Shimano BT-E8035 Integrated Battery Issue: very fast degrading and loss of range

[rafaellop]

I've bought a brand new BT-E8010 battery due to the degradation of my previous one, but it seems the new one is going to be the World's fastest degrading accu ever. Here are the battery info from STUnlocker read yesterday just after my ride:

It dropped 8% of health just after 2 cycles! During these two charging cycles I did 88 km with 3187 m elevation up and 90% of this was ECO, 10% Trial and zero boost.

I use the EC-E6000 charger.

At what values do you think I could return it under warranty?

 

[nosenada]

I've bought a brand new BT-E8010 battery due to the degradation of my previous one, but it seems the new one is going to be the World's fastest degrading accu ever. Here are the battery info from STUnlocker read yesterday just after my ride:

View attachment 60644

It dropped 8% of health just after 2 cycles! During these two charging cycles I did 88 km with 3187 m elevation up and 90% of this was ECO, 10% Trial and zero boost.

I use the EC-E6000 charger.

At what values do you think I could return it under warranty?

Shimano is unlikely to warranty the battery at 92% although I would try. If they do agree to warranty it I would use it for as long as possible as the warranty replacement may have the same problem.

I had a warranty replacement bt-e8035 go from 100% to 91% after 4 cycles and 20 days, Shimano refused to warranty it saying that they only replaced the original battery the first time at 20 cycles and 87% health as a courtesy.

I tried again to warranty 4 months later when it declined to 87% health at 20 cycles (same as the first one) and Shimano again refused to warranty it saying it needed to be at 60% health.

The battery is now only 13 months old at 78% health and 76 cycles.

 

[rafaellop]

Thanks @nosenada for sharing your experience. I'll go for a ride today and try to deplete the battery in the trial and boost mode and observe the health status change. This is inconceivable to have 8% less range just after two cycles.

 

[jerry]

I've bought a brand new BT-E8010 battery due to the degradation of my previous one, but it seems the new one is going to be the World's fastest degrading accu ever. Here are the battery info from STUnlocker read yesterday just after my ride:

I understand a Li-ion reaches its max performance only after a couple of cycles... could it be that it hasn't reached it max capacity yet?
I'm pretty aware of storage charge values, but have conflicting information on what to do to "break in" a powerpack from new. One says never to deplete, and do a couple of regular cycles; the other (a BMS-specialist) says to completely deplete it 2 times, and only the start using it as normal.

 

[rafaellop]

The only tip regarding the first time use in the Shimano manual is "The battery cannot be used at the time of purchase. Before riding, be sure to fully charge the battery". Nothing else regarding any special treatment like the two times depleting (mambo-jumbo?). Besides I have no chance to store it properly before it deteriorated the 8% of health. My frustration is high. I'm charging it for the 3 cycle at the moment. Very curious what the STUnlocker will show this time.

 

[electricbogaloo]

Are you storing it at 4%? Keep in mind that discharging it to and storing it at this level will let the cells age faster.

 

[rafaellop]

@electricbogaloo No I don't store it that way. 60-80% for storing always. Full charge only before a ride.

 

[lightning]

There's a lot of conflicting information on this thread.
Can l ask if people have noticed that when their battery has "degraded" by (say) 10% according to the Stunlocker app, if you actually are getting 10% less range?
My battery was showing 90% after 10 charge cycles.
However l've not noticed a drop off in actual range. One ride that l do, a 30 mile
road loop with 2,000 feet of climbing, leaves the battery at around 2% when l get home. lt usually flashes the red "zero range" warning on the last hill up to my house and on one occasion ran out before the top.
l did the same ride last week with the battery health now showing 90% and made it home with 2% showing on the Stunlocker app.

By rights l should have been pushing the bike the last couple of miles, if the actual battery capacity has dropped by 10%

 

[Milan]

Sorry for the late response but I have been snowed under with lots of work and biking and decided to test before posting anything. Guika, no firmware update found, still the same one 1.0.0.0. Currently, I have got 6 cycles with the new battery and 100% capacity. I am experiencing E010 per ride and my guess is it is the wiring or at least this is what Shimano diagnostics says. I will have to warranty this too. I wonder if the capacity goes down to 90% when the cycle count goes up to 9. I think I should post a pic of the battery and will keep you posted with the mileage.

 

[Milan]

Are you storing it at 4%? Keep in mind that discharging it to and storing it at this level will let the cells age faster.

I am sorry but you still do not understand that you can do anything you want and this particular type of battery degrades very very very fast. Read this whole thread and statistics and forget about proper storing and best practice charging. I know what you mean but this does not apply to this model of battery.

