Gas / Electric Swappable Power Module Kart

[snowjob]

Hi All,

We have been busy plugging away building a Predator 212 powered kart from an old two-stroke Chinese kart.

Build Thread

During the whole build we have been dealing with an annoyed neighbor. We are still hunting for the anonymous person to verify their exact issue, but I presume it is the engine noise, especially now that we have Stage 4'd the motor and upped top speed to over 50mph

The way the local laws are written, play vehicles are permitted, but off-road vehicles are not. Although not explicit, it does seem to imply that electric would be ok and gas would not.

So I am considering making the engine swappable with a completely electric drivetrain. I have some experience with this as we first overdrove an e100 scooter with LiPo batteries (until motor burnt up) and then started conversion to a brushless setup, though it is not finished yet.

Finally, let's get started with the technical bits. The original setup has a Predator 212 in stock form (6.5hp / 3600rpm) running through a 30 series torque converter before hitting a 12T/60T final drive with a wheel/tire setup that is 9.5" in diameter. It topped out at roughly 30mph. What motor/controller/battery setup will get me closest for the cheapest cost? Even better if it can get closer to the Stage4 speed, but let's keep it reasonable to start.

Will add pics in post 2.

 

[JTSpeedDemon]

Makes sense to me as a "play vehicle" .
They probably mean Power Wheels and the likes, but if they complain about it being electric, they're just being an idiot.

 

[snowjob]

Sent from my iPhone using Tapatalk

 

[itsid]

50.. on this.. with cheapest possible bicycle brakes...
can't decide if that's brave or your entry for a Darwin Award..

'sid

 

[snowjob]

Poking around common electric setup for karts and seeing a roughly 15mph top speed (48V/1800W). Wondering if it's possible to get 30mph out of a similarly priced setup. I presume the trade-off is acceleration vs top speed? If so, would keeping the torque converter from the gas engine help? Or, is the sad reality that 30mph is much costlier via electric? We were hitting 20-30 on our Razor E100 running 48V until we let the smoke out

 

[JTSpeedDemon]

A torque converter on an electric motor would be ridiculous.
An electric motor will be well spinning before it engages a TC. Electric motors are direct drive.
Yeah, electric tends to be more expensive than a gas setup initially, but you also don't have to pay for fresh oil and gas all the time.

---------- Post added at 12:04 PM ---------- Previous post was at 11:58 AM ----------

I'm surprised Functional Artist hasn't chimed in yet.....

 

[snowjob]

Ooooh, just signed up for the diy electric car forum.......my head is spinning! On the most basic level 6.5hp=4.8kW, which is over 2x the 60V/2kW combo currently in discussion on another thread here. Would be fun to run (2) 2kW motors. I am really starting to like this module swap possibility, but it looks like I will be hunting for a bargain motor/controller for a while.

 

[Shep1970]

Just a suggestion, before you buy any motor/controller make sure to look into either lead acid or lithium battery pricing. The cost of batteries may determine what motor to buy, longer ride times get costly. Good luck
Just gotta say though the torque/speed these electric motors put out is impressive...

Shep

 

[JTSpeedDemon]

Look into local hamfests(amateur radio conventions).
I went to HAMCOM recently, and I got a lightly used, 12V, 9ah sealed lead acid battery for $9, and another one for free. Since it's unusual for a young 'un like me to have a license at all, much less a second level General license, people love to give me stuff.
But there are very good deals on electrical components to be found at hamfests.
BTW - HAMCOM is the ham radio equivalent of Pate Swap Meet.

 

[Functional Artist]

Poking around common electric setup for karts and seeing a roughly 15mph top speed (48V/1800W). Wondering if it's possible to get 30mph out of a similarly priced setup. I presume the trade-off is acceleration vs top speed? If so, would keeping the torque converter from the gas engine help? Or, is the sad reality that 30mph is much costlier via electric? We were hitting 20-30 on our Razor E100 running 48V until we let the smoke out

With a little/light kart like that, you should be able to hit 25-30MPH pretty easily with an electric set up

Torsk
...48V 1,000W brushed motor (4-12V15AH SLA's)
...top speed (~24 MPH)

https://www.youtube.com/watch?v=dEolqTiJ7Do

Damien
...48V 1,800W brushless motor (4-12V 12AH SLA's)
...top speed (~25 MPH)

https://www.youtube.com/watch?v=2t2mCG68OBs&list=PLoL6eIYWPO_k-VjU_UjzolNk0grs8qqe9&index=3

Atom
...60V 2,000W brushless motor (5-12V 15AH SLA's)
...top speed (~35MPH)

https://www.youtube.com/watch?v=IRjovx-BCJ4

* IMO when going over ~25 MPH, a side walk ain't gonna do it
...just lookin' for trouble

Maybe look for large parking lots
...in the evening or on weekends, when the business is not open
...or closed or abandoned places, are even better
(old factory, closed-up big box store etc.)

