Building a go kart size Aerial Atom

[andrecht]

Like I said somewhere else:
You need a GoPro!

Ill help fund that idea..... that go kart is freeking rad!!

 

[Functional Artist]

..... that go kart is freeking rad!!

Thanks, I'm likin' it too
...seems to be very sturdy

I figured out the "break down" was "self inflicted"
…& sometimes ya gotta think "outside of the box"

She's "back in business" now

I made a video showing the malfunction, diagnostic & repair

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

* I've looked in to GO Pro cameras
...but, there's a bunch of different ones

Any suggestions or recommendations?

 

[Budget GoKart]

Hey FA do you think power wheels electrics would work well for a little kiddie trike? It will have hf wheels and go like 5mph

 

[JTSpeedDemon]

* I've looked in to GO Pro cameras
...but, there's a bunch of different ones

Any suggestions or recommendations?

This one looks good if you're willing to spend ~$100. https://www.ebay.com/itm/New-GoPro-...=333004880052bf3233de54104398b58882c479213d19

Refurbished from a trustworthy seller based on reviews. You'll need accessories, but this is better than my 1st gen GoPro.

 

[Bmr4Karts]

Hey FA, how are you getting 70amps out of that controller?

 

[Functional Artist]

Hey FA do you think power wheels electrics would work well for a little kiddie trike? It will have hf wheels and go like 5mph

Sounds plausible

Give 'er a try
…& keep us posted

 

[Budget GoKart]

Sounds plausible

Give 'er a try
…& keep us posted

Thanks i will try it if i get the stuff

 

[Functional Artist]

Hey FA, how are you getting 70amps out of that controller?

I was wondering that too
…& if i'm reading it right, it shows the wattage @ 4,000W
...but, it's only labeled as a 2,000W motor

It looked like, in recording
low gear: ~15A @ ~1,000W
med gear: ~40A (peak 70A) @ 2,000W
high gear: ~70A @ ~4,000W

So, I really don't know, just yet, anyways
...I'm learnin' as I go

 

[Tpdingo]

I was wondering that too
…& if i'm reading it right, it shows the wattage @ 4,000W
...but, it's only labeled as a 2,000W motor

It looked like, in recording
low gear: ~15A @ ~1,000W
med gear: ~40A (peak 70A) @ 2,000W
high gear: ~70A @ ~4,000W

So, I really don't know, just yet, anyways
...I'm learnin' as I go

Peak vs continuous. Motors can draw much more peak power than continuous. 4000w peak seems pretty reasonable. Don't run it for 4000w for too long or provide it external cooling.

 

[Functional Artist]

Peak vs continuous. Motors can draw much more peak power than continuous. 4000w peak seems pretty reasonable. Don't run it for 4000w for too long or provide it external cooling.

I thought peak was just a momentary "high point" usually only lasting for a second or too
...but, this thing seems to draw ~70A pretty consistently

Also, why is the "voltage drop" so huge?

In this snippet of dash recording, in high gear, it shows the voltage starting out @ ~63.5V then, dropping all of the way down to ~58V
...~5V drop ...that's a heck of a drop

*maybe due to the size of the batteries?
(5) 12V 15AH SLA's

https://www.youtube.com/watch?v=FSQ0qhfWa9g

 

[Bmr4Karts]

High voltage drop means your batteries struggle to provide the load you are placing on them.

 

[Functional Artist]

High voltage drop means your batteries struggle to provide the load you are placing on them.

Yup, that's what I was thinkin' too
...kinda like a milkshake?

 

[Functional Artist]

Yup, that's what I was thinkin' too
...kinda like a milkshake?

What?...How is a milkshake like a battery?
...well it's just an analogy to help describe, "voltage drop"

OK, that explains it
...NOT really...that doesn't make it any clearer at all

Well, I think it works like this
...the milkshake is the battery
...the semi-runny ice cream, inside the cup, is the energy
...the straw is the battery cables
...& your are the motor

So, when you (motor) "normally" draw ice cream (energy) thru the straw (battery cable), the ice cream (energy) level, in the cup (battery) slowly drops, as the ice cream (energy) is removed.

But, if "you" draw on that "straw" really hard, trying to remove lots of "ice cream" at once
...the level of "ice cream" in the cup, isn't able to drop "evenly"
…& you see the top surface of the "ice cream" begin to "sag"

IMO/I believe that's kinda like what's happing, in side of a battery, regarding "voltage drop" (or) "sag"

 

[JTSpeedDemon]

Hmmmkaaayy......

