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

leehop71

Member
Sep 2, 2023
21
12
Florida
I’m an above average anal person and the research I’m going with was the fact that it’s not worth the trouble doing the 80% method!

Charge it full, unless it’s going to sit long term, then make sure it’s at 50-60%, ride it all you can, charge it at room temperature!
 
@leehop71 As mentioned earlier it's the length of time at full charge or full discharge that degrades batteries.

If you fully charge to 100% and then use the battery right away, the degradation should be minimal. For long rides, I would always charge to 100%.

It's generally shown that when you limit the charge to 80%, your battery lifespan will be increased. Obviously you'll have to charge more often and it may not be convenient or practical. And you would also have to remember to balance the cells from time to time!

I think it really comes down to how many charge cycles (or how many years) you want your battery to last for. ;)
 
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leehop71

Member
Sep 2, 2023
21
12
Florida
@leehop71 As mentioned earlier it's the length of time at full charge or full discharge that degrades batteries.

If you fully charge to 100% and then use the battery right away, the degradation should be minimal. For long rides, I would always charge to 100%.

It's generally shown that when you limit the charge to 80%, your battery lifespan will be increased. Obviously you'll have to charge more often and it may not be convenient or practical.

I think it really comes down to how many charge cycles (or how many years) you want your battery to last for. ;)
Understood Rider! I ride everyday! I only charge when it gets to 20% and ride the very next morning! 🤷🏼‍♂️
 

Tooks

Well-known member
Subscriber
Mar 29, 2020
489
579
Lincs UK
I've followed all of the rules in this thread and have 9 or 10 partial charges on my battery and exactly 3 full charges.
This morning I did the 3rd full charge in my home (my Relay battery is removable and my garage is pretty hot) and within 5-10 minutes of the chargers full charge indicator light going green it was unplugged.
About an hour later I installed the battery and used the App to check percent of charge and it was at 98% with no pedaling done but it had read 100% charge when I previously gave it a full charge 2x.
So it would appear that at only around 120 miles of use I had lost 2% capacity.
It's not a huge deal but I'm a bit surprised by the quick degradation in spite of me doing all the things (keep battery room temp except when riding, charge to 60% after use, allow to cool before charging, never been below 20%, depart usually at 80% charge except the 2 times at 100% & now one at 98%).
Anything I should be doing differently or is this just par for the course?
If I left it fully charged longer or more often would the battery cells rebalance? Starting to think I'd be better off just charging it to 100% every ride.

Batteries store different amounts of energy dependent on the temperature, it’s perfectly normal.

You seeing an indicated 98% on the battery state of charge the day after charging it to an indicated 100% is not a measure of degradation, just the BMS giving a best guess based on what it knows.

Despite what anybody has written on here so far, albeit with the best of intentions, the only way to check a battery packs max capacity versus when it was new is via a coulomb counter check.

It’s doubtful any LBS will have one, but the BMS on your bike does a pretty good job of assessing state of charge at any given time, to within a few percent anyway.

Of all the things that will ruin your day on an e-bike, the battery is actually pretty low down the list in my opinion.
 

Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,305
5,111
Scotland
Batteries store different amounts of energy dependent on the temperature, it’s perfectly normal.

You seeing an indicated 98% on the battery state of charge the day after charging it to an indicated 100% is not a measure of degradation, just the BMS giving a best guess based on what it knows.

Despite what anybody has written on here so far, albeit with the best of intentions, the only way to check a battery packs max capacity versus when it was new is via a coulomb counter check.

It’s doubtful any LBS will have one, but the BMS on your bike does a pretty good job of assessing state of charge at any given time, to within a few percent anyway.

Of all the things that will ruin your day on an e-bike, the battery is actually pretty low down the list in my opinion.
I tested mine in eco mode when new I just do the same route once a year in same weather conditions and use factory recommended settings on levo. It works for me . No difference in range after 260 full charges and 9000miles in four years and four months . I thought I would have seen some change by now.
 

leehop71

Member
Sep 2, 2023
21
12
Florida
I tested mine in eco mode when new I just do the same route once a year in same weather conditions and use factory recommended settings on levo. It works for me . No difference in range after 260 full charges and 9000miles in four years and four months . I thought I would have seen some change by now.
Keep on keeping on Binhill!👍
 

Alexbn921

Well-known member
Sep 27, 2021
545
511
East Bay CA
It's actually pretty easy to measure battery degradation if you have the correct tools. The BMS could do this, but most manufactures don't share this information.

