Do's and Don'ts for e-bike battery care. What do you do to keep your battery performing at its best?

[RiderOnTheStorm]

Thanks @Alexbn921. I like your list of what NOT to do with an ebike battery.

Just a quick calculation, with my personal track record averaging 50 miles per full charge on a 625Wh Bosch Powertube, 500 charge cycles should give me about 25,000 miles. Or possibly 50,000 miles with 1,000 charge cyles when the battery is well taken care of. Not too shabby!

 

[RiderOnTheStorm]

Thinking about how low temperatures can affect battery life, I'm curious about winter battery care. I've been reading that e-bikes can lose 20-30% of range when riding in cold climates.

Ideally when in use the battery should be kept at a temperature around 15 to 20°C to maximize its lifespan. Below 0°C temperatures could also degrade the cells.

What do you do to keep your battery warm in very cold conditions? Are you using some kind of neoprene sleeves for your battery? Any tips?

 

[MountainBoy]

Thinking about how low temperatures can affect battery life, I'm curious about winter battery care. I've been reading that e-bikes can lose 20-30% of range when riding in cold climates.

Ideally when in use the battery should be kept at a temperature around 15 to 20°C to maximize its lifespan. Below 0°C temperatures could also degrade the cells.

What do you do to keep your battery warm in very cold conditions? Are you using some kind of neoprene sleeves for your battery? Any tips?

The battery will stay warm enough if you are discharging it quickly enough, say over the course of 2 hours. If you stop a lot in cold weather, the battery is going to get cold, even with insulation. Insulation could delay it a bit but not for hours.

I think a good strategy is to start with the battery warm, up to 80-85 degrees F and minimizing stopping. If you happen to stop somewhere to warm up indoors, bring your battery with you. On both of my e-bikes the placement of the battery is such that insulating them in any meaningful way would not really be practical.

 

[RiderOnTheStorm]

On both of my e-bikes the placement of the battery is such that insulating them in any meaningful way would not really be practical.

Same here! Was unable to find an insulating sleeve that is wide and long enough to wrap around my size Large downtube

 

[Alexbn921]

Start with a warm battery and ride in a higher setting will keep it warm. There is no way to insulate it. A neoprene sleeve r value is .15. Basically nothing.

 

[DeRailled7]

Interesting tread, I’ve been having the same thoughts and worries about the potential degradation of my battery, especially that I’m also riding during winter, down to about -15 C. So this spring i took my bike to my LBS where i bought it for them to do a full diagnosis of the system. My bike is a 2021 Trek Rail 7 with Bosch Gen2 motor. Here‘s the stat we all worried about: battery charge level 100%. Which mean there was no degradation of the battery. i was happy. More stats: total distance travelled: 3093km, number of full charge cycles: 49, max battery temp: 39C, min batt temp: -4.5C.
Seeing that my battery hasn’t degraded I’ll just continue maintaining it as i do now. Pretty simple, i always keep my battery inside the house(20C). I also charge it at room temp. I try to keep it at about 50% between rides and fully charge it the day before i ride. when i come back from riding I’ll just top it up to 50% until i need it. In the winter I’ll always start riding with a fully charged warm battery. If i have to drive I’ll either remove the battery (that’s why i got the Rail) and keep it by the heater in the rear row foot well, or load the whole bike inside the car and keep it toasty. Starting with a frozen battery is apparently the worst thing we can do. As the battery discharges it will warm itself up, that’s why my min temp is -4.5C. It was probably -20C that day.
Hope that helps.
cheers

 

[2WheelsNot4]

Because i really only use my bike for shopping or short trips out, i fully charge when the distance left is about 1/2 full charge. Outwith that its sat there. Mainly out each day, but only a handful of miles, so its maybe a fortnight-3 weeks between charges.

Thats been 2 yewars of that. summer high temps, cold winter with many runs where its freezing out. Rain, wind etc etc, thus far has performed all i expect of it.

 

[RiderOnTheStorm]

Starting with a frozen battery is apparently the worst thing we can do. As the battery discharges it will warm itself up, that’s why my min temp is -4.5C. It was probably -20C that day.

Thanks for sharing your experience. These are some cold temperatures you're seeing!

So basically from everyone's feedback, the key to avoid damaging the battery in low temperature environments is to keep the battery warm (ideally 15-20°C) at all times, before, during, and after a ride, and also when recharging it.

 

[MountainBoy]

The temperature of the battery doesn't matter much after a ride. It's mostly before the ride and when charging. During a ride the battery is unlikely to become too cold unless you stop using it.

 

[RiderOnTheStorm]

The temperature of the battery doesn't matter much after a ride. It's mostly before the ride and when charging. During a ride the battery is unlikely to become too cold unless you stop using it

Good clarification, thanks!

 

[randycpu]

While cell balancing seems to be handled by the BMS, are you saying that proper balancing won't happen unless you fully charge the battery? Trying to wrap my head around this.

