Shimano Battery Life Poll

Cyclopath1000

Active member
Apr 26, 2019
280
113
Davis Ca
I'm sticking to the warning Stephane from commencal gave me a few years ago: don't ever upgrade the firmware if ya know what's good for ya!

As for battery health,I now own 3 8010.s because #1 neg terminal plug cracked on the battery and Shimano said too bad for you dude. So one is currently a paper weight until I either get a new plug or do the mod a poster recently put up on another post. That batt was starting to degrade a bit.

If ya want to get a decent life span out of a removable Shimano battery my advice is don't remove to charge because maybe that process of taking it out and remounting it is what kills the plug that Shimano won't offer a replacement part. Charge your bike with the battery in and never ever take it out. At this point Im thinking broken plug limits battery life way more than what batt health your app happens to show.
 

robbydobs

Member
Jan 31, 2021
38
26
Sussex, UK
St Unlocker just reads the info Shimano would have access too. The battery wear also matches the range displayed on the bike.

If you get Shimanos PC or Android app and drop it into a decompiler like Jet Beans or Java decompiler online / APK decompiler - Decompiler.com you can see the code Shimano use to pull this info out, which is what the developers of the 3rd party apps did to see what Shimano were doing.

Anyway, the latest firmware clearly alters the battery wear info on the system, because the wear/range used to be 80% and 49miles and now its 90% and 55 miles so I think they'll be no chance of any warranty, despite one battery being noticeable worse than the other.
 

Spiff

Active member
Feb 27, 2019
290
150
Earth
Anyway, the latest firmware clearly alters the battery wear info on the system, because the wear/range used to be 80% and 49miles and now its 90% and 55 miles so I think they'll be no chance of any warranty, despite one battery being noticeable worse than the other.

Ther battery wear/health calculation and storage is inside the battery, but as the battery firmware is not upgradable, Shimano could not change the calculation method, so it continues to be the same bad number as before. But looks like Shimano has found a creative way to change this bad number to a good one: When reading the Battery information by etube or a Third Party APP, the flow of battery information is:
** From Battery to Motor via the CAN BUS cable
** From Motor to Display via another CAN BUS Cable
** From Display to APP via Bluetooth

So battery wear/health number calculated and stored in the battery is 80%, same and before, but when it is transfered to the Motor, then the new Motor Firmware replaces this bad number with a better one 90%, probably using a "Translation Table" without any technical re-calculation, and this new "good" number is the one that will appear in the etube or STUNLOCKER APP.
 

lightning

Well-known member
Apr 5, 2021
714
407
UK
My battery "health" had dropped to 77% after about 60 charge cycles, but the reduction in range was not as much as that.

I was getting maybe 30 miles from a full charge, and after fitting a brand new battery it's not that much better, l am still lucky to see over 30 miles.

lt makes me wonder if the battery pack is really deteriorated by the amount showing on the Stunlocker app.

What's other people's experience of actual reduction in range?

With the new battery it dropped from 100% on the 10th charge to 90% on the 11th charge.

This is surely not possible for a battery pack to degrade 10% in one charge cycle. l've stopped monitoring it after that, l may look at it if the actual range starts to drop significantly.
 
Last edited:

Apr 18, 2020
112
30
germany
So now my battery from 2019 degraded to 93%. The mileage is actually a little more, maybe close to 4k km as I deactivated the motor on longer descents. I took this afte the first 5 rides of the season so idk when it jumped from 97% when I stored it in atumnd to 93% but its interesting that I didn't bother to drain the battery to 20-30% as I did in the last off-seasons. I think it sat aroung 55% or so from november till march. But I also hauled my sister again with the bike so this could also be the reason it degraded. Last time when it showed degradation it was when I hauled her.