The internal resistance gives a near perfect picture of the health of the battery. To test it you need to keep place a constant load on the battery and measure the voltage drop. The battery should be at full charge and at the same temperature each time. First is to baseline a new battery. Then you can compare the resistance change over time.

The second way is more intensive and requires a full charge and discharge cycle to measure the total capacity. This varies with load. Since 1c is the max the bike can pull this would be a good level to check at. Of course temperature should be keep constant between test and a new baseline should be recorded.
 
The second way is more intensive and requires a full charge and discharge cycle to measure the total capacity.
Yeah, as I recall, my LBS used a capacity tester from Bosch to check the battery health doing a full charge and discharge cycle.

I found some info on this tool. See link below. Somewhat pricey though and not something I would consider buying myself!


Added description below found on manufacturer/reseller web site:

Diagnostic tool for measuring the capacity of bosch ebike batteries. In order to use the Bosch CapacityTester, the device itself and a laptop with current diagnostic software, including the diagnostic dongle, are required.
  • Can measure Bosch eBike batteries starting from the Classic+ Line.
  • The CapacityTester cannot be operated on the eBike itself (charging sockets after MY14).
  • The battery must be fully charged (≥ 98%).
  • The CapacityTester itself does not have a charging function.
  • Reference: 275007924.
  • EAN: 4047025671378
 
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Reading on this forum about e-bike battery care best practices, tips and tricks, etc. I came across quite a few interesting threads, older and newer on the topic that I thought could be mentionned here (have indexed them in chronological order ;) )

Worth perusing in my opinion if you're interested in this topic. Take a look:
  • 2018
  • 2019
  • 2020
  • 2021
  • 2022
  • 2023
 
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MasterDabber

Active member
Aug 18, 2023
104
101
Surrey
On a slightly different tack..... if I buy a new emtb what battery health indicators should I expect... presumably 100% health but how many cycles etc? In particular I'm talking Bosch CX/Kiox 300/750wh
The bike may be the one on the lbs shop floor.
 

Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,305
5,111
Scotland
On a slightly different tack..... if I buy a new emtb what battery health indicators should I expect... presumably 100% health but how many cycles etc? In particular I'm talking Bosch CX/Kiox 300/750wh
The bike may be the one on the lbs shop floor.
Not Bosch but levo says 300 cycles or 3 years . Tells you in manual so if you got manual online for the bike your after it will probably tell you all that kind of stuff. Doesn't say what's going to happen after that time or amount of charges though. Mine has passed the 3 years but only 260 cycles but still 100 percent.
 

MasterDabber

Active member
Aug 18, 2023
104
101
Surrey
Not Bosch but levo says 300 cycles or 3 years . Tells you in manual so if you got manual online for the bike your after it will probably tell you all that kind of stuff. Doesn't say what's going to happen after that time or amount of charges though. Mine has passed the 3 years but only 260 cycles but still 100 percent.
Thanks^
I guess what I was trying to understand (but explained a bit vaguely) is does a newly supplied bike typically come with "0" cycles or perhaps just "1" or "2"? And if the bike I was offered had a lot more than that what would be reasonable?
Also, when bike shops take delivery of new stock do they come with batteries at 100% charge? and if that is the case would this be bad news if the the bike has sat on the shelf for a long periods 100% charged.
Sorry if this sounds bit anal but since starting to consider an emtb for the first time these questions have sprung to mind.
 

Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,305
5,111
Scotland
Thanks^
I guess what I was trying to understand (but explained a bit vaguely) is does a newly supplied bike typically come with "0" cycles or perhaps just "1" or "2"? And if the bike I was offered had a lot more than that what would be reasonable?
Also, when bike shops take delivery of new stock do they come with batteries at 100% charge? and if that is the case would this be bad news if the the bike has sat on the shelf for a long periods 100% charged.
Sorry if this sounds bit anal but since starting to consider an emtb for the first time these questions have sprung to mind.
Mine had to be charged when I got it . It would not have been totally flat though i imagine . Also it had to be paired to my phone through the mission control app so I presume nothing would register till after that . Specialized mine though not sure about anything else.
 

