It doesn't take long for someone looking to buy a new E-bike to quickly realize that these machines boast great distances per charge!  They are amazing and why would you ever step in a car again?!?!  Well, there's a common downside to those wonderfully high 40/60/80/100+ mile per charge rating from most companies...... they're NOT REAL!  That's right, that's what I said, they are at best a guesstimated calculation to present a favorable number to you.  Because who wants to spend $1500+ on transportation that won't even get you down the street let alone across town.  But we at E-powersport.com don't believe in over inflating our numbers, much to the happiness of our investors too.  

       In the rest of this Blog Article we'll discuss how you, yes you, maybe even you, but I'm not so sure about that guy, can easily tell how much distance you can realistically expect.  There is some basic math involved and we're going to look at it from 2 different number calculations, but in the end, you'll be able to confidently go into any bike shop and tell them the realistic #s and if they're full of shit or not.  Which is your right as a consumer and potential customer.

First, let's explain why companies label their E-bikes with such high numbers as to lead you to disappointment.  I'm going to be a little absurd here, but you'll get the point.  When other E-bike companies test an E-bike's distance capability, they first go through the company and poll their staff to see who has the smallest and lightest 13 year old.  Thirteen as that's about grown up enough to handle a motorized vehicle.  This 98lb Tween is then told they will get a pony or go-cart if they pedal the E-bike on level 2 until their little legs fall off.  Sometimes they get to take a break to use the bathroom, but normally they make them wait till the battery runs out.  Luckily, the components are waterproof incase of an accident.  They then chase the child with small dogs to help keep them pedaling and when done, they round up to the nearest Tens place, yielding those wonderfully high milage numbers we're all used to seeing.  

*This is an absurd joke to demonstrate the absurdity of what is actually done in testing*

     Now, I don't know about you, but the last time I weighed 98lbs I was 10 years old.  Yeah, I was, still kind of am, the chubby kid.  Which works for you, since we rate our units on being able to move my 210lbs around.  So, when you see a distance rating on our website, you know some chunky guy was able to get 60+ miles out of it and your waifiness should be able to go a bit farther.  All that is great when it comes to buying from us, but what if you did the dirty deed and bought from someone else.  Well, I can't fault you for it, not everyone knows about us yet.  But here's how you can do a little math and make sure you know, for sure, what you're buying vs. what's being said on the marketing flyer:

To give things more context, let's look at a competitor's E-bike, the Himiway Zebra.  Himiway claims that it's 750w motor and 960wh battery will get you 80+ miles per charge.  Poppycock!  Maybe with Bob's kid riding it with those dogs at his feet, but not my fat butt.  Let's break it down and see what you can really expect.

The motor is 750w.  That means at full speed, it runs 750w average per hour.  The wattage per hour for the battery is 960wh.  If we divide 960/750 we get 1.28.  This means if you run the motor at full speed for an hour and 20 minutes you will have run the battery out of juice.  Since most E-bikes running at 48v stay around 28-30mph, we'll call it 28mph.  At 28mph for 1.28 hours you would travel 35.84 miles total distance per charge.

Taking the word problem out of it:

(Total Battery WH) / (Total Motor Wattage) = (Total Runtime per Charge) x (Avg MPH) = Realistic Expected Distance Per Charge

Now let's look at this from my favorite factor in this electrical burrito, the Amp.  If you read our previous blog entries you'll know that Wattage is a rating comprised of multiplying Voltage by Amps.  For me, since I already know what the Voltage rating is and voltage generally runs at a constant, if it's a 48v system, it's 48v going through it when on.  If it's 72v there's 72v and so on.  What changes is the applied Amperage.  The changing of the amperage is what allows companies to say a motor operates at one speed, while being able to "Burst" to a higher speed.  This is why I prefer to focus on Amps and amp hours.  It works the same, but for me a little cleaner as it take some of the guestimate work out of things.

Amps:

First, let me preface this by saying, not all companies disclose their amp ratings.  Most use Wattage because it's a rating most people are familiar with due to light bulbs.  

If you want to break it down, you can reverse factor by dividing the rated wattage by the voltage, in most cases 48v or 72v, but check your specs to be sure.  What you'll find is most of your E-bikes at 48v are running 12amps.  This means that at the highest point, when your riding up that big hill, the motor is drawing a maximum of 12amps charge.  Here's the funny thing, though your motor might be rated for a certain wattage, most will accept more amps and hence increase the wattage, as mentioned before, burst mode.  Now there are some, well most motors actually, where if it runs nominally at 12amps, it usually means it can range up to about 15-20amps, let's say 20amps multiplied by 48v equals 960w.  This is how and why there is a peak and a nominal rating for most E-bike motors.  Now, let's look at how this would effect distance per charge of our example unit, the Himiway Zebra.

