3000W 72v Quad Build, Gear Ratio?

[m4rshh]

Hey all,

New to this forum so apologies if I have missed any required flairs etc.

I'm currently upgrading my sons quad (250w -->3000w )which will see some occasional use by me too :lol:

6" Tyre's, Gross Weight is around 40KG specced with 2 SLA batteries (will be replacing with lithium) according to manufacturer.

Recently purchased a Alibaba Kunray 3000w kit which arrived the other day (link below)
https://www.aliexpress.com/item/33063503751.html?spm=a2g0s.9042311.0.0.151c4c4dw6MpK0

Now the question i'm trying to figure out is gear ratio and sprocket sizing etc, Looking for max 30-40 mph? If possible
Planning on using the stock controller for now with the future bringing maybe a phaserunner or nuclear controller as they seem to give a lot of customization?

Anyway, the Tyres are 6", current motor sprocket is an 11 tooth T8F type chain. According to the specs looking at around 5nm torque and 4900 rpm with 5800 rpm max which is presumably under 0 load?, ill post the motor graphs below if i can figure out how to.

Using this tool
https://www.blocklayer.com/chain-sprocket.aspx

I'm seeing that keeping the stock 11 tooth motor sprocket and using a 24 tooth rear sprocket will give me just about 40mph at full whack which would presumably also ruin battery life and cause a lot of heat within the motor

First time tinkerer here but come from an electronics background, just looking for some suggestions or if anyone has used this same motor before. e.g larger motor sprocket, best combinations for torque etc. any pointers appreciated

Many thanks, hope you are all well
Richard

 

[dfrydman]

electric scooter parts has a great calculator for this type of thing

https://electricscooterparts.com/drivetrain-parts-selection-guide.html

just put in everything that cant be changed like the motor wattage and tire size and play around with the gear ratio

 

[dfrydman]

i quickly put it inot the calculator and it seems you could get around 40mph but find the gear ration you would need the rated rpm of the motor
good luck

 

[amberwolf]

Looking for max 30-40 mph? If possible

Something most poeple doing this don't consider:

Is the quad *built* for 40MPH? If it isn't, you could be building it into a deathtrap. If its suspension, brakes, frame, steering / geometry, etc., are not designed for those speeds, you could be in for unpleasant, potentially fatal, surprises when you try to use it like that.

Just a heads up before anyone gets hurt.


250w typically gets about 10mph or so, at best. So it's probably only designed for that speed. Tripling or quadrupling that is unlikely to be a good idea.

 

[m4rshh]

All advice greatly appreciated, motor works fine now with a 44 tooth sprocket.

The question is now on controllers, the one the motor came with is well and all but i'd like to be able to have some customization of settings and possibly a mounted display etc.

The controller in question has the markings, GJ24S and a taobao link on the rear which brings you to https://item.taobao.com/item.htm?sp...-13309963615.3.68473650QEIRsL&id=526551000906 this site
presumably it's just a generic 24Fet board that sellers use.

The fets installed are H3210 which seem to be of a decent rating at least.
Controller IC is the https://www.st.com/en/microcontrollers-microprocessors/stm8s105c6.html STM8S105 variant, is there any possibility of adding a display and or usb ttl to program?

If not could anyone recommend a controller with decent customization? I've been looking at the Nuclear range or Phaserunner possibily, no idea on various kelly models. Would prefer one with a display and regen / variable ebrake if possible as this one doesn't seem to be capable and the aliexpress seller isn't being very forthcoming as to what Low and Hi brake wires do. :wink:

 

[amberwolf]

i'd like to be able to have some customization of settings

What specific settings do you want to customize?

and possibly a mounted display etc.

What specific things do you want on the display?


And separately, do you want the display to be able to modify system / controller settings? If so, which specific things would you like it be able to change?

is there any possibility of adding a display and or usb ttl to program?

That depends on hte specific firmware and hardware design the manufacturer implemented. You'd have to check with them about that. Most of them there's nothing you can change, because there is no software available to access anything, even if it has a port. If it didn't come with a display it may not be compatible with one at all; they are not standardized. It would be guesswork to find out if works with any specific one; there are some threads about various people asking to add a display or LCD to their controller, that might have info leading you to one that *might* work with yours.

 

[m4rshh]

Hey Amberwolf,

Sorry if i wasn't specific enough, i'm just looking for a general recommendation really to see what people use.

Display wise, things like speed, motor temp, possible adjustments of power levels via profiles would be nice also. e.g Profile 1, 2, 3, 4 and so on.

