Qs205 + controller question!

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Matthias294   1 µW

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Qs205 + controller question!

Post by Matthias294 » Jan 13 2020 11:25am

Hi guys, I’ve been rinding a nice and powerful ebike for 2 years now. I use infineon v2 and v3 controller with beef traces to get about 14-20kw depending of the controller. My motor is a cromotor v1 and I run it on 24s. The bike is 85 pounds with 1.6kw lipo pack. I think the motor is a 4t winding..

I’d like to build a new bike with more power. I thought to use a qs205 (because I’d like to keep the bike light because I love fast acceleration) and I saw people pushing the qs205 to 20kw peak with heat sink. I’d like to push it to that level when I take off or even a bit more (peak). My bike take off really fast but over 60kph it’s slower (normal but I’m trying to make it better).

I thought I could have a better acceleration with a 5t or even 6t and for the lack of top speed I thought using more voltage, like 120-150v. Maybe what I think is wrong, I was gonna ask you if you can help me choosing the right controller to have at least 20-24 kw peak.. thanks a lot for you time!!

john61ct   1.21 GW

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Re: Qs205 + controller question!

Post by john61ct » Jan 13 2020 12:13pm

Matthias294 wrote:I use infineon v2 and v3 controller with beef traces to get about 14-20kw depending of the controller. My motor is a cromotor
Wut wow! I will use search, but if you know of specific resources for me to learn more I'd appreciate it.

from my random/noob scratch notes

? Votol em72150 or EM-200

? Sabvoton zombiess version? 72V150A ?

ASI BAC 4000 but hard to tune


Matthias294   1 µW

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Re: Qs205 + controller question!

Post by Matthias294 » Jan 13 2020 7:10pm

Hi, I’d like to stay at least 96vdc (100.8v full charge)

Ohbse   10 kW

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Re: Qs205 + controller question!

Post by Ohbse » Jan 13 2020 9:00pm

You would be better served by sticking to a 20s/84v maximum voltage and running a Nucular 24f controller with a fast wind. This is the current 'sweet spot' for highly reliable, high performance and feature rich controllers at an affordable price (given all of the functionality).

Higher KV motor results in lower motor resistance, offsetting the higher amps required to achieve the same torque. It's a common misconception that slower wind and higher voltage will increase performance. This topic has been covered extensively on these forums and I'd encourage you to read further if you're interested, but as of right now a 4T 205 paired with a Nucular would be ideal for your requirements. The controller will do 300a battery @ 80v for a 24kw output, 500 phase amps which is enough to wheelie with ease at almost any speed on a lightweight, short wheelbase frame. Field weakening can extend your top speed to well beyond the natural KV limit of the motor, a 4T in a moderate wheel diameter should be capable of 120+km/h. Ensure that you are running Statorade and Hubsinks to extend the heat rejection of the motor dramatically - running at these power levels will get things hot, quickly.

Another controller capable of similar or even higher performance is the ASI BAC4000 or BAC8000 - they are however significantly harder to configure, more expensive and lack an integrated display and many other features of the Nucular. The main upside is that they're readily available, there is still currently a significant waiting list for the Nucular.

What chassis are you running? Wheel size? Tires? Brakes? There's a lot more to building a truly quick package than just throwing power at it!

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st35326   100 W

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Re: Qs205 + controller question!

Post by st35326 » Jan 13 2020 9:42pm

Even is somebody gave me a free and capable battery I wouldn't switch from 24s to 20s.

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