The battery is the most expensive single component on an e-bike and the one most affected by how you treat it. Almost all of the advice worth following fits on one page.
Charging: the four rules
- Charge indoors, on a hard non-flammable surface, within sight. Not on a bed, a sofa, a carpet, or in a cupboard full of coats. Not in a hallway or at the foot of the stairs, where a fault would block your exit.
- Unplug when it is full. Leaving a pack on charge for days keeps cells at maximum voltage, which is where they degrade fastest.
- Use only the charger supplied for that pack. Connectors that look identical frequently deliver different voltages. This is the single most dangerous shortcut people take.
- Do not charge a damaged pack. Dropped hard, dented, punctured, submerged, swollen, or unusually hot in normal use — stop, do not charge, and get it looked at.
Storage: the one number to remember
30–60%. If the bike will be unused for a month or more, leave the battery around half charged, not full and not empty.
A pack stored at 100% degrades faster. A pack stored at 0% can slip below the voltage where the protection circuit will allow it to recharge, at which point it is scrap. Top up to that middle range every few months over winter.
Keep it above 0 °C, out of direct sun, and out of an uninsulated shed in February.
Why your range is lower than the box says
Because the box is quoting a laboratory maximum: lowest assistance level, flat ground, mild weather, light rider, no luggage. It is measured that way consistently by everyone, which makes it useful for comparing bikes and useless for planning a route.
What actually reduces it, roughly in order of impact:
- Assistance level. PAS 1 to PAS 5 is routinely a factor of two.
- Hills. Climbing is simply where the energy goes.
- Cold. Below about 10 °C you lose usable capacity — often 20–30% in a real winter. The capacity comes back when the pack warms; it is not permanent damage.
- Total weight. Rider plus luggage plus bike.
- Tyre pressure. See below — this is the one you control completely.
- Headwind. Unglamorous and significant.
The cheapest range upgrade there is
Check your tyre pressure weekly.
An under-inflated tyre deforms more with every single rotation, and that energy comes out of your battery. On a heavy fat bike the effect is substantial. The correct range is printed on the tyre sidewall — and note that fat tyres run at far lower pressures than city tyres, so do not simply inflate everything hard.
A pump with a pressure readout turns this into a thirty-second job, which is the only way it actually gets done.
How long will it last?
Lithium packs age by charge cycles and by calendar time, not by distance ridden. A pack that is five years old has lost capacity even if barely used.
Most owners see noticeably reduced range somewhere after several hundred full cycles. Gradual capacity loss is normal ageing, not a fault — which is why manufacturer warranties almost always exclude it.
You extend it by: storing at partial charge, avoiding temperature extremes, avoiding routinely running to empty, and not leaving it on the charger indefinitely.
A second battery beats a bigger one
You cannot fit a larger pack than your bike was designed for — voltage and BMS communication have to match. But you can carry a spare and swap it in about two minutes.
On a bike quoted at 120 km, a second pack turns a long weekend ride from a calculation into a non-issue. See batteries and chargers. If you are unsure which fits, photograph the label on your existing pack and send it to us.
Is fast charging bad?
Slightly, over many cycles — faster charging generates more heat, and heat is what ages cells. The 8A fast chargers that fill a 648 Wh pack in about two hours are genuinely useful if you turn the bike around several times a day. If you do not need the speed, the standard charger is gentler.
End of life
Lithium batteries must go to a battery collection point. Never household waste and never a kerbside recycling bin — damaged cells start fires in bin lorries and sorting facilities, and those fires are a real and growing problem.