A couple of years ago, I assembled a 16S (60V) lithium battery module out of some Chevy Volt cells

To use it in my Sequoia racer, I'm working on a more secure battery box

The plan

Transferred to steel

Cut out

Bending it up (metal origami)

Battery box (front)

...& the back side

16S 60V 15AH Lithium battery module (naked)

...& mounted in the box

* Notice the terminal cover with "S" for Sequoia 

This 16S module has been sitting all winter

...so, I did an individual cell Voltage test 

** All of the cells voltages seem to be still pretty "close" 

...to each other

...& to last falls readings too

Ordered some XT90 connectors (for connecting the battery pack)
...& some 2-terminal Molex connectors (for connecting the wiring harness to the speed controller)

While waiting, I smoothed, rounded, cleaned & painted some parts 

Rear wheel hub (before)

...& after (Rustoleum Satin Blue)

Front wheel hubs

Swing arm (rear)

A-frames (front)

Tie Rods

...& ends

Doing some assembly on the wheel hubs 

Inner bearing, spacer 

...& outer bearing

Added a washer to "space" the bearing away from the retaining nut

Installed a Castle nut 

Adjusted the nut down to where the hub doesn't have any lateral (or side to side) movement

...but, still rotates "freely

...then, marked & drilled holes for Safety pins

Kinda like this

I've been working on the Throttle Control Assembly 

TCA Components
...pedal
...cable connector
...cable mounting bracket
...cable end/adjustor
...cable/housing
...cable end/adjustor
...electronic Hall Effect Thumb Throttle (mounted on a "peg")

* Notice the throttle pedal return spring 

...which gives 'er a nice firm feel
...& provides for some good-n-snappy pedal "return action"

**Also, notice the adjustable throttle pedal stop

...so, the throttle can be easily "floored" without overexerting the thumb throttle

After lots of "clean up" I went ahead & gave the chassis a coat of Satin Black paint

I first layed it on its side, to coat everything underneath

Then, after ~1 hour I set it upright & "made it look purty" 

Soon thereafter, a dumb 'ol bird "left a package" 

While the chassis was drying, I did some pre-assembly on the (rear) swing Arm 

...fender, wheel hub, motor & chain


I mounted the motor using (4) 5/16" x 1" Carriage bolts (up from underneath, thru the adjustment slots)
...with washers & Loc-Nuts (on top)

After a few days of letting the paint dry/cure, I started installing the sub-assemblies onto the chassis

A-frames, bushings, shocks & attachment hardware

Swing arm with bushing, shock & attachment hardware

Side view

Installed the wheels

...& now we have a "roller" 

Frontal view

A view from above

Floorboard

I harvested a couple of pieces of stainless steel, off the doors of an old refrigerator

...& going to use a piece for the floorboard

Kinda like this 

* Notice, I trimmed the front up to extend just ahead of the front mount brackets

...& curved the rear upwards to help direct fresh/cooling air into the motor/speed controller area/compartment

Safety (fire) Wall

I'm going to install a metal safety wall in between the motor/speed controller compartment & the driver

The idea is to help protect the driver in the event of a catastrophic motor failure (shrapnel)
...or electrical issues from motor/speed controller &/or connections 
...&/or chain failure (blunt force trauma)

This panel will be secured in place, at the top, by the seatbelt shoulder strap bolts

...& at the bottom, by the swing arm mounting bracket & bolts 

I painted the safety wall

While the paint was drying, I rounded up a box to house & protect the connectors for the speed controller 

...& installed a couple of ports for the wires to enter (from SC)

...& exit (going to their individual components)

This is how the SC, connection box & motor power wire connection block will be arranged, on the back side of the safety wall

Wiring

All of the smaller wires/connectors (at the top) are for control & signal circuits (On/Off switch, Reverse switch, Throttle control etc.)

