Winter Bicycling
 

This will be my first winter commuting on an ebike. I charge my battery inside my home. My question is at what temperature do you not use your ebike for commuting? Do you ride your regular bicycle at a certain temperature because it would degrade the battery? Nothing has been posted about this subject so I am curious. I would like to use my ebike down to the teens without snow or ice. What are your thoughts?

In the teens the battery loses about 50-60% efficiency. But as long as the battery is charged and stored indoors you should have no issues. Unless you have a long commute the battery should not cold soak enough to be a problem. Then just bring it inside while at work.

My low temperature cutoff point is regulated by my nose and ear temp rather than the battery!

Thank you to the original poster as I will be in the same boat. Thanks also for the answer as I was curious as well. Lucky for me, my commute is approx 9 miles so my ear/nose test won't be as critical for a less than 30 minute ride (on an ebike of course).

Store and charge inside, then insulate (if necessary) when riding. There should be data on what ambient temperature is unacceptable. I'm in CA and have ridden in snow, but doubt the temperature was much below freezing.

Batteries soon warm up to nominal in cold weather. But it's a good idea to keep it indoors in winter if you have a small or part-charged battery, else it may cut out under load until it does.

I try to ride 400 miles a month during the winter. I ride in the teens if I see the temps will go up. I wear cheap brown jersey gloves double with cheap Walmart hand warmers. I hate my nice ski mitts because my hands soak with sweat.


Since these cheap hand warmers go over 100 degrees, I will wrap a couple on my battery pack.


Since you charge indoors, tip #2 is charge right before you go. A battery being charged warms up.


#3 A battery powering something also creates heat.


#4 A warm battery thinks it is fully charged a little to early. Charge it,Take off charger let it cool then charge and warm it some more


Our reference library is my daughter. PhD EE Colorado School of Mines. She runs ultra marathons in the mountains often with snow and temps in the teens. That means headlamps at night. Lithium offers better frigid temp performance.

Winter Riding
 

Doesn't heating the battery to 100F also kill battery life? Are the batteries designed to work in all weather?

There is a lot of good (and some misleading) data on Li-ion batteries on the internet. Most refernces I have seen indicate a Li-ion battery has a max temp range of about 110 -115F. My bike has a LiFeP04 battery which is supposed to have a slightly higher temp limit. Both can be damaged by prolonged use, charging, or storage at high temps, resulting in reduced battery life.

On the cold side, performance will be reduced at lower temps, and they should not be charged when the battery is below about 40F. Optimum operating temp is in the range we humans like: 50 - 70F prox. There is a low temp point at which the battery will just cease to function - it varies by chemical compound. Memory (can't find the reference right now!) says this somewhere below 10F.

From a practical standpoint that creates some rules of thumb on battery care:
Don't leave the battery in an unheated garage/storeroom in cold weather - or in a hot one in the summer.

When storing the battery keep it in an average room temperature at about 50 -60% state of charge. (Most new battery packs are stored and shipped at 50% SOC and should be charged before using.)

Don't overcharge it (causes temp spikes) or run it into deep discharge. Life will be shortened, and a completely depleted Li-ion battery may not come back from that state. (There are stories to say it will be OK, others tell about a destroyed battery. Take your choice about which to believe. I tend to err on the safe side.)

As others have posted, the addiction of an insulated cover and hand warmers will help if the commute is longer.

I use my electric car year-round - 20 below zero to over 100, but unlike the bike battery, the car has an complex battery management system that will heat or cool it to maintain battery health. But even with that system the range will drop 20 - 25% in winter. The battery and temperature control system has enough mass that it will not cold-soak to an inoperative point overnight, but long term exposure will cool it to the point that the system will not allow it to damage itself by powering the car. In that case it will only draw sufficient power to run heaters to bring the battery to a safe point and them allow it to power the car.

With a car, bike, iPhone, iPad, laptop and random other rechargeables it seems like I always have something plugged in! But the power company loves me.

A further note: I usually don't ride when it gets below 40F. But on a 20-25 mile ride in the mid 40s I haven't seen a significant reduction in range. At those temps my garage is usually about 50F so I store and charge the bike there. When I stop riding for the season I pull the battery and store in the house at about 50% SOC.

We have all kind of battery chemistry
Some more some less affected by cold

So do not throw all in one bag.
With my winter ride I loose no more than 10% of our most battery capacity
I use NMC CHevy Volt cell build battery for my winter ride
NMC. Nickel Manganise Cobalt

I keep mine outside work in frost and snow, and it still works fine when all sparkly at 6am. Bear in mind i usually run two batteries. But i'm sure i've done it countless times each winter with one (3rd winter on Li-Po coming up).
Amps are reduced though, so carrying more capacity, and running a lower power setting, are key to preventing the thing cutting-out on you under load.

I would never leave my winter ebike in wherever belowzero temperature overnight

I store my bike outside, but charge my battery indoors. We will see how this winter goes. I might be getting another ebike, My 2017 Raleigh Retroglide was my first ebike and it does the job.

I do the same, battery has lasted well and no problems.

Calgary winter commuter (10 years), e-bike owner (1 year) and Bosch e-bike certified tech here! Yes, you can use your e-bike in winter, but you will need to take a little extra care with the battery. As others have said above - bring the battery indoors when you aren't riding, definitely make sure it is warm before you plug it in to charge, and consider some insulation around the battery when you are out and about. (I used a woolly sock on mine. It was fine!)

Physics can't be changed, and that's what dictates the slightly lowered range and efficiency of battery systems in cold weather. I have a short commute, only 5km each way, and I didn't notice any change in my range even at -20C. I stopped riding once it got colder than -25C, because I can't really breathe comfortably at that point, but according to Bosch there is no real lower limit for their systems.

I put a studded tire - Schalbe Marathon Winter - on my e-bike's front wheel, but found I didn't need it on the rear, because the long wheelbase and low center of mass make the bike a lot more stable than any of my other bikes have been. I'm also using a route with very good snow clearing, thank you, city of Calgary! I only fell once last year, which is an improvement over previous years.

One thing caught me by surprise, and that was the necessity to re-calibrate my personal layering system, which I'd refined over a decade. Suddenly I'm not working as hard on the bike, so I wasn't warming myself up as much! My -10C clothing and gloves had to be bumped up to -5C. Totally worth it.