RIPPY KART

Electric cars, trucks, ATVs, NEVs - things bigger than a motorcycle.
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RIPPERTON   100 W

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RIPPY KART

Post by RIPPERTON » Oct 12 2018 7:43pm

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jonescg   1 GW

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Re: RIPPY KART

Post by jonescg » Oct 13 2018 4:50am

Nice one Danny!

How do you find the 'diff' now? Must turn a lot nicer compared to a fixed axle kart?

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Oct 13 2018 6:24am

Yup GoKart "diffs" are the next big thing.
The chassis feels so natural going around any sized turn because its not being twisted into a pretzel and heaved up onto 3 wheels.
The steering is also effortless and I've "geared" it down where the tie rods connect to the column so there is less movement at the wheels per degree of steering wheel rotation. This concept will lend well to kids rental karts as they dont have the strength to drive a "jacking kart".
I think it does about 90kmh. At that speed the steering is of course twitchy and will do a 360 if your not careful but on a kart track I think it will be perfect.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Oct 20 2018 12:19am


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Quinc   10 W

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Re: RIPPY KART

Post by Quinc » Oct 30 2018 12:39pm

Awesome build! Any chance can you post the pics here? I am not able to see them on the other forum.

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fechter   100 GW

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Re: RIPPY KART

Post by fechter » Oct 30 2018 12:52pm

That looks like a lot of fun. What motors are those?
"One test is worth a thousand opinions"

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Oct 31 2018 1:38am

They were Motenergy 0913's but the stators were separated and new rotors made.
Just came back from a test trip at Cameron Park Kart track in Newcastle.
Clocked a 1:05.681. Not bad for its first time on a proper track.
The chassis felt good and got it to go around turns fairly well.
I had to get on the throttle gradually coming out of turns especially when I was still pointed at the grass.
When I was pointed down the straight I could floor it and it was quick. Nothing broke overheated or fell off. Awesome
https://www.youtube.com/watch?v=U88eN0xY7Js
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fechter   100 GW

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Re: RIPPY KART

Post by fechter » Oct 31 2018 9:33am

Nice work on the motors. They seem to work well. It really picks up speed fast on the straightaway.

Is it fair to make a skirt around the frame and use a vacuum to stick it to the ground?
"One test is worth a thousand opinions"

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Oct 31 2018 9:06pm

Nice work on the motors.
Thanks.
It gets out of turns well but it is geared too low.
I reached top speed about 10m into the main straight and cruised at about 90kmh for the whole straight.
The fact I am understeering or pushing under throttle coming out of turns proves my theory of splitting the axle and removing the jacking geometry increases traction in the rear end. During the turn exit, both rear wheels are gripping to the point of causing the understeer.
This doent happen in a jacking kart.
Now all I have to do is fix the understeer. I thought the controllers would comply to the differentiation in the rear wheels.
Im going to start by moving the battery boxes forward about 15cm, then move the ctlrs out to the side.
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SIDE SHOT s.jpg

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fechter   100 GW

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Re: RIPPY KART

Post by fechter » Oct 31 2018 11:13pm

I would think the independent motors should work well as a differential, but I guess you're seeing otherwise. Increasing the gearing should be pretty straightforward and should also help with the steering issue.

If you wanted to get really high tech, you could figure out a way to sense the steering and shift a little power from one motor to the other during cornering. I can think of some fairly simple analog ways to do this.
"One test is worth a thousand opinions"

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Nov 01 2018 1:27am

fechter wrote:
Oct 31 2018 11:13pm
I would think the independent motors should work well as a differential, but I guess you're seeing otherwise. Increasing the gearing should be pretty straightforward and should also help with the steering issue.
Thats right. taller gearing means the motors have less torque and less directional effect over the steer wheels.
These 2 ctlrs worked well in a Daihatsu Mira but the kart is much lighter especially in the front end and the rear wheels are so wide apart they just overwhelm the front end.

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Quinc   10 W

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Re: RIPPY KART

Post by Quinc » Nov 01 2018 12:33pm

Why not mount the batteries under the steering? Wouldn't that help with getting more weight on the front tires?

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neptronix   100 GW

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Re: RIPPY KART

Post by neptronix » Nov 01 2018 1:10pm

That thing is nuts.. excellent work sir!
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Nov 01 2018 2:39pm

Quinc wrote:
Nov 01 2018 12:33pm
Why not mount the batteries under the steering? Wouldn't that help with getting more weight on the front tires?
Probably too much. Im going to try to put the boxes in the same longitudinal position as the fuel tank.
The current position of the battery boxes is further rearward than where the fuel tank used to be so they should come forward.
Only problem there is the angle iron trays that the batteries sit in are going to rigidify the chassis in its crucial twist zone.