 

[Milan]

There's a lot of conflicting information on this thread.
Can l ask if people have noticed that when their battery has "degraded" by (say) 10% according to the Stunlocker app, if you actually are getting 10% less range?
My battery was showing 90% after 10 charge cycles.
However l've not noticed a drop off in actual range. One ride that l do, a 30 mile
road loop with 2,000 feet of climbing, leaves the battery at around 2% when l get home. lt usually flashes the red "zero range" warning on the last hill up to my house and on one occasion ran out before the top.
l did the same ride last week with the battery health now showing 90% and made it home with 2% showing on the Stunlocker app.

By rights l should have been pushing the bike the last couple of miles, if the actual battery capacity has dropped by 10%

You will notice this when your capacity goes down below 80%. This is when you will have to get off your bike and start to walk your final miles the way you use it. I do not find any conflicting info in this thread. Some guys here are fine because they have got a different model of the battery and contribute, some guys do not bike as much as I do (60 to 95 kms per day) and contribute with low kms since it will take them 3 yrs to realize the battery is a crap. Use the battery down to 76% and sure you will see your miles getting shorter. Or, what I suggest, warranty below 80% and sell your bike fast with the best new battery!

 

[eMullet]

362km, 26h, about 85% in eco mode. 3 cycles , health 100%.

I never charge my battery to 100%. I usually charge to 60-80%.

 

[lightning]

The drop to 90% usually occurs after 10 full charge cycles.

 

[electricbogaloo]

I am sorry but you still do not understand that you can do anything you want and this particular type of battery degrades very very very fast. Read this whole thread and statistics and forget about proper storing and best practice charging. I know what you mean but this does not apply to this model of battery.

Every battery ages the fastest if you leave it sitting around discharged.

 

[Milan]

Every battery ages the fastest if you leave it sitting around discharged.

Sure, no doubt about it, but those who have this battery and are contributing here, know pretty well about this

 

[Milan]

Sure, no doubt about it, but those who have this battery and are contributing here, know pretty well about this

@electricbogaloo Have you got this particular battery please? Let us please know, if so, are you the one and happy user who charges it 80%, stores it room temperature, never goes discharging it below 20% and your capacity per 13 cycles is 99%?

 

[lightning]

My battery has been OK

It did drop to 90% after 10 charge cycles, but it hasn't dropped any more since then, and the actual range seems about the same as when the bike was new.

l try to fully cycle the battery fairly often, although l am not sure if that's good or bad for the battery.
That is, run it until it shuts off before charging it.

 

[Milan]

My battery has been OK

It did drop to 90% after 10 charge cycles, but it hasn't dropped any more since then, and the actual range seems about the same as when the bike was new.

l try to fully cycle the battery fairly often, although l am not sure if that's good or bad for the battery.
That is, run it until it shuts off before charging it.

Thanks a lot, and all I can say, you are doomed. While you cannot see any difference btw 100% and 90% capacity, you will see this when you get down below 84%. I still do not understand why people think that the capacity of a battery represented in percentage is 'an illusion'? Hey guys, read this whole thread and you will soon know that if you are an owner of this battery, your days and miles/kms have started to get shorter, way earlier before you have paid for your bike.

 

[lightning]

Well, all l can say is that mine has not had these issues.

Maybe fully discharging (and then immediately recharge) the battery often is a good thing.

For a new member on the forum you seem to have a real downer on Shimano batteries.

You don't work for Bosch, do you ?

 

[Milan]

Well, all l can say is that mine has not had these issues.

Maybe fully discharging (and then immediately recharge) the battery often is a good thing.

For a new member on the forum you seem to have a real downer on Shimano batteries.

You don't work for Bosch, do you ?

I have no idea how they treat the newcomers here. I do not care, this forum has got a lots of experts who will explain how you should treat your battery and they do not undrstand that this particular battery has got a "scheme/pattern/trending" and it is present all around the globe. I am pretty mad at Shimano and people who pretend to be their reps. I have been with this particular battery since November 2020. I have got another bike with a Shimano "brick battery" and that is consistent and does what it should. It looses its capacity linearly, gradually, as you would expect. A Shimano battery for a Ghost Slamer bike from 2019. From what you write, it seems that you have not familiarized yourself with how your battery "performs". Your battery will be the downside of your bike and you are to find out soon unless you have an alternation, something differenent we all strive for. Let us know if you are different!!! I have ridden some Bosches and have been tempted No, I am not Bosch. I am really mad that I have paid this cash and am listenting to this kind of crap, both in the forum and retailers and Shimano reps. This thing is so clear. The battery is a bad design and Shimano should call all users for a replacement. It is pretty tedious to convice the people here in this forum that their battery is a crap. I have got a thesis and I have stated it in the very begining. And will not give away. I had Garry here for some days who showed up to tell me to inform me that my cause is lost. Since people do not read the thread, they contribute without actually realizing this thread is battery specific. This thread is not about best practice, best storing, etc..d all you can do to do you battery good.

