2017 - El Turbo OD/OV

[Functional Artist]

Well, got 'er all hooked up. again

Double checked everything (forward) from speed controller thru solenoids to the motor

& then double checked everything again (backwards) from motor thru the solenoids back to speed controller

*Wiring is kinda like math, it should add up (so to speak) both ways (forward & back)

Kool! everything looks good.

Lets see if this works.

---------- Post added at 02:53 PM ---------- Previous post was at 02:24 PM ----------

Oops! I got ahead of myself.

Work with me here, I was up late doin' testin' & research.

Lets back up, just a second.

The night BEFORE I did the solenoid set up (Turbo switch 3) (because I could only round up (2) solenoids) I was thinkin' (always thinkin')

Why not try just running the power thru these switches?

*We don't need no stinkin' solenoids

Got'er all wired up

Yes! It works! Yes, yes, yes

Wait (was that a little puff of smoke) don't work no more.

https://www.youtube.com/watch?v=-FhxtHi8pMg&t=33s

 

[Functional Artist]

Well, now we know not to run 24V or 36V thru 12V switches.

So, ya. lets move on to testing Turbo switch 3(b) I guess you would call it.

https://www.youtube.com/watch?v=W7YJ20-j6W4&t=8s

 

[Kbosher]

They say the mother of inventions is need

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[Functional Artist]

I think we have a Electric Turbo switch!

To be clear:
running the power thru solenoids & using switches as relays to tell the solenoids when to contact or separate is not new technology

...& neither is overvolting

But, I think that adding a Turbo (over volt/over drive/nitrous) button to an electric motor in addition to it's standard speed controller is unique.

Well, so far the bench tests we've done, on this set up, seemed successful.

Now, we gotta get every thing (on the kart) & do some "real world" or under load tests.


*But, that's where we ran into problems with the simple speed controller tests last summer.

*Learned many valuable lessons. (what NOT to do)

*Contributed to new ideas



I got the bench test set up all took apart.

Mounting everything on the kart should be pretty simple

Main problem is these switches are kinda huge to mount on the handle bars of the kart.

I need some smaller switches.

Like the micro switches in the "simple speed controller"

I found some @ a local golf cart shop but, they want $14.95 each

Kinda expensive for little dinky switches.

Ima keep lookin'

Wow, I found a (10) pack on line (free shipping) be here by next Friday for $14.95 (same switches)

So, got till Friday to get everything set up on the kart.

 

[Functional Artist]

Well, while waitin' for the microswitches we can cover some other details of this build.

Another issue we may (will probably) run into is with the solenoids.

After testing, I noticed that the (2) solenoids for the 24V side were very hot. (I had them on a lot)

The (2) for 36V side were only slightly warm. (they were used less)

After doin' more research,

I think these lawnmower (starting) solenoids are only set up for "intermittent" use, like starting a lawnmower motor from time to time.

Not for "constant duty" use like used on winches & electric golf karts.

I found them here in Toledo, for like $30.00 ea.

I found them online for like $11.50 ea.

But, that's still like almost another $50.00

So, for testing purposes, & because, my build budget is gettin' kinda low (made some recent purchases) I am going to roll with the solenoids I currently have. (lets see how long they last)

 

[Kbosher]

Or go with like a snow plow solenoids i know some of our get the crap worked out of them

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[Functional Artist]

Speaking of recent purchases

Earlier in the week

when the Turbo switch testing wasn't goin' well

& then the test Kart broke down during the speed tests

I was kinda frustrated with the whole set up

Later that night, I came across this 1,800W Brushless motor, speed controller & throttle combo for ~$200.00

I was like Hmmmmm

-Brushless (newer technology)
-1,800W (like (4) times bigger than the 450W I was workin' with)
-complete set up (except kart & batteries)
-under $200.00

I said, what the heck

The next day went on trying switch ideas & kinda forgot about it.

Well, guess what showed up yesterday (I didn't even know they delivered on Sundays)

Yup, our new Brushless motor kit

 

[Functional Artist]

So,
now, would be a good time to discuss "the numbers", I guess you would call them

The motor we are using for the El Turbo kart is a

24V 450W DC brushed motor
rated current of 25A
rated speed 2.500 rpm

so, if we divide 2,500 rpm by 24V = 104.17 rpm's per volt

seems a bit high

...that's probably max motor speed not average

...for comparison, the motor on El Dingo was rated @ 72 rpm's per volt

So,

for simpler math & maybe a bit more realistic numbers,

lets try our calculations @ 2,000 rpm

(2,000 divided by 24 = 83.33 rpm per volt)

That sounds a little more consistent with our other data

So, if were getting an average of 2,000 rpm's @ 24V

when we kick in turbo,

the motor rpm should increase to ~3,000 rpm's (84 rpm's per volt x 36 volts = 3,024)

That would be a instant 33% increase in rpm's coming out of the motor

So,

If the kart did on average 15 mph during the speed tests

...it should do ~20 mph (15 mph x .33 = 4.95)

Nothin' to write home about speed wise but, a 33% rpm increase @ the push of a button is substantial

So, to go by that:

If a bigger faster kart, did lets say 40 mph

a 33% boost would provide a 13.20 mph increase

40 mph to over 50 mph instantly

 

[Functional Artist]

Facts that brought us to this conclusion

(to try -overvolting- @ the touch of a button)

From my research,

everyone does not agree but, many say:

...overvolting an electric motor may work for short periods of time but, not continuously (biggest worry, overheating)

...some electric motors can handle overvolting but, NOT speed controllers

...if you apply any voltages higher than what a speed controller is rated for, you WILL pop/fry it.

