Electric Grom accelerates quicker than gas Grom

Discussion in 'Electric Motorcycles' started by voltsxamps, May 24, 2016.

  1. voltsxamps

    voltsxamps Advolturer

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    Well, I’m sure this doesn’t come off as a surprise to anyone when it comes to acceleration, as building revolutions to reach peak torque is no match for 100% instant torque off the line.

    A stock gas Grom has, according to a dyno test from Cycle World, 8.96 HP and 7.95ft/lb torque, but requires high rpm's to reach. Cycle World also observed a max speed of 52mph.

    image.jpg image.jpg

    The Grom rider in the video below got 50mph one direction and 53 the other for a 51.5 avg.



    It took 17.27 seconds one direction and 20.79 seconds the other way for a 19.03 second avg to 50mph.



    Comparatively, a 96v electric Grom accelerates to 50mph in half that time

    While rated at only "2hp", a 96v electric Grom is twice quicker and requires no clutch or shifting, so launches are consistently repeatable with no chance of stalling.

    Adding quickness is made possible with 2 additional batteries wired in series to the stock e-Grom’s pack for less than $100 and in under an hour to get it to 96v. (even a stock e-Grom out accelerates a stock Grom to ~35mph as I discovered racing against my buddies Grom). A gas Grom can be modded too of course fit quicker performance, but acceleration can’t be doubled for the same amount of money.

    EV riders will concede that range and time to recharge are clear advantages of gas, but if you can recharge while you're shopping, working, or sleeping (like our cellphones), then it's not that much of an inconvenience and one could argue that having to go to a gas station is an inconvenience compared to fueling up at your destination or at home. Adventurers though may find it difficult coming across available outlets, not to mention the time it takes to recharge, although on occasion, I've been allowed to plug in at gas stations when unexpectedly needing more juice between destinations.

    I love the Grom in both gas and electric forms for its size, value, and fun. Theres just something to be said about the instant torque of the electric, making a fun bike that much more thrilling to ride.
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  2. Yellow Jacket

    Yellow Jacket Been here awhile

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    Two years ago I participated in the North American Scooter Racing Association's Southern Nationals at Shadyside Dragway near Shelby NC. Not a very big event, maybe 40 bikes, but the fastest bike there was a Yamaha Vino 50 that had been converted to battery power.
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  3. bikeridermark

    bikeridermark Long timer Supporter

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    Yeah, but while you're recharging your e-grom, the gas grom will motor by, waving and laughing! and when your e-grom catches fire, the gas grom can ride by and call the fire department. Something to think about.
    Doesn't matter one way or the other to me.
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  4. voltsxamps

    voltsxamps Advolturer

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    Do you worry about the SLA battery in your bike catching fire? Me neither :)
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  5. bikeridermark

    bikeridermark Long timer Supporter

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    Nah! I just want to get where I'm going, and electric's not going to get me far enough.
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  6. voltsxamps

    voltsxamps Advolturer

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    I respect that. Range is definitely electric's Achilles heel.

    Considering I've got less than $1500 invested in the electric though, I could buy 2 and ride one around the track while the other is charging :p
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  7. bikeridermark

    bikeridermark Long timer Supporter

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    That works if you're just riding around in circles. What's the range on these things at 50mph?
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  8. voltsxamps

    voltsxamps Advolturer

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    The furthest I can currently configure mine to go at 50mph with SLA's are 38 miles running a dual battery pack before having to plug in.

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  9. EvrythingAwesom

    EvrythingAwesom Long timer

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    20160525_073118.jpeg 2016-05-25_17.11.33.jpg

    My LIFEPO4 (safer Lithium) electric 'grom' motorcycle now has over 1200 kms., and the charging is taking less time. A 20-minute charge with a 5 amp charger, while having a snack or adventure ride break, gets me going in town, no problems.

    See where my eGrom can park, right up to the door of a shopping mall, where the electric outlets are, lol.
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  10. EvrythingAwesom

    EvrythingAwesom Long timer

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    Any photo link(s) to that race?
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  11. EvrythingAwesom

    EvrythingAwesom Long timer

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    I don't have any range anxiety, since I've been charging at gas stations for free.

    2016-05-16_08.12.35.jpeg
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  12. voltsxamps

    voltsxamps Advolturer

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    You should get one of these for $2.50 (use the $2 off share coupon code)
    image.jpg
    image.jpg

    You'd love their site: http://evsticker.com

    I'm ordering one.
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  13. EvrythingAwesom

    EvrythingAwesom Long timer

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    See my 2015 electric 'Grom' aka e-Grom electric motorcycle beside Honda's and gassers.. whatcha's think?

    2016-05-17_21.54.42.jpg 20160521_080550.jpeg 2016-05-19_09.30.50.jpeg
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  14. voltsxamps

    voltsxamps Advolturer

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    I'm up to 1241km as of tonight.

