RTE (Round-Trip Efficiency)

RTE (Round-Trip Efficiency) shows how much of the energy charged into the battery storage can be discharged. If we charge 100 kWh and can take out 88 kWh, the RTE is 88%. For modern industrial lithium-ion systems, the AC-side RTE — which also includes the losses of the bidirectional converter — is typically 86–92%; the loss leaves the system as heat.

RTE is the key to the arbitrage calculation: net spread = discharge price − (charging price ÷ RTE). The lower the RTE, the larger the price difference needed for profitability. At 88% RTE, the charging price is effectively ~13.6% more expensive — the daily HUPX spread must exceed this.

The related sizing concepts — SOC range, C-rate, cycle life — are covered in detail in the knowledge base.