Best way to estimate expected range of EUCs by model name & driving conditions

[mathfux]

I'm struggling to find some good way to determine a relation between motor power, battery capacity and the range of wheel. I've seen a lot of people uploading videos with their range tests and getting completely different results. I know it depends a lot on whether conditions, riders weight, battery temp, ,,mountainousness" of the roads, etc... But feel like it's not as accurate as I would like to achieve while trying to predict what is the real range of a certain vehicle.

For instance, INMOTION v10 claims to have 60 miles range but in reality it varies from 20 to 35 miles. I'm 60kg weight, driving in 8°C, 18mph, a little bit windy, pretty plain roads and just don't know what to expect from INMOTION v10 or any other I can afford. Looks like another big issue from the perspective of freshmen in EUC industry as me. So my questions are:
 

     

• How does battery capacity vs motor power affect range? As for instance I use my KS-16S with 1200W motor and 840Wh, what's the most common range I expect to get regardless model name? What to expect from much better EUC with 2200W vs 1110Wh?
• How does weather temperature affect range? Say -10°C, 0°C, 10°C, 20°C?
• How does wind speed affect range? Say 2mph, 5mph, 10mph?
• How does [rider + vehicle] weight affect range? Say 60, 80 or 100 kilos?
• How does altitude change affect range? Say I ride 10 meters up and then 10 meters down per each mile of my journey but I can also 20 or even 50 meters if road is much more bumpy. Or 0 meters if it's completely plane.
• How does mileage affect range? As for instance I'm able to ride 40 miles with my new fully charged EUC, do I need to expect it to drop to 30 miles if I'll ride further 5000 miles?

I assume there's no need to measure full range while discharging a battery from 100% to 0% because it will shorten life of battery few times so I expect it to drop from 90% to 20% instead according to this article. I also usually ride asphalted roads around my house, my tire is inflated fully and I don't brake hard.

What are your insights on these factors? I'll try to share mine too if I find good sources.

 

 

 

 

 

 

 

 

 

[meepmeepmayer]

It's hard to answer many of these question precisely, because everything is so connected to each other - it's about the specific rider. So these are my views, don't take them as the only truth.

18 hours ago, mathfux said:

How does battery capacity vs motor power affect range?

Battery size (in Wh) is the only thing that counts here. Wheels with the same battery size will always have the same or very similar ranges.

Some people find some wheels a bit more or a bit less efficient, but it's always hard to say if it's just their riding speed, the tire, or any other factor that is different - or if there truly is a difference between wheels with the same battery size.

Motor power in general is a mostly meaningless number, and says exactly nothing about range.

18 hours ago, mathfux said:

How does weather temperature affect range?

In my experience, there can easily be a 10% difference (or more!) between riding at around freezing (0°C, where you get less range)) and riding around at room temperature (20°C - 25°C, where you get "normal" range).

18 hours ago, mathfux said:

How does wind speed affect range?

Your riding speed has a huge influence on your range, because most of the energy usage is air resistance. E.g. at 50kph you will get 20km of range from a wheel that will go 40-50km at 25-30kph.

So wind can play a big role, in effect it can act like you are riding faster.

Not sure how big a role it plays in reality, unless you have constant headwind, for example. People don't tend to ride when it's really windy.

18 hours ago, mathfux said:

How does [rider + vehicle] weight affect range?

A heavier rider will get a little less range, but it is hard to say how much of that is indeed the weight, and how much that the rider may be bigger and thus has more air resistance, which is the factor that matters.

Light and small riders can get amazing ranges compared to "normal" riders. I assume very heavy riders will get quite bad ranges.

18 hours ago, mathfux said:

How does altitude change affect range?

Relatively little. If you have really big elevation changes (e.g. on a mountain ride), you tend to ride slower there, so it balances out. Other elevation changes aren't big enough to make a difference.

18 hours ago, mathfux said:

How does mileage affect range?

In practice, mileage doesn't matter at all. So far I haven't heard of any rider who has less range on an older wheel. I'm around 10k km and get the exact same range I got when the EUC was new. Your changed riding behavior over time (maybe riding faster?) will drown out any battery degradation effects, if they exist. People talk about battery degradation, but nobody seems to have seen it.

