When the mould is gone: replacing a discontinued battery case
Short answer: measure the frame before the pack. A dead mould takes the opening dimension with it, and the opening is the number every supplier quotes — so the enquiry arrives with a pack block and nothing else. The frame is the part that did not change, and its boss spacing is what decides whether a drop-in housing exists at all. On the 8 Hailong moulds we hold drawing data for there are 6 distinct hole patterns, so "buy another Hailong case" is not a fitment plan.
Short answer: measure the frame before the pack. A dead mould takes the opening dimension with it, and the opening is the number every supplier quotes — so the enquiry arrives with a pack block and nothing else. The frame is the part that did not change, and its boss spacing is what decides whether a drop-in housing exists at all. On the 8 Hailong moulds we hold drawing data for there are 6 distinct hole patterns, so "buy another Hailong case" is not a fitment plan.
What the dead tool took with it
A mould is scrapped for reasons that have nothing to do with the part: the tool wears out, the moulder closes, the brand moves the product to a different shell. The drawing usually goes at the same time, and with it the three figures that would have settled the replacement in one line — the opening the cells sit in, the section, and the mounting pattern.
None of the three can be recovered from the pack. A pack measures smaller than its own opening on every axis, because foam, tape and the board sit in the difference. The pack also has no bosses: the rail is part of the housing, and the housing is the thing that is missing. What the pack does carry, exactly, is the cell count — count the parallel groups and multiply by the series count, and a 10S4P is 40 cells with no tolerance on the answer.
So the pack gives one number that is exact and three that are not. The frame gives the two that decide the fit.
The order to measure in
| # | Measure | Off what | What it rules out | What it costs to get wrong |
|---|---|---|---|---|
| 1 | Mounting centres, both directions | Frame, centre to centre across the bosses or the rail's fixing holes | Every housing with a different pattern — which, on our own moulds, is most of them | Housing arrives and will not bolt on. Bosses in an aluminium down tube are where they are |
| 2 | Free length along the mount line | Frame, minus anything already occupying that line | Every housing longer than the space, including ones that pass step 1 | Fits the bosses, fouls the crank at one end or the head tube at the other |
| 3 | Pack block, three axes, with the BMS fitted | The dead pack | Every housing whose opening is shorter than pack plus board | Closes on the cells, not on the board — the classic 13S5P failure, in a replacement |
| 4 | Connector face | The dead pack's socket | Port types and positions the end cap cannot carry | Harness has to be re-terminated, or the port lands where the frame is |
Steps 1 and 2 come first because the frame is the fixed side. A housing can be re-capped, re-cut or re-moulded; a down tube with the wrong bosses drilled in it cannot. If step 1 fails, steps 3 and 4 produce a housing that will not attach — and step 1 is ten minutes with a caliper.
Rail spacing on our own Hailong moulds
8 of the 14 Hailong moulds in production carry a measured pattern. The rest are set per order, which is worth knowing before assuming a drawing exists. Ordered by the long spacing, short to long:
| Mould | 18650 | 21700 | Mounting centres (mm) |
|---|---|---|---|
| ALX097B | — | 52 | 73 / 73 |
| ALX149A | 104 | 70 | 161.15 / 71.9 / 72.1 |
| ALX149B | 117 | 80 | 161.15 / 71.9 / 72.1 |
| ALX053B | 78 | — | 162.19 / 73 / 73 |
| ALX146 | 65 | 40 | 171.1 / 57 / 57 |
| ALX068 | 52 | 30 | 171.61 / 70.5 / 65.75 |
| ALX096 | 52 | 30 | 171.61 / 73 / 73 |
| ALX098 | 65 | 40 | 171.61 / 73 / 73 |
6 distinct patterns from 8 moulds — and where two moulds do share a pattern, the cell ceiling still differs: ALX149A and ALX149B share 161.15 / 71.9 / 72.1 mm but hold 104 against 117 cells on 18650; ALX096 and ALX098 share 171.61 / 73 / 73 mm but hold 52 against 65 cells on 18650. Pattern and capacity are independent axes. Matching the bosses tells you the housing will bolt on; it tells you nothing about whether your pack fits inside it.
