Distance per charge? Nuances?

[Kurt in CT]

Hey folks, I need some perspective from some of you ebike vets please. I'm trying to learn the nuances of how far I get on a battery charge, get to know my bike, and how far I can go, etc. . When my manufacturer says my bike gets up to 50 miles on a single charge, what exactly does that mean? I generally understand normal variables like hills, bodyweight, temperature. But i'm a little confused by the performance of my new bike, and no idea if it's normal or not.

Tell you what I mean: Last Saturday I charged up the battery fully. Then took 6 mile rides on 3 successive days. (18 total miles). The bike sits overnight in about a 45° garage. And my rides outside are at about the same temperature. On day 4, my battery was at about 30%. Does this sound normal? To me, that seems low and I would expect it to be a 50 or 60%. Certainly never hit 50 miles at that rate. But maybe the time and duration played a big role.

I haven't had the bike that long, have never done a long ride with it, and I've never had warm temperatures. So, this may be much to do about nothing. Would appreciate hearing some of your experience on the nuances of battery performance. Thank you.

 

[Bruce Arnold]

First off, you can pretty well ignore mileage claims from manufacturers. At best, they are like EPA gas estimates. There are some estimates that I'd trust more than others, in the EPA sense.

Second, do you know the watt-hours of your battery? Voltage x amp-hours = watt-hours.

Third, does your bikes LCD display give you figures on how many watts are being consumed, or better yet how many watts have been consumed? If so, you've got valuable information. Go out and ride, say, 5 miles on your typical terrain. Try to maintain an even pace (plus or minus a couple mph, I mean, we're not robots). Note how many watts were consumed, if you have that data, or keep checking watts currently consumed to get at least a rough idea of how much current you're drawing.

With that information you ought to be able to get a rough computation of how many watt-hours per mile your bike uses. Factor in that stuff you already mentioned, like hills, body weight, and temperature, and your own experience will tell you better than any of us what to expect.

 

[rich c]

You don't describe your rides, how much you weigh, and how much you pedal or use the throttle. So no way we can predict how you are doing. If you lay on the throttle for 6 miles, or use max assist for 6 miles, it will use up the capacity really quickly.

 

[Kurt in CT]

First off, you can pretty well ignore mileage claims from manufacturers. At best, they are like EPA gas estimates. There are some estimates that I'd trust more than others, in the EPA sense.

Second, do you know the watt-hours of your battery? Voltage x amp-hours = watt-hours.

Third, does your bikes LCD display give you figures on how many watts are being consumed, or better yet how many watts have been consumed? If so, you've got valuable information. Go out and ride, say, 5 miles on your typical terrain. Try to maintain an even pace (plus or minus a couple mph, I mean, we're not robots). Note how many watts were consumed, if you have that data, or keep checking watts currently consumed to get at least a rough idea of how much current you're drawing.

With that information you ought to be able to get a rough computation of how many watt-hours per mile your bike uses. Factor in that stuff you already mentioned, like hills, body weight, and temperature, and your own experience will tell you better than any of us what to expect.

Bruce, thanks! Yes, it shows Volts, so I can run your experiment!

Btw, here’s the specs:
Motor: 8Fun Rear-Mounted Geared Hub 500 Watt Nominal / 700 Watt Peak Output
Battery: Samsung / Panasonic / LG – 48 volt 13 ah ( 624 wh) – Lithium Nickel Cobalt Manganese (Li-NCM)
Estimated Charge Time / Estimated Range: 6.5 hrs / 30 to 60 miles

 

[Kurt in CT]

You don't describe your rides, how much you weigh, and how much you pedal or use the throttle. So no way we can predict how you are doing. If you lay on the throttle for 6 miles, or use max assist for 6 miles, it will use up the capacity really quickly.

Rich, thanks. I use virtually no throttle, 175 pounds, mix of hill and flat terrain, pedal fairly aggressively.

