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

[rideronthestorm]

What is your experience and recommendations for taking care of your lithium-ion batteries and maximize their lifespan and performance?

Over the years, I wrote down a few best practices and made the list below. I'm interested in your thoughts and feedback.

What do you do to keep your battery performing at its best?

• Length of time at full or zero charge is what degrades batteries. Never discharge the battery below 10%.
• Never keep the battery charged at 100% unless you're about to ride. For example, fully charge the battery only the night or morning before a ride.
• Charge the battery at room temperature (15-20° C). Charging at low temperatures, below 0°C will irreparably degrade the cells. Heat above 35°C when discharging or riding will degrade the battery.
• Store the battery at room temperature (15-20° C). When storing a battery for extended time, keep it at 50-60% charged. In storage, verify the charge every 6 months and recharge as needed.
• Batteries should not be recharged immediately if they are only slightly discharged. Recharge the battery only if between 10% and 20%
• Always let the battery cool down for at least 30 min after recharging it before going for a ride.
• Let the battery cool down for at least 30 min after the ride before recharging it.
• On first use, drain the new battery (10-20%) and fully charge it (100%) at least 5 times initially.

[Edited] Below list updated per forum members feedback and suggestion:

• Avoid charging to 100% unless a full charge is needed for the next ride [thanks to @Mikerb]

 

[VWsurfbum]

Is any of this based on science?

I ride mine, sometimes to flat, I charge it to 100% and keep it that way.
They get charged on and off the bike in the cave. (so not warm, not cold)

All is good.

There is a lot of scare mongering around bike batteries as there is in the car world with electric cars. They're pretty robust things and can be treated pretty poorly and still perform to a good standard. Take it all with a pinch of salt from so called experts, unless they have science to back it up, I'll keep, keeping on.

 

[unclezz]

Is any of this based on science?

I ride mine, sometimes to flat, I charge it to 100% and keep it that way.
They get charged on and off the bike in the cave. (so not warm, not cold)

All is good.

There is a lot of scare mongering around bike batteries as there is in the car world with electric cars. They're pretty robust things and can be treated pretty poorly and still perform to a good standard. Take it all with a pinch of salt from so called experts, unless they have science to back it up, I'll keep, keeping on.

100% agree.

In my personal experience (which is obviously far to be science) all devices I had/have with lithium batteries are going to full cycles (from 100% to 5/10% charge and back). I observed an excellent degradation over time, meaning that batteries are able to keep the charge with very similar behaviours after years.

Batteries that did not follow the pattern above are degrading much much quicker.

Again, this is only my personal experience in several years but as it worked well I apply it to every battery I own.

I have 7 and more years old batteries still working almost at their max capacity.

 

[#lazy]

Absolutely nothing and it’s lost about 2% in 3 half years

 

[IndigoUnicorn]

Absolutely nothing and it’s lost about 2% in 3 half years

THIS.

I just had my Bosch motors and batteries checked at my LBS. Over 2 years on all my batteries and zero degradation.

I’ve left my batteries fully charged out in my not climate-controlled shop.

I’ve pulled the battery right off the bike and slapped it onto the charger.

I’ve plugged the batteries in even when they showed a full charge.

The one thing I’ve NOT done is use them until they shut off.

That’s it. I suspect that the key to keeping QUALITY batteries in top shape is to simply not completely discharge them—which is the same as you should do for your auto’s battery.

 

[Stihldog]

Sometimes my battery charges to 97% and other times to 100%. It doesn’t seem to matter whether there’s 5% remaining or 92% remaining. I can’t figure out why?

I haven’t received any written precautions, warnings or recalls about my batteries from Trek (500wh and 625wh). My bikes live in the garage where the temperature is moderately high or moderately low. (5c-27c) but I ride in all temperatures (freezing to very hot). If my eMTB(s) is sitting around for a while (3 months) then I’ll discharge to 50%, but that’s only the wife’s bike.

My Rail (625wh) is usually charged overnight and every day regardless of charge remaining. I haven’t noticed any degradation in battery energy in the past 4 years. (2020 models).

I could be the poster-boy for battery abuse.

 

[Rando_12345]

I very much mistreated my first battery from shimano: frequently pedalled the bike home with 0% charge, charged right back up to 100%, often recharge the battery even if it had 90% charge in it, rode all year long in ~0 degree to 35 degree weather (charging was always in a temperate setting) and must have done several hundred cycles (I estimate about 15,000km ridden).

The range definitely did go down, probably by around 10% if not a touch more after 5 years, but honestly that is what I would expect. My phones have all degraded more, I have friends with early electric cars that have seen much worse degradation over long periods. The ebike manufacturers clearly have decent BMS and what our displays call "0%" is far from a full discharge that would damage the battery.

So while I imagine that good battery protocols will help, bear in mind that not observing the rules listed in the first post will most likely result in perfectly usable batteries over the lifetime of the bike.

