Used e-bikes: motor and battery checks

1Start with the basics

Ask the seller for:

• Bike brand, model and year, and the frame size (What size bike do I need?).
• Motor brand and model, for example a Bosch, Shimano or other system. CrankMart listings let sellers add the motor brand.
• Battery size in Wh (watt-hours). More Wh usually means more range.
• A photo of the frame serial number, and run it through our free serial check (crankmart.com/za/community/check).

2The battery: questions to ask

Bosch describes e-bike batteries as wearing parts: its battery guide says they age over time even when not in use, and age with use as they're charged and discharged; heat and being stored very full or very empty speed this up (source E1). So the battery's age and history matter.

• How old is the battery? Is it the one the bike came with, or a replacement?
• How many kilometres and how many charge cycles? Ask for a photo of the display or the maker's app showing the distance, and the charge-cycle count if the system shows it.
• How has it been stored and charged? For example, indoors at room temperature, and with the charger that came with the bike.
• Can you see a dealer report? Bosch says a certified dealer checks battery condition with Bosch's tools during a service (E1). For other motor brands, ask a dealer for that brand what their tools can check.

  Ask the seller whether they have a recent report, or whether they'd be happy for you to get one done at a dealer for that motor brand.

3The battery: things to look at

• The casing: look for an even, undamaged case and clean contacts.
• Has it ever been opened or rebuilt? Ask the seller. Bosch's battery guide says its battery housing must not be opened, and that worn or faulty batteries should be exchanged and recycled rather than repaired or "refreshed" (E1). A battery that's original and unopened keeps things simple.
• The charger: ask for the charger that came with the bike. Bosch's guide says original Bosch chargers are always compatible with its batteries (E1), so the original is the one to have.
• Keys: many removable batteries lock to the frame. Ask for the key (and the spare, if there is one) and try taking the battery out and putting it back.
• Charge level: ask the seller to have the battery charged before you arrive, so you can test-ride in every mode.

4The motor: a test ride in every mode

• Turn the system on. The display should start up without error messages. If an error code shows, ask about it, and ask whether a dealer for that motor brand has looked at it.
• Ride in each assist mode, from the lowest to the highest. The assist should feel smooth and even as you pedal.
• Listen as you ride, and ask the seller about any noise you're unsure of.
• Try a short climb if there's one nearby. It's the best way to feel the motor working.
• Check the display or app shows the battery level and the distance as expected.

5Software and service history

• Ask when the bike was last serviced, and whether the software has been updated. Bosch says its dealers can update the bike with their DiagnosticTool, and that the diagnosis report shows the condition of the Bosch eBike components (E3).
• Ask for any service invoices. They're a nice record of how the bike's been looked after.
• Has the bike been modified? Ask whether anything on the motor system has changed since it left the factory, such as a 'tuning' kit, a different controller or software that raises the assisted speed or power. A modified e-bike may no longer count as a bicycle under road rules, so it may not be legal on public roads and paths. If you're unsure, ask a dealer for that motor brand to check it.

6The rest of the bike

Give the brakes, tyres, wheels and drivetrain a good look too, as in our used-bike checklist. Ask when the chain and brake pads were last replaced.

Your e-bike checklist at a glance

• Motor brand and model, battery Wh
• Battery age, original or replacement
• Distance and charge cycles (photo of display or app)
• Dealer report, or OK to get one
• Battery casing and contacts look good; never opened
• Original charger included
• Battery key(s) included; battery comes out and goes back in
• Test ride in every assist mode, no error messages
• Service history and software updates
• Brakes, tyres, wheels and drivetrain checked
• Serial check done

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