How to safely/reliably mod a 48v 1200w direct drive hub motor into a 60v/72v 3k-5kw system?

[zeddrick]

I have an old ebikeling 48v 1200w direct drive kit that I'd like to modify with statorade on the magnets and heat sink fins on the hub to run it at either 60v or 72v at either 3000w or 5000w. I've seen youtube videos of people doing this with very similar cheap 1000w DD hub motors from alibaba/aliexpress and they seem to have success with keeping the heat low and tolerable.

Is there any other mechanical/electronic part inside a 1200w/1000w direct drive motor that could still overheat when modded to run at 3000w/5000w with statorade and heat fins? Is the motor cable coming out of the axle fine with going from 48v 1200w 35amps to 72v 5000w 80amps?

From what I could find it seems that direct drives are all very similar and all very sturdy motors, so what would be the build difference between something like Ebikelings 1200w DD and their 3000w DD? Would the 3000w be built differently internally/externally to handle more heat? Or are 1200w/1000w DD motors almost exactly the same but just cheaper and need statorade and heat fins to run at higher watts?

 

[pwd]

Usually, a motor with a higher watt rating will have wider magnets/wider stator that can accommodate more copper wire; and take more power before overheating. Have a look at this if you haven't already seen it: Futility of Motor Power Ratings

 

[E-HP]

I have an old ebikeling 48v 1200w direct drive kit that I'd like to modify with statorade on the magnets and heat sink fins on the hub to run it at either 60v or 72v at either 3000w or 5000w. I've seen youtube videos of people doing this with very similar cheap 1000w DD hub motors from alibaba/aliexpress and they seem to have success with keeping the heat low and tolerable.

Is there any other mechanical/electronic part inside a 1200w/1000w direct drive motor that could still overheat when modded to run at 3000w/5000w with statorade and heat fins? Is the motor cable coming out of the axle fine with going from 48v 1200w 35amps to 72v 5000w 80amps?

From what I could find it seems that direct drives are all very similar and all very sturdy motors, so what would be the build difference between something like Ebikelings 1200w DD and their 3000w DD? Would the 3000w be built differently internally/externally to handle more heat? Or are 1200w/1000w DD motors almost exactly the same but just cheaper and need statorade and heat fins to run at higher watts?

I ran my cheap 1000W ebay hub at 72V, 70A for a few months when doing some testing before upgrading my hub. I ran it with various voltages up to 22S, and decided to go with 20S (18S felt just right, but harder to find battery packs for). I only had Statorade for cooling. DD hubs can take a lot of peak power, but you have to manage things when running continuous, which is easy if you install a temp sensor, but educated guesswork otherwise, if you use the Grin simulator.

If you have long steep hills, the temp sensor is essential, since the temps can rise quickly in certain situations. Also, you need to manage your throttle, since the same motor can ride up an 8% grade indefinitely at 20mph, but meltdown quickly at 30mph, so you need self control. Here's an example of a slow wind 9C (mine was even slower), running at partial throttle up 8% (20mph), with only Statorade for cooling, and doesn't melt. At full throttle, it will overheat in 8 minutes.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

A DD hub with temp sensor and a controller or cycle analyst to roll back power when the temp rises, is a pretty reliable setup; not bulletproof, but you pay attention at all, you won't melt the motor. I wasn't paying attention a couple of weeks ago, while doing some voltage sag testing on my battery. I was paying too much attention to the voltage, and completely ignored my motor temp, and didn't realize it until the power started rolling back and noticed the motor was at 107C, but dropping by then. Moderately steep 700ft climb (video starts part way up the hill), with 17% max grade, throttle only for testing. 5T Leaf DD with Statorade.

 

[amberwolf]

Before you go much further, you should first completely define the job the bike has to do for you, under your specific riding conditions, and then use the ebikes.ca motor and/or trip simulators to determine how much power, torque, etc., that it will take to do that job, so you can be sure that what you will modify or buy will actually do what you want.