Getting the stated mileage out of a battery

[Blair]

Hi

Still to get my bike. Just trying to get my head around battery usage, if the bike is advertised to get 50 miles on flat roads out of a charge, is that 50 miles on the throttle only, or would that be 50 miles at Level 1 assist?

Obviously weight, wind etc a factor, just trying to find out which end of the scale is used to determine how far one can go

Thanks guys

 

[anotherkiwi]

In Perth that would be 50 km mate! So yeah, go for it

Question (which holds the answer): Do you trust advertising?

 

[basicasic]

Predicting battery range for a particular individual is virtually impossible. Ebike manufacturers tend to quote best case figures and many people fail to get anywhere near them.

One of the biggest factors for battery mileage is how you use the bike. The more pedaling effort you make the longer the battery range will be. You've mentioned throttle so I'm guessing you won't want to do much pedaling in which case anything the manufacturers claim will be a pipe-dream for you.

However the range you actually get might be enough for your needs but it's hard to know exactly before you buy the bike.

 

[Blair]

So if I am looking at 60-80 miles a day, pedal assist would more than likely stop at around the 40 mile mark?

 

[Emo Rider]

My bike is rated for 85 miles on a full charge. The reality is 45 to 60 miles. My weight, the route I routinely travel, wind, temperature and my input ultimately determine my range. In the wintertime I can use it up in just over 30 miles as temps around freezing reduce the batteries' capacity.

 

[Wisper Bikes]

Hi Blair,

If range is critical to you try and buy a bike with a torque sensor, and 16Ah battery. This combination should easily get you pasty the 50 mile mark.

All the best, David

 

[Deleted member 4366]

There's no magic formula. You can use the throttle only and not go very far or you can pedal very hard and go an infinite distance. All distances in between depend on how hard you pedal, your weight, external conditions and how hilly your journeys are.

What range anybody else gets is completely irrelevant unless you know their weight, what hills they climb and how hard they pedal.

 

[georgehenry]

Whatever the range it is best to keep the battery topped up as much as possible when you are using it.

I do a 26 mile return trip to work and my bike can do this if required when I have forgotten to take my charger with me, but I can charge my battery at work and this means it is full before I set off on each leg of the journey.

My Yamaha system has a battery with a handle that can be removed and carried easily and even half an hour or an hour on the charger will top up the battery significantly.

Electric bikes with lithium batteries are not like cars where you fill them up and then run them out before re-filling them. The range is there to be used on occasion but wherever possible the batteries should be topped up when you are using the bike as often as possible. This will actually help your expensive battery last as long as possible.

The exception is when you are not going to use the bike for some time when it is better not to leave the battery full but somewhere in the 50% to 75% range.

If you are leaving your bike locked up somewhere in public being able to remove the battery and display easily is a significant security benefit.

 

[basicasic]

Whatever the range it is best to keep the battery topped up as much as possible when you are using it.

I do a 26 mile return trip to work and my bike can do this if required when I have forgotten to take my charger with me, but I can charge my battery at work and this means it is full before I set off on each leg of the journey.

My Yamaha system has a battery with a handle that can be removed and carried easily and even half an hour or an hour on the charger will top up the battery significantly.

Electric bikes with lithium batteries are not like cars where you fill them up and then run them out before re-filling them. The range is there to be used on occasion but wherever possible the batteries should be topped up when you are using the bike as often as possible. This will actually help your expensive battery last as long as possible.

The exception is when you are not going to use the bike for some time when it is better not to leave the battery full but somewhere in the 50% to 75% range.

If you are leaving your bike locked up somewhere in public being able to remove the battery and display easily is a significant security benefit.

http://www.batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

These people have actually done some research on the subject of batteries.

A couple of things I noted:

Charging your lithium-ion battery to about 80% rather than 100% will roughly double the number of charge cycles obtainable. Keeping it constantly fully charged stresses the cells and reduces battery life significantly.

