E-Bike Battery Standards Explained: Watt-Hours, Voltage & Range Extenders

E-bike batteries are system-specific: a battery fits the frames, connectors, and battery-management electronics of one drive system only. Capacity in watt-hours (Wh) is the number that matters most — it's the fuel tank — while voltage is set by the system (36 V on most, 48 V on Specialized SL). Many systems also offer an optional range extender: a small piggyback bottle-cage battery that adds 160-280 Wh.

Why these standards exist

There is no cross-brand battery standard. Each drive system defines its own pack shape, latch, connector, and — critically — communication protocol between the battery-management system (BMS) and motor. A pack with the right voltage but the wrong protocol simply won't power the bike, which is why replacement batteries must come from your bike's system family.

Watt-hours (Wh) = voltage (V) × amp-hours (Ah), and it's the honest capacity number. A '500 Wh' battery holds the same energy whether it's 36 V × 14 Ah or 48 V × 10.4 Ah. Full-power eMTBs in 2026 typically carry 600-840 Wh; lightweight/SL bikes carry 320-430 Wh and lean on range extenders.

Even within one brand, generations gate compatibility: Bosch smart system PowerTubes don't run older Bosch motors, and DJI's highest-discharge packs (FP700/RS800) are required to unlock the M2S motor's full output. The system pairing — not brand — is the compatibility key.

Modern standards

What you’ll find on bikes from roughly 2018 onward. Modern means the in-tube battery era (~2019+): packs that slide into the down tube of frames designed for one system (Bosch PowerTube, Shimano BT-EN80x, DJI FS/FP packs). Older external 'rack' or bolt-on frame packs and pre-smart-system Bosch batteries are legacy and don't interchange with current motors.

Bosch PowerTube / CompactTube (smart system)

2022-present (smart system)

Also called: PowerTube 500/600/625/750/800, CompactTube 400, PowerPack 545/725

36 V; 400-800 Wh in-tube, 545/725 Wh external PowerPack

The battery family for all Bosch smart system motors (CX Gen5, CX-R, SX, Cargo). In-tube PowerTubes range 500-800 Wh; the lightweight CompactTube 400 pairs with the SX motor; external PowerPacks serve city/trekking frames. All support the PowerMore 250 range extender.

Why it exists: One certified battery family across Bosch's whole motor range lets hundreds of OEM brands share packs, chargers, and service stock.

Typically found on: Any smart system Bosch bike — Trek, Cube, Canyon, Scott, Santa Cruz, Gazelle and many more

Shimano BT-EN80x

2022-present

Also called: BT-EN806 (630 Wh), BT-EN805 / EN805-L (504 Wh)

36 V; 504 or 630 Wh in-tube

Shimano STEPS batteries for EP801/EP600-era systems. Shimano offers no official range extender; some OEMs (e.g. Thok) sell third-party extenders for STEPS bikes.

Why it exists: Shimano packages battery, motor, and E-Tube electronics as one certified system for OEMs.

Typically found on: Orbea, Merida, Canyon, Cannondale, Norco, YT STEPS bikes

DJI Avinox packs

2024-present

Also called: FS600, FP700, FS800, RS800, RS600, RS480

~36 V class (35.9-36.1 V); 480-800 Wh; FP700 uses 4680 cells at 220 Wh/kg

Fixed (FS/FP) and removable (RS) packs for the Avinox system. The 4680-cell FP700 and the RS800 are the high-discharge packs that unlock the M2S motor's full 1,500 W; other packs cap it around 1,300 W. Uniquely, DJI's RS600 can mount externally as a second battery for up to 1,400 Wh total.

Why it exists: DJI brought its drone battery engineering (high energy density, high discharge) to e-bikes as a competitive edge.

Typically found on: Amflow, Forbidden, Atherton, Commencal, Whyte, Pivot Avinox bikes

Specialized Turbo packs (Full Power & SL)

2020-present

Also called: 840/600 Wh (Levo Gen 4), 700/530 Wh (Gen 3 era), SL 320 Wh (48 V)

Full power: 36 V class, 500-840 Wh; SL: 48 V, 320 Wh

Two ecosystems within one brand: full-power Levo/Vado/Como packs (up to 840 Wh on Levo Gen 4, with a 280 Wh extender) and the 48 V SL system (320 Wh internal, 160 Wh bottle-cage extender for 480 Wh total). SL and full-power parts don't interchange.

Why it exists: Specialized designs packs around each bike family's frame rather than adopting an OEM standard.

