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

[Matt Gruber]

so my 3 spare controllers all quit working! either it was the shunt mod, or because they were 8-9 years old? any comments?
.
so i put in a new controller, and installed a safety 80a relay with left thumb momentary on push button. As the relay was for 24v, i doubled the contact distance to raise the voltage rating(to make it hard to arc across).
So anytime my left thumb comes off the switch, power is shut off, except for a 430 ohm pre charge resistor. No need to grab the brake; by then i'd could be thrown off.
.
new controller has 2 speeds. on LOW it is 15a max, 11-13 mph.
on HIGH 20a pulling away from a stop, and 17-20 mph. I never expected it go go this fast! with 7.27:1 gearing, i expected it to slow down! any comments?
.
fechter-thanks for resizing those pics!

 

[fechter]

Any idea what failed in the controllers? If you run too much power, the FETs generally short out making the controller act like a piece of wire (full power to the motor). Too much voltage could possibly blow the voltage regulator on the board.

 

[Matt Gruber]

Hi fechter,
is it possible the shunt mod, which reduced amps to 7 (from 30) was so extreme that some tiny component was overloaded?
that is all i could think of, or the parts, caps(80v and 100v, i'm 36v), being so old they just did not stand the test of time.
It didn't short, it just won't boot up. Right before it failed, it seemed to ignore the shunt mod, and blew a 10a fuse, then a 15a, but it felt like the normal old 30a, not like a short as the throttle worked. then it went dead. another one just ignored my shunt mod, but worked for a while with 3.3k in series with the hall. quit soon later. they are potted so they are junk.

 

[Matt Gruber]

So i'm updating another razor e300 with the 7.27:1 big gear and pop off camp chair. The chair now has wing nuts to secure it so it cant tilt back like the -9. I call it the PS (formely, in 2006 it was the PSEV).
Of course it gets the 36v 2 speed controller and i'm giving it the 4 makita packs from the -9.
The -9 now has power from 2 older makita packs with 2 bad cells removed, and another bad cell replaced without soldering. Looks like i'm the first here on ES to attach a wire to a cell with JB WELD epoxy. It has a 4 mv drop at 4-5 amps and during testing i was careless setting it down and it shorted by accident and the JB acted like a thermal fuse, and the wire fell off and saved the cell from damage!
Plus the JB insulates it like shrink wrap, except at the contact point. I'll be using jb anytime a cell lacks a solder tab. No more risking damage to the cell from too much heat. Takes some practice to learn how to use jb, it MUST have slight clamping pressure while it cures, to squeeze out the jb at the contact point.

 

[Matt Gruber]

made a figure 8 course in my driveway!
got tired of that and now made an oval track. this is better because i don't need to use the brakes. takes 7-8 seconds a lap. still using a throttle stop to keep speeds reasonable. takes my full attention, so, i don't need to go faster to have lots of fun.

 

[Matt Gruber]

Wore out the front tire of the -9, on my oval track in just 100 miles! Just the left side; turned it around for the next 50 miles or so.
Have ~47 charges on the Makita cells from Dr. Bass. This is the runt pack and they still work great! Almost 2 years for me, dated 2011. Even the epoxy(no-solder-no weld) experiments are working fine. Bulk charge only, with 64 minute timer. No balancing. No over discharges either. I stop at ~ 3.7-3.8v, charge to 4.05-4.10.
Today i epoxied the free-wheel. I'd like some motor braking. If it holds(doubtfull) i'd like to add a dynamic brake. A power brake! With a push button switch. Scooter band brake very poor.
I've been riding it more lately as it is so much fun, and my reaction time has improved.
Cheers!
Matt
UPDATE: motor brake works good! very quiet now, old freewheel did a lot of banging.

 

[Matt Gruber]

1-7-16 update:
motor brake failed; back to freewheel.
cells showing signs of age; final charge v creeping up. now 4.13v
137 cycles on used junk pile cells.
did a minor balance at 105 cycles; epoxy cells, the ones that were 0 v for months were .05v low.
managed to get 400 mi on rear tire, but cord showing; front replaced after flat, 370 miles.
been riding my ebike more, but it is not fun compared to the -9. the -9 is more like the ariel atom; super light; instant turn in; big grins every turn. 8)

 

[Matt Gruber]

spring break here at the beach. i'm surprised how much the college kids like the -9.
"kids" of all ages. a little girl, looked about 3 kept asking "what is that?" i said it's a razor racing scooter.
2 middle age ladies offered me pizza! said they had vespas at home.
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replaced rear tire near 500 mi. 164 cycles.
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in other news, a neighbor blonde that i wanted to meet for years followed me home when i was in my 72 corvette. i pulled out in front of an suv and smoked the tires. said she liked my car and that i timed it perfect so she did not have to hit the brakes. at last someone that appreciates max driving. However, the -9 is about 100 times more effective at meeting people! I just say "hop on i'll give you a ride" always get a laugh as the -9 is so small.

 

[Matt Gruber]

went to the corner restaurant the same time a limo pulled in. limo didnt stand a chance, -9 stole the show.
overheard " that thing corners faster than a motorcycle!"
met 6 women in 5 minutes. 4 too old, 2 too young, but lots of fun.
everybody loves it. kid riding a hoverboard said it is sick.

