Don't charge your bike battery above 80% and don't ride below 20%. Maybe, maybe not.

E

EdC

Active Member
I recently purchased an e-bike and heard from many of Court's videos the title statement, so I wrote Bosch for clarification. This is what I wrote: " I recently bought a Bosh powered e-bike. YouTube blogger Court Rye of EBR recommends not exceeding 80% when charging an e-bike battery and when riding not going below 20% battery life if you want to get the maximum life out of your batter. Is this something I should do with my Bosch e-bike?" This is the reply I received: " What he says in his videos about 80% and 20% are technically correct in theory, but in practice, it does not really make a difference unless you store the battery for prolonged periods of time, in which case we recommend storing them at a charge state around 30%-50%. As long as you use the bike daily or weekly, this micro managing of your state of charge will be negligible factor that you can safely ignore, and use the battery the way that suits you." What do you, on EBR, think? ED
 
EdC said:
I recently purchased an e-bike and heard from many of Court's videos the title statement, so I wrote Bosch for clarification. This is what I wrote: " I recently bought a Bosh powered e-bike. YouTube blogger Court Rye of EBR recommends not exceeding 80% when charging an e-bike battery and when riding not going below 20% battery life if you want to get the maximum life out of your batter. Is this something I should do with my Bosch e-bike?" This is the reply I received: " What he says in his videos about 80% and 20% are technically correct in theory, but in practice, it does not really make a difference unless you store the battery for prolonged periods of time, in which case we recommend storing them at a charge state around 30%-50%. As long as you use the bike daily or weekly, this micro managing of your state of charge will be negligible factor that you can safely ignore, and use the battery the way that suits you." What do you, on EBR, think? ED
Click to expand...

Do you know who replied to you?

Bosch eBike USA folks are not battery experts and they might have joined the firm after their MBA or some other career experiences. They will tell you what has been passed on to them.

This has been discussed here: https://electricbikereview.com/foru...and-charging-of-bosch-e-bike-batteries.23868/

If you are an Electric car owner, you would instantly know the answer. Tesla forums have so many threads on this topic.
https://electricbikereview.com/foru...0-without-a-satiator.24763/page-8#post-194248

Most electric car owners do not charge their car to 100% but an eBike is different and if you are riding only ~2000 miles a year, you don't have to baby your battery.
 
As another person who would like to prolong battery service life as much as anyone else, but doesn't feel compelled to be anal about it either, I think one set of opinions which might be both consensus as being most important *and* easy to achieve is:
  1. Avoid discharging 100% if at all possible, in any circumstances.
  2. Avoid fully charging to 100% most critically if you won't use (discharge) it for a while, and even moreso if it's going to be kept where it might get hot.
  3. If you are not going to use for an extended period (aka store), 40% is a good level to leave it at.
Since I am a bike commuter I can naturally maximize #2 by aiming to always charge while at work -- I don't always go to 100%, but even when I do, it won't remain for long because I will be draining it within a few hours max. Just a thought if you have similar usage.

I guess I'm saying I agree more with Bosch. Court seems a little schizophrenic to me, he gets very hung up on this thing, making his readers maybe anxious when they don't be, while meanwhile his reviews are pretty uncritical, he seems easily find reasons to praise components as "high quality" even when (IMO) it's not always (so if something really is high quality, how can you trust it to be?)
 
I'd like to point out that your ebike controller is usually set to not take the battery much lower than 20%, If you forget your battery training and run out of power on the road someday, relax, you haven't put a dagger into your battery.

Personally, I quit obsessing over this. I charge to 100%.
 
harryS said:
I'd like to point out that your ebike controller is usually set to not take the battery much lower than 20%, If you forget your battery training and run out of power on the road someday, relax, you haven't put a dagger into your battery.

Personally, I quit obsessing over this. I charge to 100%.
Click to expand...
Yup, while I can charge at optional levels, I have batteries I've not bothered to fuss over and they are in their 5th season. Go figure.
 
I nearly always charge to 100 percent. With two caveats.

One caveat is that I typically charge every other or every third day. And I also time the charging so the bike isn't sitting fully charged for more than a few hours.

The other caveat is that if I'm not going to be riding for more than a day I always make sure the batteries are below 80%, preferably around 40%.

