Overvolt 2000w 45A 48v motor to 60v 33A-35A or swap controller for bigger amps

1DMF

10 mW
Joined
Nov 15, 2020
Messages
25
Hi guys,

I'm at a junction in the 'pimp my Chinese eBike' project where I need to upgrade my battery having purchased a 2kw 48v 4300RPM motor to replace my 1200w 48v motor, and I naively replaced the 30A controller with a 48v/60v 33A-35A, not checking that to get proper @ 2kw you need 45A @ 48V which the motor is rated for.

Therefore I'm thinking, OK I should have got a 45A controller for my motor, If I wanted to run full 2kw on this motor @ 48V!

Either way the current battery is 48v 30A 20AH, and is being killed quick and needs replacing ASAP.

So do I correct my error and buy a 45A controller and a 48v 40AH battery or do I over volt to 60V with 25AH battery, thus still pushing 2kw 60V x 35A = 2100w and from a calculator I found takes the standard 48v RPM from 4300 - 5325 and although my motor is VEVOR , the controller is KUNRAY and the KUNRAY MY1020 60v 4300RPM motors are rated max 5300RPM.

So I'm thinking hmm, looks like these 48v motors (the photos of the VEVOR & KUNRAY look identical) will run happily on any volts as long as amps doesn't exceed 45 and watts @ 2kw before over heating.

So as my controller has a mode wire that switches it from 48v to 60v, do I.

1. Overvolt motor to 60v @ 33A-35A and buy a 60v 25AH battery.

or

2. Swap controller to a 48v 45A+ and buy a 48v 40AH battery.

The controller is also rated 2kw , so either way it's roughly 2kw!

Note: battery AH, are picked based on potential manufacturer and their dimensions of what would fit in the bike!

My goal is greater torque / acceleration not top speed, but also additional range at a controlled pace.

I appreciate all input.

Thanks,

Craig.
 
Nope this is an electric Dirt Bike, I've hacked with a 2kw BLDC motor.

kq1600-red1-600x600.jpg


I could change the sprockets but I still need a battery as it can't handle the discharge amps.

I don't want to buy another controller for higher volts & amps, as I can't fit the battery in the bike.

I was going to get a 60v 30AH but dimensions just don't work.

It's really a kids toy, and I'm just having fun pimping it as I use it to take my son to school, and we are maxing out weight limits :lol:

I know just getting the 48v 40AH 50BMS will improve performance without even replacing the controller, but 35a x 48v = 1,680w and if you only get 33a on 48v then = 1,584w so I could go full throttle for an hour and technically the battery would still have loads in it, so my range / time between charges would dramatically increase, but I would still be technically under powering the motor as it's rated 42A continuos.

Or I overvolt, giving me 5300RPM & 2kw power, but 35a full throttle would kill my 60v 25AH battery in less than an hour.

OK, I'm not going to be full throttle all the time, and nipping around town isn't going to kill the battery to quick.

I find their ratings interesting, as it is showing the 48v 4300RPM motor @ 33A as 6.9Nm torque, where as their 60v 5400RPM motor @ 33A as 5.1Nm torque.

Electric-Scooter-Motor-Kit-Electric-Go-kart-kit-1000W-2000W-36V-48V-Electric-Motor-for-Skateboard.jpg_Q90.jpg_.webp


So do I get better torque from my 48v 2kw motor if I run it at 48v, little confused by their graph?

Will I get even more if I overvolt the motor?
 
Their numbers dont look very useful. I havent done the maths, but the torque numbers look ridiculously low.
The 38V 1000w and the 48V 1600w seems to be the same kv, maybe the same motor?
There are probably more that matches.

You wont get more torque by raising the voltage, but you will get more rpm. And it will keep the same torque up to a higher rpm, so you will get more power.
To get higher torque you need more amps. If you dont want to get a better controller you can try a shunt mod, but if you do too much you might blow the mosfets.