-

In summary:

• The same battery size (in Wh) will give the same range, no matter the wheel model.
  Some wheels just make it easier or harder to go fast, and that will look like the wheels have different ranges, but with one or two specific exceptions it's all the same.
• You can't predict a range from a battery size, because it depends so much on the rider, with (average) speed being the most important factor.
• Really light riders can get amazing range, and really heavy riders may get disappointing range. Everyone in between... it's more or less the same.
• You'll get less range with cold or wind or whatnot, but it isn't so big of a difference that you can say much here. You'll always ride with some kind of reserve anyways, so this reserve will just be smaller or bigger on a given day.
• All manufacturers lie about ranges. Ignore any advertised numbers. Only Watthours (Wh) count.

As you say you weigh 60kg, that is quite good (you're light!) if you are looking for range from any wheel. Other than that, a bigger battery (more Wh) = more range, and a smaller battery means less range, that's really about it. Anything else (besides extreme temperatures or rider weights) gets drowned out by the different riding behavior of different riders. You certainly cannot quantify these factors in a meaningful way, unless you do a fully controlled scientific study. (Which would still tell you: really only battery size matters, the rest is in God's hands.)

If you absolutely definitely want a concrete number, I would say: 60kg, 18mph, 8°C = not too hot or cold - maybe 40km per 1000Wh? Maybe more. (For comparison: I get 50km of range going 30-35kph with 80kg rider and 1300Wh of battery.) This is just a rough guess, please don't see it as a guarantee Range strongly depends on how fast you are.

I made a list of wheel battery sizes here, precisely so people can find the biggest battery wheel available to them. How much range that is depends on the rider.

Edited October 3, 2022 by meepmeepmayer

[MrEUCMan]

This is easy. Take all manufacture posted range and divide by half. That's your realistic range.

[Mayhem]

40 minutes ago, MrEUCMan said:

This is easy. Take all manufacture posted range and divide by half. That's your realistic range.

100% correct & for really cold weather riding divide by 3 

Edited October 3, 2022 by Mayhem

[mathfux]

On 10/4/2022 at 2:10 AM, MrEUCMan said:

This is easy. Take all manufacture posted range and divide by half. That's your realistic range.

It's not right. I own KingSong KS-16s and manufacturer posts a 70-80 km range. In reality, I'm able to ride 70 km until full discharge. I've also seen e-shops writing it was 100km range and another one only 50-70km. I can't trust ranges provided by e-shops or manufacturers anymore so that's why I'm looking for different way to determine it.

I heard also that majority of manufacturers performs tests on ideal conditions to determine their EUC ranges. Plane road, 20°C, 70kg rider's weight, no acceleration, no wind. This might be sufficient enough to foresee what to expect in reality assuming effects of various circumstances are known very well.

By opening this topic, I encourage you to investigate contribution of various factors to EUC range more thoroughly. I'll share my efforts too.

To start with, I'll share my insights how to derive EUC range from other parameters provided my manufacturer I could trust. I'm using data of Latvian seller https://viensrats.lv/ since they provide quite realistic range estimates. There is a list of all Gotway EUC in their store (23 model names in total):
 

Gotway MCM5 V2 460wh 84V
Begode/Gotway RS 1800Wh 100v
Begode/Gotway EX.N 19″ 2700Wh 100v
Begode (Extreme Bull) Commander 20” 3600 Wh 100v
Begode Mten4 750Wh
Gotway Nikola Plus 1800Wh
Gotway MCM5 800Wh V2
Begode(Gotway) Tesla V3 1500Wh 84V
Begode Master 2400Wh 134.4V V2
Extreme Bull (Begode) X-men Yellow HT 1800 Wh 100V
Begode Master Molicel P42a 2000Wh 134.4V
Begode Master PRO 4800wh 134V
Begode Master X 3600wh 134V
Gotway Mten3 512Wh
Gotway Mten3 460Wh
Gotway Nikola 1600Wh 84v
Gotway MCM5 800Wh
Gotway Tesla V2 1020Wh
Gotway Nikola Plus 2100Wh 84v
Gotway Msuper PRO (MSP) 1800 Wh 100v
Begode/Gotway EX 19” 2700Wh 100v
Begode/Gotway Monster PRO 24″ 3600Wh 100v
Gotway Nikola Plus 2700Wh 100v

On the diagram below you could see declared ranges of these EUC compared to their batteries:

I noticed that a rate of range and capacity is not constant. It tends to decrease as batteries get bigger.  The point is, the more heavier EUC, the more load goes for motor and more power is consumed. Taking it into account, I added an extra multiplier k = (70 + w)/70 where w is the weight of EUC (since standard rider's weight used in tests is 70 kilos) and it got more predictable:

.

