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Hi! Brilliant forum... love this place, great job! I learned a TON from reading all the MX350 posts... thank you!

This list below is what I've come up with for my first mod (MX350). I would love it if someone could verify that I haven't forgotten anything. I promise to video the whole job and post a step-by-step once completed.

36V 750W motor: http://tncscooters.com/product.php?sku=106155
36V controller:
http://www.tncscooters.com/CT-660B9.php
36V 12 Ah battery pack:
http://www.monsterscooterparts.com/36vo12amphob.html
36V charger:
http://www.monsterscooterparts.com/36vo16amp3ba.html
Twist throttle:
http://tncscooters.com/product.php?sku=101102
Wiring stuff:
http://tncscooters.com/product.php?sku=102304


My goal is more speed and a bit faster response for me (140 lbs)... and to have fun modding it of course...


Any comments or suggestions are welcome.. thanks!
 

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1st off are you going to buy 3 new 12 volt 12 amp batteries because unless your bike is some exeption the mx350 uses 7 amp batteries.Well you could always buy a 36 volt 1000 watt motor because you do not have to weld to fit it in the mx350 but the only thing you will need to drill new holes in order to mount the motor.The 1000 watt motor may not fit in the stock motor space but unless you are riding off road you could mount the motor under the mounting bracket.Well what ever you do you will need to drill new holes to in the mounting bracket so you can bolt the motor down.Everything looks to be a good project.GOOD LUCK
 

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your twist throttle is right. your connecter is right.
but tget this controller
http://www.tncscooters.com/CT-312C1.php

it's a 4 wire and will match your throttle. it's only $20 and I've ran 60v on it!

ebay has the cheapest 12ah batteries. look up 'battery monster' or 'battery geek'

you want to really fly? get the 1000watt motor and 5 new 8ah batteries.

on my razor pocket mod(12in tires like your 350) I had that controller, 48v 7ah, 11/44t gearing and hit 26+mph with my 170lb self.

with your 11/80 gearing and 60v you will hit that easily with your 140lb self.
you want to order a double D sprocket though because most motors come with 8mm chain sprockets.
I'm just saying if you want to go big you might as well go all out. with this advice you will save money on the batteries and controller, take that money and put it into a bigger motor. I put a 1k into my little pocket mod and hayden put 1 in his 350, so it must be possible.

http://tncscooters.com/product.php?sku=106007

http://www.diygokarts.com/speed-calculator.html
12" tires, 5000rpm(36v motor on 60v) 80t rear 13t motor, 29mph speed

 

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Thank you loudog & hayden... great advice! you've convinced me to purchase the controller and sprocket you suggested and to upgrade to the 1000W 36V motor. Nice!

I must admit that hayden's battery comment went over my head... I thought the amp-hours were just a measure of how long the battery would last? I thought that I could choose a cheaper 7Ah or the more expensive 12Ah batteries, and the motor wouldn't care as long as they were 36V?

loudog- i might add more batteries later to upgrade to 48V or 60V depending on how this first round mod goes... thank you for the suggestion. Great video BTW...

Ride on...
 

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Thank you loudog & hayden... great advice! you've convinced me to purchase the controller and sprocket you suggested and to upgrade to the 1000W 36V motor. Nice!

I must admit that hayden's battery comment went over my head... I thought the amp-hours were just a measure of how long the battery would last? I thought that I could choose a cheaper 7Ah or the more expensive 12Ah batteries, and the motor wouldn't care as long as they were 36V?

loudog- i might add more batteries later to upgrade to 48V or 60V depending on how this first round mod goes... thank you for the suggestion. Great video BTW...

Ride on...
Well the mx350 would go faster on 12 amp batteries but the you might as well run 48 volts on 7 amp batteries then 36 volts on 12 amp batteries.A controller can take more volts on 7 amp batteries,on Loudogs, bike he ran his bike on 60 volts with 7 amp batteries but when he tried to run 60 volts in 12 amp batteries the controller died.The 12 amp batteries will give you a longer run time,so if you realy want to you could fit 5 12 volt 12 amp batteries but it would not be easy if not almost imposible with out cutting or welding.
 

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amphours do affect capacity. they also increase preformance slightly because there is more power availible...it's like putting 100octane gas in youtr car instead of 87.
i'd stick with the sm,all batteries...less weight and space, more options. remember, longer run times also mean longer charge times, so you might as well have a light fast bike.
 

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Hey guys, I just registered but I've been browsing this site for a couple weeks now collecting some awesome information. I just purchased a new mx350 w/ the 250watt motor for my son. I've already decided that a couple of upgrades/replacements will be in place soon :). I want to increase his acceleration and I'm not too worried about his top-end speed. Before I bought anything I just wanted to run it by you veterans to make sure I'm not wasting too much money lol

9t motor sprocket
http://tncscooters.com/index.php?route=product/product&path=63_90&product_id=461

36v throttle
http://tncscooters.com/index.php?route=product/product&path=65_79_84&product_id=349

36v controller
http://tncscooters.com/index.php?route=product/product&product_id=174

36v charger
http://tncscooters.com/index.php?route=product/product&path=17_72&product_id=407

12v 7ah battery
http://www.ebay.com/itm/12V-7AH-Sea...=647821109914020569&pid=100015&prg=1006&rk=1&

I'm going to keep the motor until it blows and then upgrade that depending on his skill level at that time. I would greatly appreciate any and all input on my list :D Thanks in Advance!
 

