How to get the most range?

[lotrwiz]

Well my ebike weighs around 30 kilos (65 pounds ish) I weigh around 70 kilos (don't know how much in pounds).

Me and my friends are going to be doing quite a few 40ish mile trips, cycling of course. I was wondering how to extend the range of my bike, I know about not riding full throttle and pedalling with the motor, but I don't want to be left with 20 miles to pedal my behemoth of an ebike along.

thanks in advance!

 

[andrenoites]

For me the more important aspects are:

Aerodynamics is the nº1 one to keep in mind concerning speed and range.
Above 38km/h I stop pedaling and tuck for less air resistance

The tires are also important, don't wear cross tires on road.
Changing to street tires will greatly enhance the efficiency of the bike.

If you have a mid drive mount, improve the drive chain efficiency by removing the chain tensioner from the motor chain:

 

[Ykick]

CAV3? (cycle analyst ver 3)

Not only does it offer the ability to monitor speed, power and consumption data it can also be installed/programmed to control those parameters so that you can, more often than not, achieve the distance/range you desire.

 

[dogman dan]

After you have done the low hanging fruit, like not wearing a coat that slows you down by 2 mph, riding in a tuck, not having a tire that feels like Velcro on the road, the big three are left.

Slow down.

Carry more battery, or have more staged for you where you will need it.

Really fast charging.

40 miles should be quite possible with 1000 wh of battery. 48v 20 ah, 36v 30ah, etc. My personal best range on 48v 15 ah was 39 miles, but 30 miles is easy to get by riding 20 mph. That's on very poor aero bikes too. If you are riding as slow as 15 mph, in reasonable weather, 700 wh will get you 35 miles for sure.

I have to say, if you aren't carrying 48v 15 or 36v 20 ah, (700 wh or so) you just HAVE to get more battery. 48v 15 ah will get you there, if a 20 min break half way to charge with a 5 amps charger can be possible. Just a short top up will get you 5 more miles.

 

[lotrwiz]

Wel I have a 36v 9ah Battery, I don;t suppose you could do the math on that for me, please? :/ I don't quite understand how you work it out.


Edit: I'd probably only be going around 15mph as there will be some girls with us, and keep in mind they are my age (16).

http://www.ebay.co.uk/itm/8Fun-26-Ebike-Electric-Bike-Conversion-Kit-36V-250W-8F26F36B-/321028650823?ssPageName=ADME:L:OC:GB:3160

^^That's the kit that I fitted to my Apollo Paradox Bike.

 

[lotrwiz]

CAV3? (cycle analyst ver 3)

Not only does it offer the ability to monitor speed, power and consumption data it can also be installed/programmed to control those parameters so that you can, more often than not, achieve the distance/range you desire.

I'm using a really cheap controller, that's probably not compatible. If we're even talkng about the same thing here?

 

[lotrwiz]

For me the more important aspects are:

Aerodynamics is the nº1 one to keep in mind concerning speed and range.
Above 38km/h I stop pedaling and tuck for less air resistance

The tires are also important, don't wear cross tires on road.
Changing to street tires will greatly enhance the efficiency of the bike.

If you have a mid drive mount, improve the drive chain efficiency by removing the chain tensioner from the motor chain:

Thanks a lot, that was really helpful. I'm using a small hub motor kit.

 

[dogman dan]

The math will depend on lots of things hard to quantify, like how hard you pedal, that might be different for you. The numbers I spoke of were based on my riding, 10,000 miles worth of it. ( which is becoming not so far compared to others now)

Getting a wattmeter will help you learn to ride as efficiently as possible. The stand alone cycleanalyst will work with any controller, or a less sophisticated wattmeter can be found on ebay for under 20 usa bucks.

Don't misunderstand, some people get much better ranges than I do. There is no theoretical maximum range, pedal the bike with the motor off all you can handle.