The thicker Red & Black wires (kinda in the middle) are the main power input wires (where ya connect the battery)

The 5-wire connector (I'm holding) is the for the motor's Hall sensors (rotor position signals)

The 3 thick wires (at the bottom) are the motors power wires (sends "power" to the motor)
...& they have their own thermally insulated, connector block (yellow)

So, most of the wires from the SC enter, the box, thru the side port (except the motors Hall sensor & power wires)
...then, the wires will exit thru these bottom ports

...& then, go thru a rubber gromet, to their individual components 

Let's "dive" right into the wiring 

I have/am going to use some 22/4 wire

Which has 4-22g individually insulated Coper stranded wires in a common jacket

There are going to be 3 separate 4-wire "bundles going from the SC to the steering wheel 

I labeled them 1,2 & 3

#1 is for the On/Off circuit & the Reverse circuit (2-wires per circuit)

#2 is for the 3-speed switch (requires 3-wires)

#3 is for the PZEM-051 power meter (requires 4-wires)

Let's start with the On/Off circuit AKA KSI (key switch/ignition) or in Chinese (Electric Lock) 
...& the reverse circuit

I put them (On/Off & Reverse) together, mainly because both circuits require 2-wire switches
...& are going to be mounted on the steering wheel

Like this (#1)

These are the main circuits 

* left-Throttle connection

* 3-speed switch connection

* Reverse switch connection

* right-On/Off switch connection

...& these are the accessory circuits

"The Brake" connector is for connecting the Brake pedal switch

"Brake light" connector is for connecting the brake light

The "Indicator Light" connector is for connecting a dash light, which should illuminate when the system is switched "on" (to indicate, to the driver, the system is "on")

"Battery Indicator" connector will connect to (& provide power to) the PZEM-051 power meter

...& "is" switched (turns on/off with the main On/Off switch) 

...so, it will also, "act" as an Indicator light (to indicate, to the driver, the system is "on")

The "Charging" connector is for easily connecting a battery charging port 

The speed controller(s) "signal" wires have "male" Molex connectors

...so, we had to get some "female" Molex connectors, to connect all of the individual circuits

Most circuits use (2) wire connectors (On/Off, Reverse, Brake pedal & light etc.)

Some (like the 3-speed switch & the Throttle) use 3 wire connectors

Once you have some mating connectors, you have to connect the wires to the connector's terminals

The way I do it is to strip ~2" of the outer jacket off

...& then, strip ~1/4" of insulation off of each "inner" wire

Then, (because the wires are so small) I (personally) bend the bared wires back over the insulation

Then, lay the bared/bent over wire into the terminal (end)

* Notice there are (2) "crimping areas" 

...the upper portion is to be "crimped" over the bared wire

The lower portion is to be "crimped" over a portion of the insulation (to make a stronger junction/connection)

* Looks like the camera is focusing more on the workbench, than the crimped terminal 

...but, hopefully you "get the point"

After installing all of the terminal/ends

Insert them into their designated positions in the connector

...& then, simply "plug them in" 

Circuit Breaker

This racer will have a 60VDC system

...powered by a 16S 60V Lithium battery pack

...& motivated by a 60V 2,000W brushless motor

So, to help protect the entire electrical system we are going to use a 150VDC 50A circuit breaker

Also, to help protect the capacitators in the SC from a huge "inrush" of energy, before the system is first energized, we have a pre-charge circuit

The pre-charge circuit is just a 10W 1Kj resistor, with a momentary switch, that are connected to each side/terminals of the circuit breaker

It allows the user to pre-charge (slowly fill up) the capacitators in the SC, before the system is first energized

Tested the CB & pre-charge circuit with a little 12V SLA

With CB in the "Off" position & before energizing the pre-charge feature, there is NO voltage present

Then, when the pre-charge button is pushed (& held for a few seconds) the voltage level slowly rises

...until there is full pack voltage present

...then, the CB can be "safely" switched "on"

Installed/mounted "it" in the racer, right next to the driver 

K

Next up, installing the 3-wheel brake system 

First, I got the master cylinder, installed

Then, I installed the front calipers 
* First, I got a "feel" for how easy the kart rolled, by hand 
...then, after installing each caliper, I gave 'er a "test roll" to see if I noticed any additional drag
...& I'm happy to report, I didn't notice any additional drag

 Rear caliper installed, as well

I'd say a couple of systems checks
...& she's about "ready to rock" 

Intro video 

I charged up the battery pack & took her for a first test ride

...but, it didn't turn out as planned 

I charged up the battery pack & took her for a first test ride

...but, it didn't turn out as planned 

...& here are some thoughts on/about the issues 

So, it looks like maybe a few different things "ganged up" on this motor/controller 

Weight?
GR?
Spring sag/rolling resistance?