Storing a battery at 40% charge in cool dry conditions have been shown to be best for prolonging life.

There are some really interesting articles on the Battery University website and I intend to follow their advice especially with replacement Bosch batteries going at over 700 euros a pop.

 

[Deleted member 4366]

http://www.batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

These people have actually done some research on the subject of batteries.

A couple of things I noted:

Charging your lithium-ion battery to about 80% rather than 100% will roughly double the number of charge cycles obtainable. Keeping it constantly fully charged stresses the cells and reduces battery life significantly.

Storing a battery at 40% charge in cool dry conditions have been shown to be best for prolonging life.

There are some really interesting articles on the Battery University website and I intend to follow their advice especially with replacement Bosch batteries going at over 700 euros a pop.

I wish people wouldn't keep bringing that up. It's very misleading for e-bike users.

That research is about how single cells behave. We don't use single cells: We use batteries. Our batteries have a management system in them that manages everything for us. If you try and manage it yourself, you'll end up worse off.

Also, every day, the battery manufacturers are inventing their new ingredient X, which they put in their batteries, which changes some performance characteristic. There's nothing to say that that research is relevant to what anybody has in their electric bike, unless maybe if it's an old battery.

To summarise, whatever somebody else's theory says would improve battery life, yours doesn't use that technology and isn't optimised for it, so just use it like it says in the manual, which means that you should use your bike, then plug in the charger until it goes green.

One final point: Look at the comments in relation to that article. they were written in 2010. battery technology has improved massively since then.

 

[basicasic]

I wish people wouldn't keep bringing that up. It's very misleading for e-bike users.

That research is about how single cells behave. We don't use single cells: We use batteries. Our batteries have a management system in them that manages everything for us. If you try and manage it yourself, you'll end up worse off.

Also, every day, the battery manufacturers are inventing their new ingredient X, which they put in their batteries, which changes some performance characteristic. There's nothing to say that that research is relevant to what anybody has in their electric bike, unless maybe if it's an old battery.

To summarise, whatever somebody else's theory says would improve battery life, yours doesn't use that technology and isn't optimised for it, so just use it like it says in the manual, which means that you should use your bike, then plug in the charger until it goes green.

One final point: Look at the comments in relation to that article. they were written in 2010. battery technology has improved massively since then.

Ooooo that's me had a telling off from the forum 'expert'.

My take on it is this:

Manufacturers don't particularly care about how long a battery lasts after the warranty period runs out and quite frankly it is not in their interest to maximise battery life. They would like you buy a new battery or a new bike. As far as battery 'management' for ebikes goes, I would be happy to see the evidence that it's designed to maximise battery life rather than capacity and therefore range (so figures look good in the showroom).

Likewise with the various Ingredient Xs manufacturers put in their batteries to improve battery lifetime. All the research I have read suggests it's to improve capacity and range. However I may have missed some.

Tesla's have an 8 year warranty on their batteries and the normal charge for their car battery packs are to 80% capacity to maximise battery life and they recommend you don't exceed this. Or are they using old technology?

Battery packs are made up of many of these cells that the article (which incidentally was updated 15-6-17) was testing. If you would care to point me to later research (and I mean research and not hearsay) which contradicts any of the findings of the article I pointed out I'd be happy to re-evaluate my opinion.

Oh, and another thing, as far as I'm aware it's not your forum so I'll bring up anything I feel is relevant whether you think it's misleading or not.

 

[Deleted member 4366]

You've obviously graduated from the Battery University then.

 

[basicasic]

You've obviously graduated from the Battery University then.

Whereas you obviously failed.

Joking aside, you show me the Battery University article is incorrect and I'll willingly change my opinion.

 

[Emo Rider]

Ooooo that's me had a telling off from the forum 'expert'.