 

[lightning]

The problem you have is, people have bought the bike with this battery and there's nothing they can do about it.
So people don't really want to be told that the battery is crap.
After all, now that l know that the Shimano battery in my Kona Ebike is "crap", what am l going to do about it? Carry on using the bike, it's all l can do, l can't send the battery back, as it will just be returned as "within specification"

The best thing you can do is to advise people on how they can make their battery last longer.

 

[Milan]

The problem you have is, people have bought the bike with this battery and there's nothing they can do about it.
So people don't really want to be told that the battery is crap.
After all, now that l know that the Shimano battery in my Kona Ebike is "crap", what am l going to do about it? Carry on using the bike, it's all l can do, l can't send the battery back, as it will just be returned as "within specification"

The best thing you can do is to advise people on how they can make their battery last longer.

Hi, and sorry for not to beeing to be a reasonable guy. My first words should be: Welcome to the largest community of users who have the same problem with the battery and I am very sorry that your retailer has chosen the battery you are the owner of. However, sarcastic this is, you are now part of the group who think they deserve a better battery. A battery you will charge in line with the best practices that most of the battery experts post here. They do not own this battery but know real well how you should treat it better. They sometimes call me a “new member” who knows nothing about it. Their suggestions are mostly relativizing the issues. The issue is simple: this type of battery is a crap and you can do as much as you can but you will not remedy anything. Put it under your pillow at night, take it out for a cup of coffee, provide it a nice lovely dinner in a fancy restaurant...This battery follows a pattern, a pattern you do not like…..It degrades very very very fast!

 

[lightning]

Maybe when the battery reaches the end of its life, rather than buying another one, it could be rebuilt with new cells that are better?
There are companies that repair ebike batteries and l am sure that more will appear as ebikes become more popular.

 

[Milan]

Dear Battery ..., do not post here your suggestions about how you keep the battery charged to 80% and storing it for a week or so, then prior to your ride charging it full up to 100% and draining it down to 20%, it does not help in this case.

 

[Milan]

Maybe when the battery reaches the end of its life, rather than buying another one, it could be rebuilt with new cells that are better?
There are companies that repair ebike batteries and l am sure that more will appear as ebikes become more popular.

I guess these fautly batteries can be easily replaced by companies who provide different or the same cells but the bms and and software remains the same, it will degrade the same way unless somebody changes the pattern. We need to find out who to give a ring ))))))))))))))))))))))))))

 

[Moderator]

I do not care, this forum has got a lots of trolls who will explain

Dear Battery Trolls

Dear @Milan , please refrain from referring to forum members who don't agree with you as "TROLLS".

Your approach and ranting (The second example quoted for instance, where you give a troll speech for no reason at all) only give the impression that this is a conspiracy theory and removes and chance of gathering any useful data if this really is a problem. You also keep pushing away any people who could be involved in discussions to develop any techniques to circumvent the issue for people who may have it or any discussions as to if this is a software fault or a hardware fault.

 

[Milan]

Dear @Milan , please refrain from referring to forum members who don't agree with you as "TROLLS".

Your approach and ranting (The second example quoted for instance, where you give a troll speech for no reason at all) only give the impression that this is a conspiracy theory and removes and chance of gathering any useful data if this really is a problem. You also keep pushing away any people who could be involved in discussions to develop any techniques to circumvent the issue for people who may have it or any discussions as to if this is a software fault or a hardware fault.

OK, will edit the post and leave the word out...

 

[jimbob]

I guess these fautly batteries can be easily replaced by companies who provide different or the same cells but the bms and and software remains the same, it will degrade the same way unless somebody changes the pattern. We need to find out who to give a ring ))))))))))))))))))))))))))

The BMS / firmware is unlikely to degrade the cells. It could well indicate the incorrect battery health though, but that is not in relation to the actual battery health.

I have still not seen any evidence to say that the batteries degrade at a significant rate. That doesn't mean they don't, but I have seen nothing to say they do.

As mentioned before, I'm gathering my own data to try and determine one way or the other, but would like to gather more before posting to remove some of the ambiguity which exists with my current data set.

Just my 2p.

 

[lightning]

l've not found any other serious criticism of the Shimano battery online.

lf you look, you can find some problems reported with pretty much any ebike motor or battery.

Mine's been fine and l use it almost every day (E8000 motor)

 

[Pivot]

We have to recognise that we are paying the price for being early adopters, while the industry is going through major transition.

Electric vehicles (EV) in general are relatively new market segment and actually we — e-bike-riders — are the beneficiaries of advances in batteries and BMS.

Also, e-bike batteries will be commoditised, as they are easily replaceable. Unlike EV/car batteries that one has to strip/replace large chunk of a car.

So, if you want a mature product with six-sigma quality, sit-down and wait, or alternatively join a startup that is doing battery / BMS development.

Accusing early adopters who enjoy the new (somewhat immature) technology of being trolls is laughable.