank,” said Kalyan Jana, technical product manager at Trojan Battery. “Therefore, it is important to optimize systems to meet the load requirements of a customer’s particular application requirements.

“Not fully understanding the system’s load profile for both the real energy demands and the duty cycle can have a dramatic impact on system performance.  It also can potentially cause the system to lose power or require a replacement battery bank sooner than necessary. ”

Users of the calculator fill in the appropriate information on the electronic form such as battery voltage, desired to depth-of-discharge (DOD), days of autonomy, AC and DC loads, device types with power ratings, and hours per day or days per week used, and the application automatically determines the required battery capacity.  It then recommends the Trojan battery models for their particular set up.