QS 205 vs QS 273 watts consumption

[LexHammer]

Hello,
which motor will consume less watts on the same bike, with the same speed - 30-40 km/h and 60-70 km/h.

 

[MadRhino]

They have about the same efficiency, but the bigger the motor the more power it can be fed. When you twist the full grip, the bigger motor does suck your battery like there is no tomorrow.

The QS 205 h50 is big already for an ebike, making motorcycle performance and does require a very good build to safely exploit its full potential. The 273 is too heavy IMO, its weight and power does make for the need of even more weight in batteries, wheels, suspension, brakes...

 

[MadRhino]

I will tell you what I think, even if some won’t like it. Those that I have seen who had built with a 273, are not even close to need one. They put it on a crap Chinese frame, built with crap components and 70 lbs of cheap cells. They have the bigger motor, but I beat them riding with one hand and looking behind.

 

[amberwolf]

Hello,
which motor will consume less watts on the same bike, with the same speed - 30-40 km/h and 60-70 km/h.

If you have the same controller for both motors, and you're using it the same way, and the winding is the same (meaning, the motors have the same no-load speed on that system), then they will both have about the same power usage.

But the heavier motor will take slightly more power to acclerate you each time, or climb hills, because of the extra weight. If that weight is only a tiny percentage of the total bike and rider / etc weight, then this power can be ignored.


If the windings (no load speed) are not the same between the two, then the power usage won't be the same for the entire bike usage range, so you can't compare them directly.

 

[LexHammer]

Well bike only will be around 60 kg wiht 205 and 67 with 273. With me it will be around 150 kg, so the difference will be 5% in total weight.
Also, Im not sure if the QS 205 h50 take 12-15kw without a need of fluids and cooling. If yes, then i might think about it. If not, then weight is not much of a problem for me.

 

[john61ct]

Sample #s for QS 205:

3T motor, 50V, 300A
Will do exactly the same as
6T motor, 100V, 150A

not sure if max, or for how long, heat is the limiting factor as you say

 

[MadRhino]

Well bike only will be around 60 kg wiht 205 and 67 with 273. With me it will be around 150 kg, so the difference will be 5% in total weight.
Also, Im not sure if the QS 205 h50 take 12-15kw without a need of fluids and cooling. If yes, then i might think about it. If not, then weight is not much of a problem for me.

Your weight estimate is very optimistic for a build difference with a 273. The motor alone (273H40) is 10 kg more than a 205h50 and it does require a bigger battery, bigger suspension, bigger brake, bigger... everything.

Then your power estimate for a 205 (h50v3) is pessimistic. Mine sees 25kw acceleration bursts everyday, no cooling, for 3 years. A 273 can be fed 35kw acceleration bursts, conservatively. I bet your first build won’t be safe to ride a 205 full power snd speed, and you will find your second try very expansive if you want to realize its full potential.

A 273 will ride like sh*t unless you put it on a motorcycle, or combine many motorcycle components with a very stiff and robust old school DH frame. Or, you build a taxi cab trike, a huge cargo delivery bike, something such would justify a 273.

 

[LexHammer]

Well i've seen alot of bikes with 273 motor. Also i've seen alot of sites selling bikes with 205 motor with coolers and liquid on just 13 KW. Those are 2 examples for the 273 bikes that i plan to make mine bike like https://cdn.shopify.com/s/files/1/0919/6654/products/edge_race_grande.jpg?v=1475133460
https://ae01.alicdn.com/kf/HTB1PIKUKaSWBuNjSsrbq6y0mVXa1.jpg

Yet I ask about the 273 just becasue i can get it more easily then the 205...

 

[Jonno]

Get the 273, I've got both motors and although heavier the 273 doesn't get warm yet alone hot like the 205.

As MadRhino says more weight requires better suspension and stopping power : : wink:

Jonno

 

[LexHammer]

Get the 273, I've got both motors and although heavier the 273 doesn't get warm yet alone hot like the 205.

As MadRhino says more weight requires better suspension and stopping power : : wink:

Jonno

Thank you! How is the 273 compared to 205 in terms of acceleration and top speed? I've read that the 273 has much better torque on the same voltage and amps.

 

[MadRhino]

Get the 273, I've got both motors and although heavier the 273 doesn't get warm yet alone hot like the 205.

As MadRhino says more weight requires better suspension and stopping power : : wink:

Jonno

Thank you! How is the 273 compared to 205 in terms of acceleration and top speed? I've read that the 273 has much better torque on the same voltage and amps.

Same volt and amp, same power=same torque when all other factors being equal. If one has better torque when fed identical power, it is because some other factor is different: smaller wheel diameter, different winding kv, etc...

Then, something will be different if you build with a 273: weight.
More weight does mean that more power will be required to achieve the same performance, and more battery capacity for the same range. Now, if you plan building heavy already and need equal performance, the 273 is a solution but it will have to be fed more power than a 205.

The 273 is capable of better acceleration, because it can be fed more watts.

Top speed is another story. It is not about motor size. It is about voltage, motor winding, and aero drag especially.

 

[Jonno]

Now then.........as I have bolted on a NF 24f instead of the APT 96600 the power delivery is smoother and more controllable in torque mode - max speed 112 kmh and before you ask - yes it lifts the front wheel at about 40 kmh :lol: Trail riding is excellent but I would not use it for MX.
35 wh/km without going too mad 90+ km range.