Specs:
Motor: Geared Hub 500 Watt Nominal / 700 Watt Peak Output
Battery: Samsung / Panasonic / LG – 48 volt 13 ah ( 624 wh)

 

[christob]

On my Yamaha, if I pedal at a cadence higher than 92 RPM, I can increase range by about 30-40%. That’s because power progressively drops off above 90RPMs.
So the trick is to determine at what cadence your drive is drawing the most power, and avoiding it. Often you’ll be surprised to find that extra range can be achieved with a proportionally small amount of extra effort. Another tip: start off slowly and in a low gear at red lights. If you have a lot of start/stop it can make a pretty big difference.

Any thoughts on accessories to obtain that kind of data for review, if I can't get it via my display? Don't have cadence measuring, nor can I see power consumption in detail (just 5-bar battery gauge.). Believe my battery is 48v / 10.4ah, along with 750w hub motor.

 

[Kurt in CT]

Not sure what bike you have, but I’ll give you something to explore: by changing your cadence, you can often increase range.

On my Yamaha, if I pedal at a cadence higher than 92 RPM, I can increase range by about 30-40%. That’s because power progressively drops off above 90RPMs.

This also works on a Bosch, but with different cadences. On the Bosch Performance Speed, I’d want to use lower cadences to save some energy...

So the trick is to determine at what cadence your drive is drawing the most power, and avoiding it. Often you’ll be surprised to find that extra range can be achieved with a proportionally small amount of extra effort. Another tip: start off slowly and in a low gear at red lights. If you have a lot of start/stop it can make a pretty big difference.

Jay, understood, thanks. Excellent advice. The output on my monitor does show in bars how much juice is getting consumed on a constant basis. I can adjust cadence accordingly.

 

[Bruce Arnold]

Any thoughts on accessories to obtain that kind of data for review, if I can't get it via my display? Don't have cadence measuring, nor can I see power consumption in detail (just 5-bar battery gauge.). Believe my battery is 48v / 10.4ah, along with 750w hub motor.

Look at the Grin Technologies Cycle Analyst and see if it's an accessory you'd like to add on. It provides all kinds of information, and some functionality (like a cruise control feature) that most bikes don't have.

We're lucky, in Juiced Bikes-land, that Tora has provided us a system that provides so much information, has cruise control, etc., at no additional cost. But the Cycle Analyst is not the most expensive accessory you might buy.

 

[christob]

Thanks, @Bruce Arnold I’ll look at it. My display is certainly “enough” for general riding but lacking in those more techy specs that tickle my curiosity about the bike and my riding style, when I read posts about watt hours etc.

 

[Mikey-]

Last year we posted some results from quite a number of range tests we performed IRL.

The closest test to your situation would be the Pedego Ridge Rider with a 48v 11Ah battery (it's since been upgraded to 13Ah). 500w motor, controller throwing around 12-15a I would guess. On max torque pedal assist I got 39.6 miles. It was relatively flat; total elevation gain/loss was +929 / -758
If you bike in a flat-ish valley like I do, then I'd guess real world number around 40 miles if you can competently shift gears and use PAS.

 

[JoePah]

Hey folks, I need some perspective from some of you ebike vets please. I'm trying to learn the nuances of how far I get on a battery charge, get to know my bike, and how far I can go, etc. . When my manufacturer says my bike gets up to 50 miles on a single charge, what exactly does that mean? I generally understand normal variables like hills, bodyweight, temperature. But i'm a little confused by the performance of my new bike, and no idea if it's normal or not.

Tell you what I mean: Last Saturday I charged up the battery fully. Then took 6 mile rides on 3 successive days. (18 total miles). The bike sits overnight in about a 45° garage. And my rides outside are at about the same temperature. On day 4, my battery was at about 30%. Does this sound normal? To me, that seems low and I would expect it to be a 50 or 60%. Certainly never hit 50 miles at that rate. But maybe the time and duration played a big role.

I haven't had the bike that long, have never done a long ride with it, and I've never had warm temperatures. So, this may be much to do about nothing. Would appreciate hearing some of your experience on the nuances of battery performance. Thank you.

That is a good question and I hope there is a detailed article in Battery University.. Maybe one of our admins would like to post, like Court? Throttle only bikes rarely get close to their advertised range; mostly a joke.

