Electric kart from Holland 50hp

[R03|_]

Hello,

I`m Roel, an engineer from The Netherlands.
I wanted to share this project with you guys, and see what you think.
We started on this electric kart as a test and promotion project for electric driving.
The plan is to use a ME1616 motor and a Sevcon Gen4 controller running at 96V.

We got this used donor frame intended for a twin motor setup. This has a beefier frame and double frame rails on both sides to handle all that extra weight of batteries we want to put on.

We drew up the layout in CAD to figure out the positions for the main components.

After that out comes the cardboard and tape so we can get an idea on the space claim of all the parts.

 

[Karts of Kaos]

this looks really cool!

 

[JTSpeedDemon]

Daaang! Almost too clean for this forum!! Seriously, that sounds awesome, and I’m not even an electric guy! Looks very thorough so far!

 

[itsid]

I like the cardboard dummy approach..

BUT....
don't forget about weight distribution,
so try to estimate the weights as good as you can -as long as you don't have the actual parts-
and note them on the boxes
that way you may find that shifting one more battery over to compensate for the motor weight or so
will likely improve the handling quite a bit.
putting as little weight far out or far up...
what am I rambling.. you're a mechanical engineer.. you know the drill

nice kart btw..
nice goal too

'sid

 

[R03|_]

Thanks guys,

Regarding the weight distribution; we looked at general weight distribution numbers.
Stating about 55% in the rear and 45% in the front.
The CAD model is set up that way. Once the main components are on the frame we will measure the exact weight distribution and see if we need to move some parts.

 

[itsid]

I wasn't talking front to back at all.. I meant left to right above
if you can get the CoG right under the testicles of the driver he'll have the most natural feedback.
a dead center 50/50 is the easiest to handle though
front to back is easy to adjust by shifting the batpacks a bit for or backwards..
left to right is a bit more tricky though,
since that's where it get's thrown off with the motor on one side and the seat in the center
(hence race karts have their seats usually offset a bit;
not only to make room for the engine but also to shift the drivers weight for compensation)

So two identical batpacks might not be what you want in the end

'sid

PS poor dummy looks scared... sceptical at least with his head pulled back this far

 

[R03|_]

We shifted the controller box and the radiators a bit more to the left side and that moved the center of gravity to the middle. Also the design of the batteries is finished and we ordered the sheet metal parts for it.

 

[R03|_]

The Me1616 motor and Sevcon controller arrived. We started to wire it up to see if we could get it going.

 

[itsid]

Also the design of the batteries is finished and we ordered the sheet metal parts for it.

Hmmm.. I count 72V in that batpack (assuming another set of strips on the bottom)
And while I like the thermal protection (I assume the TO220 to be thermal fuses/switches)
I'm not too much of a fan running a flex cable alongside the edges of sheets of metal
especially around that overcurrent protecting fuse ... A solid busbar would likely be better
(or think about moving the fuse over at least) that batpack will vibrate and see some bumps,
take great care that the wire can never be shortened out,
the upper two rows could then short with nothing but thermal protection
and the high current spike alone could cause some serious cell damage.

The Me1616 motor and Sevcon controller arrived. We started to wire it up to see if we could get it going.

and how did you do?
..also has someone written LoveCats on the controller, or am I listening to The Cure for too long again ?

'sid

 

[R03|_]

Hmmm.. I count 72V in that batpack (assuming another set of strips on the bottom)
And while I like the thermal protection (I assume the TO220 to be thermal fuses/switches)
I'm not too much of a fan running a flex cable alongside the edges of sheets of metal
especially around that overcurrent protecting fuse ... A solid busbar would likely be better
(or think about moving the fuse over at least) that batpack will vibrate and see some bumps,
take great care that the wire can never be shortened out,
the upper two rows could then short with nothing but thermal protection
and the high current spike alone could cause some serious cell damage.

We are using these water cooled battery modules. 24 per pack. 2P12S The voltage range varies from 4,2V to 2,5V. So 2 packs in series will give us around 100V when completely charged.

..also has someone written LoveCats on the controller, or am I listening to The Cure for too long again ?

'sid

I never knew that SEVCON is an anagram for LOVECATS but I see it now

 

[itsid]

Ah.. so 48 nominal per batpack.. I see.. makes much more sense than 72
not sure I like the idea of pumping all the amperage through both batpacks tbh,

those powerbatpacks are 12P 18650s right?
So roughly good for max 240 Amps peak I assume, running that in 2P fashion makes it
a 480 Amps peak batpack and a 550A controller...
what's the peak motor current, low enough to not pop the batpack open?
Or are you current limiting via the controller?
Ah well.. many minds at work, someone will have done the math correctly I think

keep us posted!

'sid

 

[R03|_]

The sheet metal parts arrived. Housing for the electrical components, battery boxes and a controller box. These are test fitted onto the frame.
Also the steel brackets are welded in place. The frame is send out for powdercoating.

 

[R03|_]

We have the frame back with a fresh layer of powder!

 

[landuse]

Looks great!

 

[chimmike]

I love the progress, but I am entirely too impatient to keep waiting

 

[R03|_]

We made some progress mocking up the motor and empty battery boxes.