Reduced range in the cold

With the colder weather coming, how much less range can I expect? It's going to be between -5C and 0C during my commute all week instead of 8C+ recently. 25 miles round trip and the battery already gets close to the limit if I rely on it too heavily by essentially ghost pedalling.

 

Edit - The battery is kept warm overnight but then left outside in the bike shed during the day.

In my experience it is hard to put a figure on it , but range is diminished a little.

Maybe 5 - 10%.

What I seem too see is a greater readyness to sag with a slower recovery. Not sure about range loss though.

With the colder weather coming, how much less range can I expect? It's going to be between -5C and 0C during my commute all week instead of 8C+ recently. 25 miles round trip and the battery already gets close to the limit if I rely on it too heavily by essentially ghost pedalling.

 

Edit - The battery is kept warm overnight but then left outside in the bike shed during the day.

Batteries heat up when they provide current, so if you charge in a warm house and fit the battery just before your ride, outside temperature should make mininmal difference; however, low temperature has a significant effect on your own efficiency and the effort you use for pedalling, so if you run at a low level of assist, your range would be a lot less, but if you run with a high level, there wouldn't be so much difference.

In my experience it is hard to put a figure on it , but range is diminished a little.

Maybe 5 - 10%.

• From my own experience I'd go along with those figures.
  
• What the reduction in range is down to is complex but in an article I read on this recently (link), it seems that within limits, the warmer the battery when being charged, the battery's storgage capacity is increased.
  
• I always charge my battery in the bike shed which is unheated and of course rather cool during winter so this is maybe why I experience reduced range?
  

Effects of Heat

When temperatures increase this affects the chemical reactions that occur inside a battery. As the temperature of the battery increases the chemical reactions inside the battery also quicken. At higher temperatures one of the effects on lithium-ion batteries’ is greater performance and increased storage capacity of the battery. A study by Scientific Reports found that an increase in temperature from 77 degrees Fahrenheit to 113 degrees Fahrenheit led to a 20% increase in maximum storage capacity. However there is a side effect to this increased performance, the lifecycle of the battery is decreased over time. ..........

• From my own experience I'd go along with those figures.
  
• What the reduction in range is down to is complex but in an article I read on this recently (link), it seems that within limits, the warmer the battery when being charged, the battery's storgage capacity is increased.
  
• I always charge my battery in the bike shed which is unheated and of course rather cool during winter so this is maybe why I experience reduced range?
  

When you charge a battery, it warms up. Whenever current flows in either direction, heat is produced because of the cells' internal resistance. The battery can only lose a certain amount of heat when charging or discharging. How fast it loses heat depends on how well insulated it is, how much airflow (possible water flow too) is over it and the temperature of the air. Most batteries have the cell-pack insulated with cardboard, then shrink-wrapped then medium density foam rubber to stop it vibrating, then a plastic case. I can't see it being too easy for the heat to get out.

 

Next time you charge the battery in the shed, leave it for a couple of hours charging at the normal rate, then feel the case to see how warm it gets. i'd be surprised if it's less than 20 deg. On the road, it's different because it can get an icy blast, though you could mitigate that with an extra insulating layer, like those neoprene sleeves that you can buy.

 

Personally, I wouldn't bother with any procedures or precautions. Just pedal harder to keep yourself warm, never mind the battery.

Half the round trip done (12.5 miles) this morning in -1C. No discernible difference in performance or capacity from the battery however I did have a nice lie down on sheet ice. Turns out they don't grit country lanes. Once I put my chain back on with the only light source for miles being my headlight, I was extra cautious on the wet/icy looking bits thereafter which probably reduced my consumption. Decided to bring the battery inside to keep warm for the return journey.

Half the round trip done (12.5 miles) this morning in -1C. No discernible difference in performance or capacity from the battery however I did have a nice lie down on sheet ice. Turns out they don't grit country lanes.

 

Hope you weren't injured. That's got me wanting to buy studded tyres.

Last winter I didn't notice any reduction as it got colder, but I did notice a substantial improvement in range when spring sprung! The matching reduction must have crept up on me undetected!

 

Battery indoors during cold days is a good tactic, and if you had the chance of a bit of charging time at work too, even better.

Last winter I didn't notice any reduction as it got colder, but I did notice a substantial improvement in range when spring sprung! The matching reduction must have crept up on me undetected!

