Battery charge cycles

Bobajob

Esteemed Pedelecer
Nov 1, 2019
313
140
Cornwall
The Yamaha battery as a certain life span of I think 500-750 charges before degradation or failure.
My question is when charging the battery does it count as a recharge if charging from say70% as opposed to say 10%?

I seem to be charging my battery to full capacity just prior to the ride. Is this a good idea or try and recharge less?
 
  • Like
Reactions: Andy-Mat

sjpt

Esteemed Pedelecer
Jun 8, 2018
3,642
2,652
Winchester
Bosch certainly say that partial recharges have a proportionate partial effect, so topping up from 70% would count as 30% of a recharge. Best not to let them get too low; though the BMS should protect them from too much damage.
 

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
I thought the recent bosch ones claimed 1500 cycles, and yes, partials count as partial. The dealer seems able to read that info from the battery, as well as way much info about what modes you used, and how much (Presumably those are from the controller). Big brother is watching you.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
1,425
1,251
Surrey
My 2015 Yamaha 400Wh battery is now in its 6th year and working on the face of it just like it did when new. By that I mean the display shows me that I use exactly the same amount of my batteries capacity on my routes to work and back now that I did when the bike was new.

I am very impressed with it.

It is my ride to work and back bike and has spent its whole life having about 30% of its capacity used on my 12 mile cross country ride to work and about 40% of its capacity used on my faster 10 mile road ride home, where it is brought into the house and stored at about 60% charge until I next ride to work on it.

The battery has powered me over 12,450 miles so far.
 
Last edited:

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
Yes, that sure is impressive.. Obviously you are looking after it very well compared to Joe Average, although if my math is right, you are still under 1000 charge cycles?
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
561
77
The Yamaha battery as a certain life span of I think 500-750 charges before degradation or failure.
My question is when charging the battery does it count as a recharge if charging from say70% as opposed to say 10%?

I seem to be charging my battery to full capacity just prior to the ride. Is this a good idea or try and recharge less?
Its a good question, that gives several answers, depending upon who you ask.
I myself think the very best method is to have a bike where you can swap the battery out easily (not all can!), and to have a second battery available with your ride, so when the "in use" battery gets down to 10% or less, you swap them on the road.
If you have a high capacity battery already, the second one can be smaller and therefore far cheaper.
This way, you reduce the number of charges to the absolute minimum, which I think most would agree, is best for the battery.
It really boils down to bike security when at work, which may need to be taken into account as well, probably needing some sort of bag to carry the spare battery with, maybe some sort of rucksack possibly....
This way, I would imagine that a careful user gets 6+ years life from a battery, as each battery does (approximately), half the work!
Best wishes
Andy
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
1,425
1,251
Surrey
I have not kept count of the charge cycles. Maybe my type of commuting is quite kind to the battery. Stored indoors at around 60% charge. Charged back to full close to setting off for work and back to full at work and then ridden home.

Probably my maths is wrong but based on using 70% of a full charge ie 30% getting to work and 40% getting home to cover 22 miles, then I manage 31 miles each full to empty charge and if you divide 12,450 by 31 you only get 401.

I do occasionally use the bike for leisure rides, I did a few in lock down, but mostly the bike gets used on my Home to Work and back commute.

The battery can also sit around not doing anything when I go on holiday or work from another location etc.

It will have had a 21 day break before I use my bike on Friday as I have been on holiday.

When I started commuting on this bike in 2015 I used it all the time and as a shift worker this could include riding a 20 mile round trip to work and back on the road when it was dark and not suitable for my cross country route..

I now only use my Yamaha powered hard tail mountain bike when I can ride cross country to work and only ride cross country when I can ride in daylight.

I now use a simple rear hub cadence bike for my early start shifts when I have to ride to work in the dark. So my commuting trips are now shared between two bikes.

I am still pleased with the longevity of the Yamaha battery so far.
 
  • Like
Reactions: Edward Elizabeth

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
561
77
You may find this of interest.

Its a reasonable start, what it mentions is good, but it misses out on some good infos.
Its still more than most bike manufacturers give their clients!!
Thanks for sharing.
 
  • Like
Reactions: Edward Elizabeth

georgehenry

Esteemed Pedelecer
Nov 7, 2015
1,425
1,251
Surrey
I agree.

Simple stuff.

Try to charge your battery to full close to when you are going to use your bike.

Do not charge your battery to full and leave it that way too long.

Do not use your battery until it is empty and leave it that way.

Store your battery indoors at 50% to 70% ish.