 

[Functional Artist]

But, if "you" draw on that "straw" really hard, trying to remove lots of "ice cream" at once

Um, if ya do that
...ya get an ice cream head-ache
...don't ya?

Maybe I should explain further ...now that my brain has thawed

So, from what I understand, in a milkshake, there is only "so much" semi-runny ice cream available (until more thaws) to be drawn up thru the straw
…& when drawn on "within specified parameters" the level drops nice-n-evenly
...but, if/when that rate is exceeded, instead of dropping evenly, an area on the surface begins to dip or sag


Similarly, the plates inside of a battery can only "easily" release the "energy" (in amps) at a certain rate
…& when that rate is exceeded the voltage level get's "stressed" & "dips or sags"

I think that's "kinda" how it works, anyways

 

[Functional Artist]

Advanced Milkshake Battery Theory

OK, now we'll set (2) milkshakes, next to each other
...& connect them together "in parallel"
(if ya stack 'em, that would be "in series")

In this scenario we would be basically doubling the size of the milkshake (battery)
…& also, doubling the amount of semi-runny ice cream (energy) that would be available (at any given time)

So now, when you (motor) "normally" draw ice cream (energy) thru the straw (battery cable) there is plenty of semi-runny ice cream (energy) available
…& so, the ice cream (energy) level, in the cup (battery) slowly drops, as the ice cream (energy) is removed.

But now, if you (motor) draw on that straw (battery cable) "really hard"
...the level of ice cream (energy) in the cup, still drops nice-n-evenly
…& so, there should be very little effect, to the top surface (voltage level), of the Milkshake (battery)

 

[Functional Artist]

Hypothesis 5S1P (5 in series & 1 in parallel)

Why am I goin thru this long-drawn-out analogy?

The Massive Voltage Drop (~5V) that this motor is causing to happen to the battery pack, (on the Atom kart) is very concerning.
…&/so, I'm using this analogy to help me "think it thru"

Now, let's take it a step further & say the "milkshake" is a 12V 15AH SLA battery
…& then, if we "stack" (5) of 'em, connected "in series", (like on the Atom kart) that would create a 60V 15AH "battery pack", that weighs ~50lbs. (~10lbs. ea.)

Now, to help alleviate the "massive voltage drop", we could double the whole thing (5) in series & (5) in parallel
...which would double the capacity (from 60V 15AH to 60V 30AH)
…& probably double the "instantly" available energy too (which should lessen the voltage drop)
...but, then, were in the 100lbs. range

So then, I was thinkin' what if
...just (1) more battery was connected "in parallel" with the first battery, in the series?

I understand that it wouldn't double the battery packs capacity
...but, (I'm thinkin', maybe) it would double or at least increase the "available energy" (like I kinda described in the previous post) right at the "draw point" (ie. positive (+) battery terminal)
...& thus, (maybe) have an effect on (hopefully, "softening") the voltage drop/sag
...while only adding ~10lbs.

Comments?...anyone?...Sid?

 

[anickode]

Dont know how much you're looking to spend, but the biggest bang for your buck (and weight) might be to add a car audio capacitor (1/2 to 1 farad) in parallel with each battery in the system.

You can get 1 farad caps for around 30 bucks online these days. Probably find em cheaper than that on marketplace. Much less weight than doubling your battery capacity, and will actually deliver far greater surge amps for getting moving.

 

[Bmr4Karts]

Hey FA

You just need to get with the times and go lithium. Either get some 18650s and build a pack with some vruzend connectors or buy some factory built packs from a hybrid or electric road vehicle.

I paid $500 for a single LG Chem battery pack out of a Chrysler Pacific hybrid minivan. Its 16s1p 45ah, weighs 40lbs. Can do over 200amps continuous or 400amps peak. For your current draw you'd see very minimal voltage sag.

You would need a BMS and a charger as well.

---------- Post added at 04:16 PM ---------- Previous post was at 04:04 PM ----------

Oh yeah, FA what you proposed will help you, but only fractionally.

Your idea would increase the capacity of one of your 5 batteries. Let's say that capacity increase is enough to stop the voltage sag for THAT battery. The other 4 batteries will still have the same voltage sag so you'll theoretically reduce your voltage sag by 20%

 

[snowjob]

The Sur Ron battery pack is 60V.....just sayin'. We have power tools that share battery packs, why not play vehicles?