TheSnowShark

Well-known member
Subscriber
Sep 7, 2023
243
329
French-Alpes
I share the various advice given here, except the fact of not storing with a 100% charge at room temperature, or in the garage.. you forget that there is a self-discharge which occurs naturally.. but on the other hand , it is especially important not to leave the charger in use..

An example with the same Li-Ion technology, I have been storing portable tool batteries in this way for more than ten years, and they are always in perfect condition.. :)

I would add that, as others have already said, it is very important to do complete charges/discharges from time to time, this to allow the cells to balance.
 
if I buy a new emtb what battery health indicators should I expect... presumably 100% health but how many cycles etc?
With a brand new battery (installed on a new bike or bought separately) the number of charge cycles should be zero. Meaning the battery was initially charged to a "storage" level (e.g 50-60%) but has never completed a full charge/discharge cycle.

To your question, a bike sold as new in the showroom or prepared/built specially for the customer should never be left with a battery fully charged at 100%. If that's the case I would think twice about buying from that dealer.

When I purchased my Bosch powered bikes, I asked my LBS to run the Bosch e-bike diagnostic tool (IBD software) and print the full report which includes details about the battery (number of charge cycles, max/min temperatures, voltage, etc). Number of charge cycle shown was zero, as expected. Battery was charged at ~40% if I recall.

Same thing when buying a new spare battery. Pop it in the bike and have the LBS run the diagnostic tool to check the battery condition, number of cycles, etc. If not showing zero cycle, the battery may not be new.

At some point, I really wish Bosch would make this diagnostic software available to customers who already spent a ton of cash on their Bosch powered ebikes!
 
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Regarding battery health indicators, there is a correlation between the battery's output voltage and the capacity the battery can deliver. But voltage alone cannot determine the battery's health.

See below a typical voltage chart for a 36V ebike battery (Bosch powertube for example).

To determine the battery health (state of health), different test methods can be used. This article from Battery University outlines some of them. For Bosch battery testing, see also the Battery Capacity Tester (BCT) tool.

36V E-bike Lithium-ion Battery Voltage Chart
Battery voltage (Volt)
Battery capacity % (state of charge)
42.0
100%
41.4
95%
40.8
90%
40.2
85%
39.6
80%
39.0
75%
38.4
70%
37.8
65%
37.2
60%
36.0
50%
35.4
45%
34.8
40%
34.2
35%
33.6
30%
33.0
25%
32.4
20%
31.8
15%
31.2
10%
30.6
5%
30.0
0%

Post edited/corrected per feedback
 
Last edited:

MasterDabber

Active member
Aug 18, 2023
104
101
Surrey
With a brand new battery (installed on a new bike or bought separately) the number of charge cycles should be zero. Meaning the battery was initially charged to a "storage" level (e.g 50-60%) but has never completed a full charge/discharge cycle.

To your question, a bike sold as new in the showroom or prepared/built specially for the customer should never be left with a battery fully charged at 100%. If that's the case I would think twice about buying from that dealer.

When I purchased my Bosch powered bikes, I asked my LBS to run the Bosch e-bike diagnostic tool (IBD software) and print the full report which includes details about the battery (number of charge cycles, max/min temperatures, voltage, etc). Number of charge cycle shown was zero, as expected. Battery was charged at ~40% if I recall.

Same thing when buying a new spare battery. Pop it in the bike and have the LBS run the diagnostic tool to check the battery condition, number of cycles, etc. If not showing zero cycle, the battery may not be new.

At some point, I really wish Bosch would make this diagnostic software available to customers who already spent a ton of cash on their Bosch powered ebikes!
Thanks a lot. This gives me exactly what I needed.
 
I share the various advice given here, except the fact of not storing with a 100% charge at room temperature, or in the garage.. you forget that there is a self-discharge which occurs naturally..
@TheSnowShark, thanks for sharing your feedback on the topic!

According to publications from Battery University, self-discharge of a lithium-ion battery when charged at 100% and left unused (like in storage) is extremely slow, therefore keeping the battery "stressed" at a high state of charge for a long period of time.