Probably commuting on my bike has meant that my battery has been used in a way that is sympathetic to its longevity.
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
561
77
I could have linked to some scientific papers on the matter, but in reality the article is all an end user really needs to know.
It missed the detail about the charger and the battery and how each react to the other, but that is what some here apparently cannot understand (I have explained it previously a few times, with supporting links as well!) anyway, and even that info you posted actually got it wrong as well.....
But I am grateful that you posted what you did.
Thanks
Andy
 

Bobajob

Esteemed Pedelecer
Nov 1, 2019
313
140
Cornwall
So if I charge it up from say 80% to full that would count the same charge cycle as if I charged it up from 30% ?
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
561
77
So if I charge it up from say 80% to full that would count the same charge cycle as if I charged it up from 30% ?
The following is "in my opinion only, but supported by around 20 years of first hand experience and usage, plus the designing of chargers for other cell chemistry, which after many years, are still in use today! And demonstrating very long lives for those batteries.
I try to "err" on the side of safety when possible.
Remember, nobody has to agree with me, but please even if you disagree, please refrain from rudeness and bad, unfriendly language, as it does not change my opinions, nor does it make your thoughts any more positive or interesting in this matter. Remember:- "Manners maketh Man!"
1) any length of charging, no matter how little or large, is considered to be a charge cycle.
2) Most rechargeable batteries have a finite number of charges, before they start to degrade. This finite number is affected (particularly on e-bikes) by such things as temperature, speed of charge, speed of discharge, quality of cells, quality of BMS. Plus possible other aspects that I have not yet considered.
3) Leaving the usual type of charger still connected to the mains and the battery, once charging has completed, does definitely reduce long term battery life dramatically. Possibly because the average charger (for a 36 volt battery), is set to charge to 42.00 volts. Not more. As the battery reaches this voltage (State of charge level), the current drawn reduces, and when the charge falls below a preset level, set by the charger manufacturer, but probably somewhere around 30% of a normal charge. So if a 2 amp charger is in use, once the charge sinks below 600 ma., the charger switches into standby and switches the red LED to green.
But it appears that many chargers either maintain that low current, but misleading the owner with the green LED being on, that the charger is "OFF", but regularly "checks" the battery by attempting a charge, to see if more than 600 ma will be drawn. These mini charges, still affect the finite total of charges that a battery can accept, in a negative manner.
Testing for this needs some very specialised equipment, for long term testing, which I and many others, simply cannot afford to do.
Plus, each and every charger could have its own particular method and levels, so any testing needs to made on every single different charger, also a financial drain I cannot afford!!!
Therefor my personal thoughts are that a good charger should "disconnect" itself completely from the mains, and not start a recharge cycle within say a full month.
For good quality cells, possibly a longer interval would work even better, but with some sort of "fail-safe", to prevent over discharging.
A good charger, should still be able to "check" the battery voltage, but without applying a charge, say once a week, as a good multi meter does, just to assess the SOC, before the battery sinks below the easily recoverable minimum voltage/charge level.
A good charger, should also be able to emulate a so called "0 Volt Charger" (the name is a bit misleading!), which can still recover a battery that has just slipped below the minimum SOC, the situation where the BMS is correctly preventing, for safety reasons, any further charging from a normal charger.
Many of these features will for a normal biker, not come into effect, as the bike is often being used several times a week, and charging is regularly taking place, because the battery has slipped below the minimum SOC allowed.
4) For normal e-bikers, there are three relatively simply "fixes" to dramatically improve the life of a Li-ion battery:-
a) Modify a 24 hour time switch, one of the mechanical ones that sell for very little money, so that the tiny synchronous motor, when the power off switch is activated, it also switches itself off, so remaining off, till the user activates it again.
All the user needs to know, is roughly how long his battery will take to almost fully recharge, and to set that time on the timer. Even if not "perfectly" done, it will still save the battery from a lot of stress.
b) To have two batteries, not necessarily of the same capacity, and run each battery down to less than 10%, replacing it "on the journey", so to say. Thus always starting a recharge from a relatively well known SOC, which will allow a more accurate charge time to be calculated.
But some e-bikes were not built to allow easy battery replacement without tools, I might suggest that these e-bikes should be avoided if possible.
c) Never use a "fast" charger, as the higher the speed of the charge, the more stress the battery gets, which is for the long term life, not good. Having two batteries, does help in this area as well, as a "slow" charger can be used.
This is the present state of my current thoughts and knowledge, and my posting this appears, as I have done before, seems to bring out the worst manners of certain Pedelec members.
Would they be so kind as to maintain good manners with ANY posts they wish to make, not just to me, but for all other members, OK?
regards to all
Andy
 