But on a 40 mile ride, if you can't stop for a full recharge, you are about right on with your estimate of 20 miles of pedaling an extra heavy bike.

You really have to get more battery for those really long rides. If your buddies ride slow enough, and you are using a wattmeter to make sure you dont' start squandering your available battery, I see no reason why you could not learn to get 25 or even 30 miles out of what you have.

But I don't see 40 miles as doable, except under tailwind all the way conditions. Just plan on some shorter rides, maybe where you park at some point where you can do some charging, then they ride a loop to return to where you are, with some more battery charged back up. You still get 30 miles of the ride easy, and they only ride alone a portion of the whole day. Once charged, you break wind for them going home.

 

[lotrwiz]

The math will depend on lots of things hard to quantify, like how hard you pedal, that might be different for you. The numbers I spoke of were based on my riding, 10,000 miles worth of it. ( which is becoming not so far compared to others now)

Getting a wattmeter will help you learn to ride as efficiently as possible. The stand alone cycleanalyst will work with any controller, or a less sophisticated wattmeter can be found on ebay for under 20 usa bucks.

Don't misunderstand, some people get much better ranges than I do. There is no theoretical maximum range, pedal the bike with the motor off all you can handle.

But on a 40 mile ride, if you can't stop for a full recharge, you are about right on with your estimate of 20 miles of pedaling an extra heavy bike.

You really have to get more battery for those really long rides. If your buddies ride slow enough, and you are using a wattmeter to make sure you dont' start squandering your available battery, I see no reason why you could not learn to get 25 or even 30 miles out of what you have.

But I don't see 40 miles as doable, except under tailwind all the way conditions. Just plan on some shorter rides, maybe where you park at some point where you can do some charging, then they ride a loop to return to where you are, with some more battery charged back up. You still get 30 miles of the ride easy, and they only ride alone a portion of the whole day. Once charged, you break wind for them going home.

I always get such detailed and informative replies from you, dogman, thankyou I might purchase another battery, as they just slot into the holder, and I'd carry it in a backpack.

 

[teklektik]

Wel I have a 36v 9ah Battery, I don;t suppose you could do the math on that for me, please? :/ I don't quite understand how you work it out.

The math will depend on lots of things hard to quantify, like how hard you pedal, that might be different for you. The numbers I spoke of were based on my riding, 10,000 miles worth of it.

But on a 40 mile ride, if you can't stop for a full recharge, you are about right on with your estimate of 20 miles of pedaling an extra heavy bike.

You really have to get more battery for those really long rides. If your buddies ride slow enough, and you are using a wattmeter to make sure you dont' start squandering your available battery, I see no reason why you could not learn to get 25 or even 30 miles out of what you have.

But I don't see 40 miles as doable, except under tailwind all the way conditions.

As dogman says - there are a lot attributes that are difficult to quantify, but for a simple estimate you can look at as a matter of the Wh capacity of your battery and your consumption in Wh/mi. This lumps all the attributes into a single magic 'consumption rate' - just trading a lot of little guesstimates for a single one . You have a small motor and aren't speeding along so you should be able to keep in 15Wh/mi range. Here's some spreadsheet snippets that show 36v and 48v NMC cell batteries with 9Ah and 18Ah capacities. I'm just guessing on the chemistry of your battery and that it's a 10s configuration.

Your present battery is the top row - 36v nominal @ 9Ah. The columns represent different consumption rates. As you can see, dogman's estimate fo 20 miles looks about right at the 15Wh/mi rate. The columns will give you a feel for the ranges you can expect. On the flat and using very little power you can get 30 miles but a little headwind or incline and it's a no-go for sure.

The second table shows your kit after adding a second identical battery for a total of 18Ah, . This looks good for a certain 40 mile range. The other table rows are for '48v' batteries, just to give a notion of how that changes things.