Those motors are probably far from the best you can get, but they can probably do a lot more for short bursts at least. Get a temp sensor in the windings to make sure it dosent got too hot.
Why do you want to go full throttle all the time? I think it would be much more fun if it has 3 times the power, but you may not be able to use it all the time.
 
Yeah, I don't think any of their numbers are right!

So higher volts will increase acceleration, just not torque to climb hills.

Sorry, if I gave the impression I want full throttle all the time, I was just saying a 35AH battery @35A technically could run full throttle for an hour, but no I don't want to run full throttle all the time.

I am looking at a battery capable of peek 150A and 70A continuous BMS , so increasing amps will be an option as the controller currently is 35A.

The problem I currently have is finding a battery that will fit, let alone trying to deal with China and have a coherent conversation with anyone!

Oh well, at least I have a direction I want to head in, thanks for the input.
 
Well, I got a 60v (71.2v) 25AH 50A-Continuos /100A-Max BMS battery and still the Vevor motor was running poorly.

I'm not sure if the hall/phase changes the Chinese gave me to reverse motor was correct or if the fact the motor is 48v 42A and my controller though 60v is only 33A, even though the battery is 50A BMS

I do have another controller that is up to 72v and 38A-45A, but it's pretty big and not sure it will fit under the fake petrol tank, and having stripped the bike, moved everything and totally rewired including a new 12v circuit for lights, horn, indicators etc, I thought I'd try the old 1200w 30A 48v motor.

Then found with this replaced controller, the wheel went backwards, with no learn wire I decided to follow the Indian reverse motor wiring I had seen (Blue / Yellow - Phase, Green / Yellow - Hall), instead of the Chinese.

WOW! , the acceleration just on low speed is awesome, and the torque is phenomenal, overloaded with my son sitting on the tank, I could drive on slowest setting, @ 1 mph up a steep incline and it didn't even struggle only needing a minute twist to get over the brow at the peak.

Normally I'd have to take a run up at the hill if it was to make it to the top.

Not even put it on high setting yet, and will need to do a GPS speed test, but yeah, this eBike over-volting is awesome :)
 
1DMF said:
I'm not sure if the hall/phase changes the Chinese gave me to reverse motor was correct
Unless both motor and controller come as a set, where the seller already knows the correct combinations for forward and reverse, then they generally can't give you a specific combination to make any one motor work with any other controller.

You'd need to swap any two phase wires, then start swapping hall signal wires and test at very low throttle, offground only, while monitoring battery current, until you find the lowest current that goes the right direction and operates the motor as expected. Then test that on ground and see if the battery current is normal or excessive and that the motor operates as expected.

or if the fact the motor is 48v 42A and my controller though 60v is only 33A, even though the battery is 50A BMS
The motor doesn't have an amp rating like that. It will have a *phase amp* limit beyond which it saturates, but the battery current is not applicable to it, regardless of what the manufacturer or seller marked it as.

The motor's voltage rating only applies to how fast it goes at a specific voltage. So if it was in a certain size wheel and got say 20MPH while at 48v, then it will be proportionally faster at a higher voltage. (new voltage / old voltage * old speed = new speed).

If a new controller has lower battery current than an old controller, it's likely to generate less startup torque than the old one.

To learn how all these things interact, I recommend going to https://ebikes.ca/tools/simulator.html and reading the entire page ot learn how it all works and how to use it, and then playing with various systems and changing stuff to see how interactions change results. ;)


The BMS amp rating could mean a couple of things: it could be the protection limit, meaning it will shutdown as soon as you try to draw more than 50A from it. Or, more likely, it means it's only capable of handling about 50A before stuff on it starts failing or overheating. But it won't just "limit" the system to 50A, except by shutting down completely whenever that's exceeded...*if* that is what that number means for that specific BMS. (hard to know till you test it and it either works or smokes).
 
