Maintenance Free Car Battery Specification Example for City Buses: Sealed Unit
Maintenance Free Car Battery Specification Example for City Buses: Sealed Unit
This is a worked specification for maintenance free 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 city buses is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually inconsistent hardness between lots.
Example specification
| Item | Maintenance Free Car Battery |
|---|---|
| Application | City Buses |
| Version | Sealed Unit |
| Base material | Reinforced Nylon |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | painted |
| MOQ | 1,000 pieces per specification |
| Sampling | 7 working days, 5 days per revision |
| Compliance | TUV |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Reinforced Nylon, 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
- robot welding
- injection moulding
- ultrasonic cleaning
- powder coating
- gravity casting
- surface grinding
Where this example applies
Programmes that run sealed unit most often specify this build for city buses. Related applications include camper conversions, agricultural trailers, passenger cars, emergency vehicles, construction equipment.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 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
What testing is included?
Standard lots ship with dimensional and hardness reports. TUV documentation is issued with the shipment when your market requires it.
How long does sampling take?
Samples leave the factory in 7 working days, and each revision round adds about 5 days once you have seen the first piece.
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the TUV-compliant build instead of a fresh interpretation.
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.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.
