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

[RiderOnTheStorm]

@#lazy how come? I was thinking maybe my initial post could become a running list of Do's and Don'ts and best practices for maintaining a healthy battery which could be updated from collective feedback and tips suggested by forum members. Bad idea?

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[Jeff H]

Theoretically all of that is great….if you plan on keeping your bike and same battery for a decade or two. Reality is it‘s probably gone within 5 years and the battery is still in excellent condition even after breaking those rules. Make a reasonable effort but don’t stress over it.

 

[Binhill1]

Mine 4 years old in 3 weeks. 8200 miles. I try to stick to storage at around 80 . Guilty of charging to most of the time as I do long rides but sometimes come home 20 left maybe. Still seems to be getting same distance. I will test again soon out of curiosity.

 

[Beaker2135]

I don’t want to distract from best practice in looking after an expensive component but it’s not a family heirloom and will deteriorate over time
Just get out and ride

 

[Wilko58]

I've just bought a spare Bosch Powertube 625 battery and it was 100% charged and made on 19 September 2022 - so sat in a box fully charged for nearly 8 months. If it was best to store it at less than 100% don't you think Bosch would do the same?

 

[Ronen]

hello
does anyone know
I ride 20 kilometers every morning, the battery drops from 80% capacity to 55%
Should you charge after every ride or after two rides?

 

[Mabman]

hello
does anyone know
I ride 20 kilometers every morning, the battery drops from 80% capacity to 55%
Should you charge after every ride or after two rides?

Due to the fact that the voltage drops with percentage used you will start to lose actual power past say 50% and it will get worse from there. I would suggest you keep the battery more towards the upper end which would mean charging up to 80% after every ride in your case it looks like?

 

[Ralph]

Yes...............all the criterea in the OPs post is backed by science but what we do not always know is how much control is exercised by the BMS in the latest EMTB batteries. For example, preventing discharge below a certain% and not charing to 100%/or preventing further charging when cells get beyond a certain temperature..........then charging again once they have cooled.
We also have no idea what criterea is checked when rating a used battery............quite possibly only that each cell is still operating at a given voltage? A better guide is the range the battery delivers but that is difficult to assess because of all the variables for each ride.

What is known is that lithium cells suffer potential damage when fully charged to 100% and allowed to fully discharge to 0%.......heat being the main reason. Optimum performance of a lithium battery is when it maintains a charge between 30% and 80%.
The only things I would add to the OPs list is to avoid charging to 100% unless a full charge is needed for the next ride. I have a 750w/h battery and only ever charge that to 100% once a month. Most charges are to 85%.

Note that the better EMTB chargers do not charge continuously. They go through cycles of charging often at different rates per cycle and interspersed with cycles of cell balancing.

The battery manager that is built in (BMS) to the battery pack measures each cell voltage and will disconnect when parameters are breached. It also balances the cells with a resistive load if one becomes more than another.This only happens when a cell is above a set voltage, it will not happen at 20% or 80% state of charge so if you want a healthy battery charge to your known maximum on a regular basis The parameters are unknown to us and will be set by the engineer who designed the system. It is best to trust a well known manufacturer with a great warranty.

 

[Mikerb]

The battery manager that is built in (BMS) to the battery pack measures each cell voltage and will disconnect when parameters are breached. It also balances the cells with a resistive load if one becomes more than another.This only happens when a cell is above a set voltage, it will not happen at 20% or 80% state of charge so if you want a healthy battery charge to your known maximum on a regular basis The parameters are unknown to us and will be set by the engineer who designed the system. It is best to trust a well known manufacturer with a great warranty.

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.

 

[RiderOnTheStorm]

This only happens when a cell is above a set voltage, it will not happen at 20% or 80% state of charge so if you want a healthy battery charge to your known maximum on a regular basis

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?

 

[Chairman]

My experience with a Bosch 625. Most rides are aprox 2 to 2.5 hours and 1000 to 1200 metres climbing. Do as much as I can in turbo so it comes home pretty flat and straight on charger to 100%. After two years and aprox 6000 ks of this I bought another battery so I always had a spare for big days. I have noticed the new battery is slightly stronger than the old but not enough to really make much difference

 

[MountainBoy]

The battery manager that is built in (BMS) to the battery pack measures each cell voltage and will disconnect when parameters are breached. It also balances the cells with a resistive load if one becomes more than another.This only happens when a cell is above a set voltage, it will not happen at 20% or 80% state of charge so if you want a healthy battery charge to your known maximum on a regular basis The parameters are unknown to us and will be set by the engineer who designed the system. It is best to trust a well known manufacturer with a great warranty.