So, this Turbo button idea seemed like a plausible design.

Because:

...it is only intended for temporary bursts

...& I made sure to provide back feed protection in the design (to protect the speed controller)

 

[Functional Artist]

Now, lets discuss calculating (electrical) conversion/comparison to Horse Power

From my research,

764 watts = (1) Horse Power

If you take the rated wattage of an electric motor & divide it by 764 you should get the (close) HP rating of an electric motor

So, for comparison:

The motor on Desteny's kart is only a 350W (350/764=.47HP)
That means that her motor is rated @ a little less than 1/2 HP

The motor on Double Trouble is listed @ 450W (450/764=.60HP)
If this is accurate, that means it was clockin' 15 mph with a less than a (1) HP motor (maybe overvolting will push it over (1) Horse)

The new brushless motor is listed @ 1,800W (1,800/764=2.36HP)

A 5,000W motor would be (5,000/764=6.54HP) (close to a Predator 212)

The motor on El Dingo is listed @ 8,000W (8,000/764=10.47HP)
That must be where the ad I bought it from got it's claim "build a 10 HP go cart"

 

[Functional Artist]

While I was takin' the "El Turbo switch" bench test, set up apart, I was thinkin'

* When I tried the switches alone, the (2) positive (+) switches fried but, not the (2) negative (-) switches.

* Wonder if we could set it up as a hybrid switch?

* Where the positive (+) half of it would operate using switches & solenoids & the negative (-) half would operate using switches alone.

Lets, find out!

About a 1/2 hour & a bunch of crimp ends later

...we have a hybrid switch

Lets give it a try!

https://www.youtube.com/watch?v=bBbCYNfGyIM&t=4s

 

[Kbosher]

Could you not use a relay system to acheive the same concept without having the added weight of all the switches and solenoids
Just a thought i am an automotive electrical specialist thinking of the amo draw on an air condition circuit just going thru my head.. so for so many replies to this just pretty intrigued

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[Functional Artist]

Since this is an electric fueled (battery powered) kart lets discuss batteries.

There are many batteries available, with very different chemistry's.

Lead acid, nickel cadmium & lithium Ion just to name a few.

For now, we are only going to cover info on lead acid batteries.

Now days, they are referred to mostly as SLA's (sealed lead acid) batteries.- this means no maintenance, their tops are sealed on. You never have to check them or add water like was necessary with the older ones.

They are have the lowest cost, they are the most available & are the safest for the average DIY'er to work with.

A. Standard (FLA) flooded lead acid batteries are the most widely used.

This is the type of battery that starts most cars.

But, their NOT recommended for use on EV's (electric vehicles) like go karts & golf carts for a couple of reasons.

1. they are designed as a starting battery (large, short bursts of power)like used to start a gas/diesel engine

NOT for deep discharge use (long slow drain) like constantly powering an electric motor.

They WILL work but, NOT for very long.

2. They are dangerous to use because by being full of liquid acid, if you crash, it can spill, splash or spray acid all over you

B. Another type of lead acid battery is called a gel battery.

Instead of being filled with liquid acid it has a gel acid mixture that is more stable in case of a crash.

They are designed for deep discharge use but, are NOT recommended for EV's, as they do NOT like to release much power at a time.

They are designed for low discharge situations like computer & alarm system back up power & for standby use like security lights.

C. The third type of acid battery, (recommended for EV's), is an AGM (absorbed Glass Mat) battery.

It is a deep discharge battery that has the acid solution suspended within a fiberglass type of mat, making it safer in case of a crash.

 

[Functional Artist]

Now, lets discuss amp hours.

An amp hour is a fixed rating that describes how much energy is contained within a battery.

*Meaning: (theoretically)

- A 20 AH battery can deliver (put out) 20 amps continuously for 1 hour

or to put it another way.

-a 20 amp draw would drain the battery completely "dead" in (1) hour.

So, for a 20 AH battery

It would take (2) hours to drain it with a 10 amp draw
(20AH battery/10A draw=2 hours)

...or like I said (1) hour with a 20 amp draw
(20AH/20A draw=1 hour)

...or it would only last (~30) minutes with a 40 amp draw
(20AH/40A draw=.5 hour)

BUT, that is for ONLY explanation &/or demonstration purposes!

