QS205, is there liquid cooling?

General Discussion about electric bicycles.
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mbgjt1   10 W

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QS205, is there liquid cooling?

Post by mbgjt1 » Dec 20 2020 10:53pm

So I've decided to go with a 3T winding for the QS205, which seems to have the best acceleration between 30 to 50 mps). However, I've noticed that it also requires a crazy amount of current more than the 4T to achieve the same results for lower end speeds and torque .

QS205 3T
21s12p VTC6 batteries (36Ah)
140 kg rider weight
20" wheel size outer diameter
Nuclear 24F controller (300 battery amps, 500 phase amps)

Ideally, I'll be pushing 26 kW out of this motor in short bursts of 8 seconds or less, so I would need some form of cooling.

Apart of hub sinks and ferrofluid (and maybe cutting some vents in the motor to cool it), is there a more effective way. Why hasn't anyone developed a water cooled solution?

The amount of power out of this motor is crazy, but the heating issues seem like the only short fall, i'm surprised no one has addressed this, or maybe they have and I can't find it?

Thoughts?

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DanGT86   10 kW

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Re: QS205, is there liquid cooling?

Post by DanGT86 » Dec 20 2020 11:53pm

Ferrofluid and hubsinks work very well. People on here have made liquid cooling setups with tubes that run through the bearing but its major work. If you have a machine shop and some design skills there is no reason you cant liquid cool a motor. Its just generally not cost effective. Finding the room for radiators and water pumps on a bike frame is tough. There is also an argument to be made for just adding a larger motor that wont get as hot if it weighs the same as all of your cooling system.

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dogman dan   100 GW

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Re: QS205, is there liquid cooling?

Post by dogman dan » Dec 21 2020 6:34am

Betcha you don't need it. Unless you hook up to a trailer that weighs 400 pounds, or you weigh 400 pounds.

That think gonna giddyup so fast it won't have time to overheat. Think about it,, its going to refuse to draw that much current once you get up to speed. And you are going to get up to speed FAST. Its going to be less than 8 seconds that it draws the full 26 kw. It will only draw that amount while its at 0 rpm. Then it will drop rapidly as you pass 30 mph or so.

You won't draw much more than 4000w or so once you are going 50 mph. And that wattage is not going to overheat that big ass motor.

Nothing wrong with putting that fluid in the motor, but don't drill any holes. they don't cool that good. Put the fluid in there if anything.

999zip999   100 GW

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Re: QS205, is there liquid cooling?

Post by 999zip999 » Dec 21 2020 10:27am

Have you gotten this thing together and have you ridden it ? Sounds like a wheelie monster hard to keep on the ground.

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dogman dan   100 GW

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Re: QS205, is there liquid cooling?

Post by dogman dan » Dec 22 2020 7:06am

Yeah, another reason you might not pull full power too long. Too scary if its a typical mtb frame.

I rode a 10,000 w mtb once, and I could give it about 1/4 throttle at most, till you got going about 20 mph. Even with the battery carried on the handlebars, you had to push down hard on that thing to ride it.

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MadRhino   100 GW

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Re: QS205, is there liquid cooling?

Post by MadRhino » Dec 22 2020 7:43am

Hard acceleration does require geometry mods.

It was interesting to do liquid cooling when big hubs were not available. That was a lot of work: custom cover to fit a bigger bearing in order to manage the channels in a bushing for in and out hoses, 1/4’’ alu refrigeration tubing coiled a few turns inside the stator, a small motorcycle oil cooler as a radiator mounted in front of the down tube, a small pump, a coolant reservoir to absorb the overflow, and braided hoses to resist rubbing and hits. That is simple, but lots of time. Then, it does not give more power, only longer time sustaining it.
Make it fool-proof, and I will make a better fool.

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