Published by Jinfan
Published
What to bring to the review
- Battery-powered functions and the exact startup sequence
- Battery, host, firmware and connector/harness revisions
- Starting voltage, state-of-charge basis, temperature and charger state
- Time-aligned current, voltage and host-event records with measurement settings
- Documented operating limits, observed result and unresolved questions
Separate startup capability from runtime
A runtime budget concerns energy over an operating cycle. Startup concerns the current and voltage during a particular event. Identify whether your machine powers a pump, controls, heating or a combination from the battery, and whether these loads overlap. Do not assume every coffee machine has the same electrical sequence.
Charging input capacitors can create inrush above normal operating current. TI explains the capacitive relationship I = C × dV/dt; this describes that contribution, not the entire pump, converter or machine load. Use the actual system trace rather than converting a nominal wattage into a universal startup-current rating.
Define one record for each event
Assign an event ID to cold power-on, pump start, a change of mode or an overlapping load sequence. For each one, keep the starting conditions, trigger definition, measurement locations and time window. Use synchronized battery current and voltage; record host input voltage separately when investigating a drop through the connector and harness.
Keep the original trace and an accompanying note, not only a screenshot of its maximum. Record instrument range, bandwidth, sampling and trigger settings, plus any current limiting in the supply setup. Qualified personnel should select the measurement arrangement for the actual circuit; this guide does not prescribe live wiring or instrument safety ratings.
Keep peak, duration and recovery together
A peak value without a time base cannot distinguish a brief inrush from a sustained overload. Summarize peak current, the interval used to define its duration, minimum voltage, recovery time and repetition. Retain events where the host reset or stopped; do not average them away or combine peaks from different runs into a nonexistent single event.
Confirm that the acquisition captured the event rather than clipping its top or missing its beginning. Keysight describes synchronized power-on voltage/current capture for IC characterization. Its example supports the measurement approach, not a coffee machine test specification or a requirement to buy that instrument.
Compare host operating limits and protection separately
Check the host’s minimum operating voltage and reset behavior against the recorded trace. Review the battery protection response, component limits and thermal conditions with the responsible engineering teams. A protection trip is not the same as a host reset, and a successful start does not establish continuous-current capability.
Protection devices can have different thresholds and delays. The BQ77915 datasheet illustrates configuration-specific voltage, current and timing behavior; it is not evidence that Jinfan uses this part. Check the documentation for the actual pack revision. Do not bypass protection or raise limits simply to make an unexplained startup pass.
Make the record usable for an engineering decision
A useful handoff joins an event ID, exact revisions, conditions, trace file, measured summary and observed outcome to a stated acceptance criterion. Mark a criterion as unresolved when the host or pack owner has not defined it. Record whether each event passed, failed or still needs evaluation, instead of labeling the whole pack approved.
After a hardware, firmware, cable or load-sequence change, identify which earlier records no longer represent the new configuration and agree the evaluation scope. Share the non-confidential summary and open questions through Technical RFQ before arranging any exchange of sensitive design files.