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

[RJUK]

I'd store my battery at 50% if it was easier - but having to manually work out when it might reach that point, then make sure you're around to unplug it, is a bit of a pain. Wouldn't it make sense if battery chargers came with a 2 position switch - 1) Charge to 50% and 2) Charge to 100%

That way you could charge it to the 50% after a ride, then just the switch to 100% the day before you're heading out again.

Is this overly complicated to do? Why hasn't anyone offered this?

It shouldn't be complicated. The cynic in me thinks that they probably don't offer this because they want your battery to wear out more quickly, so you'll buy a new bike...

I also think some companies downplay things so that they don't scare customers off of buying their products.

Car brands do this a lot - the battery can be as much as half the value of the car, but companies like Porsche know that they'd likely scare off their wealthy buyers if the buyer sensed any degree of "faff" at the purchasing stage, so they don't really communicate any battery care tips at all, despite the value of the battery in a Taycan.

I suspect many Taycan owners charge to 100% as a matter of course, without realising what that's doing to the battery.

Most car manufacturers do build in a software limit on the battery though, so the customer thinks the car is charged to 100% when in reality it's only charged to maybe 95% because the top 5% is locked off to protect battery longevity. This is what they mean when talking about EV battery sizes and their "usable capacity". The usable capacity is always lower because some of it is locked off to increase longevity of the battery.

It can help to think of it a bit like a balloon. A balloon is storing the most energy in it when it's pumped right up, but that's exerting a lot of pressure on the balloon. Letting 5% of the air out relieves that pressure slightly, letting 20% out relieves it even more.

This also works when thinking about leaving a balloon for an extended period - the air leaks slowly over time, kuch like a battery's charge will deplete over time.

 

[Binhill1]

Sorry, only just saw this. Personally I'd leave it at 26% and then charge as late as possible before you leave. Ideally you would have the battery finish charging, then unplug it, put it in the bike and ride it straight away. (Or maybe give it a few minutes to cool if it got warm from charging.)

I tend to try to charge mine only as much as I need. For example, I often do a quick Sunday morning ride that only uses around 30% of my Bosch 750 battery, so I charge it to around 50 - 60% so that it's around 20 - 30% when I'm done.

Through summer I've been leaving the battery in the bike and even 2 weeks later without use the battery hasn't even dropped 1%. So there seems little risk that the battery will deplete to 0% unless I were to leave it in the bike for months without use.

Mine has done well 5 years old 10,000 miles still seems OK.

 

[TimC7]

Personally I'd leave it at 26%

Why, when manufacturers say store at 60-80% ?

I tend to try to charge mine only as much as I need. For example, I often do a quick Sunday morning ride that only uses around 30% of my Bosch 750 battery, so I charge it to around 50 - 60% so that it's around 20 - 30% when I'm done.

Charging to 100% allows the cells to balance for optimum range and performance. Charging to less amplifies small differences between cells which may mean individual cells get a deep discharge which isn't good.

 

[RJUK]

Why, when manufacturers say store at 60-80% ?

Charging to 100% allows the cells to balance for optimum range and performance. Charging to less amplifies small differences between cells which may mean individual cells get a deep discharge which isn't good.

Because manufacturers are talking about long term storage. Their concern is that you leave your battery at 26% and don't ride the bike for 6 months and the battery drains to 0% and gets killed completely, as then they have to pay out on a warranty claim.

If you store it at a higher charge it will degrade the battery faster than if you store it at a lower charge, but it won't completely kill it, so for them it costs them nothing.

Cell balancing is a thing, yes, but not all that serious. For example I've never charged my Tesla to 100% in 5 years. Cell differences tend to be small. I don't think you could deep discharge just a few cells unless the battery was pretty messed up.

Either way, you could just charge to 100% occasionally if you were worried about this, right before riding, so that the battery doesn't spend too long at 100%. Certainly never store it at 100% unless you want the most degradation.

 

[TimC7]

Because manufacturers are talking about long term storage. Their concern is that you leave your battery at 26% and don't ride the bike for 6 months and the battery drains to 0% and gets killed completely, as then they have to pay out on a warranty claim.