The spread matters more than the average, because these are not adjustable features. Long spacing runs 161.15 to 171.61 mm and short spacing 57 to 73 mm — 10.46 mm and 16 mm across a family that all sells under one name. A frame drilled for 161.15 mm will not take a housing at 171.61 mm, and no bracket in the range bridges it.
If the pack was an in-frame type
In-frame housings fail differently, because there the frame is the mould. 18 of the 21 in-frame models carry a battery box section, and those 18 resolve to 8 distinct sections:
| Battery box section (W × H) | How many models | Which ones |
|---|---|---|
| 64.83 × 43.7 mm | 1 | ALX095 |
| 88 × 47 mm | 1 | ALX003 |
| 88 × 40 mm | 2 | ALX011 · ALX014 |
| 93.4 × 60 mm | 2 | ALX079 · ALX084 |
| 102.2 × 60.2 mm | 4 | ALX006 · ALX056 · ALX060 · ALX060B |
| 102.2 × 43 mm | 2 | ALX107 · ALX124 |
| 110 × 67.8 mm | 5 | ALX106 · ALX108 · ALX108B · ALX108C · ALX131 |
| 114.2 × 58 mm | 1 | ALX009 |
A frame with a cavity cut for 64.83 × 43.7 mm will not take 114.2 × 58 mm, whatever the cell count, and the cavity cannot be enlarged without cutting the tube. This is the one case where "can it be replaced" is a straight comparison of two numbers, decided before capacity is discussed at all.
When nothing in production fits
Case file, from an enquiry this autumn: a three-wheel scooter brand in Korea, 10S4P on 18650 35E, 36 V 14 Ah, 40 cells. Their housing mould was lost, so the pack could not be built. They had found a replacement case at 300 × 84 mm and could not find anyone selling it.
Capacity was never the obstacle — 40 cells sits inside a 52-cell mould with room left for the board. The obstacle was length. On the four Hailong records that state an overall length without ambiguity, the range runs 368.28 to 404.33 mm (ALX019B to ALX053B), and the shortest is 68 mm longer than the 300 mm that frame will take.
| Route | What it costs | What you get | Timing |
|---|---|---|---|
| In-production housing | No tooling. One piece minimum, so a sample can be ordered before any commitment | A housing that bolts on only if steps 1, 2 and 4 all pass — and 368.28 mm is the shortest length we tool | Sample ships within 7 days |
| New tool to the old envelope | Tooling charged first and refunded against cumulative volume at the threshold agreed in the quote | The case your frame was designed around, at the length you actually have, with the logo embossed rather than printed | Bulk runs about 45 days |
Where the frame has 368.28 mm or more, the in-production housing is the cheaper answer and no tool is involved. Where it has 300, nothing in the catalogue enters it and the tool is the only route. Saying that is worth more than quoting the nearest thing and letting it fail at the frame — the freight on a wrong housing costs more than the housing.
What to send
- Ask the old supplier for the drawing first. If the moulder still exists, the opening, the section and the rail pattern are all on it. Measuring is the fallback, not the first move.
- Mounting centres, both directions, caliper across the hole centres rather than the outer edges.
- Free length along the mount line, after subtracting whatever already sits on it.
- Pack block with the BMS fitted, all three axes, plus the cell format and the parallel count.
- A photo of the connector's mating face, with a part number if there is one. "5-pin" on its own does not define a keyway; that is covered in what a connector actually changes.
- Which route you want quoted. A sample of an in-production housing costs a fraction of a tool and settles the fit question before either is paid for.
Every model with a published opening is on the measured size table, and the Hailong configuration table maps a cell count to the moulds that hold it. If the old housing is still in one piece, the measurement method is in how to measure your frame; if a drawing does exist, read it for the opening and not the overall length — the two differ by the end caps, as the drawing guide sets out.
Common questions
My case supplier has closed. Can the replacement be identified from the old pack?
Is Hailong a standard, so any Hailong case will fit?
Can a housing be made to the old case's dimensions without the old drawing?
What is the minimum order for a replacement housing?
Send us the pack and we will confirm the fit
Cell type, series and parallel count is usually enough. If the answer is that none of our moulds fit, we will say so rather than sell you the nearest thing.