Hence I assume that there exists a linear relation between battery capacity (E) and k * declared range (R). I concluded from equation of line displayed in black color that approximate relation is:

15 + 0.1*E = (70 + w)/70 * R, or:

R = 70/(70 + w) * (15 + E/10)

So it's clear now that range of a certain EUC could be estimated pretty accurately if you know it's weight and battery capacity. Hopefully, I'll compare this result with other brand names (KingSong, Inmotion, Leaperkim, Ninebot) later and then check how other factors contributes to this theoretical value.

[mrelwood]

@meepmeepmayer answered quite comprehensively, but I have a few aspects to add.

On 10/3/2022 at 6:02 AM, mathfux said:

I've seen a lot of people uploading videos with their range tests and getting completely different results.

Which is fully to be expected. Just like if you were asking how many emails you can send with your phone on one charge.

What is constant is the amount of energy in the battery. How you utilize the energy is up to you, and riding distance is only one thing you can do with it. You can also use the whole battery just for idling back and forth, or simply just for the lights... range: 0km.

Any sort of accuracy can only be achieved if the average Wh/km (or /mile) consumption was known. Luckily this is visible in most EUC apps. Wh / (Wh/km) = km. This is practically as close as you need to get.

 

On 10/3/2022 at 6:02 AM, mathfux said:

How does battery capacity vs motor power affect range?

Capacity is clearly the main factor. You can dig in deeper into what the motor power rating actually means and how it's derived, which has been discussed here at the forum a bit as well. TLDR: Nevermind the wattage.

On 10/3/2022 at 6:02 AM, mathfux said:

what's the most common range I expect to get regardless model name?

There's a lot to consider. For example:

- Some EUCs use the battery down to avg 3.0V per cell, others stop at 3.3V. That's definitely a noticeable difference.

- Some wheels are generally used for slow and calm riding (V8), while some others even in the same size group are often ridden faster (MCM5 v2). This distorts the avg Wh/km figure.

On 10/3/2022 at 6:02 AM, mathfux said:

How does weather temperature affect range?

In my experience, I lose around 10% of range for every 10·C drop in temperature.

On 10/3/2022 at 6:02 AM, mathfux said:

How does wind speed affect range?

Like @meepmeepmayer mentioned, air resistance is the main factor that consumes energy while riding. But since a trip usually includes winds from all directions, a windy day usually only shortens the range a bit.

On 10/3/2022 at 6:02 AM, mathfux said:

How does [rider + vehicle] weight affect range?

Acceleration takes a lot of energy, so it depends on how and how often you accelerate. Comparing my consumption with others on the V11, I've seen something like 10% difference per 10kg weight difference.

On 10/3/2022 at 6:02 AM, mathfux said:

• How does altitude change affect range?

EUCs have regenerative braking, which helps a lot here. Hills do eat into the energy pool, but generally not all that much of you end up at the same height, unless you're really climbing a small mountain.

On 10/3/2022 at 6:02 AM, mathfux said:

• How does mileage affect range?

As long as you keep the battery well balanced, barely at all. Until you get to like 20000 kms.

 

On 10/3/2022 at 6:02 AM, mathfux said:

I assume there's no need to measure full range while discharging a battery from 100% to 0% because it will shorten life of battery

When you read about Li-ion battery usage tips, there's a few things you need to remember:

- Generally the usable voltage range of a cell is from 4.2V down to 2.5V. But no EUC lets you go below 3.0V (avg). So when the EUC battery is at 0%, the cell voltages are only at 30-50%. This is why percentage alone tells very little when talking about battery.

- EUC batteries have anything from 16 to 32 cell groups in series, and a dedicated BMS to manage cell balancing, overvoltage protection etc. What works for a single cell doesn't always work for a large series pack.