Typically found on: Specialized Levo, Kenevo, Vado, Como (full power); Levo SL, Creo, Vado SL (SL)

Yamaha intube / Giant EnergyPak

2019-present

Also called: Yamaha 400/500/600 Wh intube, Giant EnergyPak 400-750 Wh, EnergyPak Plus extender

36 V; 400-750 Wh

Yamaha's intube packs serve its PW-series OEM systems; Giant builds its own EnergyPak family (up to 750 Wh) for SyncDrive (Yamaha-based) bikes, plus the EnergyPak Plus piggyback extender (~250 Wh) on supported models.

Why it exists: Giant's volume justified its own battery line on top of Yamaha's OEM packs.

Typically found on: Giant/Liv SyncDrive bikes; Yamaha-powered EU brands

Lightweight packs: TQ & Fazua

2022-present

Also called: TQ 290/360/580 Wh, TQ 160 Wh extender, Fazua Energy 430 (43.2 V)

TQ: 290-580 Wh; Fazua: 430 Wh at 43.2 V (10 Ah), 480 Wh from 2025

Small in-tube packs matching the lightweight motors. TQ's 160 Wh bottle extender can even run the motor on its own; Fazua's Energy packs are removable through the down tube on many frames.

Why it exists: Sub-20 kg e-bikes need packs sized to the assist level, not maximum range.

Typically found on: Trek Fuel EXe/Domane+ (TQ); Canyon, Pivot, Santa Cruz (Fazua)

What to record about yours

These are the values worth writing down when you add this part to your quiver — the critical ones drive compatibility matching.

Spec	Matters for fit	Common values
Drive system critical	Batteries are system-specific: shape, latch, connector, and BMS protocol all belong to one drive system. The battery must match the motor's system exactly — this is the powertrain's Key-for-fit field.	Bosch Smart System · Shimano STEPS · DJI Avinox · Specialized Turbo Full Power · Specialized SL · Yamaha PW · TQ HPR · Fazua Ride 60
Capacity(Wh) critical	The fuel tank: watt-hours determine range. Full-power bikes run 500-840 Wh; lightweight/SL bikes run 320-430 Wh. Within a system, a bigger in-tube pack is often the single best range upgrade — when the frame's battery bay accepts it.	320 · 400 · 430 · 500 · 504 · 600 · 625 · 630 · 700 · 750 · 800 · 840
Nominal voltage(V) helpful	Set by the system, not chosen separately: 36 V on most systems (Bosch, Shimano, Yamaha, DJI ~36 V), 43.2 V on Fazua, 48 V on Specialized SL. Useful for confirming which system family a pack belongs to.	36 · 43.2 · 48 · 35.9 · 36.1
Range extender fitted(Wh) optional	Several systems sell an optional piggyback battery (usually bottle-cage mounted) that plugs into the charge port: Bosch PowerMore 250 (250 Wh), Specialized SL extender (160 Wh), Specialized Levo Gen 4 extender (280 Wh), TQ extender (160 Wh). Record the added Wh here when one is fitted to the bike.	160 · 250 · 280 · 600 (DJI RS600 secondary pack)

How to identify which one you have

By the bike's drive system

Identify the motor system first (badge on the drive unit, display, or the bike's spec sheet) — the battery family follows from it. See the Motor page's identification steps; batteries and motors always pair within one system.

By the label on the pack

Remove the battery (or read through the frame window): the label lists model (e.g. BT-EN806, PowerTube 800), watt-hours, voltage, and amp-hours. If only V and Ah are printed, multiply them for Wh (36 V × 17.5 Ah = 630 Wh).

By the spec sheet of the bike model

The manufacturer's page for your bike's model-year lists the exact battery and its Wh — and whether a range extender was standard, optional, or unsupported.

Compatibility gotchas

Match the system, not just the brand: Bosch smart system packs don't run pre-2022 Bosch motors, and Specialized SL packs don't fit full-power Specialized bikes. When replacing a battery, match your system generation exactly.
Within a system, larger packs are often the easiest range upgrade (PowerTube 800 in place of a 600) — but the frame's battery bay must physically accept the longer pack; check the bike maker's compatibility list, not just Bosch's.
Range extenders are system accessories, not standalone batteries: they plug into the charge port and need the system's firmware support (Bosch PowerMore 250, Specialized 160/280 Wh, TQ 160 Wh). On this site, record a fitted extender's Wh on the battery's 'range extender fitted' field rather than as a separate component.
Voltage confirms family membership but isn't a fit guarantee — nearly everything is 36 V-class. The exceptions are useful tells: 48 V means Specialized SL, 43.2 V means Fazua.
Peak motor output can depend on the pack: DJI's M2S only delivers its full 1,500 W with the high-discharge FP700/RS800 batteries. A battery swap can change how the motor performs, not just how far it goes.

References

Related components

Motor