Another way to go after an estimate is to use Justin's simulator. The run below assumes a mountain bike with semi-upright posture, uses a small Q100 motor, a battery similar to yours, and a small 15A controller (just guessing there, but the run is at less than full throttle so the controller details aren't too important). The throttle was adjusted downward to get a no-pedal speed of 15mph. Here the red circles show the motor is running at about peak efficiency and the power needed to propel the bike (black line) will take about 158W of motor power or 200W of battery power (that efficiency thing...).

If you look at the green circle, you can see an estimate of about 14Wh/mi and a range of about 22 miles - this is pretty much as estimated above. This estimate is no-pedal and perhaps a little more optimistic, so you should be able to realize some additional distance from your personal pedaling contribution (lower Wh/mi). If you plug similar lower Wh/mi guesstimates from this run into the tables above, you will see the resulting ranges.


Anyhow - nothing too different from dogman's advice, but it may help give you confidence that his '10K mile seat of the pants' estimate is pretty much spot on (or at least agree with the estimates here that are wrapped in a little arithmetic...).

 

[Architectonic]

The math will depend on lots of things hard to quantify, like how hard you pedal, that might be different for you. The numbers I spoke of were based on my riding, 10,000 miles worth of it. ( which is becoming not so far compared to others now)

Getting a wattmeter will help you learn to ride as efficiently as possible. The stand alone cycleanalyst will work with any controller, or a less sophisticated wattmeter can be found on ebay for under 20 usa bucks.

This sums it up. Yes, we can tell you about aerodynamics vs speed, to pedal etc. But the only way you will actually learn to ride efficiently is by seeing the effects of your behaviour in real time.

 

[MadRhino]

Building a bike for range and riding your actual bike to maximum range are two different things.
When building you can do a lot to optimize range, but once you are riding the only thing you can do is to keep within pedal speed to use the motor only as an assist, try to limit wind resistance with clothing and posture, and avoid using power in hard acceleration.

Best for me, is to carry enough battery to ride and not bother. That is why I build my bikes with modular battery system. Carry no more that you need for performance, and no less for range.

 

[dogman dan]

If you have a wattmeter, and know your wh/mi average, then the math is very easy.

Maybe I missed it, I thought he had no wattmeter. But in general, it's very hard to get below 15 wh/mi unless you ride really slow.

A watt hour is one watt discharged for one hour. To get your watt hours size of the battery multiply the amp hours x the volts. So if your battery is 36v, it's typically at least 40v when you use it. So 40 x 9 is 360 watthours.

360 watthours divided by 15 is 24, 24 miles range. If you ride 20 wh/mi, then 18 miles max. If your battery actually delivers the full 9 ah. I would guess you get 8 ah in the real world for sure.

15 watt hours per mile should be quite possible for you, at 15 mph. Perhaps even 10-12 wh/mi. But if you ride into wind, you might find it closer to 20 wh/mi. That's the really incalculable thing, the weather that day.

Getting some more battery when you can is the thing to do for really long rides, meanwhile go on as much of the ride as you can. When you get two batteries, you might even be able to leave one charging someplace, then return for it later in the day.

On the other hand, at 16 years age, just go pedal the 40 miles on a regular bike. I did that all the time at that age. 40 miles wasn't any big deal.

 

[teklektik]

If you have a wattmeter, and know your wh/mi average, then the math is very easy.

Maybe I missed it, I thought he had no wattmeter. But in general, it's very hard to get below 15 wh/mi unless you ride really slow.

A watt hour is one watt discharged for one hour. To get your watt hours size of the battery multiply the amp hours x the volts. So if your battery is 36v, it's typically at least 40v when you use it. So 40 x 9 is 360 watthours.

360 watthours divided by 15 is 24, 24 miles range. If you ride 20 wh/mi, then 18 miles max. If your battery actually delivers the full 9 ah. I would guess you get 8 ah in the real world for sure.

