Open up the delivery scope
One quote may cover a battery cabinet; another may include PCS, distribution, controls, commissioning and freight. Dividing both totals by capacity is misleading. List batteries, conversion equipment, EMS, metering, cables, foundations, installation, testing and training. Clarify taxes, transport and site work rather than assuming blank items are included.
Align the performance conditions
Compare nameplate and usable energy at the same DC or AC boundary. Check temperature, continuous power, efficiency conditions and warranty limits on capacity or throughput. A proposal holding backup reserve cannot be compared directly with one using all available energy for daily operation.
Identify the support responsibility
Define remote and site support, spares, response arrangements and warranty responsibilities. Confirm communications with the site system and required local documentation. Ask a low-priced supplier what is excluded and a higher-priced supplier what the additional scope solves. Price becomes meaningful after those boundaries match.
Further reading: www.energy.gov
This article supports early project discussions. Final configuration depends on site conditions.