The reason you can eek a longer life out of the battery by gaming the system is because the engineers who design the charging parameters are playing a balancing act between weight of the battery, life of the battery (how long of a warranty they can offer) and the range of the bike (as well as how much it costs).

How well do you think a bike is going to sell if it has a battery that weighs 10% more, costs 10% more, and offers 10% less range than the competition? Or, on the other side of the balancing act, how viable is an e-bike company that has 40% of their batteries replaced under warranty because the engineer tried to eek too much juice out of too few batteries?

The bottom line is the 0% and 100% discharge/charge cutoffs are designed to get almost every last battery through the warranty period without losing so much charge capacity that it requires warranty replacement. If you are happy with the duration of the warranty (and the acceptable range loss before the warranty kicks in), just charge to 100% and use it without thinking. If you think there is value in having a battery that retains more range, long after the warranty is expired, then game the system, pull it off the charger when it's 60-80% full and top it up, if need be, before you ride.

If you follow the extended lifespan routine, you should still charge it 95%-100% before you ride at least every 10-20 rides (or whenever you notice the remaining range is out of whack) to balance the cells and recalibrate the BMS.

 

[RJUK]

Agreed with these tips. As an EV driver, I'm all too aware of this and have done plenty of my own research, as in an EV the battery can be half the value of the (expensive) car, so looking after it is even more important, plus keeping the range as high as possible is also more important as you can't pedal a car home.

On my car it actually gives you a warning on the screen if you charge above 90% and advises to only do it if you absolutely need the range for a given trip. Popular opinion is to keep the battery between 20% and 80%.

I always cringe when I go into bike shops and the bikes are sat charged to 100%. I think it's just a case of bike shop employees not knowing/caring about battery degradation. Most people don't know about it and the shop doesn't care if the battery degrades slightly before it's even sold...

If you don't care about a bit of range loss then by all means deep cycle the battery. My own personal experience is with an iPad that lives in my man cave I the house, but mostly gets forgotten about. I tend to find that it's dead flat, plug it in to charge, then remember a day or two later when I find it back at 100%. I keep all my other devices religiously as close to the 20% - 80% routine as I can (I might miss the odd time when it charges to 100% by accident), but most devices of mine are fine. This iPad that kept going 0% to 100% is absolutely b*ggered and just suddenly cuts out at about 40% and often won't recharge. So yes, deep cycling can and will kill lithium batteries.

To keep them in beer shape you're better off keeping them as close to 50% as possible. That said, Bosch's advice previously in this thread was to keep it between 30% and 60%... Which would mean only ever using 30% of the battery! That to me seems ridiculously conservative... Leaving 40% on the table every time.

I dare say that would make the battery last ages though...

 

[esselite]

@RJUK thats for your car. There are cars with LFP battery, not being impacted with 100%. For LFP you do not care, it can be full all the time. But yes, ebikes are mostly li-ion. LFP batteries can (and should, according to Tesla) be charged to 100% regularly,

 

[RJUK]

@RJUK thats for your car. There are cars with LFP battery, not being impacted with 100%. For LFP you do not care, it can be full all the time. But yes, ebikes are mostly li-ion. LFP batteries can (and should, according to Tesla) be charged to 100% regularly,

Yeah, mine's not LFP I don't think. They came after. I don't think I've ever charged my car to 100%. 95% maximum and I jumped straight in and drove it when I took it off charge, so it wasn't at that SOC for long. Doesn't make much sense to go higher than that in a Tesla as you lose regen, so you lose efficiency.

For me, I'm looking at a bike with a Bosch 750 Powertube. I'll likely mostly charge it to 80% unless I know I'm going on a particularly long ride that will need more. Even then, I'd time the charging to finish just as I was going out, so it's not sat there at high SOC for an extended period.

If batteries were cheaper then maybe I wouldn't bother so much, but it's not a huge inconvenience to look after the battery.

 

[RiderOnTheStorm]

If you think there is value in having a battery that retains more range, long after the warranty is expired, then game the system, pull it off the charger when it's 60-80% full and top it up, if need be, before you ride.

If you follow the extended lifespan routine, you should still charge it 95%-100% before you ride at least every 10-20 rides (or whenever you notice the remaining range is out of whack) to balance the cells and recalibrate the BMS.

