Damien

[JTSpeedDemon]

Are you planning to keep the chain link permanently? I assume so.

 

[Functional Artist]

Are you planning to keep the chain link permanently? I assume so.

Yes the "expanded metal" is an integral part of the superstructure.

FYI,

"Expanded metal is a type of sheet metal which has been cut and stretched to form a regular pattern (often diamond-shaped) of metal mesh-like material. It is commonly used for fences and grates, and as metallic lath to support plaster or stucco.
Expanded metal is stronger than an equivalent weight of wire mesh such as chicken wire, because the material is flattened, allowing the metal to stay in one piece. The other benefit to expanded metal is that the metal is never completely cut and reconnected, allowing the material to retain its strength.
Some commonly used shapes are circles, squares, and diamonds; diamonds are the most popular shapes because of how well the shape absorbs energy and resists mechanical deformation after installation. Other design considerations are the size and angles of the shapes, which will also affect how well the metal absorbs energy and where the energy is spread throughout the expanded metal.
Expanded metal is frequently used to make fences, walkways, and grates, as the material is very durable and strong.
The many small openings in the material allow flow through of air, water, and light, while still providing a mechanical barrier to larger objects. Another advantage to using expanded metal as opposed to plain sheet metal is that the exposed edges of the expanded metal provide more traction, which has led to its use in catwalks or drainage covers.
Freshly-cut expanded metal has a large number of exposed sharp edges, requiring caution and protective clothing, such as leather gloves and aprons to prevent skin abrasions and cuts."

https://en.wikipedia.org/wiki/Expanded_metal

* Pay extra attention to the last line
...think like rosebush (thorns) on steroids.

 

[JTSpeedDemon]

Ohhh, that stuff's on my grandpa's trailer gate!
Just don't drive through puddles or water.

 

[Functional Artist]

Ohhh, that stuff's on my grandpa's trailer gate!
Just don't drive through puddles or water.

I don't plan on it

IMO electric & water don't mix too well

 

[JTSpeedDemon]

(Do I smell something burning??)

 

[Functional Artist]

Now that we can make 'er go, we need to be able to make 'er stop too

But, I messed up
...remember back on Post #91 where I said:

"Looking for a hub to mount the brake rotor on to Damien's axle.

I looked at many of the standard hubs, for sprockets & rotors
...but it looks like a lot of work to ream out the center hole, of the rotor (to ~ 1 1/2")
...& then, to center & drill the bolt holes.

Plus, the hubs cost ~$15.00 - $20.00, adds more mass for the axle to motivate & is also more overall weight on the kart.

Then, I thought maybe I can just mount the rotor to the side of a small sprocket
...& use that as a hub. (~$5.00) https://www.surpluscenter.com/Power-...-2413-15-E.axd

Thinkin' it thru, the 60t sprocket we got from Surplus Center ($26.00) https://www.surpluscenter.com/Brands...-2413-60-E.axd has a nice big & flat area on it.

Hmmmm

It looks like, if I mount the brake rotor directly to the "driven" sprocket, it will not interfere with the chain & there also seems to be plenty of room for the caliper."


Well, all of that is "mostly correct" except, I didn't take into account for the frame rail runnin' right thru there.

But, there is room for the brake system on the other side.
…just have ta mount the brake rotor on to a small sprocket/hub like this one (~$7.50)

https://www.surpluscenter.com/Sproc...ckets/21T-1-Bore-35P-Sprocket-1-2413-21-E.axd

...as opposed to something like this one ($13.00)

https://www.bmikarts.com/Steel-Multi-Patterned-Sprocket-Brake-Hub-1-Bore-_p_1404.html

…& this one looks to have too large of a diameter, that may interfere with the caliper.

 

[Functional Artist]

Some things work out better "on paper" (in theory)
...but, then during actual "real world" assembly

I realized this "oversight" when I mounted the motor & chain
...to figure out/work on the brake/caliper mounting.

So, I ordered (1) of the ~$7.50 21T sprockets, to mount on the left side & use as a hub for the rotor.


*On the plus side, it looks like I may be able to use the 54T driven sprocket, that I attached the rotor to, on the Atom kart.

 

[Functional Artist]

I'm gonna use these 10.5x4.50-6 Unilli racing slicks on Damien (~32" circumference)
...yup, she's gonna be a "low rider"

I compared the these tires, with the 15x6.00-6 tires, that I'm gonna use on the Atom kart (~43" cir.)

Big, big, big difference


This 48V 1,800W Boma should be able to muster ~3,500 RPM (even under load)
48V x ~73RPM per Volt = 3,504

So, doin' the math, using the "Ball Park Equation"
...using 3,500 Motor RPM with a 6:1 Gear Ratio & ~32" Tire Circumference

3,500/6 = 583
583x32" = 18,666"
18,666"/12 = 1,555
1,555x60 = 93,333
93,333x.000189 = 17.64MPH

So, even with these little tires Damien should do ~17MPH

 

[Functional Artist]

Got the hub, I'm gonna use, for mounting the rotor yesterday.
Surplus Center doesn't mess around.