They weren't a set, but I get a feeling the motors are from the same production line. These Chinese VEVOR & KUNRAY BLDC motors look identical?

"The motor doesn't have an amp rating like that. " well that's how they sell it 48v 4300RPM 42A 2000W. as 48v x 42A = 2,016W, that seems right don't it?

What I'm saying about 50A BMS is the battery is meant to be protected to allow 50A continuous and max 100A burst, so the battery is now more than capable of delivering what the controller (max 33A / 2000w) demands, the previous battery only 30A.

The old controller was max 30A, so I now have the old 1200w 48v 30A (which is why the UK eBike seller claims it performs like a 1600W , saying it's to do with Neodymium magnets in the BLDC) though 48v x 30A = 1,440W so sounds like sales speak to me.

Anyway it's now getting 33A @ 60v and I'm loving it :)

Thanks for the link, I'll check it out and see if I can grasp more of this a bit better.

I still have a 38A-45A 36v-72v controller, so still plenty of scope for more fun :)
 
1DMF said:
They weren't a set, but I get a feeling the motors are from the same production line. These Chinese VEVOR & KUNRAY BLDC motors look identical?
Looking identical doesn'tnecessarily mean much--practically everything out there in ebikes (and many other things) is a clone of a clone of a clone of a clone of something. :( Sometimes even broken parts of a design or a particular part are copied as if they were a required part of the clone.

Unless they both come from the same manufacturer (or seller) as a set, there is no way anyone could know what order the colored wires were soldered inside the motor or the controller, so they can't know for sure what the correct combinations are for any particular thing you want to do with it. They can guess...but not know for sure. Heck, you could literally have two controllers (or motors) from the same manufacturer, batch, model, etc., and end up with phase or hall wires in a different order, depending on who was doing the wiring that day and when their shift ended. ;) It's more likely that in that case they'd all be the smae for a particular run/batch of parts, but that could change with any other batch, and could be different from model to model, etc. I have plenty of old stuff laying around that is like that--and some of it's made by the same company, yet had different orders of wire color.

For instance, you may buy a "kit" that has bolt-together connections, rather than prewired connectors, and you'd think you could jsut connect color to color...but that doesnt' always work--even though it all came from the same place. And the kit you buy one week might need Y-G B-B G-Y, but the one from the next week might need Y-B G-G B-Y. :(

Sometimes you get lucky, and it does just work...but in the case of having problems like you are, you can't trust it unless you actually verify it via testing as noted previously. ;)


"The motor doesn't have an amp rating like that. " well that's how they sell it 48v 4300RPM 42A 2000W. as 48v x 42A = 2,016W, that seems right don't it?
The *controller* has an amp rating in that fashion, but a brushless motor does not, even if they sell it that way, that's not how they work. So yes, the v x a = w is correct, but not for hte motor itself, rather for the controller that runs it (that came with it). Some sellers that don't understand how things work label stuff that way so that they can remember which controller to use with which motor, etc. So a motor labeleld as 48v 42A requires (to them) a 48v 42A controller (though it doesn't, actually).



The old controller was max 30A, so I now have the old 1200w 48v 30A (which is why the UK eBike seller claims it performs like a 1600W , saying it's to do with Neodymium magnets in the BLDC) though 48v x 30A = 1,440W so sounds like sales speak to me.
Yeah, that's marketingspeak; they'll say whatever they have to to sell you something, including outright baldfaced lies. :(
 
Thanks for your input it really is appreciated.

I know what you mean with Chinese prod-lines and inconsistency, drives you nuts at times!

They also say any old crap just to sell it or be found in a search, I specifically bought a new throttle with volt-meter that was sold as 'half-twist', but when it arrived, it was full-twist, agghh, OK it was like £6.69 amazon prime next day delivery, it has a key-lock and volt-meter that works great and the gold trim makes the bike look dope, but it still isn't what I wanted and wouldn't have bought it if I knew it wasn't half-twist, already nearly launched the damn thing into a load of shopping trolley's while parking and I think there is also some legal technicality, and possibly why it came originally with a half-twist and why a lot of eBikes, only have a thumb-paddle.

