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Razor ecosmart Metro upgrade

 I want to upgrade the old ecoMetro. (Unite 500W 36V)

 Looking around here I see a Currie MOT-SD 36750 motor at 750W. I'm thinking this one because it's short. On this scooter the motor sticks out sideways so with a case size that's about same as mine hopefully it won't stick out worse. Also, the Currie appears to have the same 3 7/8" OC three point mounting.  (maybe I could mount a different motor but it would probably stick out farther)

I'd like to know what all parts are needed. I assume along with a motor there's a controller and throttle, and maybe other things.

I'm a reasonable mechanic and I like keeping things simple. Is this as simple and easy as I think?


Hi Eric, sorry it has taken so long to reply I had to think about this project for a while.

You could start off by installing a 750 Watt motor and then see how it works with the original speed controller. Most Razor speed controller are rated for larger motors than they are paired with, so you might notice more power by simply installing a new 750 Watt motor. The Razor EcoSmart controller is also used on the Razor MX650 Dirt Bike which has a 650 Watt motor.

If you do not notice any extra power than before, or want even more power after installing a 750 Watt motor then you could install a 36 Volt 1000 Watt speed controller such as our SPD-CT660B9 which would provide the new motor with more power than the original EcoSmart Metro speed controller does. The EcoSmart's original controller is rated at 30 Amps, and our SPD-CT660B9 controller is rated at 40 Amps.

Of course if you want maximum power right from the get go then you could install a new 750 Watt motor and 1000 watt controller both at the same time. The EcoSmart's original throttle can be used with our SPD-CT660B9 controller however its battery indicator lights can not be made to work with it. If you want a throttle with working battery indicator lights then a different throttle such as our THR-86 will need to be installed along with the new controller.

I have one more thought on this project. We have a new shipment of Currie 36 Volt 1000 Watt motors MOT-SD361000 which are due to arrive in around two weeks. They are the same size and have the same mounting hole pattern as the Currie 36 Volt 750 Watt motors do. For maximum power you may want to consider installing a 1000 Watt motor and controller.

If you will be using the original EcoSmart throttle with a new speed controller then please let me know and I will make a wiring diagram showing how to wire them together.

Please let me know if you have any questions.
Ok...so do me a favor and talk to me like a child, please. I have the EcoSmart Metro, and want some more speed and distance. I've already put about 440 miles on mine (based on a speedometer/odometer app on my phone) and want more top end and longer distance. I get about 10 miles to a charge as it is, and that's on flat roads/sidewalks here in central Florida, and almost full 'throttle' (if you will) the whole time. However it is my main mode of transportation. So getting places quicker and back without pushing seems logical. Ok, down to questions. Will my stock controller handle your 1000 watt motor? Where can I get lipo (lithium polymer) batteries that will do the job? Will my charger handle charging lipo's? I have 2 more stock batteries (totalling 5) that I can 'play' with. New batteries? New motor? New controller? What's the best options, in your opinion. I'm only 145 lbs. How bout a simple, almost step-by-step list, please. Thanks for the time and support. I'll mail ya some cookies or smiley face stickers if it all works out! 
(3.1 MB)
Oh....maybe a brushless replacement motor? Got any ideas where to find that?

For more speed a more powerful motor and controller along with a higher gear ratio achieved by installing a smaller sprocket on the rear wheel would do the job. Over-Volting the original motor with a higher Voltage battery pack and controller would also achieve more speed however that could overheat and burn out the original motor. The larger motor and higher gear ratio method is the most reliable way to get more speed.

Regarding gaining more distance, if the scooter is made to go faster the distance that the original battery pack will provide will be decreased. In order to have the same distance when upgrading from a 500 Watt motor to a 1000 Watt motor the battery pack capacity would most likely need to be doubled, and to get more distance with the 1000 Watt motor than with the original 500 Watt motor the battery pack's capacity would need to be increased even more.

The EcoSmart Metro's original 30 Amp controller should be able to handle a 1000 Watt motor on Central Florida's flat roads, however it will not provide the full power that the motor can produce and will limit is power by around 25%. A 36 Volt 40 Amp 1000 Watt controller would allow the motor to run at its full power level. The original 30 Amp controller would allow the scooter to travel more distance on a single battery charge than a 40 Amp controller though.

We have LiFePO4 batteries that dimensional wise would directly replace the EcoSmart's original batteries, however our 12 Volt 7.5Ah LiFePO4 batteries are rated for a 15 Amp maximum discharge current so they can not safely output the amount of power that the EcoSmart uses in either stock or upgrade modified form. I do not know where to get Lithium batteries that can handle a 30 or 40 Amp load however this does not mean they are not available somewhere. Our LiFePO4 batteries can be recharged with any lead acid battery charger because they have a built in battery management system. Other Lithium batteries may or may not have a built in BMS.

I do not know specifically where to purchase a brushless replacement motor for the EcoSmart, however do know that we are planning on having a larger variety of brushless motors in stock for next year.

To achieve your goals of more speed and longer distance I would lean towards custom installing a 36 Volt 1000 Watt motor (MOT-SD36100), 55 tooth rear sprocket (SPR-2555), 36 Volt 40 Amp 1000 Watt controller (SPD-CT660B9), and a 36 Volt battery pack made of six 12V 15Ah batteries (BAT-12V15A). Due to space limitations the extra three batteries would need to be placed somewhere outside of the scooter's frame like on top of the footplate, or on the rear rack. The extra capacity battery pack would require a larger battery charger such as a 36 Volt 3 Amp charger (CHR-36V3AXLR) in order to recharge them overnight.