MontyPAS

Esteemed Pedelecer
May 16, 2020
390
148
Agree with the mechanical timer to limit the time the charger is on, they are very cheap and once you know how long your battery takes to say 90% - 100% charge, set the timer to that.
Been using the same method with my 18v Cordless toolkit, and certainly does extend battery life
 
  • Like
Reactions: Andy-Mat

chris_n

Esteemed Pedelecer
Apr 29, 2016
656
399
62
Niedeau, Austria

georgehenry

Esteemed Pedelecer
Nov 7, 2015
1,425
1,251
Surrey
Hi Chris,

I had worked out that I had done around 400 charge cycles based on using 70% of my batteries capacity riding 22 miles to work and back and having ridden 12,450 miles so far. From that I worked out how far I could ride on one full charge cycle by dividing 22 by 0.7 to get 31.4. I rounded down to 31. I then divided my total mileage of 12,450 by 31 to get an estimate of the total number of charge cycles I had done so far to get 401.

When I used the workshop manual I got a different result. It indicated that I had completed 701 charge cycles or more.

It indicated that my batteries capacity was still at the highest point that it could measure falling somewhere between 75% and 100% capacity.

The battery itself continues to work as well as it always has on the 12 miles cross country ride to work, where the battery is charged back to full and then the faster 10 mile road ride home.
 

chris_n

Esteemed Pedelecer
Apr 29, 2016
656
399
62
Niedeau, Austria
Hi Chris,

I had worked out that I had done around 400 charge cycles based on using 70% of my batteries capacity riding 22 miles to work and back and having ridden 12,450 miles so far. From that I worked out how far I could ride on one full charge cycle by dividing 22 by 0.7 to get 31.4. I rounded down to 31. I then divided my total mileage of 12,450 by 31 to get an estimate of the total number of charge cycles I had done so far to get 401.

When I used the workshop manual I got a different result. It indicated that I had completed 701 charge cycles or more.

It indicated that my batteries capacity was still at the highest point that it could measure falling somewhere between 75% and 100% capacity.

The battery itself continues to work as well as it always has on the 12 miles cross country ride to work, where the battery is charged back to full and then the faster 10 mile road ride home.
So going back to the OP it must be about due to die ;) .
While I have nowhere near as many cycles as you mine was used very hard (10km with 1km climbing on one regular route for example) before I fitted the parallel battery. It has also been run to cut out on too many occasions as I was living up a 1km 17% max gradient at the time.
Mine too shows full capacity and real world riding bears this out.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
1,425
1,251
Surrey
So the batteries supplied with the Yamaha system judging by Chris and my own experience of hard long use would appear to be very high quality.

As I charge my battery back to full at work from only a 30% discharge and leave my charger switched on and attached to my battery until the end of my shift, around 9 hours, it would appear that the battery management system and charger are also well designed and the charger stops charging completely when the battery is full and balanced, judging by how well the capacity of my battery is holding up in its sixth year of use and relatively high mileage.

The long post by Andy-Mat about the importance of the relationship between the charger and the battery is not irrelevant to many systems, but this issue seems to have been accounted for in the design of the Yamaha battery, management system and charger.

So if you follow the simple advise I gave in post 11 above you will not go far wrong.

Indeed I also have a couple of Chinese derived simple cadence system rear hub bikes that are great and agree that using a timer plug is a simple way to ensure that their batteries stop being charged when they are full and this simple step will allow them to last a lot longer.

The last silver fish battery I bought for my rear hub bike cost under £200 in April 2018, and came with a charger. I just looked on Ebay and they have not changed in price.

https://www.ebay.co.uk/itm/36V15-6Ah-Lithium-ion-Battery-E-bike-Silver-fish-with-Cellphone-charging-USB/222214730187?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

To buy my original Yamaha battery from the shop where I bought the bike would cost me £650, and if you need a charger that needs to be bought separately so it is a good job they last a long time, and important you look after them.

https://www.e-bikeshop.co.uk/eBike-Spare-Parts/Yamaha-eBike-Spares/Yamaha-400Wh-eBike-Battery

https://www.e-bikeshop.co.uk/eBike-Spare-Parts/Yamaha-eBike-Spares/Yamaha-eBike-Battery-Charger
 
Last edited:
  • Like
Reactions: Bobajob