Great point! If you're looking to keep your ebike for a very long time, following some best practice to prolong battery life makes a lot of sense. On the other hand, if you're going to replace the bike before the warranty expires, battery care might be less of a concern. Boils down to our individual goals and expectations

 

[MountainBoy]

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?

The balancing happens during the final stages of charging from 90%-100%. This is necessitated by the shape of the voltage curve as each individual cell accepts more charge energy. During the bulk absorption phase the cell can accept a lot of current without the impacting the cell voltage as much when compared to the top of the charge curve. The cell voltage is the primary way the BMS knows how charged the cell is (and how much more it can safely hold), but these voltages are only good indicators at the top and bottom voltages of the charge curve.

The secondary way the BMS knows the state of each cell is that it keeps track of how much energy it has put into the cell and, how much has been consumed (during the discharge phase). As the cell reaches the top of the charge curve, it compares that amount of electricity it knows it has added, along with it's estimation of what state of charge it was at when it began charging, with the voltage. The reason this is only a secondary method of estimating state of charge is if the battery is used all the time in the 30-70% range, without ever going both above and below those values, the BMS can lose track of the exact state of charge due to small inaccuracies in the measure of energy in and out over multiple charge cycles. It needs the voltages at either end of the charge curve to recalibrate itself, so it knows where it's at.

In general, the need to balance the cells is dependent upon the quality of the cells and the accuracy of the BMS.:

1) The BMS measures cell voltage in the same way as a multimeter measures voltage. If the capacitors and resistors inside the BMS degrade over time, then the measurements will be less accurate, and the battery could be increasingly mismanaged as the components of the BMS degrade with time. More stable capacitors (and other electrical components) cost more for manufacturers to purchase but a reputable manufacturer will not cut corners on cheap components because they know they will threaten the life of the more expensive battery.

2) The more consistently the cells were manufactured, the more they will behave exactly like one another and the less need there is to balance the cells as often. Cells manufactured to a tighter quality control cost the manufacturers more money. Guess where the out of spec cells go. That's right, to less reputable manufacturers who build lower cost products. High quality lithium-ion systems can be balanced less often than cheap, bottom of the barrel systems. Some of the really crappy systems have short lifespans and should probably be balanced every time. A quality system might outlive you!

Cars have a huge advantage in terms of battery lifespans, at least the batteries supplied with the better EV's, because they have sophisticated, high-quality battery management systems that also use a liquid medium in the battery packs to keep all the cells at a more consistent temperature. This is the first time I've mentioned temperature, but all the voltage measurements used by the BMS to determine state of charge of the individual cells and to accurately balance the cells are temperature dependent. I recently purchased a used, very early Tesla Model 3 with 70K miles on it, it's over 5 years old, has had three owners, spent most of its life in California, and still has 302 miles of range out of its original 310 miles of range when new.

This leads to one more "best practices" with regard to an e-bike that does not have a temperature management system for the cells. If you return from a hot-weather ride and you have been thrashing on the battery, do not come home and immediately plug it into the charger. Put it in a cool area and let it rest an hour or two before plugging it in. This allows it to cool down and for the cells temperatures to equalize with one another. And when possible, park your e-bike in the sun on cold days and in the shade on warm days.

Most of all, don't over-think this or get too caught up in trying to take perfect care of your battery. The quality systems out there can handle all the normal situations you throw at it and even the best cared for battery's lifespan is dependent upon manufacturing tolerances of the battery and BMS design and manufacture. The best of them will last nearly forever by using a little care, but all of them will eventually reach the end of life and it's combination of usage patterns and manufacturing tolerances that will determine their eventual fate.

 

[Beaker2135]

Most of all, don't over-think this or get too caught up in trying to take perfect care of your battery. The quality systems out there can handle all the normal situations you throw at it and even the best cared for battery's lifespan is dependent upon manufacturing tolerances of the battery and BMS design and manufacture. The best of them will last nearly forever by using a little care, but all of them will eventually reach the end of life and it's combination of usage patterns and manufacturing tolerances that will determine their eventual fate.

THIS ^^^

 

[esselite]

Yes, Let's don't get to crazy about perfect care. Technology is to serve us, not the other way.

 

[RiderOnTheStorm]

If you return from a hot-weather ride and you have been thrashing on the battery, do not come home and immediately plug it into the charger. Put it in a cool area and let it rest an hour or two before plugging it in. This allows it to cool down and for the cells temperatures to equalize with one another.

Useful tip and explanation, thanks! I've heard about this before but didn't know the reason behind it.

 

[RiderOnTheStorm]

Talking about best practices for maximizing battery capacity, longevity, reliability, etc., are there any thoughts about humidity exposure affecting battery performance?

