Range, Miles/AH or WH/Mile

[llile]

I'm using a Stokemonkey, and a Cycle Analyst which gives readings of Miles/AmpHour or Watthours/Mile. I'm using Miles/AH as a gas gauge. I have a 20 AH battery from Ping.

On the first ride, I was getting 1-2 miles/AH, and feeling fine about that, because that is about what I had estimated using online calculators. But using the Cycle Analyst, I can game the amp settings, gear down, and watch out for amp-hogging situations like jackrabbit starts. I now regularly get 3 miles/AH, and have gotten it up to 6 miles/AH by reducing average speed just a little bit, esp. on hills. At 6 miles/AH I have a 120 mile range with a 20AH battery!

The Stokemonkey/Cycle Analyst combo teaches you to keep the cadence up, to maximize range and efficiency. Often I can watch the amps drop by 2 amps each time I shift down another gear. I also find that power goes up fast with speed - averaging 11-12 MPH, 16MPH on the flats and 8 mph uphill is almost twice as efficent as averaging 15MPH and hitting 10MPH uphill and 20MPH on the flats.
(I have a lot of hills)

What do people get as average miles/AH on other E-bikes?

 

[neptronix]

Miles per AH really depends on how many volts you're running.
It's more about watt-hours per mile.

But If you're running 36v-ish like i am, 2 miles per amp hour is what i get pedaling furiously going 20-27mph on a flat with no headwind.

 

[Metallover]

I get about 40Wh/Mi blasting around town with a 72v 9c setup. I can get it down to about 20 if I go slow and up to about 60 if I really get after it.

Miles/Ah isn't a very universal measurement because Amp-hours doesn't take voltage into account. The watthour/mile takes voltage and Amp-hours into account.

 

[llile]

Miles per AH really depends on how many volts you're running.
It's more about watt-hours per mile.

But If you're running 36v-ish like i am, 2 miles per amp hour is what i get pedaling furiously going 20-27mph on a flat with no headwind.

Yep, 36V setup, so 2miles/AH is about 18 WH/Mile. What kind of WH/Mile do you expect to get on a normal, non-furious commute?

 

[llile]

I get about 40Wh/Mi blasting around town with a 72v 9c setup. I can get it down to about 20 if I go slow and up to about 60 if I really get after it.

Miles/Ah isn't a very universal measurement because Amp-hours doesn't take voltage into account. The watthour/mile takes voltage and Amp-hours into account.

OK, 6 miles/AH is roughly 6 WH/mile at 36V (Math just works out that way) 3 miles/AH is roughly 12WH/Mile.

 

[neptronix]

Maybe 1.8 miles per ah?
Seriously; my furious pedaling is that of an overweight 230lb 30 year old so ..
It doesn't contribute much to the power. Not at the 26mph+ that i cruise at where aerodynamics are trying to brake you!

 

[amberwolf]

Mmmm...I don't use teh M/Ah readout, only Wh/M, but it can still be calculated from my data in the CrazyBike2 thread. Comes out to range from ~2.5M/Ah, down to ~1.9M/Ah, depending on the speeds I go, and whether carrying much cargo, etc.

CB2 is about 150lbs and so am I, typically riding at 20MPH top speed and probably 14-15MPH avg with lots of starts and stops in traffic. No pedalling. 48V pack.

 

[John in CR]

To me adding pedal effort and then quoting consumption and range numbers is like using a moped and turning the engine off on the easy stretches to pedal it and coming back to report that your get 1000mpg.

As far as slowing down to get better mileage, that's fine for joy riding and combining joy riding with transportation. As basic transportation I have to cry foul, because anyone valuing fractions of kwh's of electricity more than their own time has priorities I could never understand. Time is all we have on this rock.

Don't get me wrong, I have no issue at all with anyone using electric as true assist. Just don't go quoting consumption and range, because that's just as invalid as a cyclist using a fan and an AA battery and saying they have an EV that uses less than 1wh/mile with a hundred mile range on a single AA battery.

 

[NeilP]

Well with my setup, 84 v Lipo on a Mongoose frame, 26 inch wheels, Crystalyte 48 amp controller and a 5304
I have averaged 44 Wh/mile over the last 10 pack cycles. last night I cam home about 3 miles, no pedalling, all on the flat, at about 32 mph..not quite WOT and it was reading 51Wh/mile. max speed on this bike is about 38 on the flat nil wind...Cant wait to get my Lyen controller back

A few weeks ago, while that motor and pack was on a lighter Trek 8500 frame, and with a Lyen 65 amp controller, That was faster (50 mph max ) ...I was averaging 37 Ah/mile

 

[Spacey]

To me adding pedal effort and then quoting consumption and range numbers is like using a moped and turning the engine off on the easy stretches to pedal it and coming back to report that your get 1000mpg.

As far as slowing down to get better mileage, that's fine for joy riding and combining joy riding with transportation. As basic transportation I have to cry foul, because anyone valuing fractions of kwh's of electricity more than their own time has priorities I could never understand. Time is all we have on this rock.

Don't get me wrong, I have no issue at all with anyone using electric as true assist. Just don't go quoting consumption and range, because that's just as invalid as a cyclist using a fan and an AA battery and saying they have an EV that uses less than 1wh/mile with a hundred mile range on a single AA battery.

Great post, a few ebike sellers would do well to remember this.

 

[emotofreak]

I like Miles per kWh (M/kWh) as it is roughly synonymous with MPG. People will intuitively understand this. The xprize guys are pushing the MPGe standard.