 

[Ianhill]

Just out of interest what do u use for a throttle with the motor controller as it come with a pot ?
I have a similar affair uses a pot throttle and would like to use hall effect ideally as the pot could short to full speed in theory where hall effect only give half revs at worst when it fails and due to my power I don't like the idea of a long term pot throttle any input be great thanks.

 

[Matt Gruber]

using razor hall throttle modified for precise control and a throttle stop to limit power.

 

[Ianhill]

My razor come with a 4wire throttle looked like a twin pole on off switch to me I'll have another nose about on one with a tester but other than that I'll have to get a cable twist throttle and operate a spring loaded pot in the battery compartment if I can not sort something soon.

 

[fechter]

 

[Matt Gruber]

168 cycles and the worst 2 cells, that were at 0 volts for months, and have epoxied wires are failing. near the end of my bulk charge, all others were 4.20, bad pair at 4.38! range was down by 1/3.
time to retire the junk pack for LED's etc.
.
newer razor throttles are just on/off
mine are old style, still availabe new i think. try razorama.com
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not feeling like a chick magnet today. a 23 yr old that agreed to spend the night didn't show up.

 

[Ianhill]

Thank you for the tip its proberly my last resort, Nice to see you have had a good run on the used packs im all for repurposing to much waste these days.

 

[Matt Gruber]

i'm still flogging the runt pack, now 186 cycles. near LVC the good were 3.90, the bad pair 3.48!
huge imbalance. so i added 1 cell in P on the bad pair. it is a dubious cell that self discharges down to 3.88, then will hold there for months. 1st test it brought the range back to normal! so will continue until something gives out.
A blonde in an suv gave me a wave and we talked later. didn't hit it off, but i tell you guys, girls rarely ever notice me without the -9.

 

[Matt Gruber]

after 2 years of using an sla charger and timer, 198 cycles, i've ordered this charger
http://www.all-battery.com/tenergysmartchargerfor37v2ali-ion_lipobatterypack-01338.aspx?variation=4779
$25 shipped
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I've started doing a little "street show". when cars back up for the red light, i do 3 donuts on the sidewalk. saw a girl in a Kia Soul watching so i gave her a wave and she waved back with a smile.

 

[Matt Gruber]

took the -9 to home depot and then walmart. went 1.2 miles, shows how big those stores are and why i get tired walking around. lots of people liked it and wanted one. NOT SOLD IN STORES
4.5 mph is fast enough inside. walking i'm invisible, on the -9, i'm a popular guy, despite being bald.

.
need to choreograph my sidewalk driving. was doing side to side weaving and then a doughnut and
and 4 college kids in a mustang beeped, gave thumbs up and said it was very cool. Very strange for a bald guy to get this much attention.
Teenage girl on a skateboard smiled and said Hi, as she went by.
someday i'll have to go to the skateboard park; would be fun i'm sure.

 

[Matt Gruber]

240 cycles, junk pack still going strong just by adding 1 cell!
got 3 spare tires from razorama.com $15.99 each +ship.
'
a girl ~30 was approaching holding hands with her bf, so i mostly ignored her. i glanced up and she gave me a wave! a guy having fun is attractive, i have learned.

 

[Matt Gruber]

272 on the old pack. weak trio was going to 0 on hard acceleration and charging to 4.5v, so they are GONE. now using good used pack.

 

[NyOliver]

How do you like jbweld for the tabs now?

Do you have any pictures of this rig? Thanks

 

[Matt Gruber]

How do you like jbweld for the tabs now?

Do you have any pictures of this rig? Thanks

pic on page 1.
jbweld works great! anytime you don't want to solder a cell or 2, it does the trick. it takes time to
figure out a method to place some pressure on the joint, takes 24 hrs to cure, and is messy, so i would not build a whole pack with jb. just do repairs.
i've read about pouch cells with a broke off wire; sounds ideal to repair it with jb, a clothespin and some saran wrap so you can get the clothespin off.
thanks for reading this story,
matt

 

[Ianhill]

Its great to see this still getting use long after it's creation, my e300 is sitting idol seems a shame i may donate it to someone that is in need and will make use if it for Xmas.

 

[Matt Gruber]

so i figured out what to do with the best cells from the old makita/sony pack. i put 7s2p into my old red scooter. the 24v sla charger works great bulk, 1.2a at first, then it tapers real nice and then on stage 2 it floats too low to charge at all. 4.19-4.20/cell max when charging.
i used a 6-90v controller (cost $8.79)so i can use any pack i have lying around. handlebar switch(press to go) triggers an 80a relay and a low amp fuse that should easily blow if the controller ever shorts.
no pre charge resistor as the small cap hardly sparks; so there is no way to accidently drain the pack as the relay shuts it totally off.
i put a reverse switch in, it actually goes faster in reverse. extra fun. has a belt drive, no clutch.

 

[fechter]

That thing is like the Energizer bunny. Just keeps going and going....

I'd like to see how you ride that thing in reverse. It would be worth a video.