Lithium Ion Car Battery Specification Example for Municipal Fleets: Sealed Unit
Lithium Ion Car Battery Specification Example for Municipal Fleets: Sealed Unit
This is a worked specification for lithium ion car battery in a sealed unit programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The sealed unit version exists because the duty cycle on municipal fleets is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually reorders that did not match the approved sample.

Example specification
| Item | Lithium Ion Car Battery |
|---|---|
| Application | Municipal Fleets |
| Version | Sealed Unit |
| Base material | Magnesium Alloy |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.1 mm |
| Finish | anodised |
| MOQ | 500 pieces per specification |
| Sampling | 14 working days, 3 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Magnesium Alloy, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- surface grinding
- laser cutting
- die casting
- assembly line testing
- injection moulding
- precision stamping
Where this example applies
Programmes that run sealed unit most often specify this build for municipal fleets. Related applications include three-wheelers, agricultural trailers, aftermarket retail, construction equipment, fleet maintenance.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 2.5 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
What testing is included?
Standard lots ship with dimensional and hardness reports. SAE J431 documentation is issued with the shipment when your market requires it.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