Settings wise, id like to be able to toy with phase currents, maybe look at field weakening. Adjust throttle response/curve. Enable variable regen.

I'm a sucker for data so anything that can give me numbers and graphs would be ace.

All in all sorry if i'm asking a lot I just want to have free reign to tweak and tune things.

 

[amberwolf]

Sorry if i wasn't specific enough, i'm just looking for a general recommendation really to see what people use.

Well, that depends on what they want their system to do, and how they use it.

For instance, I use the Cycle Analyst v3 as a display, as well as modification of throttle output via various settings and sensor / pas / throttle inputs. But it does all this internally, and does not communicate with the controllers, so it cannot show me any data the controllers themselves generate. The data I typically use out of it are the max/avg speeds, Ah used, Wh used, Min/Max volts, Min/max Amps, trip times, realtime watts, speed, temperature, throttle voltages, etc. Unless I'm testing something I typically ignore all of it, since I know what the trike can do, it's range, etc., but when adding something new or changing something, it's very useful data.

My brother doesn't care about any data at all, so there's an older minimal version of the CA on his trike just to track data for me to troubleshoot it if it breaks.

A more regular bike I have as a backup has no display at all, no monitoring, just small battery, basic controller, and motor; it's only used if my trike doesn't work and I *have* to be somewhere.

Other people are using "standard" controllers that just display speed, which PAS level, battery meter, etc., stuff like that.

Keep in mind that in general, displays are specific to a brand and model of controller, as there are not really any "standards" for communication protocols and data used on them. Some versions of some displays / controllers that appear identical to others, do not show the same data nor do they allow access to the same settings; some come passworded, some don't, etc, even though they may be labelled the same, they're not. Makes all this so much more fun. :/

Display wise, things like speed, motor temp, possible adjustments of power levels via profiles would be nice also. e.g Profile 1, 2, 3, 4 and so on.

There are a number of systems that could do that; the CAv3 can do it by controlling the throttle amount vs the power monitored via a shunt (built into controller or external), and is universal for all controllers, so it doesn't matter what hte controller is capable of display-wise, or if it can even have one at all. (is easier to use on ones that have no options). It does have three presets that can control a few of the parameters, but not all of them.
https://www.ebikes.ca/product-info/cycle-analyst-3.html
ASI has stuff that can use different displays, but you should deal *directly* with ASI, to ensure you get support; at least one seller has been problematic in that regard.
The KT KunTeng controllers have an open-source firmware available here on ES, by Casainho, stancecoke, et al. that lets you customize it extensively, and compatible OSFW for some displays. Someone has started an OSFW for LiShui controllers, havent' kept track of their progress, but IIRC they use a Kingmeter display, and with the OSFW may be able to do those kinds of things.
Ther'es probably a number of high end (three to four digit plus price tags) controllers like Sevcon that could use serial or Canbus or simlilar to communicate with a dashboard (whcih you probably have to make, using a tablet or something like that), but i dont have any details on those.

Settings wise, id like to be able to toy with phase currents, maybe look at field weakening. Adjust throttle response/curve. Enable variable regen.

Phaserunner, and any other FOC controller, probably has those features. SFOC5 by incememed, it's in beta testing though. Sevcon would work (but unless it comes with the motor you want to use, already setup, you might spend a few months to a few years figuring out how to do that and actually get it to spin). I think Powervelocity has some, thread in the for sale section. Nucular, but that's at least several months to a year's waiting list to even get one. Mobipus...but while the company advertises them for sale, you can't actually reach them to buy one, so I wouldnt' expect any support if you get hold of one. Probably others I don't know about.

The route I'm going is the Lebowski brain board, but it isnt' a complete controller--you have to provide a powerstage, so it's pretty DIY. There are quite a few such projects here on ES, including the HI-Lebowski HIL project in my signature that I have been unable to get back to yet, though it is fairly close to "working".

I'm a sucker for data so anything that can give me numbers and graphs would be ace.

The controllers and displays themselves wont' give you graphs. But the CAv3, using the Analogger or anything else that can log data from a serial port stream of data, can do that, for any of the data it generates. It can't give you data from the controller itself. If a controller has a realtime streaming serial data port output, which few do, (SFOC5 in beta testing by incememed is the only one I can think of offhand) then you could do the same thing, though you may have to write the program to parse and display the data.

Sevcon might do it, depending on the controller version, but they're a nightmare to setup, even for a rocket scientist.

I just want to have free reign to tweak and tune things.

Me, too.