E-Bike Battery in Cold Weather: Range, Charging, and Winter Storage

Why a cold battery doesn’t go as far

About 15% less range below 32 °F (0 °C): that number comes from the owner’s manual for the Booster Easy, a Yamaha e-bike sold in Europe [1]. The same table rates outside temperature as a low-significance factor, behind speed and grade, which are both rated high. It’s the only percentage we found in the manufacturer documents cited here. Bosch, Shimano, and Bafang just say that cold costs capacity or range [2, 3, 4]. And “below freezing” covers a lot of ground: 30 °F (-1 °C) and 5 °F (-15 °C) both count.

The reason is chemistry. In a lithium-ion battery, lithium ions travel from one electrode to the other through a liquid called the electrolyte. When it gets cold, explains cell maker LG Energy Solution, that electrolyte gets more viscous, the ions move more slowly, and internal resistanceThe electrical resistance inside the battery. The higher it is, the less voltage and energy reach the motor. goes up [5]: the battery delivers less voltage and less energy.

The energy usually isn’t lost, just harder to get at. Once the temperature rises again, normal range comes back, Yamaha says [6]; the ADFC, Germany’s national cyclists’ association, describes a temporary loss of capacity [7]. Shimano adds a second effect: a battery charged at 41 °F (5 °C) or below goes less far on a full charge, and gets its normal range back once it’s charged at room temperature [3]. So the cold hits twice, when you ride and when you charge.

What a 500, 625, or 750 Wh battery gets you in miles and feet of climbing is laid out in our e-MTB range calculation. For a winter ride, I’d rather knock a little off that result than count on summer numbers.

Riding in winter: keep the battery warm until you head out

In freezing weather, Bosch recommends taking the battery off after a ride, keeping it indoors, and putting it back on only right before the next one [2]. Bafang, Yamaha, and the ADFC give the same advice [4, 6, 7]. A bike left outside overnight, on the other hand, starts out with a chilled battery.

Enlarge photo

For the ride itself, Bosch mentions a neoprene cover from bike shops to protect the battery below freezing, and thermal covers for longer rides [2]; the ADFC also recommends a neoprene cover to limit capacity loss [7]. A cover doesn’t produce heat, it only slows the cooling, so it does the most for a battery that goes on while it’s still warm. Your bike shop can tell you which one fits your model.

How cold is too cold to ride? Here too, your own manual matters, because the limits differ. In its 2019 manual, Shimano gives an operating range of 14 to 122 °F (-10 to 50 °C) for its batteries and warns that outside it, fire, injury, or problems with operation may occur [3]. Bosch gives 23 to 104 °F (-5 to 40 °C) for the PowerTube 750 [8]. At 18 °F (-8 °C), one battery is still within its range and the other is already outside it.

The rest of the bike has its own winter rules, from lights to tire pressure, and for you there’s the three-layer system.

Charging: only once the battery is at room temperature

On charging, the makers agree in principle, just not on the numbers. Bosch, Shimano, and Bafang put the lower limit at 32 °F (0 °C) and the upper limit at 104 °F (40 °C), or 113 °F (45 °C) for Bafang [3, 4, 8]. Yamaha recommends 59 to 77 °F (15 to 25 °C) [1]. Bosch and Bafang specifically call for room temperature [2, 4].

If the battery is too cold, the Bosch and Yamaha systems refuse to charge it. On Bosch’s PowerTube 750, three LEDs flash: disconnect the battery and let it reach the right temperature [8]. On a Yamaha, all four LEDs flash, and charging restarts on its own once the battery is warm enough [1]. Bafang tells you to give the battery enough time to reach that temperature [4]. None of the four gives a time: it depends on how cold the battery got.

Why the caution? Charging a battery too aggressively at low temperatures can, according to LG Energy Solution, cause lithium platingMetallic lithium deposited on the anode during charging in the cold.: metallic lithium builds up on the anode, which shortens the battery’s life and may also affect its safety [5]. A camper van’s lithium house battery also refuses to charge in the cold until it has warmed up, as our guide to camper vans in winter explains.

Bafang gives one more reason not to plug in an ice-cold battery the moment it hits a warm living room: a sudden rise in temperature can cause condensation inside the battery, so the maker advises charging it where it’s stored [4]. If you already keep it indoors, both problems are solved.