With regard to testing the phase / hall, where am I putting my multi-meter to check the amps being pulled, is it the main thick power on the controller / battery connections?

Also is it switch any phase and then play with hall combinations?
 
1DMF said:
With regard to testing the phase / hall, where am I putting my multi-meter to check the amps being pulled, is it the main thick power on the controller / battery connections?
Yes. All of the following steps are necessary, don't skip any!

Set the meter to Amps, highest range it has (usualy 10A).

If the battery connections are separate for postive and negative, instead of a single connector, the next step is easy. If it is a single connector with both + and -, you'll also need an "extension" wire of some kind for the negative battery wire to cnnect to the negative controller wire.

Disconnect positive battery wire from controller positive. Connect positive meter wire to positive battery wire. Connect negative meter wire to positive controller wire. This puts the meter in series iwth the battery-to-controlelr, whcih is how you ahve to meaasure current. (voltage is measured in parallel).

Setup phase and hall wires.

Turn system on.

With wheel off ground, gently engage throttle just a little bit. *DON'T* gun the throttle--you could cause a current spike so high your meter will blow it's fuse, and if it doesn't have a fuse it could be damaged. :( The controller can also be damaged if it's a wrong combo, by gunning the throttle.

If wheel spins normally in the direction you want, no wierd sounds, etc., and meter current is low (1A or maybe 2A), slowly increase throttle while watching meter; if meter always settles down to that same around 1-2A even once you reach full throttle, that's a good wiring combination.

Any grinding, stuttering, or if the wheel seems to be spinning faster than it should, or current over about 2A (usually it'sa LOT more) then it's a wrong combination, and you should mark it so you don't try it again.

There are three good forward and three good reverse combos out of 36 possible (because they are really the same two combos just "rotated" one color thru, like YGB-YBG is the same as BYG-GYB is the same as GBY-BGY, as the same hall is still matched with teh same phase). The reverse combos are not always the same colors (but swapped) as the forward.



Also is it switch any phase and then play with hall combinations?
To change from reverse to forward, yes. To figure out the combination, leave all halls as they are, and switch the phase wires (theyh're usually a lot easier to move around, but it depends on yoru connectors whcih one you should do). If you run out of combinations of phase wires with no good combo, swap any two halls and start again. (but you should find a good combo in there somewhere with the first hall set, though it could be in reverse).
 
sorry can you clarify "leave all halls as they are".

Do you mean put them back to how they were? Y->Y , B->B, G->G and then change phase till wheel turns the right way?
 
This F**King motor is driving me crazy!

I am trying to get it running with a Kelly KLS-S 240A 60V controller. I mean it is connected and working but when I get to ~50% Throttle the motor starts sputtering and cutting power off/on, no error on the controller and kelly controllers hasn't been helpful.
 
probably_autistic_08 said:
I am trying to get it running with a Kelly KLS-S 240A 60V controller. I mean it is connected and working but when I get to ~50% Throttle the motor starts sputtering and cutting power off/on, no error on the controller and kelly controllers hasn't been helpful.

Is your Kelly using torque throttle control, or speed throttle control?

If the former, and the tests you are doing are offground rather than under load, then try testing by riding instead and see if it behaves normally. If it does, it's just because torque throttle above some point (but before full) is already pushing an unloaded motor as fast as it can go; it may then cut power when the motor hits the RPM limit set in the controller; there's no error because it's not a fault, it's just how they work.

If it's speed throttle control, then you should get full range of speed control up to the RPM limits set in the controller.
 
But which mode does yours use? (Kelly can factory change the modes of some of theirs even though the end-user can't).

Which testing method are you using?

I don't know that it has anything to do with your results, but it's something to eliminate.
 
Back
Top