 

[Kingfish]

My commute recently changed and I am traveling 44 miles/day, though it is mostly urban + trails and I can’t go very quickly with knots of riders. ESPECIALLY TODAY!! It was like “Ride Your Bike to Work Day” today in Seattle. Anyways the point is I have some recent data to share. 8)

Over two days I went 88.48 miles, using 27.4 WH/mi. This calculates out to 2.424 kW. The total Ah for this period was 42.52 which suggest that my pack voltage was about 57V; I don’t agree with this figure as my terminal voltage was just below this – however it could make sense if we account for the voltage drop under load. Regardless, you want results...

Miles/kW -> 88.48 / 2.424 = 36.5 mi/kW. Though I do try to go WOT, urban traffic slows me down, thus my average speed was about 22.8 mph. My pack is 15S6P LiPo.
Miles/Ah -> 88.48 / 42.52 = 2.081 mi/Ah. I’ve calculated this figure in the past and this is on par for my riding style of the last 18 months.

Cheers, KF

 

[NeilP]

What sort of speeds are you doing to get those figures? Motor type and controller ( 40 amp? 60 amp etc)

Are you pedalling too?

I have. Trouble getting my Wh/mile figure down to 35 , and that is with pedalling, 48 amp controller at the low of 3 settings and keeping the speed down to about 32 -35 max

 

[Kingfish]

What sort of speeds are you doing to get those figures? Motor type and controller ( 40 amp? 60 amp etc)

Are you pedalling too?

I have. Trouble getting my Wh/mile figure down to 35 , and that is with pedalling, 48 amp controller at the low of 3 settings and keeping the speed down to about 32 -35 max

Neil, read my sig
Controller is just a little 25A 6FET that I modified: Upgraded caps, R12 mod, mega-beefed traces, and upgraded batt/phase wiring to 10AWG. I posted my average speed. MaxS was 41.5 mph but that could just be tire spin; normally I can't pedal faster than 35 mph; most of the time I'm doing 30 mph. And I pedal all the time :wink:

Max-Amps never goes above 45A; it's current-limited to 2 hp/1500W.

Best, KF

 

[NeilP]

Neil, read my sig

Doh....

sorry, tend to glance over the sigs, but just because it is in the sig, does not need to be the bike you are quoting.....my excuse anyway and I am sticking to it

 

[Kingfish]

No worries friend

...more coffee <slurp!> KF

 

[NeilP]

too late for coffee here...on the red wine

 

[magudaman]

If I ride with others (group rides) I can usually get around 37 wh/mi but when I ride alone on the trails I see around 57 wh / mi. I had a hill out in the east bay area here that pushed up my meter to 127wh / mi

My bike weighs around 100lbs

Watt hours is the way to go, a lot easier to compare, I see that my amp hours varies some while my watt hours is pretty dead on everytime

 

[llile]

Well, I switched the Cycle Analyst display to WH/Mile since it is more standard.

I run the same 40 mile stretch repeatedly. I have run this stretch using 6 wh/mile, when I was really babying it (nice Sunday afternoon joyride! 6 amps limit) 12 WH/Mile quite often (9 amps limit), and 20-25 WH/Mile today (still 9 amps.???).

I'm not trying to save watts with these calcs. THe point is to be able to estimate range and not run outta juice! I theoretically have 540 watthours (36 volts * 15 amp-hours). If I'm running 12 WH/Mile, then I can make the round trip on one charge. If I am running 25 WH/Mile, I can barely make it in two charges.

Using more watts doesn't make me go significantly faster, since the Cycle Analyst currently limits to 20 MPH. (Note- gotta figure out how to change that. It isn't in the setup screens on my version of cycle analyst.) Cranking up the amp limit just means more acceleration to 20 MPH and faster uphill climbs. I've been setting the amp limit so I get about 350 Watts maximum. Because of some flats and downhills on the route, this usually gets me there and back on 400-500 watts.

I am quite surprised to find I can run the same route, same settings, and see WH/Mile "mileage" vary by double. I've recently run 12 WH/Mile and 22 wh/mile. I am not sure why so much variation.

I am thinking that the stokemonkey should be significantly more efficient than a hub motor, since I can always make the stokemonkey run at an ideal 90 RPM, right in the best range. Hub motors suck a lot of amps crawling up hills, at low efficiency. I climb a lot of short, steep hills and this is one reason I steered away from hub motors toward the Stokemonkey. Since the bike calculators are all set up for hub motors http://www.ebikes.ca/simulator/ it would be hard for a potential mid-drive motor owner to estimate battery range before buying and trying. I can get far more range out of this battery than I estimated before I built the rig.

There is also the emergency situation where I realize Ihave unerestimated my range. Cycle Analyst to the rescue! Cranking the amp limit down to 3 amps, just enough to get my heavy bike up a hill, really extends the range. I could theoretically get 100 miles range on a 15 amp-hour battery by cranking it down to micro-wattage range, but still go faster than just pedaling. I was pacing a bunch of regular bikes on a trail (I was sagging gear!) using this method, and really did see 100 miles range.

 

[dogman dan]

I tend to get about 30 wh/mi commuting. That's at 20-25 mph and includes a very large hill. 9c motors, 20 amp controllers. Wh/mi depends mostly on my speed, but if I have a nice headwind going up that hill, it can nearly double. I pedal enough to make my ass more comfortable.

Riding dirt, it can be anything from 40-55, depending on the controller in use. It's a high number, but not when you consider what that bike is doing for me in the dirt. I pedal seldom in dirt.

As for the time wasted commuting slower, I consider it the best part of my day. So I don't mind it taking 15 min longer than a fast bike.