However, all of this takes time and hence please use this as a first approximation. The battery pack mass is roughly 1.6x the cell mass, based on benchmarking data from >160 packs. However, there are a number of estimation options and always the fallback will be to list and weigh all of the components.
The operating voltage of the pack is fundamentally determined by the cell chemistry and the number of cells joined in series. If there is a requirement to deliver a minimum battery pack capacity (eg Electric Vehicle) then you need to understand the variability in cell capacity and how that impacts pack configuration.
A 400V pack would be arranged with 96 cells in series, 2 cells in parallel would create pack with a total energy of 34.6kWh Changing the number of cells in series by 1 gives a change in total energy of 3.6V x 2 x 50Ah = 360Wh. Increasing or decreasing the number of cells in parallel changes the total energy by 96 x 3.6V x 50Ah = 17,280Wh.
Repeating this calculation with a 200Ah cell and the same ~400V pack requirements shows that the smallest total energy for the pack is 69kWh. Also, the increments are 69kWh for each increase in the number of cells in parallel. This could be a very cost driven pack design, but is not so flexible in total capacity.
Let us suppose we select a 50Ah cell with a nominal cell voltage of 3.6V A 400V pack would be arranged with 96 cells in series, 2 cells in parallel would create pack with a total energy of 34.6kWh Changing the number of cells in series by 1 gives a change in total energy of 3.6V x 2 x 50Ah = 360Wh.
the power of a 12V 280Ah battery pack is Power (kWh) = 12 (V) * 280 (Ah)/1000= 3.36kWh In the design phase of a solar energy system, you may often need to calculate the total power of a battery pack with different capacities of battery cells to find the optimal pack design solution.