Battery rated Capacity : 20AH

Now there's no Amp Rating, but I know it's 48v @ 750w so well, divide, 750w/48v = 15Amps

Meaning if we run at full draw of 15amps on a battery that can provide 20Amps per hour, we'll end up with 1.33 hours of runtime @28mph for a total distance of 37.24miles per charge.  

Now, that's not bad for the Himiway Zebra, considering our estimates are pure throttle usage and don't impart any human efforts applied.  But I'm still not convinced you'll get 80+miles, more like 60+ if you pedal along too, which is still a respectable DPC(distance per charge).  We prefer to use the "Scotty Principle" in our ratings.  For those that don't know, it's from Star Trek and means, we under promise and over deliver.  It's what made Mr. Scott the best Chief of Engineering Evva!

Looking at the difference between the two calculations you can see that they're relatively close, but not the same.  This is why I take the Amps calc over the Wattage.  Though Wattage is more conservative, Amps are a direct calculation without adding another variable, ie voltage.  But either way you can easily see that you're not going to get 80+ miles out of a charge on that E-bike.  

     I mean anything IS possible.  If they throw someone's Jockey sized kid on it, or maybe just hire some Jockeys.  I mean, Jockeys are literally hired based on height and weight for the exact purposes of extending the horses speed and distance.  Something for the retired Jockeys to do now!  But when it comes to E-bikes, e-Enduros, e-Motorcycles and any other electric transportation we sell, you can be assured we've tested them, we've rated them and we stand behind them.  Because if you stand in front of one you're likely to get run over!  LOL, thanks for reading!

~John 

As discussed in our previous article, E-bikes and Voltage, Why It Matters, Voltage and AMPs have a relationship in how your e-bike motor works.  If Volts are related to your expected top speed, then AMPs are related to the Torque your electrical motor and system will produce.  Where Voltage could be visualized as the speed of an electrical flow, which would lead to it's relation to top speed, think of AMPs as the depth of the electrical flow.  Similar to a wave hitting a wall.  If the wave is small it doesn't do much, but if it's a large wall of water, it could have enough force to move or even destroy the wall.  We'll get to why that's important too.  This depth of flow has the ability to "push" the motor around, and that motion is then translated into you and your electric vehicle moving forward.  

Sure, I guess, but in a later article we'll talk about how Wattage is a good general rule of thumb, but not the best reference.  Voltage and AMPs are calculated together to come up with Wattage.  For example, you might have a motor that is connected to a 48v battery.  They are then connected to a controller that has a certain rated Amperage capability and all of this is connected by wires that also have a certain ability to carry Amperage.  For the example, let's say it's a smaller 500w rated motor.  There's a 20A capable controller(the electrical "brainbox") and it's all wired for 15A.  Don't freak out, it's normal to "under-wire" an electrical system so you don't overheat the components.  In this case we're all good, check it out below.

Here's the fun math part:

48v X 15A = 720w Peak Output

As you can see, the above wired system will be able to provide more than enough wattage to meet or exceed the draw capability of the motor @500w rating.  We can adjust the number of AMPs in the displays/controllers as well.  Most of the motors are made to exceed their rating for short periods.  That's why you may find some motors that say, they "go up to" the next level of motor wattage rating.  Like our 500w motor mentioned being able to handle the potential 720w we may push to it.  What most companies are doing when they say it goes "up to" is upping the AMPs in a burst or turbo mode to give you more usable wattage from the motor.  

Keeping all of the above in mind, it's important to understand how and with what gauge your e-bike, e-scooter or e-motorcycle is wired.  You can have high capacity, high output controllers and motors, but if you have them wired to low flow power wiring, you'll be choking them off from the performance you expect.   

It's also important to understand the relationship above because you will notice it when you're riding and your voltage drains.  With e-bikes, e-scooters, e-motorcycles and to some degree all electric vehicles, there's a range of Voltage at which the motors can operate.  Your new electric vehicle or micro-mobility might be full speed when you take off for the day with a full charge.  When you're on your way home, you might notice, it doesn't get all the way to the top speed it did earlier.  This is due to that range of voltage operation.  As your battery drains down, that formula above also gets smaller.  Where before your battery was putting our 48v@15A, by the end of your riding, it might only be pushing 40v@15A=600w.

Now that's still more than our example motor would be rated for, but you will notice the reduced performance as the motor is now getting a lower overall wattage.  

Across all of that voltage and wattage drop off, the one thing that remains constant is the Amperage available.  This does fluctuate with your specific need at the time, you might only use 5A-8A at a moment to maintain speed vs. the full 15A to accelerate from a dead stop, but the electrical system is always ready to give you 100% of the torque generated by the AMPs flow at all Voltages the motor and controller can operate under.  Translated from tech speak: You get all the available torque all the time, no matter what your electric vehicle voltage at the time.  