Enlarge diagram

Storing the battery for winter: charge level, location, and checks

Winter storage is where the advice differs the most. Here it is side by side, each with its source:

Let’s do the math and stack the temperature ranges: Bosch and Shimano recommend 50 to 68 °F (10 to 20 °C), Yamaha 59 to 77 °F, and Bafang permits 14 to 95 °F [3, 4, 6, 8]. The only slice all four share runs from 59 to 68 °F (15 to 20 °C): a dry, cool-ish room in the house. For charge level, there’s no such overlap: Bosch tops out at 60%, Shimano wants about 70%, Bafang 60% to 80% [3, 4, 8]. Here, only your own battery’s manual decides, not another manufacturer’s.

Even within one brand, read closely. On paper, Bosch gives the PowerTube 750 a storage temperature of 50 to 104 °F (10 to 40 °C), and in the text of the same manual 50 to 68 °F (10 to 20 °C) for optimal service life [8]. Its 2023 battery tips say 32 to 68 °F (0 to 20 °C) [9], and its winter page says 32 to 68 °F in dry conditions and 50 to 68 °F in damp ones [2]. Four documents, four ranges, and every one of them includes 50 to 68 °F.

What about the garage? Bosch names it in its tips, alongside the basement, but at 32 to 68 °F (0 to 20 °C) and in well-ventilated rooms with smoke alarms [9]. The IFS, a loss-prevention institute run by Germany’s public insurers, and Germany’s consumer advice centers advise against an unheated or cold garage in winter [10, 11]. The two fit together: a dry garage that stays above freezing meets Bosch’s condition; one where it freezes doesn’t. A thermometer and a few cold nights will tell you which you have.

Should the battery stay on the bike? Bosch recommends taking it off for storage [8, 9], as do Yamaha and Bafang [1, 4]. Shimano allows storing the bike with the battery installed, indoors at about 50 to 68 °F (10 to 20 °C) [3]. After the break, Shimano and Yamaha say to charge the battery before the first ride [1, 3]. The IFS calls charging a battery that’s sat unused for months especially critical [10]: stay nearby for that first charge.

What to avoid in winter

• Charging an ice-cold battery. Let it warm up first: below 32 °F (0 °C), Bosch, Shimano, and Bafang don’t provide for charging anyway [3, 4, 8], and NFPA, the U.S. National Fire Protection Association, says not to charge lithium-ion batteries below 32 °F (0 °C) and to keep them at room temperature when possible [12].
• Leaving it dead for months. Bosch warns it can be damaged and lose a lot of capacity despite its low self-discharge; Shimano says to charge a dead battery as soon as possible [3, 8].
• Storing it full or completely empty. Either way, Yamaha says, it deteriorates faster [6].
• Leaving it near a heater or in the sun. Bosch advises storing batteries away from heat sources; Bafang notes that about 113 °F (45 °C) is common near heaters, in direct sun, or in an overheated car, more than the 95 °F (35 °C) up to which it permits storage [4, 8].
• Leaving it on the charger for weeks. Bosch doesn’t recommend it and advises unplugging the charger and battery once charging is done [8, 9].

Driving to a winter trip

If the bike rides to the mountains on a rack, the battery rides inside the car. Bosch advises removing the battery and the onboard computer to avoid damage [8], the ADFC to keep the battery dry [7]. The IFS gives the winter reason: rain or road salt can cause internal short circuits and, in the worst case, a fire [10].

For a long drive, say to a vacation spot, Bosch recommends running the battery down to about 30% and charging it fully only once you arrive [9]. When you get there, the rule is the same as at home: overnight in your heated lodging, not in the cold car, and onto the charger only at room temperature. According to Bosch, which writes for European rules, private users can carry undamaged batteries by road with no further requirements [8].

In winter, a battery follows one simple rule: it rides outside, lives inside, goes on the charger only at room temperature, and for every number, it’s your own battery’s manual that counts, not another manufacturer’s.

Julien de Jurquet

Vans, RVs, biking and calculators

Julien de Jurquet writes for Outfarer about camper vans, RVs, biking, and calculators. He reads manuals cover to cover and never lets a number slide without its unit, so your choices rest on math, not promises.

All their articles