Ya - the spreadsheet calculation above is identical, but also accounts for DoD - normally 80% for LiFe and assumed above to be 90% for LiMnCo (as provided by cell_man) and uses the nominal battery voltage - the mean value across the entire discharge curve (varies with cell chemistry). Using the HOC (hot off the charger) voltage or ignoring the DoD will yield more optimistic results.

As you can see above, this gives an estimate for your present battery of 291Whr which relies to some extent on the listed battery chemistry and discharge policy.

 

[dogman dan]

Yeah, I just felt I hadn't given him the simple equations he asked for.

I tend to go numb in the brain looking at graphs. It all comes up the same, he's got about 18 miles of reliable range at 15 mph IMO.

 

[lotrwiz]

Thankyou to everyone for your answers, I really appreciate the detail and effort you have put into them. I think I'l be upgrading to a 48v, much larger, rear pannier mounted battery system around christmas as I generally receive a substantial amount from my online work+family around that time.

In the meantime, I'll try a long ride with my ebike, as I prefer to ride that, it just feels much more stable and everything is the way I like it. If it doesn't go well, I'll take my nice (more or less) 15 kilogram road bike on future trips until I upgrade my current system.

Thankyou all again (and you're right, graphs do melt my mind)

 

[d8veh]

Just set the PAS level to level one, and you should be able to do 40 miles. I'm 100kg and on a route with some hills I can get about 35 miles with medium pedalling from a 36v 9aH battery and motor like yours. You can extend the range a bit by switching off when you don't need power. The faster you go, the less power you use. On your own you can pedal above 15mph, which doesn't use any power, but if you're travelling with other people, you'll probably be going slower. Most power is consumed going up hills slowly, so pedal hard on them to keep your speed as high as possible. Don't use knobbly tyres on a MTB. Schwalbe City Jets are cheap ( about £30 a pair on-line) and cut your rolling resistance right down.

 

[lotrwiz]

Just set the PAS level to level one, and you should be able to do 40 miles. I'm 100kg and on a route with some hills I can get about 35 miles with medium pedalling from a 36v 9aH battery and motor like yours. You can extend the range a bit by switching off when you don't need power. The faster you go, the less power you use. On your own you can pedal above 15mph, which doesn't use any power, but if you're travelling with other people, you'll probably be going slower. Most power is consumed going up hills slowly, so pedal hard on them to keep your speed as high as possible. Don't use knobbly tyres on a MTB. Schwalbe City Jets are cheap ( about £30 a pair on-line) and cut your rolling resistance right down.

I don't have the PAS hooked up, maybe I should. Well thankyou, I'll give it a shot and tell you how it goes.

 

[swbluto]

Wel I have a 36v 9ah Battery, I don;t suppose you could do the math on that for me, please? :/ I don't quite understand how you work it out.

40 miles with about 350wh of battery requires about 8-9 wh/mi. In my experience, this means going 12-15 mph and pedaling a lot. 15mph requires something like 15wh/mi from a regular ebike, so your pedal power would have to contribute somewhere around 40-50% of the total power required of the bike at 15 mph.

 

[d8veh]

Wel I have a 36v 9ah Battery, I don;t suppose you could do the math on that for me, please? :/ I don't quite understand how you work it out.

40 miles with about 350wh of battery requires about 8-9 wh/mi. In my experience, this means going 12-15 mph and pedaling a lot. 15mph requires something like 15wh/mi from a regular ebike, so your pedal power would have to contribute somewhere around 40-50% of the total power required of the bike at 15 mph.

That's about right. He's young and lightweight, so presumably quite fit, or if not, will soon be. He'll be travelling with others, who I guess are on non-assisted bikes. Using the level one PAS will cut power after about 11 mph because it works as a speed control like a fixed throttle position. It will still give good torque on the hills.

I have friend that's 70 years old and suffers from MS, which is taking the strength from one leg. He's about 65kg and a keen cyclist. He couldn't keep up with his cycling buddies anymore, so I helped him fit an Oxydrive kit (250w 8.8 aH). He regularly goes over 50 miles, and he's never reached battery cut-off yet, so you can see what's possible. It just depends on how you use the power. It's a completely different situation to riding a 500w MAC at 25mph.