    I've owned it for 10 weeks, averaging 77mi/week. :ricky
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  15. EvrythingAwesom

    EvrythingAwesom Long timer

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    No one has ever unplugged my charging cord.

    They know I'm keeping their air cleaner! (When asked what they think of my ecycle.)


    20160419_112529.jpeg
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  16. voltsxamps

    voltsxamps Advolturer

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    Now that my ride goes 50mph, I want to travel short distances down the freeway at 50mph between exits, staying in the right lane of course. Before I do however, federal law prohibits scooters under 150cc from traveling on interstate freeways, and since electric bikes are technically 0cc's, an electrical equivalent must be used to determine my "cc's". While my bike is rated at 2000w or 2hp, voltage has been increased to that same motor, spinning it faster, increasing the speed. As a result, I had these 4 questions:

    Does this change my power rating? Not according to the dmv.ca.gov. or the federal government. They look at the motor's wattage rating, and not the amperage or voltage as far as I know. Are vehicle codes regarding electrical power equivalents flawed in that they rate the motor rather than the max voltage & amperage output by the batteries and controller? I'm guessing that this may have been decided before brushless DC motors became popular, but even brushed motors can be overvolted to a certain point.

    :type Doing research on minimum allowable freeway speeds, I came across a poll that indicated 31% of Californians drive faster than 70mph, 58% said they drive 65mph, 11.5% said they drive 60mph, and no one answered they drove slower than that. Well, these past few days, I drove my van 50mph to observe how fast other cars and commercial trucks were traveling in the righthand lane. To my surprise, several cars and trucks were maintaining ~50mph, while other vehicles temporarily in the right lane were either merging into or out of that lane to or from from on/off ramps. I also discovered there is no minimum speed limit on CA freeways according to dmv.ca.gov, however, vehicles are encouraged to travel with the flow of traffic in your lane as long as you don't exceed the speed limit or impede traffic. According to one CHP officer online impeding traffic is when 5 or more cars are piled up behind you. Of course, in the right lane, 99.9% of people will normally just go around you and know that's the appropriate lane for slower going vehicles. In contrast to California, rita.dot.gov/ states the minimum speed on an interstate freeway is 40mph and 45mph in some jurisdictions. In any case, a catch-all law states, if you're impeding traffic, you're traveling too slow. Now I'm no LEO, but if your ride meets the federal minimum requirement of 150cc and does at least 45mph, there is the option to take it on the freeway. I know many riders who won't ride a scooter on the interstate if doesn't go at least 65mph, but there was nothing I could find that says that you couldn't.. at least in California. So can I take my scooter on the freeway? Well it does 50mph, so let's check that one off.

    But does my bike meet the 150cc minimum? My MSO lists my bike's power rating as 2000w and is also printed on the hub motor. It's also stated on my registration that my scooter is 2hp. Confused yet? Using online conversion calculators, 2hp is equivalent to 65cc and 2000w is equivalent to 2.68 mechanical hp, which brings my cc equivalent to 87cc, both falling well short of the 150cc minimum.

    What about the increased voltage I've added? Wouldn't that raise my equivalent cc's? Well, surprisingly, after doing some math, multiplying 96v with my circuit breaker's max rating of 7A nets 672 watts or a .9 hp / 30cc equivalent. If that's surprising, the stock 72v configuration nets a max of just 504 watts equivalent of .67hp / 22cc) My controller's maximum amperage limit is 62. My maximum voltage off the charger is 100v. Using maximum theoretical numbers, it's possible to output 6200 watts to the motor, however, the max rating of the motor is 4000w, and equates to 5.36hp, converting to 175cc. :hmmmmmHmm.. that just doesn't add up. If an 8.9hp gas powered Grom of similar weight can go 50mph, so wouldn't my bike also be equivalent to the same hp rating if it can go the same speed? If that is true, are the watt/hp/cc equivalent calculators I'm using flawed? Using the generally accepted 1hp=741w, using that equivalent (741 x 8.9) suggests that my bike has ~6595 watts.. While that sounds right, that's more than triple it's rated power. It's doubtful that adding just two batteries has increased my power more than 3 fold, even though it is the equivalent of a 125cc Grom. With more than one conclusion possible, perhaps someone with greater insight can make sense of why the figures are so different or share how to calculate the watt to cc equivalent properly.

    What if we did the math in reverse? To achieve a 150cc equivalent, it's necessary to produce 4.61hp, which is the converted equivalent of 3441 watts.. supposedly. Once my amp/voltage meter display arrives, (sometime in the next 2 weeks), I'll be able to know how much power I actually have and know if I have enough "cc's" to legally ride it on the freeway.
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  17. voltsxamps

    voltsxamps Advolturer

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    So I searched for other electric bikes to compare their watt to speed ratio.