Should I then leave the charger on the battery overnight for example, meaning charge the battery to 100% and continue charging for 8-10 hours so that balancing can actually take place, and repeat this process from time to time? But avoid doing this all the time so the cells won't be unnecessarily stressed?

YES.. Exactly correct

 

[randycpu]

that assumes the BMS (which is software) is the same programme in every battery built by different manufacturers. Thats very unlikely. The BMS will be more or less sophisticated in different branded batteries...............as will the charger that is supplied with them.

The balancing mechanism in BMSs used at the price point of e-bikes is 100% analog circuitry. It cannot be programmed.

 

[RiderOnTheStorm]

With our heatwave currently sweeping across the United States and Europe, are you changing any of your riding habits or routine when it comes to battery life preservation, battery care, handling, etc?

Any special precaution to prevent damaging our ebike batteries in extreme ambient heat conditions? Anything that should be avoided when outdoor temperatures reach 40-50°C (120°F)?

When does an ebike become potentially unsafe to ride in the heat, thinking if the battery is overheating?

 

[randycpu]

With our heatwave currently sweeping across the United States and Europe, are you changing any of your riding habits or routine when it comes to battery life preservation, battery care, handling, etc?

Any special precaution to prevent damaging our ebike batteries in extreme ambient heat conditions? Anything that should be avoided when outdoor temperatures reach 40-50°C (120°F)?

When does an ebike become potentially unsafe to ride in the heat, thinking if the battery is overheating?

Keep your batteries inside if at all possible, especially while charging.

As for me, I am using the "Trail" power setting more often during rides instead of "Eco" to keep me from getting overheated.
I rode this morning in 95F (35C) and still climbed 1500 feet (460m) in an hour.

 

[Plummet]

Ok battery guru's. What about the repeated vibration and trail impacts resonating through the frame?
How does this affect battery life? My assumptions is that this will degrade batteries also.

I don't cruise around. All my rides I ride like I stole my bike.

 

[RiderOnTheStorm]

Keep your batteries inside if at all possible, especially while charging.

Yep this is consistent with what I've been reading. I just found the guidance below in the Bosch Power Tube instruction manual that came with my spare battery (BBP290):

• Technical data - Battery operating temperature: -5°C to 40°C
• The battery has a temperature monitoring function which only allows it to be charged within a temperature range of 0 °C to 40 °C

So if I read this correctly, once the temperature outside goes beyond 40°C, no more e-bike riding! Is that right?

I'm wondering if other bike/battery manufacturers have the same thresholds and limits when it comes to battery operation temperatures.

What are the risks though to ride my ebike in temperatures above 40°C (104°F)?

 

[Stephen B]

Heatstroke!

 

[RiderOnTheStorm]

For the rider, definitely, with temperatures expected to get even hotter this week!

Let me rephrase, what are the risks for the battery when riding my ebike in temperatures above 40°C (104°F)?

 

[jimbob]

Low. It might degrade the battery very slightly faster, but it isn't going to explode!

 

[RiderOnTheStorm]

Low. It might degrade the battery very slightly faster, but it isn't going to explode!

That's reassuring. Good to hear! I'll just look for shaded areas and avoid direct sunlight on the battery.

Interesting enough, the battery care instruction guide from Bosch (below) mainly covers winter usage, but nothing about "global warming summer use" or how to maximize battery lifespan and range under the scorching hot temperatures we're seeing!

 

[RiderOnTheStorm]

What about the repeated vibration and trail impacts resonating through the frame?
How does this affect battery life?

That's a very good question and I haven't seen much being written about it from battery manufacturers.

I would think that a battery not fully secured (or loosely attached) inside the frame, could move and rub against it, wear out the main connectors prematurely, and could cause mechanical or electrical issues down the road that could certainly affect battery life or performance.

I personally think that the more secure the battery is from vibrations, the longer it will last. I noticed on my Bosch powered e-bike that some foam padding ("powertube damping plate") was glued on the main electrical connector, I presume for vibration dampening and to prevent battery movement during rough riding.

I would say ensure your battery is securely mounted so it doesn’t vibrate and won’t rub on anything. If needed, just add plenty of padding.

As far as internal battery components are concerned (cells, BMS, PCB), I'm not clear how sensitive they are to vibrations and shocks. It would be interesting to know what shock & vibration testing or certifications ebike batteries go through during their development. Anyone knows?

 

[randycpu]

Ok battery guru's. What about the repeated vibration and trail impacts resonating through the frame?
How does this affect battery life? My assumptions is that this will degrade batteries also.

I don't cruise around. All my rides I ride like I stole my bike.

A well made battery should not be affected by shock and vibration. There is little room for movement, which causes fatigue and strain.
Having said that, I am deep into rebuilding a friend's e-bike pack that was made with nickel-plated steel interconnects.
Nickel-plated steel is well known in the battery building community as a common fraudulently sold material (as opposed to pure nickel strip). I am curious as to whether this was an error by the maker or a conscious cost-cutting decision.