 

[dogman dan]

Sure, a speed limiter of any kind set low enough would make it last. It would be about the same in effort though, as running out half way.

He's young and strong, it might be quite easy for him to just use the assist on the hills and have plenty of range. But yeah, to have a better assist all the way, the calculation needs to be made based on about 15 wh/mi. When he gets more battery, he can just carry both for the long trips. The holidays come soon, so the problem will be fixed pretty soon. He doesn't need that much more to get 40 miles at 15 mph.

Meanwhile, go ride anyway, and just pedal hard. If you can hold the throttle low enough, you can go the 40 miles. It's just that most don't. About 75 watts is all you need to make the bike ride like it's lighter. But you would still need more to make it ride easy up the hills.

 

[lotrwiz]

Sure, a speed limiter of any kind set low enough would make it last. It would be about the same in effort though, as running out half way.

He's young and strong, it might be quite easy for him to just use the assist on the hills and have plenty of range. But yeah, to have a better assist all the way, the calculation needs to be made based on about 15 wh/mi. When he gets more battery, he can just carry both for the long trips. The holidays come soon, so the problem will be fixed pretty soon. He doesn't need that much more to get 40 miles at 15 mph.

Meanwhile, go ride anyway, and just pedal hard. If you can hold the throttle low enough, you can go the 40 miles. It's just that most don't. About 75 watts is all you need to make the bike ride like it's lighter. But you would still need more to make it ride easy up the hills.

I've been doing 20 miles on a 15kg road bike recently, and that really wasn't a problem at all, so I reckon I can just go for it and see how it goes, if it takes me a bit longer to get home, I won't mind, my friends will probably be more tired than me anyway

 

[tony67]

If you do go for it, remember you should not run your battery beyond 80% DOD meaning you really only have 260wh available to you not 324wh, that's 6.5 wh/mile!!!. On occasion you can discharge deeper but it is not advisable to make a habit of it.

With such little energy available to you and such a long ride planned, you will find you are either running very slowly or pedalling for most of the journey.

There comes a point when you would be better off on a standard non-e bike due to the fact you a lugging around all the ebike equipment but pedalling for most of the journey. IMO you are beyond that point.

TBH you really need more battery capacity. I would suggest 44v 10 ah of lipo as an auxiliary battery provided your controller can take it, which it should. Charge it up and put it in a back pack. It would be light enough and small enough. Run your 36v9ah to 80% DOD and switch to the lipo. In total you will have ~620wh available. With care and not an insignificant amount of pedalling this will see you through your 40 mile trip.

Tony

 

[swbluto]

There comes a point when you would be better off on a standard non-e bike due to the fact you a lugging around all the ebike equipment but pedalling for most of the journey. IMO you are beyond that point.

For those kinds of trips, I'm a big fan of freewheeled geared hub motors. I don't own one myself, but I could see it being particularly advantageous for long distance trips where you don't want the equipment dragging on you when you're not using it. (Weight, by itself, is a tiny concern at speed on flat land.)

I personally use a 9c motor on my ultra-long-distance bicycle and I've found that having a higher no-load speed from using a higher voltage battery actually reduces the wh/mi. consumption when I'm trying to be sparing while maintaining ~15 mph. It appears the extra cogging affect with a no-load speed of 15mph at 24v ends up reducing the overall efficiency at 15 mph.

That bicycle above is theoretically capable of 200miles on a single charge with 1kwh of batteries at 20-mph, but you'll run out of daylight long before getting close to depleting the battery.

 

[d8veh]

If you do go for it, remember you should not run your battery beyond 80% DOD meaning you really only have 260wh available to you not 324wh.....

His battery as a BMS so he doesn, t have to worry about that. It's already taken into account in the 9aH.