Screenshot_20220501-184458.jpg
 

lightning

Well-known member
Apr 5, 2021
714
407
UK
Well you are doing better than me with that battery, because my new BT-8035 bought in December is down to 87% after 24 charge cycles
 

gtaadicto

Member
Jan 26, 2019
96
77
Leon,Spain
My year old BT-E8010 hit 40 cycles today,. Its health dropped from 85% to 82%. But I feel its range is way better than my 3 year old battery, also at 82% health at 190 cycles.
 

lightning

Well-known member
Apr 5, 2021
714
407
UK
lt's not good is it, this battery degradation. It's a good job mobile phone and tablet batteries don't do this

Any ideas on which is the better charger to use? Most bikes seem to be shipped with the "slow" charger but some have said the "fast" charger is better at maintaining battery health.

As these chargers are about 1/6th the price of a battery, it might be worth investing in one.
 

robbydobs

Member
Jan 31, 2021
38
26
Sussex, UK
Well, I've done a range test on my old battery vs a brand new battery. I think the older battery has lost at least 20% capacity after 14 months.

This is *not* just reporting problem with ST Unlocker or E-Tube. The range and capacity loss is real.

I rode the same trails (Steyning), same trail conditions (dry), same bike (Meta Power) and tyres (Maxxis DD), mostly used Boost unless it made sense to use Trail (due to lack of grip up the climbs)

Battery 1, BT E8010 purchased June 2021, gave 801m, 1,229kJ energy used according to strava.
Battery 2, BT E8010 purchased July 2022, gave 986m, 1,485kJ energy used according to strava.

So with the new battery compared to old:
23% increase in climbing
21% increase in energy used

I logged all this with a Garmin so it has captured the battery % used over the ride.

I'm going to try and warranty the old battery, though I don't hold out much hope given Shimano have altered the reported battery wear and removed the 80% guarantee from their website
 

Growmac

Well-known member
Subscriber
Dec 4, 2020
256
255
Wilts, UK
Well, I've done a range test on my old battery vs a brand new battery. I think the older battery has lost at least 20% capacity after 14 months.

This is *not* just reporting problem with ST Unlocker or E-Tube. The range and capacity loss is real.

I rode the same trails (Steyning), same trail conditions (dry), same bike (Meta Power) and tyres (Maxxis DD), mostly used Boost unless it made sense to use Trail (due to lack of grip up the climbs)

Battery 1, BT E8010 purchased June 2021, gave 801m, 1,229kJ energy used according to strava.
Battery 2, BT E8010 purchased July 2022, gave 986m, 1,485kJ energy used according to strava.

So with the new battery compared to old:
23% increase in climbing
21% increase in energy used

I logged all this with a Garmin so it has captured the battery % used over the ride.

I'm going to try and warranty the old battery, though I don't hold out much hope given Shimano have altered the reported battery wear and removed the 80% guarantee from their website

I got nowhere with Madison on similar, actually slightly worse, issue. Ended up going down the fit for purpose route with the supplying dealer as they were insistent that it was not a warranty issue. I felt bad, but their service was truly atrocious so I didn't lose any sleep.

I filed a Small Claims Court claim. It went to mediation and I'm not allowed to say how it went, but I'm very pleased I did.
 

jimbob

Active member
Aug 3, 2020
390
286
stevenage
I got nowhere with Madison on similar, actually slightly worse, issue. Ended up going down the fit for purpose route with the supplying dealer as they were insistent that it was not a warranty issue. I felt bad, but their service was truly atrocious so I didn't lose any sleep.

I filed a Small Claims Court claim. It went to mediation and I'm not allowed to say how it went, but I'm very pleased I did.
Was that a claim against the supplier if its possible to say?
 

lightning

Well-known member
Apr 5, 2021
714
407
UK
l made a claim on my Shimano battery earlier this year after it had dropped to 78% after 60 charge cycles.

This was on the app, not actual measured degradation as tested above.

I returned the battery to the supplying dealer and after a few questions (mainly how often the bike is used) a new battery was sent to me.

What l have found with these batteries is, when you are out on a ride and it's down to one "bar" on the display, if you hit "Turbo" the battery can shut down, and then you've a slow ride home.

This has happened to me twice.

I no longer use "Turbo" when l am down to one bar on the display!!

l have to say that, despite showing a 78% "health" on the app, the battery definitely hadn't lost 22% of range, it was more like 10%.
 
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