But?

For comparison: 
My Atom kart (mini-Aerial Atom) 2018

...is a heavy beast (IMO)
...& even has an extra wheel

Build thread (if interested) 
https://www.diygokarts.com/community/threads/building-a-go-kart-size-aerial-atom.40167/

This kart has the same 60V 2,000W motor & controller (bought at the same time)
...is running at about the same GR (Atom has 10T drive & 54T driven = 5.4:1) & (Sequoia has 10T drive & 50T driven = 5:1)
...& both were tested with the same battery pack (custom made 60V 16S Lithium)

This is the type of performance, I "was" expecting  

So, for reflection & comparison, I got out a couple of my 3-wheeled karts over the weekend (Mini-Slingshot, Polaris & Sequoia)


The Mini-Slingshot has (60T ~7" sprocket (6:1 GR) on a ~13" wheel)

* Notice that the driven sprocket is ~50% of the size of the wheel?


Polaris has (72 T ~9" sprocket (7.2:1 GR) on a ~20" wheel)

* Notice the driven sprocket is also ~50% of the size of the wheel?


Sequoia has (48T ~5" sprocket (4.8:1 GR) on a ~16" wheel)

* Notice the driven sprocket is ~30% of the size of the wheel? 


So, yea! I'm thinking that I got a bit too aggressive with the ~5:1 GR (50T driven sprocket...after double checking it is actually a 48T)

To "back 'er down a bit" I found (& ordered) a 60T sprocket from BMI karts for ~$10.00
...which will give us a 6:1 GR

Sprocket #35 60T (No Bolt Holes) | 774154 | BMI Karts And Parts

Sprocket #35 60T (No Bolt Holes)
Product Specs:
Chain Pitch: #35
Teeth: 60
Bore: 1-1/2"
Can be used on a multitude of projects
Sprockets have surface rust from storage

Also, I have to deal with the front suspension "sag" issue
...which leads to the front wheels "toeing outwards"
...which then, dramatically increases the rolling resistance

Here I am pre-weighting the front of the kart with my foot, to demonstrate how the wheels "splay" outwards

Also, wanted to mention that when the front wheels of a vehicle change direction, when/as the suspension "travels", is called or referred to as Bump Steer
...& it usually "comes & goes"

But, this situation is worse
...because the bump steering doesn't "come & go"

When the front suspension on this racer "sags"
...& the front wheels start "toeing outwards"
...this "toeing outwards" situation gets continually worse
...because as the kart travels, the front wheels "continue" to creep "outwards" more & more & more
...& as they do this, they suck the suspension down even lower & lower & lower
...making the problem continually wors(er) & wors(er) & wors(er) 

IMO the suspension in a performance or race car should be kinda "stiff"
...& shouldn't really "travel" very much

It's mainly to help absorb road irregularities, which should help keep the wheels "planted" on the road & not bouncing around
(like in a Corvette, where the ride isn't super smooth but, the wheels "hug" the road)

So, Ima thinking we need some stiffer shocks 

There are always a lot of different ways to approach anything...

Very stiff springs could reduce the effects of bump steer.

Working on the steering/suspension geometry could reduce the causes of the bump steer in the first place.  If you get rid of the bump steer, then you could still test and compare soft vs. stiff springs, but directly w/o other complications.

Computer-based tools make it easier to figure out steering/suspension geometry, but it is possible to do some analysis with pencil and graph paper, or cardboard and thumbtacks, and 2-D front/top/side views.

Most of the info online discussing bump steer assumes double A-arm suspension.

You can look at your single A-arm (swing arm) suspension as a version of double A-arms where the upper and lower arms share the same inboard pivot.

If the inboard end of the tie rod also lines up on the suspension arm pivot axis, then bump steer should go away (at least, when driving straight ahead).

The location of the outer end of the tie rod (and the fore-aft location of the inboard end of the tie rod, and the steering arm) will determine bump steer when turning (along with steering rate, Ackermann, etc.)

