I’ve not looked at e bikes for a while an my folding Benelli has a 10.4 ah battery and the book says aprox 15 miles range , yet I’ve just seen other folders that have 7 or 7 ah battery saying the will go as far as mine , my bike is a 2018 but I dint think batteries had moved on that much, though son this would be good like change the control unit or display, I have a kt speed display, and a 350 15 amp controller about 3-4 years old thanks
New e bikes with small ah batteries
- Thread starter Swinman
- Start date
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Erin0110
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the bike market has changed a lot, now they have introduced a cool Blix Ultra 28 MPH fat tire electric bike, touts 1,350W motor and 80-mile range
What does it weigh?
Ultra Fat Tire eBike
The Ultra is a powerful all-terrain fat-tire ebike built with a modular design to adopt to your needs. Customize it for off-road adventures and practical everyday on-road use with Blix accessories and heavy-duty cargo capacity. With unmatched versatility and performance, the Ultra features a...
blixbike.com
A 10.4Ah battery is a 10.4Ah battery and a 7Ah a 7Ah. Assuming the voltage is the same (24v/36v/48v), the only thing that will have changed since 2018 is the degree to which manufacturers will exaggerate the range achievable.
My folding e-bike has a 36v 11.6Ah battery and an advertised/claimed range of up to 100km/62 miles. That's optimistic, or complete tosh, depending on how you look at it. It's about 35 miles in the real world, with favourable conditions, at best.
I'm sure you must be getting more than 15 miles from your 10.4Ah battery with sensible use? If not, is might just be knackered after 4 years.
My Mirider has a 7Ah battery, if l thrash it the battery can be empty in around 12 miles.
Being a bit more careful (but still riding at the assist limit speed) l've done 18 miles before the battery expired.
l guess if you used the lower assist levels and on flatter ground (it's all hills round here, my shortest route involves 1,000 feet of climbing) you could approach the "40 mile range" claimed by Mirider
This is a typical route from last night, the battery expired on the last hill. The ride included some off-road and several out of the saddle climbs
Being a bit more careful (but still riding at the assist limit speed) l've done 18 miles before the battery expired.
l guess if you used the lower assist levels and on flatter ground (it's all hills round here, my shortest route involves 1,000 feet of climbing) you could approach the "40 mile range" claimed by Mirider
This is a typical route from last night, the battery expired on the last hill. The ride included some off-road and several out of the saddle climbs
The distance achieved depends on terain and the amount of assist you are using. The LCD display does show how many Watts the system is using.
My own 36V 11ahr setup contibutes circa 85W at assist level 1 and 520W on assist level 5.
So if the battery is 36V x 11Ahr there is 396WattHr of power available. So assuming you are on the flat and travelling at max permitted speed, the 'distance' achieved is;
Assist 1, 396/90*15.5 = 68miles.
Assist 5, 396/520*15.5 = 11.8miles.
And those figures will of course vary depending on terain and person weight. In practice at assist 2 (125W) I get around 35miles on a flat route.
Given that there is probably only a small difference in different eBikes electrical effieciency, the range achieved for a particualr battery size is likley very similar across most all ebikes.
So as suggested by @cyclebuddy its easy for a manufacturer to quote a range that could be a fantasy for a particular circumstance.
My own 36V 11ahr setup contibutes circa 85W at assist level 1 and 520W on assist level 5.
So if the battery is 36V x 11Ahr there is 396WattHr of power available. So assuming you are on the flat and travelling at max permitted speed, the 'distance' achieved is;
Assist 1, 396/90*15.5 = 68miles.
Assist 5, 396/520*15.5 = 11.8miles.
And those figures will of course vary depending on terain and person weight. In practice at assist 2 (125W) I get around 35miles on a flat route.
Given that there is probably only a small difference in different eBikes electrical effieciency, the range achieved for a particualr battery size is likley very similar across most all ebikes.
