Electric motor controller

[Kickstart]

Hi

I have had a google, but not sure enough of the terms to enable me to find anything useful.

We have an old electric scooter floating around. The control for speed on this is very crude (to put it politely). Effectively seems to be a series of contacts with different resistance, but the return spring on it needs to be fairly strong and this seems to sometimes try and pull the contacts apart.

I was umming and ahhing about trying to do something with it.

It could do with a better way to control speed, probably using a pulse width modulator to control it. However struggling to find something suitable for reasonable money.

Any suggestions on what might be suitable (something that works directly off a twist grip, or can easily be connected to a cable would be best) and where to source one?

All the best

Keith
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[G]

Is it brushed or brushless?

If it's brushless, does it have hall sensors?

Do you know what wattage/voltage the motor is?

There's quite a lot of reasonably priced options available for the 'ebike' and similar market.

Ebike throttles work on a 1-4v range and for some reason I forget don't work quite so well just sticking a pot in there.

[Northern Monkey]

Not sure on the current, but radio control car speed controllers work at around 200hz and are very efficient.

You should be able to get one that runs up to about 40 or 50 amps.
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Fisty: after polishing the tank with the glistenng beads of sweat from my full hot scrotum, I filled the headrace bearings with 10cc of my manmilk

[Northern Monkey]

Wow - some googleing and things have moved on since a little in the last 15 years,

https://www.ebay.co.uk/itm/2013-Futaba-MC330CR-ESC-w-Reverse-13-T-/200957733861?pt=LH_DefaultDomain_3&hash=item2eca03abe5

this one runs at 1500hz, and can handle 200 amps.
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Fisty: after polishing the tank with the glistenng beads of sweat from my full hot scrotum, I filled the headrace bearings with 10cc of my manmilk

[G]

You can get similar ones that'll go north of 400A! Though more for planes rather than cars.

Hobbyking sells an outrunner rated at around 10kw and other places will go higher - though, things are starting to get pretty pricey at this point - and when you go for ebike specific stuff, which tends to have more extended periods of high amp draw when pulling away, price goes up even more when ta;king a good bit of power.

The one you linked to is around 25v max, so will be ok ish for 24v, but not if it's 36v+. Also, it's presumably designed for sensorless - which while it 'work', it'll have issues pulling away with 'cogging' as it doesn't know where it is - and likely drawing rather large loads too.

[Kickstart]

Hi

Not a clue if it is brushless or not. Not really any markings on the motor.

Appears to use 2 batteries (wired in parallel).

Few pictures here:-

https://www.alfa-pages.co.uk/TempPicture/ElectricScooterMotor1.JPG

https://www.alfa-pages.co.uk/TempPicture/ElectricScooterMotor2.JPG

https://www.alfa-pages.co.uk/TempPicture/ElectricScooterMotor3.JPG

With the RC PWM unit, how is that controlled? Anything cheaper? Not sure if it is worth spending that much on it just to try and see if it can be made to do anything useful.

All the best

Keith
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[gavcarter]

Quickest way to see if its brushless or brushed is unfortunately to just open the motor ( think like a bigger stator motor , couple of bolts pop the back of it and look for brushes in the top ).

If it is brushless then you need a variable resistor type throttle capable of your voltage and wattage, which I GUESS FROM SIMILAR scooters to be around 24v - 500w range..

I dont think its brushless as there is no control module between the contact and the motor.

Usually brushless motors are electronically controlled to prevent burning of the coils, stalling etc.
The usually work off a small resistor or hall sensor which sends back a voltage to the controller, for example 0-5v, on my electric dirt bike 0v was flat out, and 5v was no throttle at all.
The controller picks up this voltage and then lets a pre-determined amount of voltage through to the motor, all being well if you wack open the throttle the motor will see full voltage and you will take off.
If the shaft speed sensor ( fitted to motor incase of stall - trying to do a burn-out for example) or temp sensor are relaying back problems the bike / scooter may shut-off or reduce voltage to prevent damage.


your appears to be a lot more primitive with a cable operated contact plate.

You either need to run the live wire to battery through to a variable resistance throttle and back to motor ( so the throttle can regulate how much current passes and therefore regulate the motor) - Or look for a 1/2 turn variable resistor of the correct size and fit a small arm to it - that will allow it to be operated by cable.

You could also repair the contact plate.

Easiest way would be use round headed coach bolts so the contact arm can pass over the heads smoothly, and connect each one individually to the motor ( or a common rail next to the motor ) with big resistors wired in ( more work but could be very cheap in the long run).

there is loads of resistor calculators online, and you need the first bolt to have NO CONTACT to the motor - so it gets no power. The last bolt should just be wire - no resistor so it can get full power.
Bolts in-between should have the voltage divided roughly equally.
So with 5 bolts we would have 0v,6v,12v, 18v, 24v.

It would be quicker to measure the resistance of the contacts installed and copy them though.

