BESS Sizing Calculator
Battery Storage for Solar Projects (2026)
Size battery energy storage (BESS) for self-consumption, peak shaving, backup, arbitrage, or microgrid. Accounts for Depth of Discharge (DoD), round-trip efficiency, and cycle life per chemistry.
Total daily kWh consumed by facility
LFP is JUSTSOLAR standard — safer + longer cycle life. NMC for density-critical apps only.
Typical modern LFP systems: 90-95%
Your BESS Recommendation
60% of daily load (typical residential + small C&I)
Nominal capacity = usable ÷ (DoD × efficiency) = 300 ÷ (0.95 × 93%) = 340 kWh (rounded up to 340)
Battery cost benchmark: $130/kWh battery only, +30% for BOS. 2026 market. Actual pricing varies by supplier + volume.
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Why LFP for Solar BESS?
Safety
LFP has highest thermal runaway threshold of lithium chemistries. No cobalt = no ethical supply chain concerns.
Longevity
6000+ cycles at 80% DoD = 15+ years at 1 cycle/day. NMC typically 3000-4000 cycles only.
Cost
LFP 2026 cell cost ~$90-110/kWh, ~20% cheaper than NMC. Lower density but irrelevant for stationary BESS.