48V 1000W Kit from China - Possible to change to a higher amps controller?

Marv1337n

1 W
Joined
Jul 7, 2018
Messages
55
Location
Germany
Hello

I've recently got one of these common 48V 1000W chinese kits and I'm wondering if I can change the controller.
It's this kit in particular: https://www.ebay.de/itm/elektrisch-E-Vorderrad-Umbausatz-48V-1000W-26-Rad-Fahrrad/162991246601?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

It's got a controller which says 48V 17A which would lead to 918W power. The thing is the motor is pretty loud and is creating a squeaking noise everytime it hits around 35 km/h. Goes away after like 1 second and comes always back when you reach 35 km/h. So that got me thinking whether or not I should get a sine wave controller, especially this one which comes with a LCD aswell: https://www.aliexpress.com/item/1200W-Brushless-Controller-DC-Sine-Wave-With-Hall-Sensors-And-Electric-Bicycle-36V-48V-LCD-Control/32798878157.html?spm=a2g0s.13010208.99999999.261.68513c00CWNAep

The thing is that that controller is rated for 35A which is double the amps which the original controller can handle so the question arises whether or not my motor can handle that much current? I'm pretty sure I'd have to change the wires from the motor to the controller because they look a little bit too thin for me.

Thanks in advance guys
 
If you jsut want the sinewave and not the higher current, then if it has two shunts inside teh new controller, desolder or cut one of them, and then it'll be half the current limit.
 
amberwolf said:
If you jsut want the sinewave and not the higher current, then if it has two shunts inside teh new controller, desolder or cut one of them, and then it'll be half the current limit.

Yeah but what if I want to have the higher current? Will my motor be able to handle that when I upgrade the motor wires?
 
Depends on the motor and conditions.

If it's really a "1000w" motor, then it can probably handle peaks of double that easily. Continuously, it might, as long as it stays cool enough.

If it's really a "500w" motor intended for 1000w peaks in the kit, then putting what might be four times that power thru it for short peaks will also work, but it probably couldn't handle it continuously.

So if you aren't using that doubled power continuously, just for bursts at startup, etc, it's unlikely to be a problem.


If youre climbing mountains or big hills with it, or going really fast, it may overheat the motor.


Back in the Death Race days, people ran these motors way over their intended power levels, and some had no problems, and some got cooked pretty thoroughly--but it depended on a lot of thigns as to which result occured.


Also, your battery has to be able to supply that current, and if it's not designed for that, it may damage the battery to continously use that much power.

It probably would be ok for short burts, as long as the BMS doesn't overheat the discharge FETs, or overstress teh cells (especially if it's not a well-balanced battery).
If
 
amberwolf said:
Depends on the motor and conditions.

If it's really a "1000w" motor, then it can probably handle peaks of double that easily. Continuously, it might, as long as it stays cool enough.

If it's really a "500w" motor intended for 1000w peaks in the kit, then putting what might be four times that power thru it for short peaks will also work, but it probably couldn't handle it continuously.

So if you aren't using that doubled power continuously, just for bursts at startup, etc, it's unlikely to be a problem.


If youre climbing mountains or big hills with it, or going really fast, it may overheat the motor.


Back in the Death Race days, people ran these motors way over their intended power levels, and some had no problems, and some got cooked pretty thoroughly--but it depended on a lot of thigns as to which result occured.


Also, your battery has to be able to supply that current, and if it's not designed for that, it may damage the battery to continously use that much power.

It probably would be ok for short burts, as long as the BMS doesn't overheat the discharge FETs, or overstress teh cells (especially if it's not a well-balanced battery).
If

Thanks for that detailed answer but that makes me wonder how I can determine if my motor can handle that? Is there anything to look out for while testing the higher current before it's too late?
 
If you can add a temperature sensor to monitor the motor windings, that would help you keep an eye on it.
 
pwd said:
If you can add a temperature sensor to monitor the motor windings, that would help you keep an eye on it.

So only the heat will be a problem then? Nothing else limits the power?
 
The motor in that kit look very much like the motor I bought from a similar kind of kit on ebay. Mine behaves very much like the 9C 2706 motor as modeled on the Grin Motor Simulator. If you are concerned about using a lot of power and possibly overheating this motor, you can give yourself a bit of added safety margin by injecting about 6 ml of Statorade into it.

The controller you linked to is not all that powerful. They are listing the max amps. The nominal rating of that controller is probably around half of that. My "1000 watt" controller is rated for 13 amps continuous and 26 amps maximum meaning a possible battery draw of about 1400 watts. I've been running it in the Phoenix area all summer with no extra cooling features at typically battery watt levels between 300W and 700W and peaks in the 900W+ range. Its doing fine. Keep in mind that just because the controller could deliver almost 1900 watts (35 amp with a fully charged and hence 54 volt power supply), you wouldn't be pulling that kind of power all the time. If you have steep hills, that kind of power might be handy to have from time to time.

Also, they show an LCD3 with that controller. You can use that LCD panel to dial back the maximum power to as much as half the rated maximum in seven discreet steps. So if you do find that you are overheating the motor (not likely IMO), you don't have to mod anything. Just go into the LCD and change your C5 setting to limit the amount of power that it will deliver. BTW, that LCD panel will provide you a fair bit of flexibility for doing things like setting motor assist levels, enabling regen, fine tuning PAS assist levels and more.
 
Back
Top