Find a case by opening length
If you have already laid out the cell block and know how much length it needs, enter that figure and this lists the housings that provide it — 81 of our moulds, from 110 mm to 538 mm. No email required.
Your requirement
The length the cell block needs inside the housing. A 13S5P on 21700 is roughly 13 × 18.5 mm of cell plus the holder, so around 260–280 mm before the BMS.
Set this if you also need a floor on capacity. Leave at 0 to see everything.
Housings with at least 350 mm of opening
What opening length means
It is the usable length inside the housing, the space the cell block sits in. It is shorter than the exterior length of the case, because the end caps, the connector block and the cable exit all take space at either end. Manufacturers quote it because it is the number a pack builder needs, and it is the one figure that tells you whether a mould will do the job.
What it does not tell you. Opening length says nothing about width or depth, and a pack can fail to fit on either. It also says nothing about the BMS compartment, which is usually the real constraint on a 13S build. Use this finder to narrow the field, then ask for the interior drawing before committing. There is a guide on the four dimensions worth asking for in what internal dimensions to ask a supplier for.
How much opening does a pack need
Rough working figures, before the BMS:
- 10S4P on 18650 — about 200 mm
- 13S4P on 18650 — about 250 mm
- 13S5P on 18650 — about 250 mm, plus width for the fifth column
- 13S5P on 21700 — about 265 mm
- 14S6P on 21700 — about 285 mm
Then add 30–50 mm for the BMS and the wiring. The pack calculator works out the cell count and capacity for any configuration; this page works out whether it will physically fit.
Other ways in
- Pack calculator — by series and parallel count
- Every configuration — 71 buildable combinations
- Case selector — by cell count
- Which voltage — 36 V to 72 V compared
Send us the drawing and we will confirm the fit
If you have the pack layout, send it over. We will say which mould matches, or that none of them does.