And we know that higher the state of charge of the battery over time, lower the number of charge cycles we can get from the battery, hence a lower lifespan. On the other hand, more time the battery spends below 80% state of charge, the longer the lifespan.

batterycycles.png


Charging at 100% is fine if you intend to use the energy quickly. ;)
 
Last edited:

jimbob

Active member
Aug 3, 2020
523
433
East UK
Regarding battery health indicators, there is a correlation between the battery's output voltage at 100% charge and the capacity the battery can deliver.

See below a typical voltage chart for a 36V ebike battery (Bosch powertube for example).

After fully charging the battery, the voltage measured is one indicator of the battery capacity (%) at any given time. The table shows the max voltage the battery can charge to when charged at 100%, hence giving an estimation of the battery's capacity % in comparison to a new battery.

As an example using the table below, if my battery voltage measured after charging at 100% is 39 volts, then my battery max capacity is down to 75% from its capacity when new. In other words, my battery lost 25% of its original capacity.

If the voltage becomes too low, it's most likely time to get a new battery. If the voltage of my Bosch battery drops below the 60% capacity threshold within the warranty period (~2 years), so under 37.2V, a battery replacement may be possible under warranty. Check battery manufacturers warranty conditions.


Battery voltage (Volt) when charge level is 100%
Battery capacity % when charge level is 100%
42.0
100%
41.4
95%
40.8
90%
40.2
85%
39.6
80%
39.0
75%
38.4
70%
37.8
65%
37.2
60%
36.0
50%
35.4
45%
34.8
40%
34.2
35%
33.6
30%
33.0
25%
32.4
20%
31.8
15%
31.2
10%
30.6
5%
30.0
0%
Sorry, but is this correct? Lithium cells will always be charged to a fixed voltage to be 'full'. I think this table is about the maximum charge voltage and the associated resultant capacity relative to the what is deemed a 100% charge voltage which is normally 4.2V/cell, hence 42V for a 10S configuration.

If the max charge voltage is lower, the battery holds less energy, as shown in the table.
 

Over 260 posts so far about battery care!! Awesome contributions from forum members sharing best practices, tips and also opinions! Thanks, everyone! 👏

As a recap it becomes clear (or clearer) that performance and lifespan of our ebike lithium-ion batteries can vary depending on many factors: their quality, their age, how they are used (or abused), how they are stored, maintained and cared for over time.

Interested in what battery manufacturers say about battery care and maintenance, below are links to guides and other resources available to e-bike owners:

ManufacturerBattery guide
ShimanoPDF, PDF
Yamaha/GiantPDF, HTM
BoschPDF
Brose/SpecializedPDF, HTM
BafangPDF, HTM
TQPDF, HTM
SRAM AXSPDF, HTM
 
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If you ever wondered how old is your Bosch battery pack on your ebike, or want to check the age of a battery before buying it, fairly simple. The first 3 digits of the battery serial number is the manufacturing date code.

Here are a few steps to use the Bosch battery date "decoder ring" and find the age of your Bosch battery:
  1. Locate the serial number on the battery (long number)
  2. Read the first 3 digits of the serial number e.g. 337
  3. Find this 3-digit number in the table below.
  4. Lookup the corresponding year (column) and month (row) in the table, and you will know the battery manufacturing date. For example, with the code 337, the table shows that the battery was manufactured in January 2023.
  5. You'll notice that the first digit of the battery serial number is the last digit of the manufacturing year e.g. 3 -> 2023, 2 -> 2022, etc. So you can quickly find out the battery's manufacturing year without using the decoding table below.
Bosch Battery Date Decoder
Year
Month
'24'23'22'21'20'19'18'17'16'15'14
Jan437337237137037917817717617517417
Feb438338238138038918818718618518418
Mar439339239139039919819719619519419
Apr440340240140040920820720620520420
May473373273173073953853753653553453
Jun474374274174074954854754654554454
Jul475375275175075955855755655555455
Aug476376276176076956856756656556456
Sep477377277177077957857757657557457
Oct478378278178078958858758658558458
Nov479379279179079959859759659559459
Dec480380280180080960860760660560460

The above table appears to have a consistent pattern, so future codes can be inferred, until Bosch changes the date code pattern or sequence. ;)
 
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When mapping new rides and calculating trip distances from gpx, I often wonder about my battery range.🤔

Will my fully charged battery cover the distance? Should I charge to 100% or 80%? Do I install my 625Wh battery or use my 500Wh instead? Should I carry a second battery with me to have enough energy to finish the ride?