So as suggested by @cyclebuddy its easy for a manufacturer to quote a range that could be a fantasy for a particular circumstance.
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I think the worst I've seen is a 6 mile range for a full charge on a e-mountain bike which was used for extensively steep up hill sections off-road. I think it was a 300Wh Bosch battery and it only lasted about 30-40minutes of riding but was an extreme test. However it's clear in those conditions the bike was performing well above the 250W legal limit to exhaust the battery so quickly unless the battery had reduced capacity I suppose.
I just go with the Watt hours shared by 10 equals approximate range in kilometres rule. So a 600Wh battery gives 60km range or around 40 miles. Yes its only a very rough guide for average use and average assistance. Grin Technology have done a lot of tests on different motors and the watts per kilometre isn't miles apart with different motor systems and it seems like each motor system can be the most efficient for certain applications. So if someone has a 36V 7Ah battery on their ebike thats about 250Wh so 25Km or maybe 18 miles range on average. So when you see the very low capacity batteries of 150Wh its only 15Km or around 10 miles but then many of these type of ebikes are quite light and with small geared hub motors not to bad to cycle unassisted compared to some high capacity ebikes which are very weighty and a real pain to cycle unassisted. So the bigger the battery the more annoying it can get if you run out of charge during a ride.
I'm surprised there aren't ebikes that don't assist at all until you get to a hill and then a little sensor would pick up the gradient of the road and kick in automatically. Such ebikes could have huge ranges on small capacity batteries. Many ebikes assist all the time which is a complete waste of power. I don't see the point of assisting where human legs can easily provide enough power anyway if your goal is exercise especially as we are limited to 15.5mph assistance.
I just go with the Watt hours shared by 10 equals approximate range in kilometres rule. So a 600Wh battery gives 60km range or around 40 miles. Yes its only a very rough guide for average use and average assistance. Grin Technology have done a lot of tests on different motors and the watts per kilometre isn't miles apart with different motor systems and it seems like each motor system can be the most efficient for certain applications. So if someone has a 36V 7Ah battery on their ebike thats about 250Wh so 25Km or maybe 18 miles range on average. So when you see the very low capacity batteries of 150Wh its only 15Km or around 10 miles but then many of these type of ebikes are quite light and with small geared hub motors not to bad to cycle unassisted compared to some high capacity ebikes which are very weighty and a real pain to cycle unassisted. So the bigger the battery the more annoying it can get if you run out of charge during a ride.
I'm surprised there aren't ebikes that don't assist at all until you get to a hill and then a little sensor would pick up the gradient of the road and kick in automatically. Such ebikes could have huge ranges on small capacity batteries. Many ebikes assist all the time which is a complete waste of power. I don't see the point of assisting where human legs can easily provide enough power anyway if your goal is exercise especially as we are limited to 15.5mph assistance.
What I worry about with these small battery packs is how much strain you are putting on the cells. If it is a 7Ah pack, you're looking at only 3 cells in parallel, maybe 2 for high capacity cells. So for a typical 15A controller system you are pulling 5 A or more from each cell near continuously in some conditions. Not too much of an issue for very high quality cells, but a real strain for cheap ones. So I would not expect the pack to have a long cycle lifetime. If you are going to use a 20A controller, things get even worse.
You also have to bear in mind 7Ah is the manufacturer's label from a test done under ideal conditions from 100% full to completely empty and probably at a low discharge rate. In reality, you would probably get about 5 Ah out of the cells at best. You are pulling a lot of current out of the cells very quickly in the real world and you would not take the pack all the way down to zero capacity. The current drain at full power on a 30% charged pack means voltage drops significantly and could trip the LVC. Hence you will get much less than 7Ah out of it in most cases.
Then, what happens in cold weather? I notice a big drop off in performance once the outdoor temp goes below 10 C. Lower than that and you really feel things getting sluggish.
