System quotes mix panel, charger, and battery efficiency into one line item. This battery system round-trip efficiency estimator isolates the storage round trip—Wh in vs. Wh out—so planners see deliverable energy after the bank, not just nameplate kWh.
Benefits
- Estimates storage round-trip % from planned or logged Wh in/out.
- Separates battery yield from inverter and MPPT layers.
- Feeds usable kWh estimates for daily load and autonomy math.
How it works
- Estimate or measure Wh into the battery bank per cycle (charge side).
- Estimate or measure Wh delivered from the bank to DC/AC loads.
- Read round-trip %—apply to gross bank Wh for usable energy planning.
FAQ
What does a battery system round-trip efficiency estimator do?
It projects how much stored energy returns to loads: efficiency % ≈ (Wh out ÷ Wh in) × 100 for the battery subsystem. Example: estimating 9.2 kWh out from 10 kWh in → 92% storage round trip before separate inverter loss.
Is this the same as whole-home solar efficiency?
No—this focuses on the battery charge/discharge leg. Panel-to-MPPT and inverter conversion are additional multipliers. Use this estimator for the storage block, then stack other efficiencies for end-to-end yield.
What assumptions should I document on proposals?
Note chemistry, charge C-rate, average DoD, and temperature band used for the estimate. LiFePO4 at moderate DoD often models 93–97%; aged lead-acid may estimate 82–88%. Replace estimates with measured Wh after commissioning.
Technical specifications
- Estimated round-trip % = (Wh_out ÷ Wh_in) × 100.
- Usable_Wh ≈ gross_Wh × (estimate% ÷ 100) per cycle.
- System yield = MPPT × battery × inverter efficiencies (stacked).
- Related: battery-round-trip-efficiency-calculator, battery-energy.