# Battery capacity.



## justin70 (Sep 17, 2007)

I’m just getting into ebikes and researching the options. It looks like 400-500Watt hours is about the typical capacity of these batteries. What can I expect in the real world for range for Clydesdale rider 250-300 lbs through mountainous terrain? For example, 3500 ft elevation gain over 8 miles? Will these batteries last? And if not are larger capacities available?


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## fos'l (May 27, 2009)

Coincidentally, there are two ascents (8-9 miles, 3500' elevation change), that I've ridden with a number of different eMTB's and 500 or so w-h. Used 80-100% of the battery capacity in every instance with moderate pedaling (except one glorious ride on a 2WD bike that had a stuck torque sensor --- should have purchased that bike), 180 pound rider. You might be riding home with a dead battery.


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## Bigwheel (Jan 12, 2004)

Totally dependent on your speed over ground expectations. If you use the motor as an assist in your lowest gears you should have no problem keeping the wh/mi in the 20-30 range. You will still be going faster than your normal pace. If you want to blast up and over then you may have issues but even @ 50 wh/mi (twice the normal average you can probably expect at your weight combined with a 50 lb. or more bike) a 500 wh battery should last 10 miles ride 3500' in 8 miles.


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## justin70 (Sep 17, 2007)

Well I’m not afraid of a getting a workout to some extent. Ideally I’d use the ebike to go on long exploring rides in the mountain trails around my house. 3500’ of gain would be typical, but even more gain, like 7000’, for an epic ride would be awesome. 

Are there bikes coming stock with higher capacity batteries? Or is it realistic to carry a 2nd 500watthour battery to swap?


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## AGarcia (Feb 20, 2012)

Depends upon how much effort you put in yourself. For example, if you run it at a Levo at 100% assist, you won't make it at your weight. If you run it on about 15%-20%, you'ed be ok.


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## AGarcia (Feb 20, 2012)

justin70 said:


> Well I'm not afraid of a getting a workout to some extent. Ideally I'd use the ebike to go on long exploring rides in the mountain trails around my house. 3500' of gain would be typical, but even more gain, like 7000', for an epic ride would be awesome.
> 
> Are there bikes coming stock with higher capacity batteries? Or is it realistic to carry a 2nd 500watthour battery to swap?


Here's an example of a ride I did to figure out my range on a Levo (with a 460w battery). https://www.strava.com/activities/774939938

For reference, I'm about 235 in my birthday suit and about 250-255 lbs all geared up...

In order to get that high/far on a single charge, I used the Specialized Mission Control App to modify the standard power output. I modified the settings to start out at the absolute lowest setting (10% of max boost output). After 3000 feet of elevation gain, I found I had a little more than 60% of battery life left, so I adjusted the output to 15% of max for the second 3000 feet of climbing. Acceleration response and max motor current settings were also set to the minimum settings throughout the ride. Additionally, I turned off the motor assist during "flat-ish" sections of the ride in order to make sure I had some battery life in reserve in case I got tired for the final climb back to the car. Sure enough, I had about 5% battery life when I finished the ride.

At the lowest settings, it's giving some assist, but a workout for sure. Looking at my Strava Suffer Score, that's pretty equivalent to the same effort I would put out on a regular bike during a 3 hour ride with about 3000 feet of climbing.

If you lose some weight, or get a higher capacity battery (the higher end Levos have higher capacity batteries, for example) 7000 feet of elevation gain should be within reach if you use it sparingly.


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## matt4x4 (Dec 21, 2013)

Grinspector is only $195cdn


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## Tracer16 (Nov 6, 2017)

I have a 17 turbo levo with a 504w/HR battery and weigh in at 270lbs.

7000 feet of climbing is not possible on one battery. I'm in relatively decent shape and manage about 22 miles and and 3000 feet of elevation gain

This is rough Pacific Northwest terrain with the assistance set at 15%.

I wanted to do longer rides so I purchased a second battery. I removed the bladder from my osprey pack and use it to haul the second battery. Weight doesn't seem any worse that a full 100 ounce bladder. I strap it in with a bungee and use a seat post bottle cage holder so I have 2 water bottles for the long rides. Can't use the dropper but need the water more.


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## fos'l (May 27, 2009)

Guess I have a "lead foot" since I've ridden the following up one or both of the 8 or 9 mile, 3000' ascents: 1) 2017 Easy Motion 2WD 600w (total) with a 550w-h battery; 2) 2016 Haibike NDDURO with a Bosch system (396 w-h); 3) BBS02 with a 52V, 10 a-h battery; 4) 36V, 350w Dillenger front hub with a 600w-h battery; 5) 36V, 350w MXUS rear hub with the same battery as in #4 and 6) 2016 Specialized Levo. There may be more, but those are the most prominent ones. I ride considerably faster than the same trail on an MTB since there was a group to keep up with. In every instance the battery was > 80% depleted.