 

[snowjob]

Fantastic! Pointing me in the direction of the Atom build was exactly what I was looking for. I think I missed it since it wasn't in the electric section. Now I have a reasonable confidence that the 60V/2kW combo can achieve what I want, so now I need to start piecing together a rough configuration, along with pricing. Seems like a good place to start is selling our spare/stock Predator engine that was in service briefly while building our Stage 4 predator. Gonna need some $$$.

 

[Functional Artist]

Here is a link to some info on this set up http://www.diygokarts.com/vb/showthread.php?t=40239
…& most of what you would need

60V 2,000W motor/controller (~$185.00)
https://www.ebay.com/itm/2000W-Watt...:USPSPriorityMailSmallFlatRateBox!43607!US!-1

Thumb Throttle (~$15.00)
https://www.ebay.com/itm/Universal-...469840?hash=item25b0e33390:g:ID8AAOSwQoFWPm4V

Batteries (~$25.00 ea.) (x5)
https://www.ebay.com/itm/Mighty-Max...=13139246326187a9f7d28cf547ac92415e0b47838ad4

...or Lithium equivalent

Plus a few switches & your good-to-go

 

[Bmr4Karts]

Go with a single 60v boma setup. If its not enough add another wired in parallel. You'll need a battery than can deliver over 100amps. That is your most cost efficient option at $400 or less for 2 60v setups. Any other motor and controller combo will cost at least twice that.

I have a 48v boma setup (running 56v though) on a 110lb kart that does 35mph with my 200lb frame.

My reason for building electric karts is the same as yours, don't want to annoy my neighbors. In my opinion I think a loud weedwacker running up and down the street is very annoying.

 

[snowjob]

Thanks for that. I am still liking the idea of a single motor setup and trying to convince myself on keeping or losing the torque converter. Frankly, it is easier to swap out the motor while leaving the converter in place, it will just mean I need some type of coupler to drive it. It also seems like the mechanical/temporary gearing advantage of the torque converter would either lower the power requirements of the electric drive system or make the kart accelerate faster.

I did take note of your battery discharge rate comment and a quick search found this article: Lithiom-Ion vs AGM

Seems high discharge rate dramatically reduces capacity, so at some point traditional batteries won't cut it. Unless I can find a source for cheap Lithium batteries, a single motor setup may be the only viable option.

 

[Functional Artist]

1.) Keep the convertor for your gas engine
...it won't help with an electric motor

With electric's, you only need a drive sprocket (on the motor)
...your driven sprocket (on the axle)
...& a chain connecting 'em
* just be sure to use the same chain sprockets (#35 or #40 etc.) on both

2.) There is a lot more to AGM vs. Lithium
...safety, balance, BMS (battery management system), charging & dis-charging rates etc.

Here is more info on Lithium batteries
http://www.diygokarts.com/vb/showthread.php?t=38167
*IMO for a "novice" SLA's are a much simpler & safer choice

3.) Have you seen !Arriba!?
http://www.diygokarts.com/vb/showthread.php?t=37852

She has dual 48V 1,000W MY-1020 motors
…& (4) 12V 12AG SLA's

https://www.youtube.com/watch?v=eLCojNpCPu0

 

[snowjob]

All this thinking electric has motivated me to finish version 3 of our Razor E100 scooter. I may hate electronics, but if I think about them long enough, it all seems to start getting clearer. The scooter has a 56-63 195kv KEDA motor and has a 48V 5.2Ah pack of RC LiPo. It seems like the 48V controllers have come down a ton since I last looked, so although I have gotten the motor spinning with a 350W Amazon special, I am going to start looking for something in the 2000W+ range as that matches the motor rating and with a calcuated top speed of 29mph, I am guessing it will be wide open the full time it is in use. Perhaps getting comfortable with a brushless controller will inspire me on the go-kart or even convince me to share some parts between the builds (other than the motor).

 

[Quinc]

What you are going to want is a heavy duty 24-60v 1hp+ motor, 200-500+ amp controller and enough battery juice to run it(can handle 200+ amps for more then a few seconds). The power to price ratio of this cant be beat. ebay will hopefully be coming out with holiday 10-20% coupons in the next few weeks so keep an eye out for those.

1hp kart setup I built will smoke a stock 6.5hp predator off the line and in top speed.
http://www.diygokarts.com/vb/showthread.php?t=39038

*Note* not all motors are equal. A heavy duty 1hp American made motor will kick the snot out of a 2hp Chinese scooter motor.