[G]

2 wires to the motor means it's brushed - brushless uses three wires - I believe they are basically a three phase motor, but the phases are artificially 'created' by the ESC.

2 batteries in parallel suggests 12v.

A bit of digging gets that it's probably one of these:
https://www.badsey.com/old/emx.html

As it uses two batteries I'm presuming it's not the 'racer' model, but seems the others use 24v, so batteries wired in serial, or 24v batteries (which are very rare) .

Working on 24v...

It says 1hp, so 750w.
If you were looking to use it, I'd certainly consider swapping to lithium at some point - you can get 7s (similar to 24v lead acid) lithium packs with a reasonable ah for not too much and they are significantly lighter.

This doesn't specify a price, but seems to be the sort of thing you are looking for (it does say 'low cost'):
https://www.deltasense.co.uk/products/variable-speed-drives/24v-brushed-dc-drive/

This is a more common sort of thing and suited to purpose:
https://kellycontroller.com/kds24050e50a12v-24v-mini-brushed-controller-p-72.html

Typically when power levels get up to 750w, most things are going to 36v. Also, a lot of modern stuff tends to be brushless as it offers better performance and less hassle (no brushes wearing down, which get metal dust everywhere etc).

Here's an RC one that fits the spec:
www.ebay.co.uk/itm/261554288499

However, again note that often the RC stuff isn't intended for the same use - generally it won't be dealing with sutained period of high amps, where an electric motor is more likely to - saying that, I have a feeling brushed motors may not draw so much at low rpm, where they often don't work as well as brushless.
My RC car doesn't have wheels THAT much smaller than your scoot and has more power - however if you try and use it at low rpm you either spin the wheels of flip it (will do a back flip from standing easily), so can't sustain that amp draw.

If you were spending a bit of money on, I'd consider just replacing it with something like this - https://alienpowersystem.com/shop/kits/alien-power-system-120amp-2-0kw-sensored-single-motor-kit-evolution-3/
£120 for the motor, esc and a throttle to match which gives you 2kw sensored brushless.
You would probably want to add a fan to the motor as it's pretty compact - if they get the 3kw available, that'd make more sense as it's bigger surface area will handle heat better.

They are out of stock of that one at the moment as someone ordered one a few days ago it seems. I'll report back on the findings .

First off - I think I'd just find the resistances and see if I could replace them with a pot and see what that does. Might be able to use a standard ebike throttle, or a variable pot, maybe setup to a thumb throttle for ease.

I'd be tempted to just stick an ad on endless sphere seeing if anyone wanted to buy it - wouldn't be surprised if a few were interested for the 'history' .

[Kickstart]

Hi

That kind of setup is how it is now. Problem is that the power feed goes to the contacts from the battery, through resistors, and then makes contact with the arm. An issue is that the cable from the battery contacts with the arm but the cable is fairly hefty and needs to bend as the arm moves.

I could clean up the contacts and have it working again (subject to spending £50+ on new batteries) but would rather have it working some way without just using a bunch of resistors. Hence hoping I could find a sensibly priced PWM controller.

The other option would be to set up the contacts to just connect to a set of relays, one for each contact. Hence the actual contacts with have minimal power going through them, and also no need for the heavy cable onto the arm.

Probably should mention that this scooter is close to 20 years old.

All the best

Keith
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[gavcarter]

https://www.ebay.co.uk/itm/24V-500W-Motor-Brush-Speed-Controller-for-Electric-Bike-Bicycle-Scooter-Duter-/261327284940?pt=UK_Motorcycle_Parts&hash=item3cd851eacc

and

https://www.ebay.co.uk/itm/Electric-Bike-Scooter-TWIST-THROTTLE-Electricscooter-12v-24v-36v-48v-Conversion-/171426475394?pt=UK_Sporting_Goods_Scooters_LE&hash=item27e9d06d82

SHOULD get it going....

Chinese controller usually comes with English labels on, Ive had to order one before but not sure of which seller it was.

Hall sensors are pretty much generic, they return a small voltage to the controller.

You can test it with two old bike / car batteries , its not until you try and ride it the load will kill a battery ( save you buying batteries if the motor is duff)

[Kickstart]

Hi G

The one you linked to is about the right model (although this one has a seat). Closest match is the Hot Scoot.

I think they are a pair of 12 volt batteries wired in parallel. No cells are obvious to count, and no markings beyond those about charging (ie, ~13.5 volts - can't take a photo of them as there is a strap in the way that holds the 2 batteries together).

All the best

Keith
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[Kickstart]

[gavcarter]

[Kickstart]

Hi

Cheers. I have ordered those bits.

Why does the throttle have 3 wires?

There is no facility for a brake light switch on the brake lever. But that bit is easy enough to fix.

That unit is 24V. But not sure what the motor is.

All the best

Keith
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[G]

If they are 12v and if it is 750, then all bets are off and I think you're going to have trouble finding a controller designed to take that without it costing a fair bit - both because of the high amps and that it's uncommon.