Hillhater   100 GW

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Re: RIPPY KART

Post by Hillhater » Nov 01 2018 4:25pm

RIPPERTON wrote:
Oct 31 2018 9:06pm
During the turn exit, both rear wheels are gripping to the point of causing the understeer.
This doent happen in a jacking kart.
Now all I have to do is fix the understeer. I thought the controllers would comply to the differentiation in the rear wheels.
Im going to start by moving the battery boxes forward about 15cm, then move the ctlrs out to the side.
Yes , you are in virgin teritory for kart handling with a diff.
But you are probably right to move weight forward ,..normally in a kart, that would be changing the seat position as a primary set up adjustment, followed by changes to wheel position (track width) on the rear axle, tyre pressure , etc. track changes probably wont have the same effect with a diff ?
In a solid axle kart, you rarely have understeer on exit as the normal driving technique is to go just fast enough to break traction at the rear, after initial turn in (using the jacking) , then "balance "the drift through the turn and on exit with throttle.
This forum owes its existence to Justin of ebikes.ca

StuRat   100 W

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Re: RIPPY KART

Post by StuRat » Nov 01 2018 4:45pm

Awesome! I want one.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Nov 01 2018 8:11pm

StuRat wrote:
Nov 01 2018 4:45pm
Awesome! I want one.
Make your own !
The perfect time to be a pioneer.

Youre in virgin territory....
I like virgins !

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Dec 09 2018 12:45am

The new 120kmh sprockets are on and the kart still has that same launch power but its at a slightly higher speed.
I thought the taller gearing would kill the corner exit speed.
The new sprocket hubs took ages to make but the are great and will also make some new 90kmh sprockets to fit them just in case.
Attachments
120kmh.jpg

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nuxland   100 W

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Re: RIPPY KART

Post by nuxland » Dec 14 2018 12:49pm

Just for curiosity :) What is your sprockets sizes for 120km/h.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Dec 14 2018 5:15pm

nuxland wrote:
Dec 14 2018 12:49pm
Just for curiosity :) What is your sprockets sizes for 120km/h.
13-35, 2.7:1, The Motors are still doing 6200 rpm even after being ripped in half.

After 6 years and 4600km of racing and practice in the race bike, some of the YGS LiPo cells are starting to go low voltage, ie they wont charge above 3.8v. This started to happen to the previous Enerland cells after 2 years, (2011-2012).
So the kart pack is showing some cell blocks with persistent low voltage.
When I try to balance a bad block up to 4.2v, the bad cell produces heat and
conducts the heat to every other cell in the block through the bus bar. This heat is also conducting into the 2 neighbouring cell blocks through the bus bars, (red arrows).
For this reason, the bad cell probably wont go thermal because its being cooled by 17 other good cells around it
As I dont have any spare cells at all, best solution is to leave this whole block out and replace it with a bus bar, then use the 5 good cells to replace other bad cells else where in the packs.
Its the most practical repair as it only lowers the battery voltage by 4.2v and is the minimum reduction in capacity...assuming I can fix every other bad cell block with the 5 good cells.
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BAD CELL 1.jpg
BAD CELL 2.jpg

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Samd   1.21 GW

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Re: RIPPY KART

Post by Samd » Dec 15 2018 3:10pm

Awesome. Subd.


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"Knowledge is knowing that a tomato is a fruit. Wisdom is knowing that a 165mm rear shock can't deliver 220mm of rear swingarm travel." - Oprah Winfrey.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Dec 20 2018 6:40pm

Heres the Z shaped busbar in place. Bending the 4mm alloy plate 90 degrees causes cracks so had to weld it back up. Preheating the bend zone helps a lot.
Pic showing LiPo cell swelling. This cell was low voltage. Not sure what causes the swelling.
Attachments
PACK TUNEUP 4.jpg
PACK TUNEUP 3.jpg
Last edited by RIPPERTON on Dec 21 2018 3:35pm, edited 1 time in total.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Dec 20 2018 6:44pm

Heres the new battery pack layout.
Moved them forward a bit for more weight on the front wheels.
Positioned them parallel to the kart and upright to broaden the weight and
also provide a big hole to stand in while getting in and out the kart.
Allows the ctlrs to be mounted further out and forward leaving more room
for radiators behind the seat.
Attachments
NEW LAYOUT 3.jpg
NEW LAYOUT 4.jpg

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jonescg   1 GW

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Re: RIPPY KART

Post by jonescg » Dec 21 2018 8:50am

RIPPERTON wrote:
Dec 20 2018 6:40pm
Pic showing LiPo cell swelling. This cell was low voltage. Not sure what causes the swelling.
Usually swelling is because the layer of lithium salts which precipitate on the anode start to decompose into carbon dioxide, causing the cells to puff. Hitting them with high discharge rates, letting them get too hot, or generally running them outside their happy voltage range will contribute to it, but they all start to puff eventually.

They don't need much compression - just to be constrained. In fact LG cells come with a statement that swelling of up to 6% is considered normal over the life of the cell.

I think 1000 series ally is the best for busbars as it's way more malleable, and being almost pure ally it's the best conductor in the range. 5000 series is good too.

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RIPPERTON   100 W

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Re: RIPPY KART

Post by RIPPERTON » Dec 21 2018 3:38pm

Yeah but this isnt a gaseous puff, its a buildup of solid matter just on one end of the cell.
I circled it in red in the previous post, its gone wedge shaped. Ive seen cells like this still perform
and charge up to 4.2v and not be lossy.

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