Razor 350w 24v Scooter -> 1/3 scale RC

[mwkeefer]

Hey all,

Well I've been working on a razor go-kart I grabbed from the rubbish pyle some time ago - it's one of those little kid (supposedly 12-16 but it does 15mph with me + my 4 year old so 240lbs)... Pulls 25A maximum @ 26A and is quite speedy..

It came stock with a pair of SLAs which had been too badly abused to be worth squat - I promptly built up a pair of 7S packs (5AH) combining 2S and 5S parts - this keeps me right in the 24v range.

Tonight was the first ride - 1 AH for 14.6mph maximum with 240lbs load, not great for economy but it's also the stock motor still and using a rusty #25 chain reduction.

My son and I had a blast - ran 3 laps around our development (I was trying to make it drift but it just wouldn't!) with him on my lap (wearing a helmet) and it was really fun (so close to the ground it feels 2x the actual speed easily).

Tommorow will begin the upgrades:
1.) RC Outrunner in place of the stock 350w motor - driving still a #25
2.) 33t to replace the 20t currently in place - this will compensate for the higher RPM which the outrunner will spin up at.
3.) HV85 controller - I have it laying around and plan to limit this quite low, approx 30A maximum and running on 6 or 8S (haven't yet decided).
4.) Installing high torque servo on the steering tounge
5.) 6 channel RC receiver module

The idea is to make this much more efficient, add some torque and finally I will replace the controller with a normal infineon 6FET type (once I fit some hall sensors to the little outrunner).

The second goal is to have a fully remote controllable (able to override an occupant) gokart I can let my son "drive" while maintaining parental override on steering and throttle!

It's a project my boy has bugged me to get on for some time (I was brainstorming with him one night, he got the idea of putting the outrunner on the cart to make it faster - the RC gear is my idea)...

I'll post some pics of the stages for anyone who is interested - honestly at 37 years old and 175 lbs - this damn thing is already fun here!

-Mike

 

[AussieJester]

I'll post some pics of the stages for anyone who is interested - honestly at 37 years old and 175 lbs - this damn thing is already fun here!

-Mike

As i just this morning posted in Recumpence potatoe spud gun thread..."The only difference between big boys and little boys is the price of their toys" Your young-in will love the cart...if he can get dad out of it that is

KiM

 

[mwkeefer]

Lucky for him its a tad too short for my 6'1" frame (although I managed with moderate discomfort today) - but I suppose there could be some room with the lipo to move the seat position aft about 4-5" - I literally had to lean back to rear balance and keep traction, without the 20ish lbs of SLA in there it's front biased.

Then there is the main body pan, sheet of steel - could just as well be a sheet of aluminum...

Combined with perhaps a new seat mount system and a better harness with a seat that extends above head level (like a high back golf cart type seat) - it would be much safer in the event of a roll and much lighter but with a better weight balance.

To be honest - other than the BLDC conversion to RC from My101X motor crap and the decent lipo, not really sure what else I'm going to do to this one other than speed limit the poop out of it _

-Mike

 

[Jeremy Harris]

One of the gifted chaps over on the UK Battery Vehicle Society forum built this EV for his kids:

I believe he also built some sort of remote control over ride for safety. Going the whole hog with RC steering and throttle sounds even better.

Jeremy

 

[Hillhater]

Electric powered "race" kart have been built and raced ...

http://www.youtube.com/watch?v=qePTYYgqa7A&feature=related

 

[AussieJester]

Electric powered "race" kart have been built and raced ...

http://www.youtube.com/watch?v=qePTYYgqa7A&feature=related

uuuuhm...yes and the relevance to this thread is what exactly? Mike
is building a remote controlled electric cart for his son to drive not race.
There are also several examples of high powered slider karts already on this website.

KiM

 

[mwkeefer]

Actually after modding the stock DC controller for 36v (which is why I am sure I can mod the late model 24v currie controllers for 36v now) and running on a 10S pack - the bugger screams around and I can drift.

Granted after I soaked the chain and sprockets in CLR then oil then cleaned them in alcohol and added wd40 followed by white lightning, also disassembled and soaked the bearings in WD40 for the day .... drained them (mostly) and will soak in synthetic motor oil later tonight (works good for me) but I went for a 10S test like this and maxxed at about 1240w 1.65 hp and 20-24 mph (honestly 20 is perfect I need to calculate the voltage and current for my outrunner (which is why I'm doing this now!)... I may also attempt to switch to a belt drive (v type) for fair efficiency and built in slippage, should be fine in the 2kw range (where it will be without my son on board).

For my son, the speed will be limited to about 9mph... the steering gets "squirley" above that and feels like a covette with a broken tierod, very, very touchy. The remote control will be cool because we can walk to the park about 1/2 mile away and make it follow or go ahead of us without either of us in it (just like an RC) then go running around in the park on the little blocked off areas bringing it home the same way... it's actually large enough that I could "drive" him home at low speeds with a remove (most of the way) which reminds me too much of those darn spy hampster movies I've seen!

I have other kids in my neighborhood and all their parents are always enthustiastic about my "inventions" and "odd toys" I come up with, even when my son isn't here... they end up asking if I can come out and play (it's all good, I know their parents quite well and they appreciate this "supervised" playtime... gives them a while to unwind and me a chance to have fun!)

Another project (I will begin a thread when I get all the parts) - partially inspired by my eFriend Jermey Harris (lucky retired bugger) will be an underwater or submersible at least propulsion system powered via aqua ducted jets, water cooled ESCs and sufficent thrust to propel a normal diver (or pool goer in my case) all around beneath the water for much more accurate recovery and easier rescue of drowning victims. In truth - I want to make it cause I think it will be a freaking awesome toy for the pool - and not just for my kid, but for me and all the rest of the pool goers... Add to it remote directional control and you can give the kids a ride around the pool ... enough thrust, heck maybe you could water ski the pool

So... I've begun ordering parts for the first proof of concept for that one, knowing nothing about RC boating... its a bit of a learning curve as things are a tad different than other diciplines of the RC hobby and I may indeed be requesting as much assistance with that project as I may with this one.

I've ordered (just FYI) some monster servos to use for linking the steering and written arduino mini code to intercept the throttle control signal and allow me to override it remotely via an RC received, just orderd my first RC received and Transmitter (I grabbed a 2.4ghz 8 channel remote and matching received) as I figure I'll have more than this for use... Also added a POV transmitter, the idea is it's for the underwater propulsion system to allow it's use as a remote deployable mid range reconassiance device underwater to inspect whatever (oil leaks) - think Keyno's from the Stargate Universe series but submersible.

Well... that's it for me... last thought, wondering if I can design shock towers for this gocart to take up some of the impact - or maybe go to 6" pneumatic tires to remove some of the bone jarring effect of 4" hard wheels!

Thanks all!
-Mike

 

[John in CR]

To be honest - other than the BLDC conversion to RC from My101X motor crap and the decent lipo, not really sure what else I'm going to do to this one other than speed limit the poop out of it _

-Mike

I've got one. Turn the limiter off, hand the kid the remote control, and you get aboard.

 

[mwkeefer]

Yea - and I can begin my career as a Crash Test Dummy right? LOL, I rode the thing today again - it is too cramped for me but man is it fun!

-Mike