My take on it is this:

Manufacturers don't particularly care about how long a battery lasts after the warranty period runs out and quite frankly it is not in their interest to maximise battery life. They would like you buy a new battery or a new bike. As far as battery 'management' for ebikes goes, I would be happy to see the evidence that it's designed to maximise battery life rather than capacity and therefore range (so figures look good in the showroom).

Likewise with the various Ingredient Xs manufacturers put in their batteries to improve battery lifetime. All the research I have read suggests it's to improve capacity and range. However I may have missed some.

Tesla's have an 8 year warranty on their batteries and the normal charge for their car battery packs are to 80% capacity to maximise battery life and they recommend you don't exceed this. Or are they using old technology?

Battery packs are made up of many of these cells that the article (which incidentally was updated 15-6-17) was testing. If you would care to point me to later research (and I mean research and not hearsay) which contradicts any of the findings of the article I pointed out I'd be happy to re-evaluate my opinion.

Oh, and another thing, as far as I'm aware it's not your forum so I'll bring up anything I feel is relevant whether you think it's misleading or not.

I believe if you go back and read d8veh's comment again you will see that he is refering to comments made in 2010 and not the artice itself. I personally did not see where he was disagreeing with you. I have read the same artice in the past and things have changed since the original. And as for battery life. That will always greatly depend on how the owner uses it and looks after it during its life span. I have a 2015 Yamaha battery that has trucked me along 12 months a year for over 2,100 miles and shows little sign of degredation. I have also seen batteries used up in under two years, mostly due to high milage and daily charging. But it did its job. I think that people expect and demand too much from lithium batteries. They do wear out and they are replacable.

 

[Deleted member 4366]

Whereas you obviously failed.

Joking aside, you show me the Battery University article is incorrect and I'll willingly change my opinion.

I didn't say it's incorrect. What I said is that people cannot start charging their e-bikes to 80% and get longer battery life. That article is aimed more at the management systems. He's arguing that the BMS's should be more flexible in the way that they manage charging to extend battery life. We just buy batteries with BMS's already installed. Unfortunately, they're not optimised for battery life and there's very little we can do about it.

For your information, I have something like 50 or more e-bike batteries in my house (sheds and garage), I disassembled many of them. I have a bespoke battery tester to test their capacity as well as several individual cell testers and cyclers. I spend a lot of time analysing and repairing batteries. I taught electronics in a secondary school for 10 years and I'm a graduate engineer. I might not be an "expert", but I have a good understanding of how they work.

Where did you get your experience from?

 

[georgehenry]

I use my Haibike sDuro Yamaha simply to commute a round trip of 26 miles.

As a non expert my own take on looking after my own battery means doing a few simple things.

If I am not using my battery I remove it from the bike and store it in a dry cupboard inside my house until I next use the bike which could be as much as three weeks Later if I am on a main holiday.

My battery will have up to 65% left from my ride home, and that is how it is left.

If I am riding to work for a number of consecutive days I do not charge immediately when I get home but take it into the house and leave it in the dry cupboard at about 65% charge give or take 7% dependent on outside temperature (I use my bike all year). I then charge it to full so that the battery reaches full as close to me leaving home as possible.

I am lucky to be able to leave my bike in a dry room at work and can also charge it which I do. So if I am working a 9 hr shift it will be fully charged for when I need it. It will however have spent a few hours fully charged waiting for me while I am working.

Used in this way my bike has covered 6512 miles since I bought it in March 2015, and I am really quite impressed that the battery appears to be working exactly as it did when it was new.

Now I know the battery must be degrading and it will show at some point but so far so good.

I am also a heavy bloke 100kg+ and carry a pair of full panniers.

I did however wear my Yamaha motor out after 6000 miles but that is another story! The shop I bought my bike from (Ebike shop Farnham) were good enough to replace it free of charge.

 

[basicasic]

I didn't say it's incorrect. What I said is that people cannot start charging their e-bikes to 80% and get longer battery life. That article is aimed more at the management systems. He's arguing that the BMS's should be more flexible in the way that they manage charging to extend battery life. We just buy batteries with BMS's already installed. Unfortunately, they're not optimised for battery life and there's very little we can do about it.