It appears e-bikes electrical components are generally rated at IPX4 minimum, meaning you can ride them in the rain as they're protected from splashes from all directions.

What is your experience/guidance for riding in wet or humid climates when it comes to battery performance? Do batteries degrade faster when exposed to humidity in the long run?

Do you do anything to protect the battery from moisture and humidity? Like sealing the battery compartment for example.

 

[Alexbn921]

Battery should be very well sealed, but things like spraying it with water while it hot and cooling down is not the best idea.

I take impeccable care of my bike. The drivetrain is always clean, lasts for 1000's of miles and shifts perfectly every time. My suspension is always serviced before it becomes a problem. My battery is cooled before charging and always storage charged.

It's part of my routine and take my zero extra time after the initial setup. When I want to ride, I know that my bike is ready and it tip top shape.

 

[RiderOnTheStorm]

@Alexbn921 That's awesome thanks for sharing your routine. From my end I always dismount the battery after a ride if I need to clean the bike with water.

Although my battery looks well sealed (except maybe for the electrical connectors), I don't want to risk getting water on it. I guess that's a trade-off when you have a bike with a removal battery. Bikes with non-removal batteries may provide better protection against humidity and dust as the battery compartment is somewhat sealed.

 

[RiderOnTheStorm]

I came across a bike.com post about ebike battery care which made a few interesting points in my opinion.

• Charge to 80% by using a timer as reminder to remove the battery from the charger, or by using a common household lamp timer to fully automate the charging time by turning off the power to the charger.
• Don't leave your charging battery unattended.
• Use only the charger that came with the bike or the battery. Check with the battery manufacturer before using a third-party substitute.

Full article : eBike batteries - the do's and don't of proper battery care

 

[billium]

Get a smart plug and Google or Alexa.
Then set up a voice command to charge the bike to 70-80% when you get home and another command to charge to 100% to run at 4am when needed.
This way you only normally charge to 80% but if you need all 100% you can get there just before you need it so minimizing time at 100%.

I use smart plug and Alexa.
When I get home: 'Alexa, charge bike for 90 minutes" ( because I know that 90 mins will get me to about 70-80% from 40%)
She responds: 'ok, waiting 15 minutes' ( let the battery cool down before charging it)

Normally that's it - the charger will turn on for 90 mins then turn off.

If I expect a long run tomorrow and want my battery fully charged:
'Alexa, Top up bike Battery '
she responds: - ' Ok, topup enabled, battery will charge at 4am for four hours'

Once setup, this is pretty much foolproof - just plug charger in bike and tell Alexa to charge the bike for xx

 

[socal_rider]

Get a smart plug and Google or Alexa.
Then set up a voice command to charge the bike to 70-80% when you get home and another command to charge to 100% to run at 4am when needed.
This way you only normally charge to 80% but if you need all 100% you can get there just before you need it so minimizing time at 100%.

I use smart plug and Alexa.
When I get home: 'Alexa, charge bike for 90 minutes" ( because I know that 90 mins will get me to about 70-80% from 40%)
She responds: 'ok, waiting 15 minutes' ( let the battery cool down before charging it)

Normally that's it - the charger will turn on for 90 mins then turn off.

If I expect a long run tomorrow and want my battery fully charged:
'Alexa, Top up bike Battery '
she responds: - ' Ok, topup enabled, battery will charge at 4am for four hours'

Once setup, this is pretty much foolproof - just plug charger in bike and tell Alexa to charge the bike for xx

I like this idea. Nice.

 

[Chairman]

That sounds like a brilliant idea. Now I just need to work on figuring out what a smart plug is and get on with it

 

[RiderOnTheStorm]

Get a smart plug and Google or Alexa.
Then set up a voice command to charge the bike to 70-80% when you get home and another command to charge to 100% to run at 4am when needed.

Awesome suggestion! @billium Can you share more details about the "smart plug" you're using? I'm also very Interested in trying this. Tired of forgetting that I left my battery on the charger and need to pull the plug!

 

[Paris Doo]

I don't have much experience on ebike batteries (I got my first ebike 5 months ago) but I let it cool down first and then charge it to 100% with a "slow" charger the night before each ride.

 

[RiderOnTheStorm]

I let it cool down first and then charge it to 100% with a "slow" charger the night before each ride.

Ditto. I started using the small 2A charger from bosch which charges slowly but helps preserve my battery cells from stress It also doesn't get as hot as the 4A charger.