I found this basic Range Calculator (for Bosch systems) which has helped me in the past for estimating a range based on some input parameters (rider, bike, type of ride, average speed, assistance level, environment, etc). Here's a link:


Has anyone used this range calculator? Or can you recommend other tools to estimate battery range when planning a ride?

Example below is my estimated battery range which seems about right with the input I provided.

rangecalc.png
 
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Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,305
5,111
Scotland
Spare battery is a dead kind of weight to carry plus all other things if you are needing for a 40 plus miles but if you need it . . I would be needing my dinner and stove etc for anything over 30 miles in winter. Just wonder if you could get a calculator for wet stodgy trails ?? permafrost rings to mind.
 
A few tips posted on bike.com for charging e-bike batteries. Nothing earth shattering, just a nice recap of best practices and guidelines in my opinion:
  • Control the temperature
  • Use the right charger
  • Don't take it to 0%
  • Don't overcharge
  • Keep it dry
  • Give it some room
  • Don't use an extension cord
 

I've been wondering how ebike riders can properly take care and maintain their batteries if they are non removable or non detachable? 🤷‍♀️🤷‍♂️

I detach my batteries when I need to charge them at room temperature and cannot leave them outside (cold winter or hot summer). I quickly swap my batteries during longer rides. I remove them when loading/transporting the bikes on the bike rack on the car.

Battery removal & charging access is essential in my opinion and something I would check before buying an ebike that sports a frame integrated battery design. A few questions always cross my mind:
  • Can the battery be quickly removed and replaced by myself without tools and without going to a bike shop ? Or is the bike/frame designed as such that the battery cannot be immediately removed by the rider?
  • Is there a charge port on the bike? Can the battery be easily charged directly from the bike (without removing the battery)? Is the charge port on the bike well designed, conveniently positioned on the frame?
  • Can a new battery for my bike be easily sourced if I want to keep a spare or purchase a replacement post warranty?
Is your ebike battery removable? If not, do you see this as a drawback or limitation?

I've started compiling a list of recent eMTB models which DO NOT have removable or detachable batteries, or require some tools for removing the battery. Here is my list so far:

🚫 e-bikes with non-removable batteries*
BrandModel Year
CanyonNeuron:ON CF 92024
Canyon

Spectral:ON CF

2023
FocusJam2/Sam22022/23
MeridaeOne-Sixty2023
MondrakerCrafty XR2023
NukeproofMegawatt Carbon2023
OrbeaRise2022/23
OrbeaWild H102023
OrbeaWild M-LTD2023
PivotShuttle SL2022/23
Santa CruzHeckler SL2023
Specialized Levo SL Comp Carbon2023
SpecializedTurbo Levo SL S-Works2023
TrekFuel EXe2023
(*) battery is fixed inside the downtube or built into the frame and cannot be easily or quickly removed by the rider or by the dealer without the use of tools.
[Updated above table per feedback]
 
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Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,305
5,111
Scotland
I've been wondering how ebike riders can properly take care and maintain their batteries if they are non removable? 🤷‍♀️🤷‍♂️

Battery removal & charging access is essential in my opinion and something I would check before buying an ebike that features a frame integrated battery design. A few questions always cross my mind:
  • bike batteries are incorporated into the frame and ?
  • Can the battery be quickly removed and replaced by myself without tools and without going to a bike shop ? Or is the bike/frame designed as such so that the battery cannot be removed by the rider?
  • Can the battery be easily charged directly from the bike without removing the battery? Is the charging port on the bike well designed?
  • Can a new battery for the bike be easily sourced if I want to secure a spare, or for after warranty replacement?
I started compiling a list of recent eMTB models which unfortunately DO NOT offer self removal batteries or require tools for removing the battery. Here is my list so far:

BrandModel YearNote
OrbeaWild M-LTD2023
NukeproofMegawatt Carbon2023Tooling required

Is your ebike battery removable? If not, do you see this as a drawback or limitation?
Surprising the number of folk who have bought a Ebike and don't know or bother to read the manual about the basic charging procedures. I'm talking about in my area there are a lot of people who were never cyclists before ebikes were popular. I'm guessing they just charge it up when they want to go for a spin. Probably go in shed to go out and find it's flat , scary when you think of the replacement cost.
 

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