*Battery rule

It is best to NOT discharge batteries below 50% (1/2) of their rated capacity.

*Because

Once below the 50% charge rate, the lead sulfate crystals, within the solution, begin to harden and cannot be dissolved back into the solution. (sulfication)

Once sulficated, a battery cannot accept or give up much of a charge.

*Sulficated batteries are 90% of all premature battery failures.


Now, we need to discuss "actual" usable capacity. (50% of a batteries rated capacity)

So, if a 20Ah battery can supply 20A's for (1) hour

It's 50% usable capacity is now ONLY @ ~ a 1/2 hour

So, using our earlier examples:

a 10A draw would drain it to 50% in ~ (1) hour

a 20A draw would drain it to 50% in ~ (.5) hours

a 40A draw would drain it to 50% in ~ (.25) hours

 

[Functional Artist]

Now, we know some of the good & the bad about batteries now the ugly

Their super heavy because their full of LEAD hence the name "Lead acid battery"

Duh! but, I figured I should cover it.

Next, we'll discuss run time

...this is where it gets really difficult

It's ALL about the variables.

...total weight vehicle (vehicle, driver, batteries -everything)

...rolling resistance (# of tires (2-bike, 3-trike or 4-kart)
(size of tires -height & width)

...gear ratio (more stress applied to motor = higher amp draw)
(or less stress = lower draw)

...driving style (more aggressive driving would also require a higher amp draw)

...& terrain (smooth, flat or lumpy, bumpy or off road, thru grass or up hill)

ALL these variables affect "actual run time"

So, to estimate your run time


Start off with the Amp Hour rating of the battery your using

then apply, the only drain to 50% capacity rule

then factor in ALL the variables (mentioned above)

...& then you'll have an approximate estimate of "actual run time" for your kart.

 

[Functional Artist]

Now, lets talk about, batteries on karts

the fuel (gas tank) so to speak

as we have covered, SLA (sealed lead acid) batteries are bulky & heavy

The main advantage batteries have over a standard gas tank (on a kart) is their versatility (options).

Sure (on a gas kart) you can use a bigger or smaller tank

remove it from the engine & place it some where else

but, with batteries

...you can separate them (spread out/balanced on kart)

...turn them side ways

...stack 'em

...tuck 'em under the seat

If you add a battery, you add power (added in series) (36V - 48V)

If you add a battery or batteries - you can lengthen run time (added in parallel)

So, more is best?

Nope! not always.

For optimum benefit, you have to find the happy medium

You gotta do the math!

You gotta supply enough power (voltage) to go & enough bulk (amp hours) to maintain going for a while.

but, not too much

...too much weight stresses the kart & motor

...too much voltage will kill the controller or motor

...too much run time stresses the motor/controller (builds up too much heat)

Piling 100 lbs. of batteries WILL provide lots of power but, you waste lots of power luggin' them around

So, it seems to be most beneficial to only add enough batteries (fuel) to get the job done

 

[Functional Artist]

Could you not use a relay system to acheive the same concept without having the added weight of all the switches and solenoids
Just a thought i am an automotive electrical specialist thinking of the amo draw on an air condition circuit just going thru my head.. so for so many replies to this just pretty intrigued

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Please provide details, drawings & more info.


* I have NO electrical training what so ever!

I'm just wingin' it here!

All knowledge I have about electrical systems is from workin' on cars

...ALL the stuff I learned from Sid on this forum

...& info I gathered from extensive research

 

[Functional Artist]

Got my micro switches in

Although, the Turbo switch III only uses (2) micro switches

I'm gonna build a switch with (4) switches

so I can reconfigure the set up

or at least have options available without building another switch.

 

[Functional Artist]

The new switch is set up pretty much like the previous switches

The way these switches are nice-n-flat

I should be able to sandwich them between (2) layers of plastic, like before (just nicer)

I can run the mounting screws all the way thru to hold it all together

& It seems I can overlap (2) switches to make it more compact

Made a new lever for it (with custom, dipped handle)

Yup! That should do it

 

[Functional Artist]

This kart will have (3) separate electrical systems operating simultaneously off of (1) battery pack

So, to simplify things (for me & you)

I broke the wiring diagram into 3 separate diagrams

First one is for the 12V circuit that powers the solenoids

Second shows the 24V circuit that powers the speed controller (standard drive)

& the third shows the 36V circuit that provides our "Turbo power"

I got our solenoids mounted on a board & on the kart

...right in front of the seat & below the steering wheel

out of the way but, still close to everything:

...the turbo switch will be right above on the handle bars

...the speed controller & motor are right behind (under the seat)

...& the battery pack is right behind the seat

Here is a comparison of the original switch & the new switch

To make it easier to make the connections for the motor positive (+) & negative (-) & the speed controller positive (+) & negative (-), I made a 4-way junction port with 1/4" terminals

coated the back w/liquid electrical tape (to seal up the back side)

Ya, that looks good-n-solid