The steel strip failed due to corrosion and fatigue. Several parallel groups have failed by shorting, which must have been somewhat spectacular.
This is on a now 5 year old carbon road bike from a medium volume European manufacturer that had a broad range of bikes before they suddenly withdrew from the market. It was VERY surprising for me to find the steel interconnects.

 

[RiderOnTheStorm]

I found more details on the foam padding (damping plate) that sits on the socket of my bosch battery connector in the downtube. The manufacturer part# is 1270015683.

This foam plate seems to be doing the job because when the battery is mounted, it's all nice and tight betwen frame, connector and battery. I never felt any battery vibration during rides even when going downhill on rocks and roots.

 

[Plummet]

If heat is the main issue to charge to 100% what about a 2 stage charge program?
change to 70, let cool then charge to 100?

 

[randycpu]

If heat is the main issue to charge to 100% what about a 2 stage charge program?
change to 70, let cool then charge to 100?

First off, batteries with quality cells charged with an OEM charger will charge at a relatively slow rate. Most cells are rated at a 1C rate. This means you could charge to 100% in one hour. But the OEM chargers charge at a very conservative rate of ~.2C (or so). So the cells do not get thermally stressed during normal charging.
One problem is that they don't like being charged to 100%, which is 4.20 volts for the cell chemistry used in all ebikes. The longer they are left at 4.20 volts, the more of their "lives" are consumed. You would see this with reduced capacity after many charge cycles.
Having said that, the cheap BMSs used in ebikes only balance as they approach 100%. It is MUCH more likely that an imbalanced battery will kill the pack long before the cells wear out from being charged to 100%.
What does this all mean? Use your bike until you feel you need to charge. Charge back to 100% every time, cuz that's when cell balancing happens.

 

[Plummet]

Do we have any data battery degradation difference from optimally cared for V not optimally cared for?

From some of the responses in this thread is seems that there is little actual impact as users have treated their batteries poorly and still have good service life after 3-5 years of use.

I will be honest. I am not likely to own the bike I have now in 3 to 5 years time. I expect be moving it on at the 3 year mark.
I also expect that from the point of manufacture batteries will degrade until they are no longer usable. A 4 year lifecycle for a battery is what I would deem to be acceptable.

I will engage in reasonable battery care. But, at this point I don't see evidence to be super anal with the additional admin that that requires.

 

[RiderOnTheStorm]

Many factors are in play when it comes to battery longevity and performance, so assessing battery degradation based on how well it's been cared for may not be that easy.

In general, proper charging routine and proper storage, respecting optimal charge levels (%) and ambient temperatures, avoiding humidity and water, seem to be the most common best practices to follow at the bare minimum without going overboard with this.

At any rate, I'd suggest to follow the battery manufacturers guidelines for proper battery care.

As an example, below is a chart showing the number of useful cycles you could expect from e-bike batteries based on charge voltage (full charge %). This may be an oversimplification, but when more charge voltage is applied overtime, less useful cycles can be expected from the battery.

Hence the battery charging guidance and best practices many have brought up in this thread

It's been said in this thread before, if you don't plan on keeping your bikes in the long haul, or are going to replace them every 3 years or so, you will probably see little benefit from going the extra mile with battery care.

Others may have different views or expectations, as always YMMV.

 

[RiderOnTheStorm]

Here is an informational video that I watch (and rewatch) from time to time to remind myself of what to do and not to do with my ebike battery. Nice recap of best practices for good battery care IMO:

 

[RiderOnTheStorm]

Having said that, the cheap BMSs used in ebikes only balance as they approach 100%. It is MUCH more likely that an imbalanced battery will kill the pack long before the cells wear out from being charged to 100%.

@randycpu, thanks for these tips! Appreciated!

I'm puzzled about your comment above. Can you elaborate on this? Why would imbalanced cells degrade, or worst case scenario, destroy the battery pack?

 

[randycpu]

@randycpu, thanks for these tips! Appreciated!

I'm puzzled about your comment above. Can you elaborate on this? Why would imbalanced cells degrade, or worst case scenario, destroy the battery pack?

Because whatever caused the initial imbalance (likely higher cell resistance) will likely get progressively worse. The parallel cell group at a lower voltage when the charging stops will remain at a lower voltage (cuz no balancing).
If they are only 5 mV down with each charge cycle, eventually they are down so far that there is no capacity left in that parallel group. Your pack is "dead" because there is no headroom between where you are charging and the low voltage shutoff of the BMS (that still works).
These packs can be recovered by taking them apart and carefully charging each parallel cell group using a "hobby" charger made for RC vehicle batteries. But maybe not.
I damaged my Gen1 Levo battery by always charging to 80%. My rides are shorter (only 90 minutes), and I could still get 4 rides out of it. Just before the 2-year warranty ran out, the pack started throwing errors that indicated a cell group's voltage was too low. I got a new battery under warranty but vowed to always charge the new one to 100%.