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## AGarcia (Feb 20, 2012)

Tracer16 said:


> I have a 17 turbo levo with a 504w/HR battery and weigh in at 270lbs.
> 
> 7000 feet of climbing is not possible on one battery. I'm in relatively decent shape and manage about 22 miles and and 3000 feet of elevation gain
> 
> ...


Wow. I imagine the rough terrain makes the difference. On the 6000 foot climb I made with the 460w battery, it's about 99% fire road climb.


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## AGarcia (Feb 20, 2012)

fos'l said:


> Guess I have a "lead foot" since I've ridden the following up one or both of the 8 or 9 mile, 3000' ascents: 1) 2017 Easy Motion 2WD 600w (total) with a 550w-h battery; 2) 2016 Haibike NDDURO with a Bosch system (396 w-h); 3) BBS02 with a 52V, 10 a-h battery; 4) 36V, 350w Dillenger front hub with a 600w-h battery; 5) 36V, 350w MXUS rear hub with the same battery as in #4 and 6) 2016 Specialized Levo. There may be more, but those are the most prominent ones. I ride considerably faster than the same trail on an MTB since there was a group to keep up with. In every instance the battery was > 80% depleted.


Was the trail pretty rough uphill, or was it fire road? If you're familiar with the OC trails (I think you might be). My 6000 foot climb was from Cooks Corner I climbed Santiago Canyon road, to Modjeska Grade, to Harding Truck Trail, to 4 Corners, to Main Divide, up to Santiago Peak... 6000 feet. I was also going pretty slow though.... Riding the same pace as my non-e friends.


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## fos'l (May 27, 2009)

That's a long ride; good for you. Most of mine were Maple Springs and I was always with other e-bikes so (for me) a fast pace. One time a young racer-type on an MTB accompanied us and basically kept up. As you know, that's a fire road, but pretty eroded. A few times it was quite cold (including ice at the top) which may have impacted capacity.


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## Tracer16 (Nov 6, 2017)

I think the start/stop of rougher terrain drains it quicker. I can do 30+ on fire roads with 5000 feet of climbing


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## dkw (Jan 14, 2018)

A lot of my rides are in the southern Sierras. My stock 500 watt hour Bosch is nice but it's just not quite enough so I bought a spare one. The short profile of the Bosch battery fits in my back pack nicely. Now I'm sporting 1000 watt hours of turbo bliss!


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## JesusEbike (Feb 15, 2018)

With a 48v system you can overvolt it to 52v which means that 50% of your power draw will be above 48v overvolting is not possible with a 36v system.


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## Moe Ped (Aug 24, 2009)

It's pretty easy to calculate regarding the climbing portions of a ride; weight times elevation equals work done. So a 3500' climb and a 350 # Clyde and e-bike combo is 1,225,000 ft/lbs or 461 Wh; right in that 400~500 Wh battery size mentioned. But that's in a friction-less world at absolute zero. Add in real world friction and such you'll be lucky to get 70% efficiency; a rider needs to make up for that with one's legs.

I have a fairly fit buddy who at around 200 # usually gets 25~30 miles and 4000' on his Levo's battery in mountainous terrain; he's played with custom settings (a bit above "eco") to where he'll hit the parking lot with a completely spent battery.


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## richj8990 (Apr 4, 2017)

Moe Ped said:


> It's pretty easy to calculate regarding the climbing portions of a ride; weight times elevation equals work done. So a 3500' climb and a 350 # Clyde and e-bike combo is 1,225,000 ft/lbs or 461 Wh; right in that 400~500 Wh battery size mentioned. But that's in a friction-less world at absolute zero. Add in real world friction and such you'll be lucky to get 70% efficiency; a rider needs to make up for that with one's legs.
> 
> I have a fairly fit buddy who at around 200 # usually gets 25~30 miles and 4000' on his Levo's battery in mountainous terrain; he's played with custom settings (a bit above "eco") to where he'll hit the parking lot with a completely spent battery.


OK so that means one watt/hr equals 2657 ft/lbs of torque? That's pretty cool, I'm more used to lb/ft of automobile torque.

Please let me know if this is correct: in my case, more casual riding, the goal is 20 miles in two hours, only 1000 foot climb (but a 10-20% incline), 210 lbs total x 1000 feet = 210,000 ft/lbs / 2657 ft/lbs constant (above) = 79 watt hours. If I have a 360W battery that's 10.5 Ah and only two hours of riding I should be fine correct?