Back on 24v, which does seem more likely for 2 batteries - parallel is generally considered a bad thing and for 12v it's unusual you'd have two batteries until you get to *big* batteries, or people being lazy when making motor-homes and the like - as in most cases you might as well just get a bigger 12v battery.
These do actually seem to have had at least a little thought behind them.

I had been searching for 'brushed', seems you get more options searching for 'brush' as per gavcarter's link - www.ebay.co.uk/itm/121169901668 - gives us a 24v rated at 700w.

I believe you would be strongly advised to avoid ones rated for 500w - as I believe that would be quite likely to result in stuff melting, possible fire and the like.
[edit] Or, maybe a little late - I'd stronger suggest checking up and consider cancelling the order - they may well have a bit of a margin, but I wouldn't really trust cheap chinese stuff running at 150% of it's rated capacity for long.[/edit]
On RC stuff they advise going for a controller rated at 125% of the motor, so you're not pushing it. Though, ebike stuff tends to be more likely to use ones listed for the power of the motor.

If you're going to spend on batteries, definitely look at lithium options. Keep an eye out on ebay, or Hobbyking have some good deals - make sure you select sort by 'UK Warehouse' or whatever, so you don't end up ordering from various other places in the world. You would then need a lithium charger, but they can be got pretty cheaply. They also have pretty impressive amp ratings - ie I was looking earlier for one to make a car jump starter and for around £40 I can get one that deliver 500 'cranking amps', which should be plenty for most stuff.

[gavcarter]

[Kickstart]

Hi

Unfortunately no markings on the motor to know how much power it consumes. It is not a quick scooter (probably 10mph max when it was working) which would take well under 750W but no idea of how (in)efficient it is.

All the best

Keith
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[gavcarter]

I would just go with 20 amp fuses and a cheap controller, sounds to be just a "fun toy" rather than purposeful.

You could always pop a new motor in, they are roughly £40 for a 500w unit if you wanted to retro-fit a different shaped one, ( most use mini moto chains - should be simple)

that will get some extra speed out of it.

Also if you do find the motor to be too powerful for the controller, get smaller batteries, if the batteries cant supply more than 20amps, you cant damage the controller. Obviously they wont last as long per charge, but they will be safer.

Ill have a dig around later on, see what i can come up with ( mrs wants ebay on the screen)

[Kickstart]

Hi

The motor is belt driven at the moment. A motor might be possible, but then with a battery added the price starts adding up.

All the best

Keith
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[G]

I wonder if it should be running on 24v, but has been wired up for 12v?

If it's the ones I linked to, which seems most likely, they specify 1hp.

They also state 1500 for their faster model - which doesn't seem unreasonable for something likely a bit more of a 'premium' product for both versions than today's cheap chinese stuff.

I'd certainly expect more than 10mph - or expect it to be very nippy getting there. Have you tried it with a well charged decent size battery/batteries?
Older batteries can have pretty reduced current.

As idea, a 500w push bike hub motor will probably do around 20mph.

[Kickstart]

Hi

That was when it was going (we got it new many years ago). Although has to be said the charger was a bit naff so whether it ever really charged the batteries is another question.

The 2 batteries are definitely wired in parallel.

All the best

Keith
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[gavcarter]

[gavcarter]

Cant find anything on a 12v scooter made by Badsey. They had another one called the EMX cruiser but this is 24v also.

I found a page with a little , probably useless info on it about them

https://octopup.org/stuff/badsey

and a manual for the emx racer https://octopup.org/img/stuff/badsey/Electric--Scooter--Badsey-EMX-Racer--Manual--1999.pdf

All the scooter I can find already have PWM installed so they are definitely not your model.

As for motors, this looks about the best ( i can find ) "size wise" but is only 150w - there are 120W version for around £12 on ebay.
https://www.ebay.co.uk/itm/Small-Electric-E-Scooter-Bike-MOTOR-24-Volt-DC-150-Watt-24v-150w-Belt-Drive-/191303633443?pt=UK_Sporting_Goods_Scooters_LE&hash=item2c8a95ca23

Personally, If you dont want to have to swap for chain drive I would squeeze this in https://www.ebay.co.uk/itm/Electric-E-scooter-24-volt-250-watt-Motor-belt-drive-/390914989365?pt=UK_Sporting_Goods_Scooters_LE&hash=item5b04595d35

Im struggling to come up with much other than change motor, or chance it on 24v....

Everything is on chain drive these days it seems...

You could possibly compare shafts and swap sprocket for the belt drive to save chewing on with back wheel?

[trisers]

You could just fit this

https://www.ebay.co.uk/itm/75cm-Earth-Cable-Strap-Braid-8mm-240A-Hardly-used-/151391498430?pt=UK_DIY_Material_Electrical_Fittings_MJ&hash=item233fa2f0be

[Kickstart]

Hi

Problem with swapping anything on the motor is getting sprocket / pulley wheels, etc that match without spending a lot.

Simplest solution would just be a big relay and a go button!

All the best

Keith
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