Compared to Sequoia, the steering rack on your Mini-Slingshot puts the inboard ends of the tierods much closer to the suspension pivots.  In theory the bump steer should be better on it?

I am not saying Sequoia necessarily needs a steering rack (the chain-based rack is cool, however).  You could retrofit something like a drag link plus center link on idler arms.  Or make your suspension arms pivot along the centerline of the car...

Hey Oapfu,

Yup, I agree
...& thanks for the input
...& helping to expand the conversation ;)

I'm going to just "bypass" the front suspension issue (for now) 

...by installing a couple of "props" in place of the coil-over shocks

Also, switching to a 48VDC system

A MY-1020 48V 1,000W brushed motor

...with a WYYS 48V 1,000W speed controller

...& a 14S 52V

20AH Lithium batt pack

I removed the 60V motor, controller & batt pack

* Notice how just by unhooking the rear shock provides ample access to the motor, controller & connection box 

Then, I did some exploring

...& it looks like the green "power" wire & connection "pad" has some heat damage

Wow! the green "power" wire burned right out of its socket 

The underside shows that the "pad" for the yellow "power" wire has some heat damage too

Most of the control/signal wiring, switches & connections were compatible with both the 60VDC & 48VDC systems

...so, installing/switching to the 48V 1,000W motor & speed controller was pretty simple 

* Notice how the connection box protects the connections

...& helps maintain a nice-n-clean installation 

...but, still allows ample access to...everything

...& having all of the circuit/connectors "labeled" also made the "switch" super easy

All "buttoned up" 

I made a battery box (basically a (5) sided cover) to protect the battery pack from external damage
...& (more importantly) to protect the driver from any potential battery issues
...& also, a device/method for securely mounting the batt pack to the chassis

* It's NOT a sealed container
...but, more like a "fire wall" between the driver & batt pack
...which will give the driver more time to exit the vehicle, in the event of an emergency

The plan (on paper)

The plan (layed out on a piece of sheet metal)

Cut out, rounded & smoothed

Bent up

Test fit over the battery pack

Here are the (2) battery packs
...60V (16S) lithium battery pack (left)
...& 52V (14S) lithium battery pack (right)

Before installing the battery pack, I had to install a shunt (data collector for the PZEM-051 power meter)
...because for some unknown reason (seemed like a good idea at the time) I installed the shunt, on/inside of the cover on the 60V battery pack

This piece of vinyl tube will "serve" as a protector/insulator for the shunt

I'm thinking that it should be pretty well "safe" if mounted, under the seat

I have to "cut out" a section of the Negative "cable"

...to be able to "fit in" the shunt

Like this

Here is the shunt

...all "wired up"
...& then, slid inside of the protective "sleeve"

Here's the battery pack/box & shunt
...mounted on the racer 

I did up a video kinda summarizing most of the modifications, that I've made recently
...& even did a test ride/run

* Spoiler alert...I didn't have ta push 'er home...this time

I took the racer out for another test run & speed test

Also, talk about/compare a freewheeling rear wheel vs. wheel with direct drive 

The racer has been doing so well, I figured it was time to take 'er out for an endurance run
...start off with a 15 min run
&
Then, "if" everything seems "good", maybe keep going for a whole 1/2 hour
...but, nope, today was NOT the day :mad2:

* This is why test running a racer is so important, BEFORE race day 

I've been looking for a test track site, to be able to test run my racers

Here are the requirements, as per the EA Rulebook

COURSE REQUIREMENTS
Events are typically held on parking lots, paved race tracks or velodromes where access onto the track can be safely controlled. EA strongly encourages events to be held on actual race courses when possible. This is to alleviate hazards inherent in street courses. Where road or parking lot courses cannot be avoided, extra care should be taken to identify possible hazards and have them barricaded or flagged to prevent collisions. Such hazards shall be identified and strategies for avoidance discussed at the drivers meeting Courses must be closed to all other vehicular traffic. Adequate precautions must be taken to prevent access onto the track. This may include, but not be limited to, signs, barricades, banner tape, and traffic cones.

