We do not own the lines we buy from — so the inspection has to be ours, in writing, with a record attached to each serial number. Every unit is aged at rated output for at least four hours before packing. Not a batch sample: every unit.
The BOM, cell grade and enclosure are locked in writing before the line starts. Any substitute part needs your written approval, not ours. We issue the sheet with the model code, the connector drawing and the thresholds — the same document the factory builds from.
Cell batches are matched against capacity and internal resistance on arrival. A batch that does not match is rejected whole rather than sorted through — because a sorted batch is how a weak cell ends up in somebody's unit six months later.
100 % of units, minimum four hours at rated output. Capacity, transfer time and thermal rise are logged against the serial number. A unit that drifts outside tolerance is pulled, not derated and sold as a lower grade.
Transfer time, waveform and enclosure are checked again before packing, together with the accessory set and the manual language. The test record and batch photographs travel with the shipment, so your incoming inspection has a baseline to compare against.
Send the serial number and what the unit did. Because the aging record exists, we can usually tell within a day whether it is a cell, a BMS threshold or a load problem — and we replace rather than ask you to ship a lithium pack back across a border.
Four of these five answers usually resolve the case without a return.
We will send a redacted test record from a recent batch for the model you are considering, so you can see what the document actually contains.