- A full EUC battery cycle is only 80-90% of a full Li-ion charge cycle capacity. And cells usually degrade to 80% capacity after 300-600 full cycles. For the 1500Wh V11 that means roughly 20000-40000km. So trying to extend the lifetime of a battery by limiting the usability at all rarely makes any logical sense.

For example the article you linked to, strongly promotes 85% charging to extend the battery life, without a single reference to what the difference is in practice, or to the barely sufficient balancing currents on EUCs.

If you're interested in 80% charging, you need to watch this:

 

[Eucner]

3 hours ago, mrelwood said:

 

Acceleration takes a lot of energy, so it depends on how and how often you accelerate. Comparing my consumption with others on the V11, I've seen something like 10% difference per 10kg weight difference.

EUCs have regenerative braking, which helps a lot here. Hills do eat into the energy pool, but generally not all that much of you end up at the same height, unless you're really climbing a small mountain.

Acceleration converts batteries chemical energy to kinetic energy and regenerative braking converts it back to chemical energy. There is of course some losses due to inefficiency. Acceleration works same way as riding hills.

The most important parameters for energy consumption are combined weight of rider and wheel, surface area and drag coefficient. Riders weight and surface area has nonlinear correlation.

[Tawpie]

Thank you @mathfux! I always like to see deep dives into relationships like you've done, they're fun.

My two cents and these are just based on looking at EUCWorld statistics:

1. total payload (and rider weight can be a huge influence) is a larger factor in reducing your range than I would have expected and I suspect this has to do with the amount of energy required to balance a large payload as opposed to a small one. It makes sense to me that the short term corrections to keep a heaver (or taller) rider balanced will require quite a bit more instantaneous current that they would for a lighter/shorter rider. I ride faster than average but spend 30% fewer wH/km than other riders on my models of wheel and your 'wheel weight corrected' graph supports that… my riding weight is in the 60 kg range.
2. speed (drag) becomes a big part of the energy consumption when you're going faster than say, 35 km/hr. The spandex folks estimate that the power to maintain a given speed goes up by the cube of the velocity—I don't find that this plays out in real life quite as much as theory, but given the physics you can easily imagine that higher speed = lower range. And by quite a bit.

Most manufacturers have fine print to explain the test conditions that they use to claim a certain range. KS for example typically indicates 25 km/hr on flat ground, no wind, constant speed, rider weight 60 kg. If these conditions are consistent across manufacturers, then their numbers can be compared. But if you want the comparison to be anything more than relative (this wheel will take me half as far as that one), you'll want to develop a fudge factor for rider weight/total payload. And perhaps another fudge factor for riding style... aggressive, chill cruiser, tourist.

For the most part though, when comparing go with @mrelwood and @meepmeepmayer's advice: battery wH is king, more will go farther. For individual range guesstimates, I do wonder if there is an adjustment constant for rider weight.

Be very very happy you're a light weight! This is one of a few activities where being bigger isn't an automatic bonus.

[Begodecrashtestdummy]

I would say on average…every 1.61km / (1 mile ) uses 40wh ..so a 2000wh battery should get 80km (50 miles ) 

[mrelwood]

On 10/5/2022 at 2:56 PM, Eucner said:

Acceleration converts batteries chemical energy to kinetic energy and regenerative braking converts it back to chemical energy. There is of course some losses due to inefficiency. Acceleration works same way as riding hills.

Not quite that simple. Regen braking doesn't activate on a 1° downhill slope, I remember a discussion that had found out that it takes a certain amount of braking power for the wheel to start using regen. Also if you brake very hard, it also uses battery power to brake. In my experience a trip in a hilly terrain includes more accelerations and gives me a noticeably shorter range than a trip on flat ground.

On 10/5/2022 at 2:56 PM, Eucner said:

The most important parameters for energy consumption are combined weight of rider and wheel, surface area and drag coefficient. Riders weight and surface area has nonlinear correlation.

Yes.

18 hours ago, Dosingpsychedelics said:

I would say on average…every 1.61km / (1 mile ) uses 40wh ..so a 2000wh battery should get 80km (50 miles ) 

That would be ~25Wh/km. I think that's a reasonable average for rough calculations. I'm a bit heavier guy at 108kg, so my avg might've been a bit higher. Still below 30 though.