If you store it at a higher charge it will degrade the battery faster than if you store it at a lower charge, but it won't completely kill it, so for them it costs them nothing.

Cell balancing is a thing, yes, but not all that serious. For example I've never charged my Tesla to 100% in 5 years. Cell differences tend to be small. I don't think you could deep discharge just a few cells unless the battery was pretty messed up.

Either way, you could just charge to 100% occasionally if you were worried about this, right before riding, so that the battery doesn't spend too long at 100%. Certainly never store it at 100% unless you want the most degradation.

I agree, and yet multiple folk charge theirs to 100% after every ride and never suffer degradation . .

 

[RJUK]

I agree, and yet multiple folk charge theirs to 100% after every ride and never suffer degradation . .

Or so they claim...! Even if you did everything perfectly with the battery you'd suffer some degradation even after as little as a year, so to claim no degradation after thousands of miles and many years is just being wilfully ignorant of the facts. As much as I'd love batteries to go on for many years and thousands of miles with zero degradation, it's just not the way current batteries are.

I guess some of it is just ignorance, some of it is people not realising that lithium batteries need to be handled differently to older types of battery and some people just don't care.

I think a lot of people are following old NiCad guidelines to fully charge and fully deplete the battery for best practice, so probably actually think they're doing the best for their battery, when in fact the opposite is now true.

It's not like I'm sharing some sort of contrarian theory though. This information is widely available and agreed upon. It's why electric car manufacturers build in unusable capacity and why the cars and their associated apps recommend not charging above 80 or 90% for daily usage.

Even Specialized give you the option to stop the charge at 80% to increase battery longevity and so do the latest iPhones.

 

[Tooks]

I see this thread is still rumbling on!

I think people should worry less, and ride more.

Most e-bike batteries and their BMS are very primitive compared to those in electric vehicles. When e-bike batteries are liquid cooled/heated, have top and bottom buffers, and use the highest quality cells like those found in electric cars and have a BMS that can balance at less than 100% SoC, maybe we can start comparing them.

18650 batteries like those used in most bike batteries will degrade with charge/discharge cycles. My oldest e-bike is a 2018 Focus Jam 2, with the small in-frame pack. It’s still going strong, I haven’t noticed any real world difference in range/support, but then not really surprising when any bike ride is so variable in my own versus the motors support.

All this angst doesn’t really change anything in the real world, your battery will wear out whatever you do simply via age/time, but you will likely have changed or disposed of the bike long before it matters, or you‘ll have had it replaced under warranty if it was a duffer.

 

[Binhill1]

I see this thread is still rumbling on!

I think people should worry less, and ride more.

Most e-bike batteries and their BMS are very primitive compared to those in electric vehicles. When e-bike batteries are liquid cooled/heated, have top and bottom buffers, and use the highest quality cells like those found in electric cars and have a BMS that can balance at less than 100% SoC, maybe we can start comparing them.

18650 batteries like those used in most bike batteries will degrade with charge/discharge cycles. My oldest e-bike is a 2018 Focus Jam 2, with the small in-frame pack. It’s still going strong, I haven’t noticed any real world difference in range/support, but then not really surprising when any bike ride is so variable in my own versus the motors support.

All this angst doesn’t really change anything in the real world, your battery will wear out whatever you do simply via age/time, but you will likely have changed or disposed of the bike long before it matters, or you‘ll have had it replaced under warranty if it was a duffer.

True the battery is one of the few original parts on my 2019 . Frame ,motor , wheels all changed to name a few parts. I think it's the thought that you may get stung about £900 to renew battery on a bike that's maybe only a couple of years old . Not everyone changes their bike every two years. Safe and happy charging everyone .

 

[RJUK]

I guess it's up to individuals and their own mechanical sympathy. If it makes no odds to you what charge you keep the battery at or when you charge it, then try to keep it at a lower SOC and charge it just before you use it. But if you're not worried about the extra degradation and it's more convenient to you to charge it after a ride, then do that.

Obviously, this thread is about how to look after your battery, which is why I've given the advice I have. I would expect those visiting the thread to be looking for information on helping their battery last longer. To me I like to look after my stuff, which I why I've researched it. The same principles can be applied to anything with a lithium battery, phone, laptop, bike, EV etc. so it can be useful to know.

