Battery longevity

[Gubbins]

Just reading another thread which prompted me to post this.
I still own my Giant road e+1 which I bought in 2016 so the battery is approaching 5 years old and of those 5 years 3 of them have been spent using a speedup device. I dont let the battery go flat generally charging after each ride so rarely has it been bellow 50%.
Obviously there has been some degradation, but it isn't obvious. This week I rode 12 miles, mostly at 20mph so using power all the time and used around 15% of available battery.
There are lots of threads about poor battery performance so just wondering if mine is unusual.

 

[D C]

wondering if mine is unusual

I hope not, I'll be pleased if our Giant batteries last for another 4 or 5 years and at my age will be delighted if I need to buy another!
Dave.

 

[georgehenry]

Hi Gubbins,

I bought my entry level Haibike sDuro Yamaha hard tail mountain bike in March 2015 and am still using the original 400Wh battery which will be 6 years old in March and like you although there must have been some degradation it still works amazingly well using the same amount of its capacity for the journeys I use it for and having the same range it did when new.

I rode to work on it yesterday, 16 miles cross country in very challenging conditions, and 10 miles back on the road through the wind and rain. I record my bikes mileage and when I got home last night noted I have ridden it 12,912 miles.

This battery does not get an easy life as I am heavy, over 100kg, and carry two full panniers, and the motor has been able to assist me above 15mph from when I bought it enabling me to average 20mph for my 10 mile ride home on the road.

I use my bike only to commute to work and back and think that this may be kind to the battery, as I only use about 30% of my batteries capacity on the cross country ride to work, where I can charge the battery back to full in a well heated room, and around 40% on the 10 road ride home where I use higher assistance levels to travel faster.

At work the battery will be left attached to the charger while I do my shift, somewhere around 9 hours, so the charger and battery manage system must also be good.

I always bring my battery into the house, and leave it at the charge level it has reduced to on my ride home (55% to 65% charged) until I need to use it again.

Sometimes the gaps between use can be several weeks. Then I charge it up to either full or very close to full as close to the time I will set off for work as possible. Whatever the reason, the battery is lasting amazingly well. Good job as a new one costs £650.

 

[vfr400]

All batteries use standard cells, so you could find the same cells in your Bosch or Yamaha battery as a Chinese kit battery from Eclipse or Aliexpress. They all charge to 42v. I can't think of anything that the manufacturer could do to affect the battery life other than choose cells on the basis of long life rather than light weight, high capacity or high discharge rate. Each type of cell has its own ingredient X, which gives its specific characteristics. Other than than the type of cell, the life is more likely down to how the battery is used or luck with how the variance in quality favours your particular battery.

Bosch and Yamaha batteries are very well put together. I've disassembled both. The wire routes are very well planned and tied down. All the soldering and welding also looks very well thought out and controlled. I can believe that there's less chance of random defects, like wires coming off or welds breaking; however, both batteries that I looked at were bricked by faulty BMSs. The Bosch one was draining the battery continuously with a small current even beyond LVC. The Yamaha one just switched itself off and refused to switch on even though the cell-pack was OK.

 

[georgehenry]

I tend to agree vfr400

The battery on my 2015 Haibike is fitted externally to the down tube and very easily taken off and put on. Because of this I always remove the battery and store it in the house.

I also do not store the battery fully charged.

I try to only charge the battery to full before I set off to work.

I mention the charger and battery management system as at work the battery is connected to a switched on charger for quite a few hours after it has fully charged and ascertain from this that the charger does not keep charging the battery once it is full.

The Yamaha system is a torque sensor system that dependent on the level of assist you choose can I think draw less power from the battery than a simple cadence system.

I find the Haibike Yamaha crank drive very easy to ride with no assist from the motor, where as my admittedly quite old (2011) Oxygen rear hub bikes do not allow a no assist option and are therefore always drawing some energy from the battery.

As you know I have a couple of old Oxygen rear hub cadence system bikes that I also love and their batteries have not lasted as long for whatever reason but are much cheaper to buy.

I think that if you store your bike in an unheated garage or shed where you might also charge the battery up, this will have an effect on the longevity of your battery.

Buying a bike where the battery is easy to remove may be a more important factor in the longevity of your battery than you might think when you buy the bike in the first place, as it makes it easy to bring your battery into the house to store and charge.

 

[Gubbins]

Actually I don't do any of that. Mine stays in a cold garage and is always left fully charged often for weeks at a time. The only time I have brought it inside is when its well below zero for an extended time.

 

[mike killay]

I did wonder what the effect of freezing temperatures is, so I put a small 18350 battery from my vape pipe in the freezer for few days.
I then took it out, after it had thawed I could not notice any degradation so I am not sure just how cold a lithium battery has to get before it is damaged.

 

[D C]

Actually I don't do any of that. Mine stays in a cold garage and is always left fully charged often for weeks at a time. The only time I have brought it inside is when its well below zero for an extended time.

I always treat my batteries in the way manufacturers and many informed folk suggest,
I don't generally discharge to less than 40 %,
I store and charge off the bike, a few hours before using and not straight after use,
every three or four months I run right down and give a long recharge,
and I always store in a cool but not cold area between 60-80 % though its never for long as I ride at least three times per week even in winter.
I'm wondering if these recommendations are misinformation and judging by your experience, not necessary for good battery performance and longevity.
I'll continue to treat my batteries like this but I'm beginning to think it may be a complete waste of time.
Dave.

 

[Nealh]

The cold doesn't affect the lithium life, the only thing that affects batteries in the cold is charging. Charging in the cold simply reduces the cells ability to accept full capacity though voltage will say full, once the battery is returned to warmer charging temps it will then accept the full capacity(dependant on ageing/condition).

 

[Gubbins]

Something else I do which maybe I shouldn't is to leave the charger connected and powered on sometimes for days! I used to follow all the advice but over time I found that I'd doesn't seem to make much difference.

 

[vfr400]

Something else I do which maybe I shouldn't is to leave the charger connected and powered on sometimes for days! I used to follow all the advice but over time I found that I'd doesn't seem to make much difference.

Some chargers latch off when they give the green light, so you can leave them on all the time. The cheap Chinese ones generally don't, but there are exceptions.