 

[Suteki]

DoD (depth of discharge) and storage definitely does kill batteries over time. Over discharging or leaving batteries over discharged or full charged will definitely effect the batteries total capacity and discharge capability over time. If you've ever been into remote control aircraft of any kind (especially if you have been into racing FPV drones) you can see it happen real quick because of how much abuse those batteries go through.

The lithium ion batteries in ebikes isn't as bad, but if you want to keep the battery in its best condition over the longest period of time, not leaving it sitting fully charged or over discharged will definitely help it to live longer. I would typically only charge my bike the night before I'm going out, and if I don't end up using it, I try and get a ride in to discharge it to around 50-70% in the next few days.

Quite why manufacturers don't provide chargers with a storage charge functionality is beyond me.

 

[Mikerb]

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.

 

[rideronthestorm]

There is a lot of scare mongering around bike batteries as there is in the car world with electric cars. They're pretty robust things and can be treated pretty poorly and still perform to a good standard. Take it all with a pinch of salt from so called experts, unless they have science to back it up, I'll keep, keeping on.

I'm no expert in electrical battery design and just compiled guidelines and advice gathered over time from bike manufacturers and dealers. I'm sure there must be valid science and some truth behind this or battery manufacturers wouldn't bring this up and repeat the same message to e-bike users. Here is what bosch is saying:

 

[Stihldog]

I misread the second line;

“Storage at over 30°C ambient temperature”

Apparently this is a ‘Don’t’

Sudden expansion and contraction due to changes in temperature can’t be good on electrical connections. Especially small internal connections. A tungsten light bulb would probably last a very very long time if it was never turned off. How many connections in an eMTB battery?

 

[rideronthestorm]

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.

Good point. A full charge only if needed for a longer or more demanding ride Definitely one to add to this list.

 

[Alexbn921]

I tested the voltages that the stock Specialized BMS would allow and it's 4.2v per cell or 100% max charge. It's zero is also 0%.

The BMS does not save you and these batteries are not managed in any meaningful way. They are balanced charged and at least that is good.

The cells used, should last 10 years at a 100 cycles per year to 80% capacity.

The stock battery health app report is USELESS. It's just like the temperature gauge in your car. Look its right where it needs to be, but no real numbers.

Most people abuse there batteries and change bikes every 2 years so it doesn't matter. I love all the options of clueless users that have never researched or managed batteries that "it's okay to just keep it on the charger at 100%". Bullshit and you don't know what your talking about.

 

[rideronthestorm]

Thanks everyone so far for sharing your experiences and best practices for using your batteries.

Many different schools of thought and questions apparently . Are such "rules" needed or completely useless?

As a battery is a rather expensive piece of equipment on our bikes, does it really need special care to help maximize its lifetime or performance? How long can we expect e-bike batteries to last before replacement, with good care and without any?

For what it's worth I have updated my initial list of Do's and Don'ts with some of your feedback Keep it comin'

 

[Ark]

Most people abuse there batteries and change bikes every 2 years so it doesn't matter. I love all the options of clueless users that have never researched or managed batteries that "it's okay to just keep it on the charger at 100%". Bullshit and you don't know what your talking about.

Same people that constantly top up their mobile phones to 100%
Do people notice their ebike charger is only warm until the battery is about 70% and then the charger gets hotter and hotter until the battery reaches 100%?

The battery will be doing the same.


Fast discharging will do the same , so running turbo mode all the time probably degrades the cells as well.
Sometimes you see people selling bikes that are advertised as "barely used" only a few hundred miles on the clock.
and their photos will show the battery at 100% lol.... you know damn well that battery is just sitting at 100% for months at a time....

 

[unclezz]

Same people that constantly top up their mobile phones to 100%

This is what I am doing since day 1 with all my phones.
Result? Batteries are rock solid after years and years of usage. Better than the batteries of my wife's phones that after two years last half the time of mine

P.S.: Obviously my wife does not do (almost) full discahrge and then full charge)

 

[rideronthestorm]

I came across a YT video with many tips on battery care. Thought it touched on some key areas being discussed here:

 

[Bob88]

Same as many people above, 3 year old bosch 625 powertube. Always left at 100%, mostly ridden on turbo/emtb, rarely ridden to flat, rarely ridden in serious cold. Ridden in high heat when available. Always kept indoors. Zero noticeable reduction in range from a full charge.

 

[rideronthestorm]

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.

On the recharging topic, I saw that Bosch offers different charger types, a 2 Amp version (slow charge), a 4 Amp version (standard) and a 6 Amp version (fast charge).

Besides recharging time, are there any reasons to use one or the other? Is using a 2A charger better for the battery (maybe less heat generated) Conversely, should 6A chargers be avoided?

 

[Mikerb]

On the recharging topic, I saw that Bosch offers different charger types, a 2 Amp version (slow charge), a 4 Amp version (standard) and a 6 Amp version (fast charge).

Besides recharging time, are there any reasons to use one or the other? Is using a 2A charger better for the battery (maybe less heat generated) Conversely, should 6A chargers be avoided?