I used the same procedure, as I used to mount the rotor to the 54T sprocket (now, for the Atom kart)
...to align, mark, drill & tap this one.

Yup, didn't use nuthin' fancy, mostly just Harbor Freight hand tools
…& a drill press (also Harbor Freight) just to make the holes as perpendicular, to the hub, as possible.

 

[Functional Artist]

It was ~72* here yesterday.

Couldn't wait

https://www.youtube.com/watch?v=g2hGUzKdWd4

I'm still using the wheels off of the Torsk kart
...so, she won't be a "low rider" until after paint

 

[JTSpeedDemon]

What's it's top speed?
Also, how quiet is it? I know electric motors are supposed to be quiet, but the karts at K1 Speed are pretty loud.

 

[Functional Artist]

What's it's top speed?
Also, how quiet is it? I know electric motors are supposed to be quiet, but the karts at K1 Speed are pretty loud.

Didn't check the speed...yet

I was just out havin' fun.
…& checkin' functionality

Didn't seem too loud
...see/listen to it in the video

 

[J.S.@SMS]

Yeah, it was pretty quiet. How's the acceleration, and can it squeal the tires?

 

[Functional Artist]

Yeah, it was pretty quiet. How's the acceleration, and can it squeal the tires?

The acceleration is really good
...not quite torque enough to squeal these 13" tires

It maybe able to squeal the smaller 10" Unilli tires (when I put 'em on)
...but, it'll probably loose some of the top speed

So, far from my first ride,
The rear suspension works great
...smoothest ride I've had in a while

Acceleration & handling was great
...but, them live axles like to "push" ya thru turns a lot

So, reviewing the video, I noticed

A.) What is up with the MASSIVE voltage drop?
see @ 5:30 meter shows ~50V
...then went all of the way down to 44.8V (~5V drop REALLY?)
also see @ 6:05 meter showing 49.8V then, dropping down to 44.2V (again ~5V drop?)

B.) It looks like the Amp meter is showing down to the tenths
...but, not showing a decimal point. (maybe because I used a 50A shunt instead of a 500A shunt?)

The top Amp draw seems to be ~30.3A with an average draw of ~20A
...NOT ~303A with a 200A average.

 

[Tpdingo]

The acceleration is really good
...not quite torque enough to squeal these 13" tires

It maybe able to squeal the smaller 10" Unilli tires (when I put 'em on)
...but, it'll probably loose some of the top speed

So, far from my first ride,
The rear suspension works great
...smoothest ride I've had in a while

Acceleration & handling was great
...but, them live axles like to "push" ya thru turns a lot

So, reviewing the video, I noticed

A.) What is up with the MASSIVE voltage drop?
see @ 5:30 meter shows ~50V
...then went all of the way down to 44.8V (~5V drop REALLY?)
also see @ 6:05 meter showing 49.8V then, dropping down to 44.2V (again ~5V drop?)

B.) It looks like the Amp meter is showing down to the tenths
...but, not showing a decimal point. (maybe because I used a 50A shunt instead of a 500A shunt?)

The top Amp draw seems to be ~30.3A with an average draw of ~20A
...NOT ~303A with a 200A average.

A couple of small SLA packs vs 30A. Of course it was going to drop 5V. Thats only around 1V per cell which for a 30A load...I don't see much of an issue.

Also...LITHIUM ION MAN!!!! Stop living in the dark ages...recharge quicker, go longer, get more power. Its all around a win win deal...well except for price. Get some cheap cells from a Nissan Leaf...2Kwh pack might run you 400$. I mean compared to some other batteries, that aint bad. Used could probably drop that another 100-150 depending on the deal you get. And I'm not even including junkyard pulls or whatnot.

 

[Functional Artist]

A couple of small SLA packs vs 30A. Of course it was going to drop 5V. Thats only around 1V per cell which for a 30A load...I don't see much of an issue.

Also...LITHIUM ION MAN!!!! Stop living in the dark ages...recharge quicker, go longer, get more power. Its all around a win win deal...well except for price. Get some cheap cells from a Nissan Leaf...2Kwh pack might run you 400$. I mean compared to some other batteries, that aint bad. Used could probably drop that another 100-150 depending on the deal you get. And I'm not even including junkyard pulls or whatnot.