As an additional note, don't be confused over the AMPs a motor or controller can handle and the AMP capability of which the whole system is rated.  You could have a super duper motor and controller, being held back by limited wiring.  Ask what AMP flow or Ampacity the wiring has going to the components and how that matches up with the capabilities of the respective components.

Now, for most of you, that should be good.  You should be able to go out in the world and ask, "How many AMPs is my new e-bike capable of?" and actually know what the salesperson is telling you.  Or maybe you just stumped them.  Good for you!  

But, if you want to get in the mind of our resident "Mad Scientist" and Founder (I'm not actually a scientist and I've never played one on TV, why do you think me "mad"?) keep reading below.  

First I have to say, I'm not mad, maybe a little crazy, but I like to think we all are in our own way.  As long as that crazy doesn't hurt anyone, who cares if I have a wild head of poofy mad scientist hair and live in a castle on the hill.   I don't like in a castle on the hill, but the hair thing is true.  More so, I just look at things a little differently and that's the same here at E-Powersport.  Enough about me, let's talk about AMPs.  So you kept reading and want to get deeper on Amperage and what you need to look for in your next purchase.  Yes or No?  

Yes, good, let's climb in this rabbit hole......

We already gave you a lot to work with above, what more can I say?  Well, to start with, Gauges!  No not like the speedometer, but I like how you think.  The gauges of the wires being used as well as the connectors and battery BMS.  That right, to really get to the beginning in all this, we need to go directly to the power source, the freaking battery and BMS.  These are both rated at certain Ampacities.  They will normally have 2 ratings, one that is nominal or normal functioning AMP rating and one that's the MAX, normally expected for very short periods of time.  The wiring coming from the battery pack, is rated for a certain Ampacity and stated at its MAX AMP Rating, but wait, there's more....

The connector used to connect the battery pack to the motor has, what?  That's right, a certain Ampacity.  And so on and so on and so on, till we finally get to the motor that turns all the AMPs that finally made it into mechanical energy.    Woohoo!  Now go raise some heck with your new knowledge!  

Still there?  OK, what else can I say about AMPs and how freaking important it is to know the overall Ampacity of your e-bike, e-scooter, e-motorcycle or other electric vehicle?  From my perspective, Voltage and AMPs are a much better way to think about your new transportation's capabilities.  Wattage is a fluffy bunny # that doesn't mean much when you start adding things like weight into the equations or by that I mean real world use.  As we had shown above, those short burst can be as high as 50% increase in total power consumption.  Forget Wattage and Watt Hours, that's for home use.  On these, you want to focus on Voltage and how many AMPs are being delivered to the motor over what time period.  Are they giving you an AMP boost capability, like we talked about and how will that effect your distance, or are these nominally functional AMPs for a steady AMP flow?  Don't get me wrong, I think Wattage has it's place, but it's more about usage than a scaled rating.  

Another important aspect of AMPs and AMP flow is how that can relate to usage and distance.  As the AMP flow usage fluctuates it takes certain amounts of the Batteries Ampacity or as batteries are rated, Amp Hours or AH.  This could be used to calculate "time x amps used" to display remaining Amp Hours available in the battery pack.  There's already the ability to view Volts left in a battery on most e-bikes, e-scooters, e-motorcycles, but knowing how many AMPs are left for draw could be a more accurate indicator of time/miles left on a charge.  And I guess, you could always slap the two together and give a remaining wattage level of the battery.  But I think the more discerning or power user, will want to know the Volt/AMPs too.

Here's a crazy thing to think about:

1 Joule = 1W per Sec = 1NM (Newton Meter)

Do we really need three of the same metric?  What the What?!?!

When motors are measured for Wattage it's in hours.  Our previous 500w motor example would be expected to use 500w an hour, not per second.  Keep that in mind, now the Newton Meter is a normal measurement for Torque of an Electric Motor.  Most 500w motors are rated @60nm.  That means a 500w motor is using 60nm, or 60watts per second, or 60 joules to propel you at its top power usage.  Even crazier is there's no rated Watt.  A Watt is as Watt, but a Watt can be applied to a measurement of time, there hasn't been a standardization across the Electric Vehicle or other electric industries.  However, both a Joule and a NM have been set in ratings.  Speaking of wheels and ratings, one of my favorite teams to reference for knowledge are the team at GRIN Technologies in Canada.  Rather than reinvent what they've already defined in both a deeply technical and eloquent way, I'm going to provide a link to their related article here.  

They get so deep, I use their tools, just awesome stuff:

Futility of Motor Power Ratings

There's more we can cover, we could talk about how electricity doesn't actually flow in a wire, but is a wireless transmission being provided by a series of magnetic fields generated across the wire.  But we'll save that for later....