I think 7Ah is ok for a lightweight bike where you just use power intermittently for small hills, or a bike for children. But for an everyday adult commuter bike for trips over 5 miles each way, or a user in hilly country, I think it's a bad idea. If you want to charge to only 41V to extend pack life, you have even less capacity.
I like 15Ah packs, I think they are a good all round compromise between weight and range.
You also have to bear in mind 7Ah is the manufacturer's label from a test done under ideal conditions from 100% full to completely empty and probably at a low discharge rate. In reality, you would probably get about 5 Ah out of the cells at best. You are pulling a lot of current out of the cells very quickly in the real world and you would not take the pack all the way down to zero capacity. The current drain at full power on a 30% charged pack means voltage drops significantly and could trip the LVC. Hence you will get much less than 7Ah out of it in most cases.
Then, what happens in cold weather? I notice a big drop off in performance once the outdoor temp goes below 10 C. Lower than that and you really feel things getting sluggish.
I think 7Ah is ok for a lightweight bike where you just use power intermittently for small hills, or a bike for children. But for an everyday adult commuter bike for trips over 5 miles each way, or a user in hilly country, I think it's a bad idea. If you want to charge to only 41V to extend pack life, you have even less capacity.
I like 15Ah packs, I think they are a good all round compromise between weight and range.
The market is relatively settled now in this respect, compared to the extremes of the past. For example the Panasonic crank motored Giant Lafree sold well from 2001 to 2006 with a 24 volt 6.5 Ah battery, so only 156 Wh, but was so well managed by its software that most riders of very differing abilities and in differing terrain could get 20 miles range. That's just 7.8 Wh per mile.
Conversely in the same period Ezee were selling a couple of powerful models with 36 volt 10 Ah batteries, so 360 Wh, but most riders only got 15 miles range from either in any terrain. That's a whopping 24 Wh per mile, over three times the Lafree's consumption.
Just having a hill sensor isn't sufficient, since the assistance is often needed against head winds as well, especially in very flat areas like Holland and our Eastern counties where unobstructed winds build up so much in strength.
However some firms did have a crack at this market for a light road bike with a light assist system for hills, notably in this country by Cytronex. They converted known good road bikes like Cannondales by adding a small front hub Tongxin Nano very low drag roller-drive motor, using a custom controller with simple on/off button on the bars. Combined with a small 24 volt 6.5 Ah bottle battery, the same 156 Wh the Lafree had, the intended way to use them was to ride unpowered normally, only pressing the button for hills or headwinds.
A few bought and liked them achieving long ranges, but not enough. Others trying to use them like any other e-bike failed to get good ranges, one of our members only getting 12 miles at most and quickly selling his. So Cytronex eventually failed in this venture and today is just a bike shop at Winchester.
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it's not the e-bike's fault. The battery is used to make up for the difference between energy required to maintain the bike's speed and the rider's own physical input.
On flat roads, that assistance is useful against headwinds.
I think in some ways cycling is ideal for health because roads vary up and down and this means the requirements for the human body vary too and this seems to be ideal for maximising fitness and health. I.e. you struggle up a hill and then when you get there you have a pleasant flat bit or enjoy frewheeling down a hill. However very steep hills are a real struggle often more demanding than many people are comfortable with which is ideal for ebikes to assist with without sacrificing the benefits of cycling to fitness levels. That's the way I view it. It wouldn't be difficult to combine a torque sensor in the bottom bracket with a sensor that tells the motor when you are going up hill in order to make more demanding sections easier.
Lets say the ebike always kicks in so the rider never has to produce anymore than 100 watts of power. Yes that could be ideal for a commuting run where you don't want to arrive sweaty but is not very good for fitness.
It's a bit more nuanced than 'all the time' and 'complete waste of power'. Only throttle equipped bikes assist all the time, and if assistance reduces journey time by increasing speed, who's to say that's a waste?
The rider chooses the level of assistance 'in the moment', and if it suits them to have assistance when they could manage without, they are just using the machine to it's full capability. Keep an eye on range, no harm done.