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Well the mx350 would go faster on 12 amp batteries but the you might as well run 48 volts on 7 amp batteries then 36 volts on 12 amp batteries.A controller can take more volts on 7 amp batteries,on Loudogs, bike he ran his bike on 60 volts with 7 amp batteries but when he tried to run 60 volts in 12 amp batteries the controller died.The 12 amp batteries will give you a longer run time,so if you realy want to you could fit 5 12 volt 12 amp batteries but it would not be easy if not almost imposible with out cutting or welding.
WHAT???


AH rating simply put is equal to volume of energy contained in a battery, it has nothing to do with motor speed.
Voltage is pressure

If your buying crappy ebay batteries they probably do not have the rated voltage output for more than a short period of time.

With a given motor and a controller rated at 36-48v input, the motor will turn faster by ~30% when run at 48v when compared to being run at 36v under no load.

If your battery pack is undersized for the load ie 7amp vs 12amp you might experience voltage sag (junk battery) which would account for the scenario you described. The mosfets in chinese controllers can usually be run at 6v over rated voltage safely, a 12v overvolt will usually cause them to fail rather quickly if not immediately.

Hugh
SDscooters
 

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A 12 volt 12 amp has more capacity or c rating then a 12 volt 7 amp battery that is why a bike running on 12 volt 12 amp batteries is 1 or 2 mph faster than a bike running on 7 amp batteries. Besides being very light that is why lipo batteries are the choice for many electric drag cars because they can put out the amps that those motors require in order to run properly.
 

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Not the reason exactly, 12ah batteries have larger interconnects, they are able to maintain voltage for longer periods. If the current draw on the battery is high enough internal resistance will build enough to restrict the voltage which equals slower speed with lower ah battery.

Lipo's have small voltage sag over time and drop rapidly at the end. SLA's drop gradually, its why your bike feels lively for ~25% of the time, not bad for ~50% and like a dog for the rest of the run time. That together with the low weight is why Lipo's are now preferred for racing applications.

Before the price of Lipo's came down all of these racers were running Hawker batteries. I've seen video of someone dropping a wrench across the terminals on a 28ah Hawker battery, the wrench obviously fried. Battery was fine. Try that with a similarly sized Lipo pack (BOOM).

Hugh
SDscooters
 

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your twist throttle is right. your connecter is right.
but tget this controller
http://www.tncscooters.com/CT-312C1.php

it's a 4 wire and will match your throttle. it's only $20 and I've ran 60v on it!

ebay has the cheapest 12ah batteries. look up 'battery monster' or 'battery geek'

you want to really fly? get the 1000watt motor and 5 new 8ah batteries.

on my razor pocket mod(12in tires like your 350) I had that controller, 48v 7ah, 11/44t gearing and hit 26+mph with my 170lb self.

with your 11/80 gearing and 60v you will hit that easily with your 140lb self.
you want to order a double D sprocket though because most motors come with 8mm chain sprockets.
I'm just saying if you want to go big you might as well go all out. with this advice you will save money on the batteries and controller, take that money and put it into a bigger motor. I put a 1k into my little pocket mod and hayden put 1 in his 350, so it must be possible.

http://tncscooters.com/product.php?sku=106007

http://www.diygokarts.com/speed-calculator.html
12" tires, 5000rpm(36v motor on 60v) 80t rear 13t motor, 29mph speed

http://www.youtube.com/watch?v=cvJbLZ_vz-g

thats awesome
 

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375 Posts
WHAT???


AH rating simply put is equal to volume of energy contained in a battery, it has nothing to do with motor speed.
Voltage is pressure

If your buying crappy ebay batteries they probably do not have the rated voltage output for more than a short period of time.

With a given motor and a controller rated at 36-48v input, the motor will turn faster by ~30% when run at 48v when compared to being run at 36v under no load.

If your battery pack is undersized for the load ie 7amp vs 12amp you might experience voltage sag (junk battery) which would account for the scenario you described. The mosfets in chinese controllers can usually be run at 6v over rated voltage safely, a 12v overvolt will usually cause them to fail rather quickly if not immediately.

Hugh
SDscooters
More ah = more runtime. i understand that. I've also had a bike run 1mph faster on 12ah vs 7ah, but as you said that just maybe due to the 12ah having enough capacity to bring the bike up to its true speed. that being said i related it to an octane boost which would make your fuel burn more efficiently and give better performance.
given the extra weight of 12ah, you could run the smaller 7ah and even run more in sereis to increace preformance. that's all i'm trying to get at. more speed for the same battery weight.
Thank you for clearing up my hillbilly explination with the actual science behind it. lead is heavy and as you said poorly peddled. I bought a bad batch of sla's, but i reasoned it out they were the cheapest choice for my project. A lot of newbies just want to get started. so theey are going to buy lead. myself, i didn't realize the size difference of 12ah to 7ah was so much. if someone were to try and overvolt thier little razor with the larger batteries, they may encounter mods they weren't ready for. me, i just ratchet strap the batteries in and ride. i'm not concerned about looks.
I try to provide the basic info, and I'm glad you gave a great explanation behind the battery choices out there.
 
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