For your information, I have something like 50 or more e-bike batteries in my house (sheds and garage), I disassembled many of them. I have a bespoke battery tester to test their capacity as well as several individual cell testers and cyclers. I spend a lot of time analysing and repairing batteries. I taught electronics in a secondary school for 10 years and I'm a graduate engineer. I might not be an "expert", but I have a good understanding of how they work.

Where did you get your experience from?

Well now that we've established that the article is in fact correct and that BMSs that are supplied with our bikes tend not to be optimised for battery life in practical terms I think georgehenry in his post above has the right idea. Charge it up fully, use it, leave it partially charged in a cool, dry place and then charge it up when you want to use it again. That way you have the maximum range available to you and the cells are being stored in a relatively unstressed state.

For my part because I don't have any range anxiety I usually charge my battery up to 4 full bars (out of 5), then use it as and when, and recharge it when it drops to 2 bars or below. I plan to fully charge it once a month. I've only had my bike 2 months so time will tell but it's an interesting experiment (albeit fairly unscientific). If I can cover 6512 miles in 2 years like georgehenry with the battery working like it was new I'll be very pleased.

As far as qualifications go I'm a graduate engineer too (in polymers in fact) and spent my working life as an engineer in IT. I've probably tested and checked hundreds of batteries ranging from lead-acid to lithium in old clapped out kit over the years. That doesn't make me an expert in lithium ion technology any more than your qualifications/experience makes you.

I have no idea why you so rudely and condescendingly dismissed the article I referred to when it's based on actual testing and research and still very relevant to ebikers who would like to maximise the life of their very expensive batteries.

 

[georgehenry]

If you want a rather crude way of deciding how long you want your battery to be charged these plugs can help. They also provide a second safeguard that cuts the current to the battery if the charger were to malfunction.

 

[philliptjohnson]

(legal disclaimer... I'm a newbie, definitely not an expert and views are not my own )

Here are the details from suntour's website on battery storage and charging (this is the battery on a Carrera crossfire e)...


What is the best way to store the batteries?
Preferable storage condition is 40~50% charge level at 15~25℃.
If the battery level becomes less than 40% of its capacity, it is recommend to re-charge the battery.
It is recommended to check the battery every three months in order to keep the battery capacity at the minimum 40%.


How long will the battery last?
Battery life is influenced by the number of charging cycles and storage conditions.
Store and re-charge the battery at a temperature between 15~25℃. See the manual for more details.

Source http://www.srsuntour-cycling.com/service/e-bike-service/

Personally I'm just going to charge my battery when it gets a bit flat or if I think I'm going on a longer ride and might need a full charge... I'm probably going to be using my bike a couple of times a week when the weather is nice (fair weather rider) so not going to overthink battery storage and recharge. I expect to buy a new bike long before the battery on my current one becomes unusable. I do understand though that if you use your bike daily or are planning on keeping your bike as long as possible and you really want to get as much as you can out of the battery then this type of stuff is inputting to you.

 

[Woosh]

Still to get my bike. Just trying to get my head around battery usage, if the bike is advertised to get 50 miles on flat roads out of a charge, is that 50 miles on the throttle only, or would that be 50 miles at Level 1 assist?

The information about range is pretty useless as you have found out.
If asked, I usually look at the shape of my customers before replying.
If the person looks like 12st or under, that will be 8WH per mile, then add 1WH per mile for each additional stone. 14st = 10WH, 16st = 12WH.
After guessing the approximate battery usage, I divide the battery capacity by the WH to get to the miles. For example, most of my bikes are sold with 36V 15WH battery, 36V * 15AH = 540WH. If you weigh 14st, I'd say 50-55 miles on a full charge.
On my website, I divide the battery capacity in WH by 11 before rounding it down to 0 or 5.