Makes sense
I even went back & reviewed the data of this motor/controller when I tested it on e-Lemon-aid
…& that meter also showed ~4V drop

https://www.youtube.com/watch?v=ffzQf7ppw5g&list=PLoL6eIYWPO_l4g47Zt_YPcBOLSOtLXNqM&index=18

Specs:
e-Lemon-aid has tires ~11" & (really low) 8.4:1 gearing
Damien has ~13" tires & 6:1 gear ratio

So, it seems that the smaller tires & the lower gear ratio on e-Lemon-aid = less load on the motor
...which also = less average amp draw (~10A vs Damien's ~20A average draw)
...but, it didn't seem to affect the max Amp draw (~30A on both)
…or the voltage drop (~4V on both)


On Lithium batteries, yup I agree lighter, more powerful, last longer & recharge quicker.
...but, the cost (x4) ($400.00 vs. $100.00) is a HUGE factor
...& the increased danger level (x100) is even HUGER

* I'm kinda cautiously creepin' my way into Lithium

 

[Functional Artist]

A couple of small SLA packs vs 30A. Of course it was going to drop 5V. Thats only around 1V per cell which for a 30A load...I don't see much of an issue.

Also...LITHIUM ION MAN!!!! Stop living in the dark ages...recharge quicker, go longer, get more power. Its all around a win win deal...well except for price. Get some cheap cells from a Nissan Leaf...2Kwh pack might run you 400$. I mean compared to some other batteries, that aint bad. Used could probably drop that another 100-150 depending on the deal you get. And I'm not even including junkyard pulls or whatnot.

I've been thinkin' about this a bit more. (went on a road trip, lots of time to think)

To go from Lead (SLA's) to lithium, the cost is NOT really (x4) $100.00 vs. $400.00
...you just have to buy (4x) the battery (up front)

4 - 12V 12AH SLA's connected in series = a 48V 12AH battery pack.
(~$25.00 ea. = $100.00) (~10lbs. ea. x 4 = ~40lbs.)
vs.
1 - 45V 45AH Lithium (Volt battery) = a ~48V 45AH battery pack.
(~$400.00) (45lbs.)

But, in actuality, with the Lithium, you'll have (4x) the battery capacity, on board, for ~ the same amount of weight.

Any thoughts as to the potential voltage drop from a 30A draw on one of these 45AH Lithium battery packs?

 

[Tpdingo]

I've been thinkin' about this a bit more. (went on a road trip, lots of time to think)

To go from Lead (SLA's) to lithium, the cost is NOT really (x4) $100.00 vs. $400.00
...you just have to buy (4x) the battery (up front)

4 - 12V 12AH SLA's connected in series = a 48V 12AH battery pack.
(~$25.00 ea. = $100.00) (~10lbs. ea. x 4 = ~40lbs.)
vs.
1 - 45V 45AH Lithium (Volt battery) = a ~48V 45AH battery pack.
(~$400.00) (45lbs.)

But, in actuality, with the Lithium, you'll have (4x) the battery capacity, on board, for ~ the same amount of weight.

Any thoughts as to the potential voltage drop from a 30A draw on one of these 45AH Lithium battery packs?

Well not totally sure but most Lithium Ion cells are rated at over 10C...so given 18650 that's 25-35A per cell....and that's the basic ones. Higher ones can go up to 80 so a few hundred amps per cell. I don't know about 30A draw, really depends on the pack. Each 18650 has like 35mOhms per cell but if you have like 10 -20 in series then it drops down to like 2-4mOhms. Then across like 12x it's like 48mOhms. SLA 12ah is like 13mOhms per pack so like 56mOhms total. Not much savings but the extra capacity will be. Also weight savings!! And LI-ION is much more forgiving for a slight undercharge than SLA as you probably know. Also forget about having to deal with the battery dying in storage. Charge it to 75% and check on it every 3mo and your battery will last year's and years.

 

[Functional Artist]

Been workin' on mounting the brake caliper

It's been a PITA

The caliper mounting bracket has to be attached to the swing arm, clear the side of the pillow block bearing & hold the caliper in alignment with the rotor, on the outer side of the (moving) frame.

Plus, it must be "beefy" enough (& attached well enough) to handle, maintain & hold the caliper in place while stopping the kart.

First, I tried a piece of 1/8" steel bracket material
...but, it would have held the caliper too close as to where the rotor would not clear the frame rail.
…& it seemed too thin (not heavy duty enough) for the task.

Second, I bent up a piece of 1/4" x 2" steel
...but, it seemed a little too heavy duty
…& I also kinda wanted a mechanical bond (bolted) teamed with a metallurgical bond (weld) to double up the attachment strength.

Third, I picked up some 3/16" x 2" steel & bent it up into an S shape, like the previous bracket
...but, I added a hook to the top of this one so, I could use one of the pillow block bearing bolts to bolt 'er down too.

 

[Functional Artist]

That was easier said than done.

The first bracket I made out of the 3/16" steel aligned the caliper perfectly, where the rotor would clear the frame nicely
...but, when I went to mark the caliper mounting bolt holes, I fount that I cut the bracket a bit too short.

Second, when I went to bend up a longer piece, I couldn't get it to fit into the bender far enough
...& it didn't come out right.

Third, I finally ended up doing the (2) end bends with the bender
...& the middle part of the (S) curve with a piece of scrap steel & the bench vise.

Next, I marked & drilled the caliper mounting bolts
...& then, marked & ground out the center a bit to accommodate the caliper body.

Yup, I think that will work.