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My Shimano e8000 battery seems to be becoming less capable of holding a charge. I charged it up on Friday night to go out on Saturday, but couldn't make it until today. In the intervening six days charge is down to about three quarters even though it was kept in a warm room. Shimano say you should get 1000 charges before 'significant power loss' , whatever that means.So have I just been unlucky or is this the best you can expect? It's 4 years old but has only been charged about 150 times.
It’s all a bit subjective IMO. Have you kept the battery fully charged all the time when it’s not in use as this may shorten its lifespan. Have you let it discharge to 10/20% periodically and then fully recharge?
You could try riding it until it’s at 10% or so and then fully recharge to “recalibrate” it.
I was told to keep it around two thirds charged when not in regular use and to never run it completely flat. I probably don't let it get to 10% very often so I'll try that next before I start thinking about a new battery
I've got a 6 year old e8000 battery. Apps says 80% health, but in cold weather I'd says it's more like 50-60% range. My lesser used but almost as old battery is a bit better, but still not like new, so I'd say they age badly. Always stored cool and not fully charged.
No personal experience with e-bikes, but do know a good bit about li-ion batteries.
I was told to keep it around two thirds charged when not in regular use and to never run it completely flat
That’s correct. Good advice that I’m glad you’ve followed.
less capable of holding a charge
the problem you’re describing is a potential case of self-discharge. It shouldn’t really be happening.
Temperature has a huge effect on li-ion battery performance so let’s dig into that. You say it was stored warm. Ironically self discharge is minimised when stored cold, but room temperature still shouldn’t be as problematic as you’ve had. Any chance you charged it cold? If you did it would have a limited ability to take charge when cold. Once warmed to room temp this would show as a lower state of charge.
Another possibility is that the 75% state of charge after you left it for 6 days is actually a lie, the BMS is at best estimating how much charge is in there. Go ride it and see how you fare. Using it and charging it is the best way to get the individual cells to balance and give the Battery Management Sustem the best chance to estimate stored charge (aka “calibration”, which is a bit of misnomer but does get the point across nicely)
Sorry to hop onto the thread, as I have nothing constructive to add. Are you guys saying a battery shouldn't be charged or kept in the cold? I'm considering an ebike, but living in the north of Scotland, and only having a cold shed to store and charge it in, this could be a concern.
Ours lives in garage, showing as 95% after 4 years. Charged maybe 15-20 times and used 4+5 times a year.
Had my Levo for over 4 years now
Fully charged after each ride (tend to use most if not all the battery on each ride) once home i fully recharge and then its left for a week or sometimes longer till the next ride, i repeat this process, been doing it this way for 4 years and according to the app the battery still has 99% of its power and ive not noticed any difference when riding
Two years and 6000 miles on my bosch battery. No discernible difference in capacity I have noticed but cold weather definitely lowers range a bit. Mixture of charging from empty to full to somewhere in the middle. Bike gets used daily so I don't overthink it.
5 1/2 year old battery on my Kenevo showing 86%. Been run flat, charged up full, left in a cold shed over winters. Not sure how many charges, but into the hundreds
I’m considering an ebike, but living in the north of Scotland, and only having a cold shed to store and charge it in, this could be a concern.
You’ll not be wanting to charge it at near zero temperatures. Either charge it in the house just before you ride… or get an ebike where you can remove the battery to charge that in the house. Or… get a small oil filled radiator in the shed for use when charging.
My bosch ebike manual states that the old ideas of how to charge the batteries are outdated given modern battery management and to not worry about this at all and to just keep it topped up.
I've had my Levo for around 3 yrs now and it lives in my unheated garage. Like Escrs there ^^ I top up the battery immediately after every ride. I rarely use more than 50% of the battery on a ride as I'm almost always in Eco mode and have the assist dialled right down. I think I've run it down to the point where the battery cut out once in the time I've been riding it. The horror of riding that bloody tank the last 8km home with tired legs was what prompted me to look at and adjust the level of assists to give me about an extra 20% range! My battery is still showing 100% health and the only time I see any sort of drop in range is when it's properly cold outside.
The only ebike I ride is my GSD so the usage differs from MTBs, but it I don’t notice much difference in the battery performance in over 11,000 miles.
We had two Kenevos for just shy of four years.
Both of them got used and re charged straight away at least once a week.
Both of them were still showing 100% on battery health.
Interesting....
My Shimano battery has been in storage for ~18 months. Had been kept warmish (certainly not below 0°C) in my mates house since then.
Will be interesting to see how it has faired in that time.
My Shimano battery aged quite quickly. There's some threads on emtb forums from people who noticed similiar. Shimano used to claim 80% capacity after 2 years but removed it from their literature and removed the battery condition check from their app.
I think they used 18650 3500mah cells which degrade more quickly than lower capacity ones.
Are you guys saying a battery shouldn’t be charged or kept in the cold?
Storing in the cold is fine.
Charing in cold but above 5 is fine but will take longer and possibly result in less stored charge than in the warm, this can be quite significant. Using a cold battery will also result in less range than a warm one.
Charging at below zero is a big no no. Permenant cell damage possible, risk of fire.
Nearly 3 years and 2500 miles on my Bosch 625 battery and no discernible deterioration. 24 miles yesterday and it had just dropped to 3 bars out of 5.
My bosch ebike manual states that the old ideas of how to charge the batteries are outdated given modern battery management and to not worry about this at all and to just keep it topped up.
Yes and no.
The battery has a battery management unit as part of it, which will prevent you from over charging and over discharging the cells. It also manages charge monitoring the temp of the cells, to stop them overheating.
However, any Li-ion cell will last longer if it is less stressed ie not charged fully and not discharged fully.
You can't damage the cells, but if you always charge to the 100% mark (which isn't the actual real cell max voltage) and discharge to the 0% mark (which again isn't the actual cell min voltage), the lifespan you will see will be less than sticking between say 15% and 80% (which is what Tesla recommend their drivers do most of the time).
The problem when comparing different Li-ion systems, is unless you know what exact voltage 100% and 0% are, you can't really compare as you don't know how close to the limit of the chemistry you are getting.
If a manuf wants to prioritise product longevity they will dial in more margin, if they want to boast max Watt Hours in their spec, they may dial down the margin, which will decrease the battery life for people who regularly go between the two pre-set limits.
Here is a Dyson hoover Li-ion battery pack, quite a lot of gubbins for the battery management unit. The charger is just a dumb DC source and has no idea what it's charging...
[url= https://live.staticflickr.com/65535/52685697787_7973ca8e1e.jp g" target="_blank">https://live.staticflickr.com/65535/52685697787_7973ca8e1e.jp g"/> [/img][/url][url= https://flic.kr/p/2ogDYpM ]Dyson V8 battery pack internals[/url] by [url= https://www.flickr.com/photos/brf/ ]Ben Freeman[/url], on Flickr
It's actually pretty sophisticated, it's monitoring every cell as well as the pack, so will be able to stop one cell getting over stressed (as all the cells always have slightly different behaviour due to manuf tolerances).