We test for the worst Tuesday
A lab test proves a pack works. A field test proves it survives the week nobody planned for.
A battery datasheet describes a controlled world: a fixed temperature, a clean charge profile, a known depth of discharge. Indian fleets do not operate in that world.
The field is the specification
A pack in a delivery fleet sees a hot afternoon, a partial charge at a roadside socket, a rough handover and a route that changes when a customer calls. The pack that survives the datasheet may not survive the Tuesday when all four happen together.
So the test plan starts from the field, not the datasheet. We reproduce the conditions that actually shorten life: heat soak, partial state of charge, high current bursts and long idle periods at a warm temperature.
What we measure
- Cell temperature spread across the pack under load.
- Voltage divergence between cell groups after repeated partial cycles.
- Capacity fade against a realistic duty cycle, not a single constant-current discharge.
- Behaviour when the BMS has to derate: does it protect the cells without dropping the load?
The failures that matter
Most field failures are not dramatic. They are a connector that loosens, a cell group that drifts, a seal that lets dust in, or firmware that misreads a sensor. A test programme that only looks for thermal runaway misses the failures that actually strand a vehicle.
Why we publish less than we test
A test report is easy to turn into a marketing claim. We would rather ship a pack that survives the route and describe the limits honestly. A customer who knows the limit can plan around it; a customer who was sold a number cannot.