 

I can understand a reduction in range not being noticeable if you ride regulalrly and the change in seasonal temperature is gradual and you are recharging way before your maximum range.

 

For my first 15 months of riding my ebike, I would monitor the recharge in Watt Hours and log this against the miles ridden and from this it was clear that in the colder periods I was not getting the same miles per Wh used i.e. range was less.

 

There have been several views expressed as to why this perceived range reduction may come about (or not), but the bottom line for me is, I know that for my riding style (and I do ride more enrgetically when its cold to keep warm vs doodling along observing nature in the warmer weather) , battery characteristics, battery charging/discharging routine and so forth, I get less range in the colder months.

Thicker winter clothers not only increase mass, but also significantly affect air resistance. So you'll be going up hills slower and have an overall lower top speed.

Cold air increases tyre rolling resistance by approx 6% for each 10 deg F.

Cold air is denser than warm air. Air at 0 deg c is 8% more dense than at 20 deg c, so air resistance increases substantially at the same speed.

When you're cold, you become lethargic and put in much less effort. If you pedal at 200w, you might get a performance improvement because your legs won't overheat, but an average enthusiastic commuter pedals around 100w, and a lot less when cold.

 

Basically, you have a choice of longer journey times or turn up the power and get less range.

Hope you weren't injured. That's got me wanting to buy studded tyres.

Thanks, not injured at all. I found myself laughing as the slide on my back felt like it went on forever. Less laughing trying to get the chain back on. Studded tyres would be nice but I don't know how they perform on thawed tarmac. I'm going to disguise myself as a car driver until temps are above freezing again.

 

No ice on return journey but I ended up pedalling a lot to keep warm and to save battery for the main road close to home. Notably, my headlight was nearly out of charge after one commute day where I normally get two. I don't treat that battery as nicely, it sits in the cold garage and is charged there.

if you had the chance of a bit of charging time at work too, even better.

I have been very tempted, just concerned the attention it would bring as my charger fan is quite loud. Yesterday, I kept the battery in my bag and no one had any questions.

Thanks, not injured at all. I found myself laughing as the slide on my back felt like it went on forever. Less laughing trying to get the chain back on. Studded tyres would be nice but I don't know how they perform on thawed tarmac. I'm going to disguise myself as a car driver until temps are above freezing again.

 

No ice on return journey but I ended up pedalling a lot to keep warm and to save battery for the main road close to home. Notably, my headlight was nearly out of charge after one commute day where I normally get two. I don't treat that battery as nicely, it sits in the cold garage and is charged there.

 

I have been very tempted, just concerned the attention it would bring as my charger fan is quite loud. Yesterday, I kept the battery in my bag and no one had any questions.

I have schwalbe studded tyres on over winter no problem on tarmac etc, just a little noisy. Worth it for the security/safety .

After a few more days commuting, it is noticeable how much harder the cold is on the battery. I have to kick it down a few gears and pootle along to keep enough charge to make it home. Will be interesting next week when the temperature increases by 15c over three days! Forecast says Friday morning is -3c and Monday morning is 12c.

After a few more days commuting, it is noticeable how much harder the cold is on the battery. I have to kick it down a few gears and pootle along to keep enough charge to make it home. Will be interesting next week when the temperature increases by 15c over three days! Forecast says Friday morning is -3c and Monday morning is 12c.

How much is the cold affecting your own pedal power?

My range fell drastically, I didn't go out.

How much is the cold affecting your own pedal power?

Personally, it allows me to pedal harder because my limiting factor is how sweaty I am on arrival.

Returned from run into town with my petite passenger showing only 2 bars left out of 5, when it's usually 3 left. Dropping 1 gear more on inclines (spinning in 1st is tiring, but hills are hills, phew!). Full assist, -2degC ("feels like -5").

 

Are the 5 bars an accurate 20% each or an approximation? Who knows, hehe! I see comments like, "the first couple bars go slowly, the rest more quickly", suggesting it's far from linear.

(672wh external type)

Personally, it allows me to pedal harder because my limiting factor is how sweaty I am on arrival.

Wishful thinking!

Wishful thinking!

The cold air makes me sweat less for the same effort is what I meant.

The cold air makes me sweat less for the same effort is what I meant.

