cut out 9" from E300 razor to race around my oval track.

Matt Gruber · Mar 8, 2014

EDIT
so many changes, deleted most of this post.
It ended up being an oval track scooter; lots of fun racing around my oval track.
Only bad thing is tires don't last long, maybe 100-200 miles. Less if i really push it.
Original plan was to use it at events, like car shows.

robnewyork · Mar 8, 2014

should be interesting , for slow cruising u wont need much

Matt Gruber · Mar 9, 2014

robnewyork said:
should be interesting , for slow cruising u wont need much

i'm thinking anyone could use an old scooter for large flea markets, farmers markets, and swap meets. will be able to carry bargains under the seat and hanging from the handlebars. a neighbor gave me this scoot years ago. Will the guys be jealous at the car show? :lol:

sobotek24 · Mar 9, 2014

this shure looks like an interestnig poject.. ill be looking forward on this.. 3wheeled single seater

or a 4wheel..

Matt Gruber · Mar 9, 2014

sobotek24 said:
this shure looks like an interestnig poject.. ill be looking forward on this.. 3wheeled single seater or a 4wheel..

the razor E300 is a 250 watt 2 wheeler, 42" long, nearly 1.1 meter. with a folding handlebar.
i cut out the entire SLA battery box :shock:

new length will be 33"
since each tire is 10", there will only be 13" between the tires! the seat is cantilevered ~3" past the rear axle. the new deck will form a foot rest along side the front tire, also cantilevered. 3/4" plywood can do this, but not thinner.
should weigh about 38# when completed.
thanks for the comments!

robnewyork · Mar 9, 2014

cool, share pics, will not be stable at high speed but who cares.. maybe gear it heavy for towing stuff when need be

Matt Gruber · Mar 9, 2014

robnewyork said:
cool............ maybe gear it heavy for towing stuff when need be

Great idea! I forgot i have a 7.5" sprocket lying around (instead of the 4.5")
This is a game changer as i could then use a controller and not go too fast with that short wheelbase.
it was 12 mph at 24v
should be more efficient with a big gear.
big gear,24v is 7 mph, but easy to go any slow speed.
36v is only 11 mph. 36 is easier for me to charge, and i could always put a resistor to limit it.
.
i like the big gear, partly because i've never tried it. i have new 25 chain too.
'
will post pic when it is ready to test

sobotek24 · Mar 9, 2014

cant wait forthose pictures..

hydro-one · Mar 9, 2014

one thing i noticed with the stand up scooter like that is when the controller pops (closed-eg mosfet shorted eg full power brushed controller) :mrgreen:

, at higher voltages(more than 60v) the scooter just wheelies out from under you leaving you running, no big deal as long as your going slow. mine just rocketed! zing!!! thing was 25 feet away when it landed! haha you wont have time to throw a switch or anything for sure......

you will burn the motor , they suck

Matt Gruber · Mar 10, 2014

good point about a failed controller. what do you think would happen if i use a 10 amp fuse? this would be with 37v 2p10s makita tool packs and a razor 36v controller with the shunt modified to 10 amps max. this is todays idea.
.
UPDATE the large sprocket is 80T and 6.5" dia. i estimate 12 mph at 36v. does anyone think 12 is too fast with the short wheelbase?
.
found the new chain and master links, even half links!

Matt Gruber · Mar 11, 2014

opened up a spare 36v razor controller, has 1 80v cap and 1 100v cap, schottky rectifier mbr1560ct, 60 v.
it is potted, and rated 30 amps max. everything else covered in epoxy.
i think i found the shunt sticking thru the epoxy near the motor wires. i can clip it and solder on a thinner wire to hopefully get around 10 amps. will just be a guess.
edit: so the shunt is about 1/2" long .088" dia. and stainless steel. since ss is about 40x more resistance than copper, i tried a .048 awg14 copper wire about 7" long. just a wild guess, but have to start somewhere. since i don't know how many amps it needs, can't bother to be precise. somewhere 5-15a should work, but have to try it and see what i like.
if anybody does the math, make your prediction!
.
3-12 edit- so it took 2 hrs to adapt the big gear. had to drill holes for valve stem access
.
3-13 edit- took an hour to bolt on the big sprocket- very tight fit.
chain now comes within 1/4" of frame. may contact frame as it bounces
old was 55T, new 80T 36v 80T should be 12.5 mph vs. 12 mph 55T 24v

Matt Gruber · Mar 15, 2014

controller tests 10.7 amps!
i could not wait, so i rigged up a quick test. i put vice grips on the motor :twisted:

so it looks like the controller mod is in the ballpark. (was 30a)
i'm planning to ride around where there are lots of people, so i don't want this scoot to lurch into anybody by mistake. plus with a 10a fuse, a cont. failure should pop the fuse. and with used konions 2p, i doubt they could do more than 20-30a anyway without a huge sag. For 30a it would need 6 makita 18v packs, but with 10a i can use just 2 packs and still get good cell life.
.
3-16-14 made up a new chain and installed rear wheel.
next is to cut the new deck!

Matt Gruber · Mar 18, 2014

the free 3/4" plywood had 2 problems.
a missing inside ply 2.5" all the way across the 46" piece. and black ants made a condo in there! :roll:

so i got rid of the ants, sounds easy but it took 2 days, and cut a 15.5x28 deck.
i had some thin plywood, so i hammered it into the slot with glue. it broke off partway so i repaired about 10" of the 15.5" width. it is clamped and drying. so if the cantilever fails, this will be the spot.
cut front half of the deck to clear the front wheel, and the plywood foot rests come out alongside the wheel since the 9" removed is where you normally put your feet.

