From small backup systems to whole-house storage, these are the configurations DIY powerwall builders use.
7S20P Samsung 50E
Voltage: 25.2V nominal
Capacity: 100Ah / 2.52kWh
Entry-level powerwall for small solar setups. 140 cells total. Good for powering lights, routers, and small loads during outages.
14S40P Samsung 50E
Voltage: 51.8V nominal
Capacity: 200Ah / 10.4kWh
Serious home storage. 560 cells deliver enough to run a house overnight. Compatible with most 48V hybrid inverters.
14S40P LG HG2
Voltage: 51.8V nominal
Capacity: 120Ah / 6.2kWh
Using 18650 HG2 cells or recycled equivalents. Lower capacity per cell but often cheaper, especially with salvaged cells.
7S40P Samsung 50E
Voltage: 25.2V nominal
Capacity: 200Ah / 5.04kWh
24V system for off-grid cabins. Pairs well with common 24V charge controllers and inverters. 280 cells total.
14S80P Samsung 50E
Voltage: 51.8V nominal
Capacity: 400Ah / 20.7kWh
Full Tesla Powerwall equivalent. 1120 cells but delivers massive storage. Multi-day backup for an efficient home.
14S60P Sanyo NCR18650GA
Voltage: 51.8V nominal
Capacity: 210Ah / 10.9kWh
Popular with recycled cell builders. The NCR18650GA is common in laptop packs and has excellent energy density for storage use.
Powerwall cells are discharged slowly over hours, not minutes. CellBench shows you how cells perform at 0.2C-0.5C rates, where high-capacity cells like the Samsung 50E truly shine.
Rated capacity and usable capacity are different. Simulate your expected discharge rate and see how many actual watt-hours you get from each cell before hitting cutoff voltage.
The cheapest cell per unit is not always the cheapest per kWh of storage. Compare different cells on a cost-per-usable-kWh basis to make the best investment for your build.
How many cells do you actually need? Simulate your target capacity at your expected load and see exactly how many series and parallel groups to buy. No overbuilding, no surprises.
High-capacity cells optimized for low-rate, long-duration energy storage.
5000mAh / 9.8A
The top choice for powerwalls. Highest capacity per cell means fewer cells for the same storage. Excellent cycle life at low discharge rates.
3000mAh / 20A
Popular and affordable 18650 option. Good cycle life and widely available, including as recycled cells from laptop packs.
3500mAh / 10A
High capacity 18650 commonly found in recycled laptop packs. Excellent for low-drain storage applications.
It depends on your target voltage and capacity. A 7S configuration gives you 25.2V nominal (for 24V systems), while 14S gives you 51.8V (for 48V systems). A typical starter powerwall might be 7S80P using Samsung 50E cells, giving 25.2V and 400Ah (10kWh). Larger builds can use hundreds or thousands of cells.
The Samsung 50E (5000mAh, 21700) is ideal for powerwalls because it has the highest energy density and excellent cycle life at low discharge rates. The LG HG2 (3000mAh, 18650) is a popular budget option, especially when using recycled cells. For powerwall use, capacity matters more than maximum discharge current since the per-cell current is very low.
48V (14S) is generally recommended for larger systems because it reduces current flow for the same power, meaning thinner wires, lower losses, and wider inverter compatibility. 24V (7S) is simpler for small setups and compatible with many off-grid charge controllers. CellBench can simulate both configurations so you can compare efficiency.
Yes, recycled laptop cells are commonly used for DIY powerwalls. However, they vary widely in remaining capacity and internal resistance. CellBench helps you understand the performance characteristics of different cell models, which you can use as a baseline when testing and grading recycled cells.