Air temperature doesn't affect how much you sweat. It's body temperature that counts. Sweating is the main mechanism your body uses to lose heat. If you go out in the cold, your body becomes cold, so no sweating. A cold body is less efficient than a warm one, but then efficiency drops off again when temperature goes too high. When an athlete cycles on a cold day, the exercise is enough to heat the body up to an opti umbrella condition, but the 100w that you would make won't compensate for your loss of heat unless you're substantially insulated, and if you did have such insulation, it would hamper your pedalling, meaning some of your 100w is not making motive power, and it would produce a lot of drag.

 

In summary, air is denser, which causes more drag. Rolling resistance increases. Clothes for insulation cause drag. Lack of insulation causes body efficiency to go down and you can't pedal as enthusiastically.

 

The only way to know which of those factors affect you and by how much would be to compare a winter ride with a summer ride on a non-assisted bike, or listen to any guy that commutes on a non-assisted one, as they will all tell you winter rides take longer.

Fwiw I have noticed a significant drop in power over the last few weeks even with a fully charged battery, My return from shopping will take me up a (mostly) smooth uphill length of cycle track which with nominal effort from my legs I could sail up at 15-16 mph until recently.

 

Currently im finding myself travelling at 12-13 mph up the same hill after pushing the pedals what seems like quite a bit more, (still not a lot compared to pre motor) hey it stills beats walking or cycling uphill without a motor at all.

 

Tbh ive not paid attention to the battery level displayed on the headset, I will next time out and see if its associated with a drop in reported voltage level.

I would think an insulated 'jacket' for the battery would solve the problem.

 

Waterproof quilted material here,

https://www.eufabrics.com/quilted-fabrics/812-quilted-reflective-waterproof-fabric.html?gad_source=1&gclid=EAIaIQobChMInOrZwKXogwMV_5xQBh3CgQzWEAQYBCABEgKXrvD_BwE

Double or triple thick the material by folding, then stitch velcro in long lengths to join it.

If its the long battery type on the modern bike, then its going to wrap around the whole down tube, but other types you might need to use a sewing machine to create the right shape. Then maybe straps, snap closure, adjustable loops etc to hold it in place.

 

I'd an idea to make a full waterproof cover to fit on my full suss ebike. Might not be 100% as its got to get around cranks, tuck tightly behind a chainring, around rear shock etc etc, but im quite sure I could come up with something that covers enough of the electrical areas to keep the worst of the rain off them.

As a furniture maker I was trained in upholstery too, so a dab hand with the old Singer

Edited January 19, 20242 yr by AndyBike

I'd an idea to make a full waterproof cover to fit on my full suss ebike. Might not be 100% as its got to get around cranks, tuck tightly behind a chainring, around rear shock etc etc, but im quite sure I could come up with something that covers enough of the electrical areas to keep the worst of the rain off them.

As a furniture maker I was trained in upholstery too, so a dab hand with the old Singer

 

Tartan?

 

Edited January 19, 20242 yr by guerney

Air temperature doesn't affect how much you sweat. It's body temperature that counts. Sweating is the main mechanism your body uses to lose heat. If you go out in the cold, your body becomes cold, so no sweating. A cold body is less efficient than a warm one, but then efficiency drops off again when temperature goes too high. When an athlete cycles on a cold day, the exercise is enough to heat the body up to an opti umbrella condition, but the 100w that you would make won't compensate for your loss of heat unless you're substantially insulated, and if you did have such insulation, it would hamper your pedalling, meaning some of your 100w is not making motive power, and it would produce a lot of drag.

 

In summary, air is denser, which causes more drag. Rolling resistance increases. Clothes for insulation cause drag. Lack of insulation causes body efficiency to go down and you can't pedal as enthusiastically.

 

The only way to know which of those factors affect you and by how much would be to compare a winter ride with a summer ride on a non-assisted bike, or listen to any guy that commutes on a non-assisted one, as they will all tell you winter rides take longer.

I don't doubt your research. I am looking forward to warmer weather but the wind that comes with it this time of year is even worse for efficiency.

I would think an insulated 'jacket' for the battery would solve the problem.

Would be worth it if spending many months in sub-zero. Or if there was some easy way to fit. But kneeling down, wrapping and unwrapping the battery each journey is added faff for a tiny bit more range.