Matt Gruber · Mar 24, 2014

1st test! LOTS OF FUN! short wheelbase gives a nervous ride

blew 10a fuse. controller mod didn't work :oops:

plenty of power, easily climbs hill in my driveway with 5-8 amps.
will cruise around at ~5 mph on 2 amps.
hit 20+ amps going down the street so mod totally ineffective.
using 2 makita packs 40.4v , 15 min later 39.2v seems to have good range. only 3ah.
fits easily on front seat. weighs about 38#.
still have work to do, i just had to try it out. I LIKE IT! FUN FUN FUN

sobotek24 · Mar 24, 2014

give us a pict or a video.. i would really like to see how short it really is

Matt Gruber · Mar 25, 2014

i have used my kick scooter at car shows. an adult model with 100mm wheels, no motor. it is 31",
e-short is 33". only 2 " longer.
will post pic after it is painted. raw plywood too ugly to photograph!

Matt Gruber · Mar 27, 2014

this thing can make a U-turn on a 2 foot walk! WOW!
that is because it has a 23" wheelbase. goes in tight places and turns around under power :twisted:

.
so i'm working on a throttle limiter. next i'll try a 3.3k in series with a 1k trimmer pot. i found 3.8k gives plenty of power, 10a peak, and a 3 amp cruise.
.
i like riding this so much, i'm making a wire harness to allow adding 2 more makita packs, 4 total .......... pics after paint.

Matt Gruber · Apr 1, 2014

wiring-
using a 3 position on/off/on 3pdt main pwr/precharge switch.
each pole rated 15a, 3 poles wired in parallel for long life (can do 45a)
onA connects 500 ohm resistor to charge caps. this brings caps to 29.2v (also tried adding 220 ohm, gives 35.8 from a 40,2 pack)
so bench testing i learned the green throttle light goes out at 33.5v. this is real nice to know. will be easy to see when to charge when the light goes out on acceleration, until my 15-120v waterproof voltmeter comes in from hong kong.
switch from onA to onB for normal ON.
made my own push in copper terminals for the makita packs, coated in solder to reduce corrosion.
painting it soon!

fechter · Apr 1, 2014

Pictures!

I agree on the safety (or lack of it) when using a brushed motor on a stand up scooter. I had the controller fry on my Zappy and it almost killed me. Best to have some kind of main disconnect relay or switch that can remove power from the motor. Most brushed golf cars have a 'pedal switch' in the accelerator pedal that opens the main relay to the motor anytime you let off the pedal. Something similar could be done on a scooter. I've also seen guys make a disconnect jumper out of Anderson connectors and tie a rope on to it. You pull the rope and it unplugs the jumper, which is in series with the battery. Not something you can do in a panic easily.

I suppose on something that doesn't go too fast, you can always just jump off.

Matt Gruber · Apr 1, 2014

Hi fechter!
i did take your safety advice on my mbike- 2 truck 80a relays and a handlebar micro switch. let go and pwr is cut.
Here i'm using a 10a fuse. Blew one during testing, and was in no danger of falling off. Now with the throttle limiter working good, it should not blow in normal use. But a failed controller and it should POP!

Matt Gruber · Apr 6, 2014

pic at last. next to my kick scooter.
and on my car front seat.

Matt Gruber · Apr 8, 2014

just ordered a 6 v to 90 v controller. i've got 3 more scooters, so what to do with them?
it is rated 10 amps just right for level FL, 15 overload protected with a 20a fuse. never saw a 6-90v controller before, so i have to try it as it is only $8.79 inc shipping from china. it might burn up, but the seller has 99% positive on ebay. If it works, i could run a wide range of packs and see what combo works best.

Matt Gruber · Apr 10, 2014

went in 2 stores with the -9, as i'm calling it. in the 2nd store i loaded it up with 33#. Got 6 bags of flour on sale, as i bake my own rolls. 6x5#=30# plus celery and green beans. Very easy and fun to ride, no looking for a cart to push around.
I'd call it fully loaded at 33#, but i guess i could hang more stuff on the handlebar if necessary.

Matt Gruber · Apr 12, 2014

went to the NSB car show! good thing i had the -9 as there was no parking, had to park far away and ride it in. It was popular, i'd say as popular as most cars there. I showed how it folds up several times. nobody expected that. Did some ZTR turns to show it off. a U turn on the sidewalk at 5 mph takes full attention. Would have to rent a road course track to have this much fun in the vette, and the engine would probably blow.
rode around/talked for 90 minutes. used only 0.9 AH at 36v. much less than i expected.
saw many nice cars, i liked the rat rods, rusty junk that looks so cool, you can't take your eyes off it. :twisted:

The -9 is WAY more fun than most people can imagine.

Matt Gruber · Apr 14, 2014

replaced the 7" of 14 with 3 FEET of 16 for a shunt. works great! about 7 amps max, matches the 250w rating of the 24v motor. now 7 ampsx36 volts=252w.
as to why i modify the shunt for less amps, and other do MORE amps,
i don't ride in traffic! no cars to deal with so no need to try to keep up.
cops say scooters illegal on the street, but OK on the sidewalk. sidewalk far from smooth, so high speed equals back pain.
Ordered a speedometer, as it seems to go plenty fast with just 7 amps.
Low amps also gives a longer ride, especially on windy days, without needing to charge. Using 4 makita packs, so it doesn't need a charge every day, which it would with just 2 packs.

cut out 9" from E300 razor to race around my oval track.

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