 

[Tooks]

True the battery is one of the few original parts on my 2019 . Frame ,motor , wheels all changed to name a few parts. I think it's the thought that you may get stung about £900 to renew battery on a bike that's maybe only a couple of years old . Not everyone changes their bike every two years. Safe and happy charging everyone .

Agreed, we really should be further along the road with all round e-bike longevity and long term supportability by now.

Mind you, when you see what we spend on bikes these days in terms of wheelsets, drivetrain and suspension forks/shocks etc, £900 on a battery after even 4 or 5 years doesn’t seem like a massive ask. The problem comes when you find you can’t actually buy one at all.

Manufacturers should be forced to provide spares for 10 years or something.

 

[Tooks]

I guess it's up to individuals and their own mechanical sympathy. If it makes no odds to you what charge you keep the battery at or when you charge it, then try to keep it at a lower SOC and charge it just before you use it. But if you're not worried about the extra degradation and it's more convenient to you to charge it after a ride, then do that.

Obviously, this thread is about how to look after your battery, which is why I've given the advice I have. I would expect those visiting the thread to be looking for information on helping their battery last longer. To me I like to look after my stuff, which I why I've researched it. The same principles can be applied to anything with a lithium battery, phone, laptop, bike, EV etc. so it can be useful to know.

I don’t disagree with the principle of mechanical (or electrical!) sympathy, but when a perceived care regime appears to get in the way of the normal and enjoyable use of a product then probably something isn’t quite right.

I’m sure bike manufacturers have the data with regard to battery failure rates etc, it could be they design them to last the average life of a bike, and they cover any premature failures, probably more cost effective than making a longer life pack etc. Perhaps they don’t even do that much, and leave it all to Shimano, Bosch, Brose etc. I really wish they would keep them on the shelves so that your average joe can actually buy an out of warranty replacement battery if and when the time comes though.

 

[RJUK]

I don’t disagree with the principle of mechanical (or electrical!) sympathy, but when a perceived care regime appears to get in the way of the normal and enjoyable use of a product then probably something isn’t quite right.

I’m sure bike manufacturers have the data with regard to battery failure rates etc, it could be they design them to last the average life of a bike, and they cover any premature failures, probably more cost effective than making a longer life pack etc. Perhaps they don’t even do that much, and leave it all to Shimano, Bosch, Brose etc. I really wish they would keep them on the shelves so that your average joe can actually buy an out of warranty replacement battery if and when the time comes though.

Yeah, the waste isn't great, especially when they're trying to push people into ebikes as a greener way to commute.

For me, charging before a ride rather than immediately after one isn't reducing the enjoyment at all. It doesn't really make any difference to me and at least if I charge just before riding then I know the battery has a fresh charge in it.

One of the guys in my riding group carries a spare battery with him on a lot of rides and his bike isn't even that old. I think he always charged to 100% after a ride and now both of his 500wh batteries combined last around the same as my one 750wh battery.

Everyone will have their own take on how important battery care is to them, as with care of anything. I'm well aware I'm one of the more careful people with this sort of thing and it doesn't bother me to make the effort.

 

[Tooks]

One of the guys in my riding group carries a spare battery with him on a lot of rides and his bike isn't even that old. I think he always charged to 100% after a ride and now both of his 500wh batteries combined last around the same as my one 750wh battery.

Perhaps he uses more support than you?

With the way e-bikes just give support rather than powering the bike 100% of the time, it makes it very difficult to measure not only versus other people even on the same bike but also the degradation over time and use.

I’m not critical of the way you’re using your bike, your bike your choice at the end of the day, I just wouldn’t want anybody to think they have to do it.

I charge both my factory e-bikes to 100% after each ride, if I’ve used a large part of the capacity anyway, and then leave them like that until the next ride. Sometimes that’s a few weeks as I’m fortunate to have plenty of bikes of all sorts to ride, and the oldest one is 6 years old now and still shows the same range on startup as when it was new.

Maybe I’m just lucky, maybe some other people are unlucky, in any event motors seem to be the main point of failure with any e-bike sadly.

Where’s that thread?!