These are facts you should remember regardless of your actual range:

1. The battery charge indication on eBikes is total crap.. It is anything but linear, plus when battery charge drops below 15% you can easily lose power at any time.

2. Cold weather has a significant impact on battery performance, much more so than hot weather.. Storing your battery in a 45F room is fine..

3. Range is affected by hills; it is not a zero sum game.. You expend a lot more energy going up than you save going down the same hill.

4. Range is affected by speed; if you can keep your bike below 15 mph and don't start and stop a lot, your range will increase dramatically.

5. Pedal assist ebikes can increase range significantly; you don't say if you have that.


Best thing you can do is write down battery level at different distances (every 5 miles or so), and at different times of the year, at your normal steady speed.. At least this way you will know what YOUR range is. and that's what counts.

And avoid running your battery until it shuts off, if you can... Improves cycle life.

 

[Kurt in CT]

Update: I filled up the battery and just took a 12.6 mile ride on rolling blacktop terrain. This time, per the excellent advice in this thread, I purposefully worked a little bit harder ( not killing myself) and paid attention to my cadence. As a result, there were significant portions of the trip that I did not use any power, but... definitely used pedal assist on every grade. No throttle used. Result: by my calculations (looking at volts used on the monitor and what the mfg says is the depletion number), I used up 14.3% of the battery power. And if my math is correct, that extrapolates to 88 miles in potential range at that rate.

Admittedly, I was frugal on the power use. But at least I'm starting to get to know the capabilities of myself and my bike, and feel a little better about things. Needless to say, there's a little more to this than they tell you when you buy the bike!

The other thing I will mention is the different overall experience when using power versus not using power. I guess it all depends on what you want to accomplish when riding. If you have to get to work and time matters, then this subject is particularly relevant. When I leave the power on all the time for pedal assist and don't really pay attention to conservation, I go a whole lot faster. And the opposite is true. When I'm flat terrain and not using pedal assist, I move along OK, but with this 50+lb bike, its kind of slow and lumbering. Fine if I'm sightseeing, but not if I want to move along at a faster clip.

 

[Kurt in CT]

Last year we posted some results from quite a number of range tests we performed IRL.

The closest test to your situation would be the Pedego Ridge Rider with a 48v 11Ah battery (it's since been upgraded to 13Ah). 500w motor, controller throwing around 12-15a I would guess. On max torque pedal assist I got 39.6 miles. It was relatively flat; total elevation gain/loss was +929 / -758
If you bike in a flat-ish valley like I do, then I'd guess real world number around 40 miles if you can competently shift gears and use PAS.

Thanks Mikey. Your service on this subject is a great one. Btw, in your tests, im assuming the PAS is always on and using juice (as opposed to my recent test ride above where I turned off the PAS on flat and downhills), correct?

 

[christob]

I'm still working out gauging my realistic range as well... Which I realize is just too variable to emphatically ever state a simplified, "I get X miles". Weather (coming out of winter cold morning commutes now), headwinds, terrain, my slowly decreasing---already down 12lbs since biking!---yet still overweight body...
I managed a 36 mile trek with careful attention paid to using lower PAS settings and lower gearing as needed -- returned home with 3 'battery gauge bars' still showing.
Today was 32 miles r/t (I think with about 835ft cumulative elevation gain if I used the veloroutes map tool correctly) also ending with 3 bars remaining -- again on this trek I switched between levels (and gears) a lot, giving preference to Level 1 -- spent a good amount of the ride in the 12 - 17mph range. Also tried to remember to dip into Level 0 on flats and longer stretches of subtle down-hill.
But I'm still painfully aware of the day my battery died after only 20 miles... granted, it was chilly, it was very hilly, and it was super gale-warning windy...

 

[ROJA]

I log all my rides using Strava and I include in the filename the power setting used and the % of battery left at the end. After a bunch of rides, this has given me a good idea of my effective range under a variety of conditions.

It's also really fun to use Strava and track your progress! www.strava.com