Courses should be free of obstructions such as chuck holes, speed bumps or protrusions that would create a hazard to the competitors. The entire course surface should be the same material and texture. Dips or bumps which may damage the vehicles must be corrected or sanction will not be possible. Barricades must be provided to define the course and may include traffic cones, saw horses and police tape and/or hay bales, etc. Courses should be clearly marked to identify all corners, boundaries, start/finish and any obstacle that could pose a safety problem. There must be a positive physical barrier between spectators and the course. The barriers surrounding the course must be sufficient to stop Electrathon vehicles. Street curbs are not an effective barrier. Hay bales, tire walls, or suitable barriers must be provided to separate the course from spectators. Spectators must not be allowed near the course. Specified spectator areas should be designated with signs, barriers, or at minimum marking tape. There must be enough personnel/security provided for crowd control. Road Course layouts should be designed to offer a variety of turns and straights unique to the location. Courses from 1/4 to 2 mile lengths are used. Courses should alternate from clockwise to counterclockwise from event to event, to reduce tire wear, vehicle stress and offer variety. However some race tracks are specifically designed for vehicles to travel only in one direction. Do not run in a reverse direction if it compromises safety in any way.
Courses should be of adequate width and length to safely accommodate all competitors and allow safe opportunities to pass and maneuver. If a course cannot handle the number of vehicles present then separate heats should be run with a safe number of vehicles in each heat.

LENGTH MINIMUM COURSE LENGTH FOR A SANCTIONED EVENT:
Flat Course: 1/4 Mile (1320 feet, 402.34 m) Banked Course: 1/4 Km (820.21 feet, 250 m) Courses should be long enough to permit vehicles to attain their top speed at some point on the course. A 500-700 foot straight is desirable. Course length must be measured with a measuring wheel. On an oval track the distance is measured as the minimum distance a vehicle's inside tire could travel. On a track with reverse turns, the distances are measured with tangents from inside turn to inside turn.

The distance covered by a vehicle in one hour may be determined by an alternative method if that method can be shown to be more accurate than the current method, and has prior approval from the board of directors. An alternative method may be used to determine an official record of distance/time, but may only be used to determine the finishing order of a race if every competitor uses the same method.

WIDTH RECOMMENDED MINIMUM COURSE WIDTH: 25 feet

Course width must be free of obstructions such as cones, barriers and channels.
Surface must be same across entire width.
There may be no obstacles in the entire course width which would limit the free movement of any vehicle from side to side.

RADIUS MINIMUM CORNER CENTERLINE RADIUS : 25 feet

So, basically we need a good sized, close-able course, that's paved
...& I have some potential future ideas, like in some of our local college university parking lots &/or large Church parking lots
...but, probably gotta "drum up" some interest/support in the program, first

So, check this out:
The old Champion Spark Plug site is only ~1 mile from my house
...it was the main factory & world headquarters for years
...but, it's all gone (they are probably Made in China now)

It's mostly just a big 'ol weedy fenced in parking lot now, surrounded with No Trespassing signs

But, I found a couple of over-flow employee parking lots
...across the street from the main factory site
...that are not fenced in
...or have any signage whatsoever

So, I'm gonna do a little bit of clean up like
...broken glass, rocks & bricks & garbage

...& also, remove some of the "natural speed bumps" grass/weeds growing thru the cracks

Then, "run" Sequoia around a bit
...like this (my daughter Sierra helped & got in on the fun too) 

Still doing track clean up
...& also, tried another test run at the Champion track

Note to self: Always make sure the lug nuts are tight 

Then, while giving everything a quick look over I also, found another issue 

...but, it turned out to be a pretty easy fix 

After repairs, I took this racer out for another test run 

I found another issue 

...which happens quite often when designing & fabricating things 

The "good thing" about these "issues" is that they are great for expanding on topics, thru "real world" learning experiences 

...usually referred to as R&D

So, I did an end of season evaluation video (its getting kinda cold to test drive around here)

...to help explain the "new" issue (the rear axle seems to be bending)

&

Also, have some questions about the "effects" of "back spinning" a motor 

...like on the added (drag) of from having to "spin" the motor (& chain) like when coasting

...&/or any potential "value" of having a "freewheeling" rear wheel

* This forum is to discuss things like this

...so, why is no one discussing...anything...on here...but me?