Going faster than necessary in a car is orders of magnitude more wasteful. 10Wh per km is easily achieved on an ebike, which compared to calorific value of petrol is like doing 4,300 mpg.
Ebike use needs to grow, and that will largely be people who at least at first need assistance most of the time.
The rider chooses the level of assistance 'in the moment', and if it suits them to have assistance when they could manage without, they are just using the machine to it's full capability. Keep an eye on range, no harm done.
Going faster than necessary in a car is orders of magnitude more wasteful. 10Wh per km is easily achieved on an ebike, which compared to calorific value of petrol is like doing 4,300 mpg.
Ebike use needs to grow, and that will largely be people who at least at first need assistance most of the time.
Some modes are getting a bit cleverer than the fixed percentage assistance approach. The percentage goes up as the measured torque goes up, which gives an automatic response to increasing steepness.
lf you're worried about excessive cell current draw, maybe avoid the highest assist level?
My folding ebike has five assist levels and it's perfectly fine on level 3, although l turn it up on hills, only because l want to go as fast as the bike will let me.
l never use the maximum 300% assist level on my main ebike, which has the Shimano 504Wh downtube battery and E8000 mid motor.
Despite this, there are still issues with battery pack degradation and l've had one replacement under warranty.
So l would say, just ride your ebike and don't stress about how much current it's taking from the battery pack....life's too short.
My folding ebike has five assist levels and it's perfectly fine on level 3, although l turn it up on hills, only because l want to go as fast as the bike will let me.
l never use the maximum 300% assist level on my main ebike, which has the Shimano 504Wh downtube battery and E8000 mid motor.
Despite this, there are still issues with battery pack degradation and l've had one replacement under warranty.
So l would say, just ride your ebike and don't stress about how much current it's taking from the battery pack....life's too short.
I don't know much about ebike batteries, but perhaps quoted range for 10ah batteries are higher for reasons other than fraud? Could battery cell chemistries have improved, so a lower battery protection level can be used? I suspect it's fraud.
In any case, a battery protection level of 31% on a 10ah battery leaves 6.9ah usable capacity. To get a usable 10ah, wouldn't I need to buy a 14.49276ah battery?
It's annoying that manufacturers don't state what battery protection level their ebikes are using. In my case the battery protection level is set on the bbs01b controller at 31%, I have no idea what it's set for on the BMS. But taking 31% away from my 36V 19.2ah/691.2wh battery leaves a usable 13.248ah or 476.928wh. I get about 45 miles range using my usual zero effor/high power/knee protection settings, so I'm using 10.5984W per mile.
In any case, a battery protection level of 31% on a 10ah battery leaves 6.9ah usable capacity. To get a usable 10ah, wouldn't I need to buy a 14.49276ah battery?
It's annoying that manufacturers don't state what battery protection level their ebikes are using. In my case the battery protection level is set on the bbs01b controller at 31%, I have no idea what it's set for on the BMS. But taking 31% away from my 36V 19.2ah/691.2wh battery leaves a usable 13.248ah or 476.928wh. I get about 45 miles range using my usual zero effor/high power/knee protection settings, so I'm using 10.5984W per mile.
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The curious streak I so frequently fail to suppress just tapped me on the shoulder and asked: is it 31%, or 31V?
Lol, it's my damned CSR plagued eyes again! I'm used to seeing battery protection levels as percentages on laptop batteries, not voltage, and my brain appears to have made up a reality my eyes couldn't see, again - see below, it's set at my controller at 31V. I did think 31% was a bit high, but as I said, I don't know much about ebike batteries. So what is 31V as a percentage for a 19.2ah 36V battery?
And it's still annoying that manufacturers don't state if their quoted amp hours for batteries include what's left, after battery protection level is taken into account. A bit like how a 1TB will not be a 1TB after formatting, which is also annoying.
(These aren't my latest settings BTW, but I've left battery protection level alone)
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