Please let me know if I missed any questions or if you have any further questions.

You did just fine. However, the rear sprocket you suggested comes in a variety of mounting applications. Can you provide the exact measurements for the sprocket I need? Your site offers 3 pages of similar sprockets with different mounting options. Are all center freewheel hubs the same diameter? Which 'spr-2555' will mount directly to my hub? And thank you for your timely responses and patience to my ignorance.
Oh, and what about going to 48volt? Like I said, I have two extra replacement batteries. The original charger burned out one of the original batteries and Razor replaced all three. So I do have two extras. A buddy added an extra to his, and he gets a little more speed and a little longer run times then I, but he has to use an automotive charger on the 4th battery which requires taking off the bamboo just to charge...I don't want to do that.

All of our freewheel hubs that chain sprockets bolt onto are the same size. SPR-2555 measures 4-1/2" OD x 2-1/8" ID and is a direct replacement for the Razor EcoSmart's original 65 tooth sprocket - it will bolt directly onto the existing freewheel. We have a new Chain Length Calculator which can be used to determine what size chain is needed when installing different sprocket sizes. It is recommended to replace the old chain with a new chain when installing a new sprocket because old chains stretch out over time which can cause new sprocket to wear out faster than they should.

If you use the original motor and modify the battery pack from 36 Volts to 48 Volts then the motor will spin faster at 48 Volts than it does at 36 Volts so the wheel sprocket will not need to be changed to have an increase in top speed.

The EcoSmart's original 36 Volt battery pack could be increased to 48 Volts and then you could use the scooter to see if the controller and motor will handle the extra Voltage. If the scooter is only used on flat ground there is a good chance that it will. If the original 36 Volt charger was replaced with a 48 Volt charger then it would charge the 48 Volt battery pack without the need for a second 12 Volt charger and taking off the bamboo footplate.

So the sprocket and upping to 48v would be adequate for now. Does your company carry a 48v charger that would work for my application?
...what about a larger motor sprocket to compensate chain length?

A larger motor sprocket would increase the number of chain links needed for the modification however it would also make the gear ratio higher. The gear ratio and top speed needs to be kept in line with the power of the motor so the motor can run near its top RPM and not be lugged. If the motor is lugged its power output will be significantly lowered and lugging could also cause the motor to overheat and burn out. The EcoSmart's original 18 MPH top speed is a perfect match for its 500 Watt motor. The original 500 Watt motor spins at 2250 RPM and with the scooters original 5.91:1 gear ratio and 16" wheels it has an 18 MPH top speed. If the original motor was ran on 48 Volts then it power would increase to 887 Watts and its shaft would spin at 3000 RPM and with the original 5.91:1 gear ratio the scooters new top speed would be 24 MPH. Traveling on a scooter at 24 MPH requires 812 Watts of power on flat ground so for flat ground riding 24 MPH would be a perfect top speed for the scooter if the motor's Voltage was increased to 48 Volts. To put this into more simple terms do not change the sprocket sizes if you upgrade the battery pack to 48 Volts.

The reason it takes an extra 387 Watts of power to go that extra 6 MPH is that drag (air resistance) significantly increases between 18 MPH and 24 MPH.

Here are my resources for the calculations above:





Not even with the 1000 watt motor and controller? 55tooth wheel sprocket, larger (like 1 or 2 teeth) pinion or motor sprocket, 1000 watt motor and controller at 48v. With all that, it wouldn't be used at full speed all the time. Which would pull less drain on the batteries and less load on the motor making the whole system more efficient...yes? I mean a Prius can go over 100mph but not practically or every time it's driven. Nor is it safe at those speeds. But....it's capable of it. And that's what I want. Something I can cruise on, or make use of speed and power if need be. And feel free to correct me if I'm wrong. By the way, I still owe you cookies and stickers!
A scooter could be designed for reliability with a slower continuous cruising speed and a faster momentary full power speed like cars are, however the full power speed could never exceed the limits of the correlation between the power of the motor, and the drag that is encountered at the vehicles top speed. That's why gearing the scooter for the right top speed is so important. With a 1000 Watt motor and controller the gearing should be calculated for a top speed of around 26 MPH. With a 1000 Watt 3000 RPM motor that has an 11 tooth sprocket, a 55 tooth wheel sprocket, and a 16" wheel the top speed would be 28.65 MPH. This is very close to 26 MPH so I think that this combination of parts would work out very well. The 28.64 MPH calculated top speed does not account for drag so it will be slightly lower than what is calculated anyways.
So I think we've found my best option. Finally! So when I process my order for parts, I'll have to tip the tech with, as promised, cookies and stickers! Again, I appreciate the time, effort, and energy you've put into this topic.
OK, so I am preparing to order and another question came to mind whilst going through parts to order. Do I need to replace the controller to handle the new 1000 watt motor? And ...and if I want the battery indicator lights to continue to function, do I need to replace the throttle as well? I'd like to order and receive everything at once so there's only one disassembly and reassembly process. Which is why I'm asking prior to ordering. It's 8 miles to work everyday, and I'm anxious to get to and from quicker. I ride alongside the road with cars going 45-50 mph. So I can't wait to get to and from quicker, dealing with less traffic by being on the road less time. Again, your assistance has been ridiculously appreciated.

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