A replacement e-bike battery is one of the largest costs of ownership, and most of what shortens a battery’s life is avoidable. None of it is difficult.
Prices vary enormously with capacity. Small packs start around £200, but the 600–840Wh batteries fitted to the bikes we sell are considerably more — typically several hundred pounds more. Ask us for the current price on a specific model rather than budgeting from a general figure.
How long one should last
A good lithium-ion pack gives 500 to 1,000 full charge cycles before dropping to around 70–80% of its original capacity. For most riders that is three to five years. A “cycle” means a full charge’s worth of energy, so two half-charges count as one.
Note what happens at end of life: the battery does not die, it shrinks. A pack at 75% still works, it just gives you three quarters of the range. Plenty of people ride on quite happily.
The five things that matter
- Do not leave it sitting at 100%. A lithium cell is under most stress when full. If you are not riding tomorrow, stop the charge around 80–90%. Many systems have a setting for this; use it.
- Do not store it flat either. A pack left at 0% for months can drop below the voltage its protection circuit will recover from, and then it is scrap. For winter storage, leave it around 60% and top it up every couple of months.
- Keep it out of the cold when not riding. Cold does not damage a battery, but it temporarily cuts usable capacity, and charging a battery that is below freezing genuinely does damage it. Bring it indoors and let it reach room temperature before charging.
- Keep it out of real heat. A car boot in July is the worst place an e-bike battery can be. Heat is what actually ages cells.
- Use the charger it came with. Cheap third-party chargers are the single most common cause of e-bike fires. This is not manufacturer protectionism.
Charging safety, briefly and seriously
E-bike battery fires are rare but they are fierce and they produce toxic smoke. The fires that make the news almost always involve a damaged pack, a converted bike, or a non-matched charger.
- Charge where you could walk away from it — not in a hallway that is your only exit, and not overnight while asleep if you can avoid it.
- Never charge a pack that has been dropped hard, is swollen, or smells odd. Stop using it and contact the manufacturer.
- Do not cover the battery or charger while charging; both need to shed heat.
- A damaged lithium battery is hazardous waste. It does not go in the bin, or in the household recycling. Your local authority or the bike shop will take it.
Cleaning without wrecking anything
Take the battery out if it is removable. Wash the bike with a bucket, a sponge and ordinary bike cleaner. Never use a pressure washer on an e-bike — the seals on motor and battery housings are designed to keep rain out, not a jet, and forcing water into a motor is an expensive mistake that no warranty covers.
What it costs to charge
At the current UK price cap of around 24.7p per kWh, a 500Wh battery costs roughly 12p to fill from empty; a large 840Wh pack around 21p. Charging an e-bike every day for a year costs less than a single tank of petrol.
Battery capacity, and what it means for your riding, is on every electric bike page we publish.