Let's put the OP's variables in the equation above: 300 lbs x 3500 ft = 1,050,000 ft/lbs / 2657 constant = 395 watt hours. If they have a 480W battery, assuming a 70% efficiency then it's going to be close, they may not make it.

Is there any way for a moderator here to make a new sticky with all of the important equations, like the one above, and some easier ones for us newbies, like definitions of basic stuff, Watts, Amps, Volts, Amp hours, Watt hours, ft/lbs, the equation constant above, etc., and various real-world examples as above. I now have most of what I need to know (I think) but other newcomers would benefit greatly from an info. sticky.


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## Moe Ped (Aug 24, 2009)

richj8990 said:


> OK so that means one watt/hr equals 2657 ft/lbs of torque? That's pretty cool, I'm more used to lb/ft of automobile torque.
> 
> Please let me know if this is correct: in my case, more casual riding, the goal is 20 miles in two hours, only 1000 foot climb (but a 10-20% incline), 210 lbs total x 1000 feet = 210,000 ft/lbs / 2657 ft/lbs constant (above) = 79 watt hours. If I have a 360W battery that's 10.5 Ah and only two hours of riding I should be fine correct?
> 
> ...


Maybe start a new thread for converting stuff? (Two threads, one for metric and one for standard???)

You're on the right track although ft lbs force in torque is a little bit different than ft lbs force in work. And then there's power. (When time enters the equation)

The mother of all conversion sites is here

FWIW my DIY e-bike is more like 60% efficient.


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## richj8990 (Apr 4, 2017)

Moe Ped said:


> Maybe start a new thread for converting stuff? (Two threads, one for metric and one for standard???)
> 
> You're on the right track although ft lbs force in torque is a little bit different than ft lbs force in work. And then there's power. (When time enters the equation)
> 
> ...


OK another question. I've noticed in the few apps I've done offroad (hiking or biking), that they measure the min and max elevation. So you subtract the min from the max to get the net elevation increase. Here is the problem with that. Most of the time, you are not just going up one hill or mountain, turning around, and going back down to a level surface and then back to the car/home garage. You are going through a lot of inclines and declines just to even get to the hill or mountain with the highest elevation.

So, for example, if your goal is a 2000 ft mountain and 20 miles of biking, and there are ten smaller inclines averaging 100 feet before the mountain, do you now put 3000 feet into the equation instead of 2000 feet?

Secondly, if you are theoretically on a flat surface for 20 straight miles, then there is no "foot" of elevation to multiply with pounds. Is that where part of the inefficiency constant of 30-40% comes in? For simplicity if you are doing 100% throttle for 20 miles, you would not in this case rise a single foot in elevation but the battery is still being used. How is that use calculated?


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## Moe Ped (Aug 24, 2009)

richj8990 said:


> So, for example, if your goal is a 2000 ft mountain and 20 miles of biking, and there are ten smaller inclines averaging 100 feet before the mountain, do you now put 3000 feet into the equation instead of 2000 feet?


Right; you sum all the climbs---almost all GPS apps (like Strava) do this for you.



> Secondly, if you are theoretically on a flat surface for 20 straight miles, then there is no "foot" of elevation to multiply with pounds. Is that where part of the inefficiency constant of 30-40% comes in? For simplicity if you are doing 100% throttle for 20 miles, you would not in this case rise a single foot in elevation but the battery is still being used. How is that use calculated?


Level road you're looking at just aerodynamic drag and rolling drag; both can be measured in pounds force---knowing how how long it took to travel those 20 miles will allow a calculation of energy used. Simpler just to monitor power use with a watt meter/battery gauge. Use a bicycle drag calculator like this and then compare results to estimate efficiency. (There are dozens of similar bike calculators out there)


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## Whiptastic (Mar 14, 2016)

I like to use this simple Rule-Of-Thumb calculation to estimate range:

(Amp Hour * Volts) / 20 = Miles Estimated Range

Example:
(21Ah * 48V) / 20 = 50.4 Miles Estimated Range

I’ve squeezed over 100 miles out of my BBS02-B 750W/48V eMTB with 21Ah/1008Wh battery riding between 14-16mph on flat ground with pedaling. That said, this setup seems to deliver a very reliable 50-60 miles under my normal riding style.

The reality is, real world range has a huge amount of variables that are hard to pin down. Using this simple Rule-Of-Thumb calculation gets you right in the ball park for most applications.

FYI: 6’2”+ 230lb. Clyde here.


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