E-bike battery protection for United States makers now has a proposed federal rule behind it, and one passive on the charge path has a voltage ladder worth checking: Walsin’s low-voltage varistors. We counted 11 rungs from 18 V to 120 V. Only 4 sit above a 14S pack’s 58.8 V full charge, even after a ±10% tolerance.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin Technology (Walsin) varistor export of 379 rows, and this post is written from it. It is for a design engineer or buyer at a United States e-bike, conversion-kit or charger maker who wants to know what a Hong Kong source can offer on the charge and battery port. Every part number is real and every count is ours. Where the post states a rule or a standard, it names the source, its date and the day we read it.
What did the CPSC propose for e-bike batteries, and why does it reach a component buyer?
It proposed mandatory battery standards for e-bikes and similar products, and the proposal reaches everyone who puts a covered product on the United States market. The Consumer Product Safety Commission’s notice was published on 24 June 2026, with written comments due on 24 August 2026 and a compliance date of 180 days after any final rule. We read four summaries on 21 October 2026.
SGS reports that the proposal sits at 16 CFR 1265 and points e-bikes to UL 2849, personal e-mobility products to UL 2272 and loose battery packs to UL 2271, each with modifications. The mofo.com summary (16 July 2026) lists tamper-resistant battery enclosures, reverse-polarity tests, protection against incompatible chargers and expanded warning labels. The bdlaw.com summary (14 July 2026) reports that the Commission cited 227 battery incidents from 2019 to 2023, with 39 deaths and 181 injuries, and that the scope includes replacement packs, aftermarket chargers and conversion kits. PeopleForBikes still describes it as a proposal in its September 2026 update.
Our view, labelled as ours: the rule is about the pack, the enclosure and the charger. The charge port is where an incompatible charger meets the pack, and a clamp part there needs a voltage rating chosen against the pack. That choice is the one part of it a distributor’s export can inform.
Which Walsin varistor rung clears a 10S, 13S, 14S or 20S e-bike pack?
Six rungs clear a 10S pack, four clear a 13S or 14S pack, and two clear a 20S pack. We parsed all 379 rows of Walsin_MOV_ALL.xlsx: 51 rows have a varistor voltage of 120 V or less, in 11 steps from 18 V to 120 V, every one with a ±10% tolerance. We kept a rung only if its lower bound, 90% of the stated voltage, sits above the pack’s full charge.
The pack voltages are our arithmetic, not a source’s: a pack of 10, 13, 14 or 20 lithium-ion cells in series charges to 42.0, 54.6, 58.8 or 84.0 V at 4.2 V per cell. Cells with a higher charge voltage move every figure up, so read your cell datasheet. The export’s varistor voltage is a direct-current figure, which is why we use it.
| Pack | Full charge (our arithmetic) | Rungs of 11 whose lower bound clears it | First rung that clears | Full charge as a share of that rung’s lower bound | Match / mismatch (a clamp that stays off at full charge) |
|---|---|---|---|---|---|
| 10S | 42.0 V | 6 | 47 V (SR470K10D) |
99.3% | Match on the rating, with almost no margin |
| 13S | 54.6 V | 4 | 68 V (SR680K10D) |
89.2% | Match; the 56 V rung (SR560K10D) is a mismatch, its lower bound is 50.4 V |
| 14S | 58.8 V | 4 | 68 V (SR680K10D) |
96.1% | Match on the rating, thin margin; 56 V is a mismatch |
| 20S | 84.0 V | 2 | 100 V (SR101K10D) |
93.3% | Match; the 82 V rung (SR820K10D) is a mismatch, its lower bound is 73.8 V |
We have not seen this counted anywhere: a 13S and a 14S pack share one clearing rung, 68 V, and the 14S pack leaves only 4% between its full charge and that rung’s lower bound. The next rung, 82 V, takes the 14S share down to 79.7%. How much margin you want is a design decision, and leakage near the knee is not in the export, so we leave it to you and to the Walsin datasheet.
The export also gives the working voltage only in alternating current. We counted the Max Working Volt. column: 379 of 379 rows read Vac and none reads Vdc. A direct-current working rating for a pack port is therefore not in our data. The 68 V rung is listed at 40 Vac and the 82 V rung at 50 Vac.
What does the first clearing rung give up in surge rating?
A quarter to a fifth of the next rung’s peak current at the common disc sizes. At 5, 7, 10 and 14 mm the 68 V part carries 100, 250, 500 and 1,000 A, and the 82 V part one step up carries 400, 1,200, 2,500 and 4,500 A, a ratio of 4.0 to 5.0. The 14S pack’s clearing rung is the weak one.
| Disc size | 68 V part | Peak current | 82 V part | Peak current | Match / mismatch (against a 14S port wanting a bigger surge rating) |
|---|---|---|---|---|---|
| 5 mm | SR680K05D |
100 A | SR820K05D |
400 A | Mismatch on surge at the clearing rung; 82 V has 4.0 times more |
| 7 mm | SR680K07D |
250 A | SR820K07D |
1,200 A | Mismatch; 82 V has 4.8 times more |
| 10 mm | SR680K10D |
500 A | SR820K10D |
2,500 A | Mismatch; 82 V has 5.0 times more |
| 14 mm | SR680K14D |
1,000 A | SR820K14D |
4,500 A | Mismatch; 82 V has 4.5 times more |
The step is already in our post on MOV peak current per square millimetre. What is new here is where a pack lands on it. A 14S design that wants the bigger surge rating has to take the 82 V rung or a bigger disc and accept less margin below the knee, or take the 68 V rung and accept the smaller rating. The 20 mm size starts at 39 V and steps from 2,000 A at 68 V to 6,500 A at 82 V, a ratio of 3.25. Our post on reading varistor voltage from the part number explains why to read the column, not the code.
