When an e-bike battery loses capacity or refuses to charge, the question arises: buy a new one, or restore the old one? The market offers three routes — the original battery from the manufacturer, a "compatible" battery ordered online, or professional reconditioning of your existing pack.
Let us compare them honestly on price, safety, real capacity and lifespan — and see why a "new" battery pulled from a warehouse can turn out to be a worse deal than reconditioning.
The three options at end of life
1. A new original battery
Going through the manufacturer's network is the usual reflex, but it has blind spots.
- Advantages: full compatibility with the motor and the bike's mount, and a seller's warranty — note that NORDIX also applies a 2-year warranty on reconditioned batteries.
- Drawbacks: a high price, often between €500 and €800, and the risk of old stock — a battery that has slept two or three years at a distributor has already lost part of its chemistry.
The NORDIX experience
The real drawback of the original battery is that it inherits every design flaw of its series. The first production runs of Xiaomi M365 batteries, by the thousand, suffered systematic nickel tab failure due to an unfortunate design. Buying exactly the same new battery means reproducing exactly the same failure. In reconditioning, we correct those original defects.
2. A compatible or imported battery
Online you will find "compatible" copies two to three times cheaper than the original. We strongly advise against this route.
- Advantages: low purchase price.
- Drawbacks: protections absent or fake, false stated specifications, and a fire risk while charging.
The NORDIX experience
We regularly see copies whose label claims capacity equal to or greater than the original. On opening them, we find the cheapest anonymous cells on the market, 2.0 to 2.2 Ah, assembled with tab that is far too thin and driven by a BMS without a single temperature sensor.
We have even come across cases where, to save money and hit the stated weight, half the cells in a parallel had been replaced with dummies — empty cans filled with sand instead of real lithium-ion cells.
3. Reconditioning your original battery
Reconditioning replaces the entire cell block with new branded cells, keeping your case and your electronics.
- Advantages: a 2-year NORDIX warranty, 100 % new cells from proven suppliers (Samsung, LG, Sanyo), a complete file with an outgoing bench test report, the option to raise capacity by up to about 40 %, and retention of the original BMS board.
- Drawbacks: the time the work takes. A top-end reconditioning, with maximum-capacity high-discharge cells, can exceed the price of a standard original battery — for noticeably better performance.
The technical case for reconditioning
Often more range than a new original
Cell technology moves faster than bike model ranges. Cells produced five years ago, around 2,200 to 2,600 mAh, have given way to 3,500 mAh in the same 18650 format.
By reconditioning, we fit those denser cells into your original case, which can deliver up to 40 % more range than the day the bike was new. That is the purpose of our capacity increase service.
Keeping the original BMS and motor compatibility
On protected systems — Bosch PowerPack, Shimano STEPS, Yamaha — a third-party battery simply does not work: the motor requires digital authentication from the BMS board.
The NORDIX experience
Technically, any original communicating BMS should be kept as long as it works. Buying a new board with the right telemetry and the right firmware is usually impossible on the market.
To lift that constraint, our laboratory is developing its own interoperability modules. They will allow custom high-capacity packs to be used even with systems that require a communicating BMS on a proprietary protocol.
Branded cells and a documented test
Unlike imported assemblies whose cell origin is unknown, a NORDIX reconditioning uses only certified cells from recognised manufacturers.
Every restored battery goes through a cycle on a load bench. You receive a test report with the discharge curve and the capacity actually measured, supplied with the battery.
When is reconditioning not possible?
Reconditioning is possible in the great majority of cases, but there are strict exclusions.
- A destroyed case. If the plastic shell is broken or deformed by a fall, sealing can no longer be guaranteed.
- Water ingress.
The NORDIX experience
Where water has got in, we never repair the electronics: we replace them outright. Cleaning oxides from under component packages on a dense surface-mount board is illusory, and electrochemical corrosion under voltage destroys the tracks in no time.
Batteries showing the slightest trace of water — including a humidity indicator merely turned red — are automatically classed as unstable in our workshop. For the user's safety, those packs often go to recycling with no possibility of repair.
The three options side by side
| Criterion | New original | Imported copy | NORDIX reconditioning |
|---|---|---|---|
| Price | High | Low | Mid-range, or premium depending on cells |
| Warranty | 2 years | Absent or doubtful | 2 years |
| Cell freshness | Risk of old stock | Low-grade chemistry, even dummies | New branded cells |
| Capacity | Factory standard | Often half what is claimed | Factory standard, or up to +40 % |
| Safety | High, but series defects inherited | Critical: fire risk | Industrial standard, with test report |
| Traceability | Variable | None | Batch numbers and test report |
Have your battery assessed in Bourgogne-Franche-Comté
Not sure whether your battery is worth restoring? Describe the symptoms and give the model of your bike.
We will point you to the nearest partner workshop. The service receives your pack, NORDIX engineers run the bench test and tell you whether reconditioning is possible and what capacity gain you can expect.