I suspect the main reason for introducing the faster chargers was to keep charging times reasonable with the introduction of 625 replacing 500w/h and now of course 750w/h. I have seen no reports a bout ideal charge rates but on the basis a larger battery is distributing the charge a cross a greater number of cells maybe the higher rate chargers are ok on the larger batteries.

 

[Mikerb]

Same as many people above, 3 year old bosch 625 powertube. Always left at 100%, mostly ridden on turbo/emtb, rarely ridden to flat, rarely ridden in serious cold. Ridden in high heat when available. Always kept indoors. Zero noticeable reduction in range from a full charge.

............that said it is normal for lithium batteries to maintain their output but then die suddenly.........unlike previous battery technologies which typically lost power progressively so Im not sure how the health of a lithium battery can be measured.

 

[Alexbn921]

A 700 battery is 20 amp hours and can safety charge at 1c or 20amp with very little to no damage.

You test batteries by measuring there internal resistance. At full charge you apply a load and watch the voltage sag. It's an effect way of monitoring lipo health. The bms should be able to do this and is probably how it reports health.

You can also do a full cycle and measure actual capacity. Higher draw = lower capacity.

Both are important. Ebike batteries have very low draw(max 20amps or 1 C) and even lower charge rates. My rc car pulls 25C out of 5ah. Or 125 amps

Edit. Chargers should be 1C or 15-20amps depending on size.

 

[Kingerz]

You'd be surprised how much batteries change over time. If you have a Windows laptop, you can see every detail of every charge by doing the command at the end of this page

 

[Growmac]

On the recharging topic, I saw that Bosch offers different charger types, a 2 Amp version (slow charge), a 4 Amp version (standard) and a 6 Amp version (fast charge).

Besides recharging time, are there any reasons to use one or the other? Is using a 2A charger better for the battery (maybe less heat generated) Conversely, should 6A chargers be avoided?

I have a 2A charger available as it came with our Cube town e-bike. I must admit I've started using it as an alternative to the 4A quite a lot of the time for my Rail's 625 battery on the unscientific basis that slow charging is likely to cause less degradation. I also always leave the battery at about 50-60% until the day of a ride, and I'll bring the battery inside to charge when it's really cold.

 

[rideronthestorm]

Quite why manufacturers don't provide chargers with a storage charge functionality is beyond me

Yep, this is something I've been asking myself each time I recharge my drained battery when I know I won't be using the bike for some time. Sort of a short-term storage scenario.

In that case, what do you do to make sure you don't charge your battery over 50 or 60%? I've tried to roughly calculate how long I need to recharge, but never get it right

 

[rideronthestorm]

Here is the charging table I've been using for my bosch Powertube battery. Has helped me estimate the recharging time.

 

[Planemo]

Yep, this is something I've been asking myself each time I recharge my drained battery when I know I won't be using the bike for some time. Sort of a short-term storage scenario.

In that case, what do you do to make sure you don't charge your battery over 50 or 60%? I've tried to roughly calculate how long I need to recharge, but never get it right

TBH it's perfectly fine to store anywhere between 20 and 70% so thats a pretty big window and avoids having to think too much about getting a pack to 'storage charge'.

If it's really down to less than 20% just stick it on a charger for an hour and you'll be golden. Don't overthink it too much, the only real problem is storing at 100%. Li-Ions really don't like it, despite the fact I know many riders are quite happy do so and claim all is good . Li-Ion battery tech is well understood and it's the one clear thing that test papers agree on. Degradation from prolonged periods at 100% is also something I have personally experienced and quantitively measured several times with both Li-Ion and Li-Po so it's something I will never do. Others can do what they like

Discharging our ebike batteries to 0% isn't a problem. Even 0% will still be above the cell minimum voltage.

Always charge to 100% if not for storage, cell balancing only occurs between around 95 and 100% charge (usually between the 4v to 4.2v stage). Unbalanced cells are a big reason for pack failures and somewhat understandable when the average joe thinks going to 100% is stressing the battery, which is kinda true but still far less damaging than unbalanced cells. It's also brought about from the cellphone advice of not going to 100% which again is true but crucially cellphones don't need balancing.

 

[rideronthestorm]

Always charge to 100% if not for storage, cell balancing only occurs between around 95 and 100% charge (usually between the 4v to 4.2v stage).

The technical side of Li-Ion batteries (cell balancing, operating temps, electrical and physical properties, etc) is very interesting and certainly helps better understand how batteries should be treated to get the most out of them.

 

[rideronthestorm]

The cells used, should last 10 years at a 100 cycles per year to 80% capacity.

I've been trying to figure out how long would a battery typically last if well taken care of with no abuse. Are we looking at 5, 10, 15 years? Most battery manufacturers claim 500-700 cycles without degradations. How would this translate into years of service at peak performance?

And on a related note, would you recommend getting a second battery and alternate them, which would theoretically give you 1,000-1400 cycles?

 

[#lazy]

For what it's worth I have updated my initial list of Do's and Don'ts with some of your feedback Keep it comin'

That’s cheating