Our view, labelled as ours: a varistor is a transient clamp, not an incompatible-charger defence. Disconnecting a wrong charger is the job of the battery management system and the charger design. We do not suggest the rule asks for a varistor.
What do we hold in stock, and what do we not hold?
No varistor, and no battery document. We counted our stock list as at 23 September 2026, 1,125 part numbers: none is a varistor, and of the 28 Walsin datasheets we hold, 451 pages, none mentions a battery, lithium, an e-bike, a scooter or micromobility.
We hold no datasheet at all for varistors, so every figure above comes from the parametric export. The 379 varistor rows have a blank packing, SPQ and MOQ field, and the order quantity has to be confirmed with Walsin. We hold no UL 2849, UL 2271 or UL 2272 document, and we state no pack approval for any part. UL file E182369 is held for the safety capacitor series, and we make no claim for it beyond that. The stock list is a dated snapshot, and the ready stock page shows what is held in Hong Kong now.
How can Venatech help a United States e-bike maker?
We cross-reference against 800,000+ crossable parts, hold what Walsin publishes, and say what is missing. Venatech Limited is an authorised Walsin distributor in Hong Kong. Walsin is our only authorised line, and the other lines we supply are Stackpole and Viking.
- Cross-reference. Paste your incumbent varistor or capacitor number into the free cross-reference tool, which decodes 18 manufacturers’ part numbers across 800,000+ crossable parts, and read the Walsin candidates with match and mismatch stated field by field.
- BOM check. Upload a charger or battery-management bill of materials to /bom/ and have each line checked against the same engine.
- Ready stock. The ready stock list is a Hong Kong snapshot dated 23 September 2026, never live-synced.
- Service. Hong Kong-based, small lots, cross-referencing help, and a quote requested through the site. Our address is Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong, telephone (852) 2628 4777.
A worked example from our own export: a 13S charger with a 10 mm, 68 V disc on the port maps to SR680K10D at 40 Vac and 500 A, and the one-step-up SR820K10D at 50 Vac and 2,500 A is the part to compare. Our varistor range lists the families. Confirm against both datasheets and qualify in your own circuit.
The short version
The CPSC proposed battery standards for e-bikes on 24 June 2026, and the rule is still a proposal in the sources we read. On the charge port, 4 of Walsin’s 11 low-voltage varistor rungs clear a 13S or 14S pack, the first of them is 68 V, and it carries a fifth to a quarter of the surge rating of the next rung. None of the 1,125 stock lines is a varistor.
Send us the varistor from one charger or pack port and we will return the Walsin parts with the differences stated. Which matters more on your port, the margin below the knee or the surge rating?
Sources
Fetched 21 October 2026. The regulatory statements above are taken from these pages; the part data comes from our own Walsin export and stock list.
- SGS, “New US CPSC proposal targets battery safety in micromobility devices”, June 2026: https://www.sgs.com/en/news/2026/06/safeguards-08926-new-us-cpsc-proposal-targets-battery-safety-in-micromobility-devices
- mofo.com, “A New Charge for Micromobility: CPSC Proposes Mandatory Battery Standards”, 16 July 2026: https://www.mofo.com/pdf/resources/insights/260716-a-new-charge-for-micromobility-cpsc-proposes
- bdlaw.com, “Electric Scooters and e-Bikes: CPSC Proposes Lithium-Ion Battery Restrictions”, 14 July 2026: https://www.bdlaw.com/publications/electric-scooters-and-e-bikes-cpsc-proposes-lithium-ion-battery-restrictions/
- PeopleForBikes, “Regulatory update, September 2026”: https://www.peopleforbikes.org/news/regulatory-update-september-2026
Frequently asked questions
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What did the CPSC propose for e-bike batteries in the United States?
A mandatory safety standard for lithium-ion batteries in micromobility products, published on 24 June 2026, with written comments due 24 August 2026. Summaries cite UL 2849, UL 2272 and UL 2271 with modifications. It is a proposal, so check the notice and your compliance team.
Which Walsin varistor clears a 14S e-bike pack?
At 4.2 V per cell, a 14S pack charges to 58.8 V. Of 11 low-voltage rungs, 4 have a lower bound above that, and the first is 68 V, for example SR680K10D. The margin is thin, with full charge at 96.1% of the lower bound.
Does the 68 V rung carry less surge current than the 82 V rung?
Yes. At 5, 7, 10 and 14 mm the 68 V part carries 100, 250, 500 and 1,000 A, and the 82 V part carries 400, 1,200, 2,500 and 4,500 A. The ratio runs from 4.0 to 5.0. Choose against your own surge requirement.
Does the Walsin export give a direct-current working voltage for varistors?
No. We counted the Max Working Volt. column: all 379 rows read in volts alternating current. The varistor voltage is a direct-current figure. A direct-current working rating and the leakage current are not in the export, and we hold no varistor datasheet.
Do you hold varistors in Hong Kong stock?
No. As at 23 September 2026 none of our 1,125 stock part numbers is a varistor, and the order quantity has to be confirmed with Walsin. The ready stock page shows what is held now, and it is a dated snapshot.
Does the CPSC proposal require a varistor?
Not in the summaries we read. They list tamper-resistant enclosures, reverse-polarity tests, protection against incompatible chargers and warning labels, and none names a passive component. A varistor on the port is our design view, not a requirement.
Do you hold a battery or e-bike approval for these parts?
No. None of the 28 Walsin datasheets we hold, 451 pages, mentions a battery, lithium, an e-bike or micromobility, and we hold no UL 2849, 2271 or 2272 document. We make no pack-level claim. Qualification stays with you.