    Here's figures from a reputable electric dirt bike manufacturer http://www.kuberg.com/young-rider.html

    1000w/24v = 15mph
    3000w/36v = 17mph
    8000w/48v = 34mph

    While the gearing is likely different, is apparent that the motor power has little to do with speed and voltage has almost everything to do with speed, as long as the motor/controller can handle it.

    Otherwise, using the figures above, a 2000w e-Grom would only go 16mph. :baldy Clearly, more research is required.
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  18. voltsxamps

    voltsxamps Advolturer

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    The basic requirements to ride your scooter on the interstate are:
    1. you are going no faster than the speed limit
    2. you are not impeding the flow of traffic
    3. It's properly licensed and registered
    and 4. that it's at least 150cc. Now let's say LEO has you pulled over. Will they check your cc's or equivalent and on an electric, how? Would they look at the motor's power rating, use a multimeter to measure your voltage and look at your controller's output rating on it's sticker, look at your MSO or registration's power rating? My guess is the latter, if anything, but honestly, the first 3 are likely going to be LEO's primary concerns.

    Still, I would just like to have all of my t's crossed / i's dotted before I embark on the interstate and that means having proof of minimum cc equivalents. Using a round number equivalent of 150cc = 10hp = 55mph, I've got to add one more battery knowing a stock Grom goes 50 with 9hp, we can deduce that 1hp = ~5.5mph. I've also deduced that each 12v battery added to an e-Grom will conservatively yield 5.5mph, matching the 1hp equivalent. The following is an extrapolation of known figures of the e-Grom and the Grom:

    Batteries in e-Grom / Speed / Grom & Met / cc / cc (adjusted)
    6 batteries / 38.0-40.0mph / 4.9hp / 75 / 50
    7 batteries / 42.5-44.5mph / 7.0hp / 100 / 87
    8 batteries / 48.0-50.0mph / 8.9hp / 125 / 125
    9 batteries / 53.5-55.5mph / 11.0hp / 150 / 162

    One flaw with the first column of cc equivalents are that when I extrapolate towards 6 battery to cc's, it suggests that 75cc's = 38-40mph. A 50cc Metropolitan can do that, so the figures are not linear. The 2nd row of cc equivalents is probably more accurate, reflecting the actual values of a Honda Met and a Honda Grom.

    Using either linear or adjusted cc value, adding a 9th battery should give me the 150cc minimum equivalent to legally ride on the interstate freeway, but these figures are extrapolated from ICE scooters, so this likely explains why one method of equation doesn't yield similar results with another. Back to the drawing board?

    :mullyedit: So after more calculation, research, and comparison, I've finally concluded that by using Zero S performance figures: (max speed of 95mph with 54 hp) I can cut these #'s in half and get a hp equivalent for my 48mph e-Grom which is 47.5mph / 27hp.

    Now, how many cc's is 27hp? Well if the generally accepted equation for 10hp=150cc, then my 96v bike is equivalent to 405cc's. Wait, what?!! While I think this is actually quite a bit high, I feel that using the most well known electric street bike's manufacturer's hp figures might be the simplest way to calculate a 96v e-Grom's cc's.

    I think the actual cc equivalent is somewhere between the extrapolated Grom/Met numbers and the interpolated Zero numbers. I really need to get this on a dyno to know my actual hp/torque. That, and my v/a meter display when it arrives.
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  19. EvrythingAwesom

    EvrythingAwesom Long timer

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    Check out the YouTube video where a shot is fired into a LIFEPO4 Lithium battery (that's the type on my eGrom) and .. it just vents.

    While on YouTube, look up the motorcycle crash compilations. Many of them burned up.

    Re: Fire Departments. During the prehistoric days of electric bikes and scooters with a range of only 8 kms, I occasionally charged my ecycles at fire houses, for free. Was never turned down. Then, I found out that gas station attendants also love EV's and let me and my e-buddies charge our ebikes/EV's at any gas station!

    I don't need to worry about range now. Out in the boonies, a farmer let me plug into her genset. (Hope that didn't sound like a farmer's-daughter-joke, lol.)

    This year, I spoke to a Nissan Leaf owner who said he charges for free, everywhere, too. Except at home, were he pays for his home's electricity.
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  20. voltsxamps

    voltsxamps Advolturer

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    Found an old youtube video from Evoke promoting the differences between an electric and a gas motorcycle.



    And an even older videos of these DIY conversions, from 750 Ninjas to a 48v electrics:



    Specs at 4:40



    These last 2 are examples of early pioneers using the tech of the time. We've come a long way in recent years. At 565lbs, the converted Ninja is a full 260lbs heavier than my bike and top speed is a full 10kph slower, but it shows the simplicity of how an electric motorcycle works.
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