The bike is stored in a garage that isn't too hot in the summer and not too cold in the winter.

On journeys I say heck with it and charge to 100% every day.

My own calculations and guesstimates are that with this usage pattern my batteries might last five years or more. Which seems like plenty to me.
 
Last edited:
Mr. Coffee said:
I nearly always charge to 100 percent. With two caveats.

One caveat are that I typically charge every other or every third day. And I also time the charging so the bike isn't sitting fully charged for more than a few hours.

The other caveat is that if I'm not going to be riding for more than a day I always make sure the batteries are below 80%, preferably around 40%.

The bike is stored in a garage that isn't too hot in the summer and not too cold in the winter.

On journeys I say heck with it and charge to 100% every day.

My own calculations and guesstimates are that with this usage pattern my batteries might last five years or more. Which seems like plenty to me.
Click to expand...
I bought a Giant Twist with twin battery’s in 2009. I’m still using the original batteries after over 20,000. I’m only getting 40% of the range when new but that’s about 25 miles. Ed
 
I’ve read somwhere (?) that it is recommended to go to 100% sometimes to balance the battery cells? Can’t remember how often.
True or false?

! Edit
I should have watched the video that Ravi included in his post just 3 post up. The answer to my question is there:)
Thanks Ravi!
 
Last edited:
Like the OP, I contacted Pedego about these charging issues and was told pretty much the same thing. I was told the BMS in many batteries, including Pedego, won't allow discharge much below 20%. While long term storage below 80% is recommended, charging to 100% will not significantly shorten battery life.

I find it interesting that there are many posts here about bigger batteries and maximizing range. The 80 - 20 charging "rule" is in direct opposition to these principles. You can't have it both ways.

Even if it means replacing every 4 years instead of 5, I'm OK with using the full capacity of my battery.
 
Why would you need a 50 mile range if your butt is only good for 20? With a max "butt range" of 20 miles, a battery capacity that would go 25 is plenty. Bonus being it's going to be lighter and less expensive.
 
I bought my e-bike retrofit to use, not to baby. On a two year old BionX 556wh battery I have a range of about 35 miles if I ride it from 100% charged to mostly empty here in White Mts of NH. If I followed the 20/80% rule I'd reduce that range by 40% to 21 miles. I'd be turning around at 10 miles into each ride to return home to watch my charger! I would barely make it to the coffee shop and back! I'm going to trust the manufacturer's expertise as to what level the charger says "That's enough" and at what point the display and performance of the motor says "Stop, go home and plug me in now".
 
AHicks said:
Why would you need a 50 mile range if your butt is only good for 20? With a max "butt range" of 20 miles, a battery capacity that would go 25 is plenty. Bonus being it's going to be lighter and less expensive.
Click to expand...
I’m 75 year old and I did a 50 mile bike trip last weekend. Of course I’m not using the seat that came with the bike. Ed
 
It's pinching pennies. Just charge and ride.

Here are the numbers.

Let's say the battery's do 1000 cycles, and each cycle is worth 50 miles. That's 50000 bike miles. Ideal hypothetical.

But let's be conservative and only estimate 30 miles and 800 cycles. (Hills,wind, weight variation, high temps exposure low temp exposure, poor battery care in off season, battery degrades over time, whatever).
Pick a high price of $700 for a fairly small 11ah, 36 Volt battery.

Divide that by 24000 miles ridden of pure enjoyment and spent a wopping 2.9 cents per mile! Woe is me. I'm going broke! OMG Im Going back to my crappie regular No joy bike, or 55 cents per mile car where I get zero exercise. (In case you didn't detect it, that's heavy sarc)
 
You must log in or register to reply here.

Similar threads

S
Battery charging procedure
Replies
4
Views
949
6zfshdb
6zfshdb
G
Don’t Know Where To Start
Replies
3
Views
831
PCeBiker
PCeBiker
O
Using Aventon batteries on other e-bikes
Replies
6
Views
640
OldK
O
TimDean
Trek FX+2 charging issues & charger reset
Replies
11
Views
8K
fabiossigeno
F
A
As I have an e bike and love being out on it for some long rides, but then you remember about keeping an eye on your battery charge so you have enough
2
Replies
25
Views
3K
m@Robertson
m@Robertson
Back