Hope this helps.

Jonno

 

[MadRhino]

Now then.........as I have bolted on a NF 24f instead of the APT 96600...

that is capable of feeding 600A right? Let’s say, about 50kw acceleration burst in theory. Lots of battery required, as I said. Sure far from using that power, to achieve 35 w/h per km.

before you ask - yes it lifts the front wheel at about 40 kmh

Irrelevant. That is a matter of geometry, not torque. You can build one that won’t lift at all, or another that will lift with very little power.

We have the same top speed exactly. I do 70 mph. Yet, I guess your bike is much heavier, maybe double and that is making a very different ride.

 

[markz]

Now then.........as I have bolted on a NF 24f instead of the APT 96600 the power delivery is smoother and more controllable in torque mode - max speed 112 kmh and before you ask - yes it lifts the front wheel at about 40 kmh :lol: Trail riding is excellent but I would not use it for MX.
35 wh/km without going too mad 90+ km range.

Hope this helps.

Jonno

What is the voltage and Ah of the battery pack to obtain your 90+ km range?
How much pedaling are you doing to help reduce the battery power demands to increase the range?
What kind of terrain, lots of hills or pretty flat?

 

[Jonno]

one like this
https://ae01.alicdn.com/kf/HTB1PIKUKaSWBuNjSsrbq6y0mVXa1.jpg

92volts 36ah
pedalling is no help apart from pas and yes I live in a hilly area 4 x 280ft climbs 1.6 miles each (4 laps of the same area)

Last ride average speed 14.9 MPH Max 50
max phase amps 498.7
Distance covered 26 miles
range remaining 42 miles

jonno

 

[minde28383]

If you can get 273hub easier go for it. Both have its own good and bad sides, nevertheless I did not hear unhappy 273 owners. 205 are happy too. It's just good powerful motors. Yes it is heavy. You can't jump high with it. On obstacles rear wheels goes in the air, it bounces little bit, but good suspensions helps little bit. Very nice, silent motor. pools like a train. Need very good bicycle fork and very good brakes, because of weight and high speeds. Everybody is excited about acceleration. The same applies to 205.

Every one advices in this thread is correct. I read all posts and can't disagree with none.

273hub is heavier but on roads it is good. Tons of power in light setups. You need to aim for 200amps if you want scary powerful setup. But you should know that you don't need such power for day to day use. We are talking about crazy fast setup with 200a.
205hub is crazy powerful too if you feed if lots of amps, ~150battery or 200 amps. It might heat or not depending on how you ride it and how much you feed amps, depends where you ride.

Both motos are great. Both needs lots of amps, especially high kv versions (so called fast versions ~12kv).
Slow versions pools even better from stand still. Don't listen who claims otherwise. Nevertheless if you can get very good battery get fast version.

You need lots of amps, less sag from your battery, good cells, many in parallel and high discharge cells. Talk with battery builders. Batteries are expensive and core element, controller too core element. None of these motors will run good with week battery or weak controller.
Good suspension including brakes for your comfort and everybody's safety.

If you ask about pedaling then you did not try these powerful motors yet I assume. Once you make test ride you know yourself that you can't assist much to powerful ebike with your regular pedaling because pedaling gives few hundred watts and we are talking about quite a few kilowatts here of power though people pedal for exercise which is good enough.
Get any which is accessible and have good rides. Be safe.

 

[john61ct]

Please find a better English word than "pools" for that meaning, no idea what you're trying to convey there

 

[HK12K]

"Pulls", I suspect

 

[MadRhino]

Meaning accelerate I guess, but wrong statement. Slow windings of the same motor don’t have any more torque starting from a standstill. They just require less power to achieve their optimal acceleration, but fast windings can be fed more power, for a longer period. So, acceleration is more economical with a slow winding, but potentially, slightly better with a fast winding of the same motor because it has lower impedance.

 

[minde28383]

Please find a better English word than "pools" for that meaning, no idea what you're trying to convey there

If you have no idea than context makes no sense to you. Pronounce the word and find if sound assimilates to something meaningful to you.
Appearantly word is: pulls. It can be substituted with other words like thrust but even with correct spelling it might be complicated.

 

[minde28383]

Meaning accelerate I guess, but wrong statement. Slow windings of the same motor don’t have any more torque starting from a standstill. They just require less power to achieve their optimal acceleration, but fast windings can be fed more power, for a longer period. So, acceleration is more economical with a slow winding, but potentially, slightly better with a fast winding of the same motor because it has lower impedance.

Who says slow windings have more torque. Nevertheless
I'm saying that slow wounded motor will have better acceleration from stand still.
If you tested slow and fast wounded motor like qs 205 and tested it with 150a or 200a and 72v than you would know how it is. You are reapeating what others wrote which is misleading for new forum members and those who had no option to perform tests themselfs.

 

[MadRhino]

Meaning accelerate I guess, but wrong statement. Slow windings of the same motor don’t have any more torque starting from a standstill. They just require less power to achieve their optimal acceleration, but fast windings can be fed more power, for a longer period. So, acceleration is more economical with a slow winding, but potentially, slightly better with a fast winding of the same motor because it has lower impedance.

Who says slow windings have more torque. Nevertheless
I'm saying that slow wounded motor will have better acceleration from stand still.
If you tested slow and fast wounded motor like qs 205 and tested it with 150a or 200a and 72v than you would know how it is. You are reapeating what others wrote which is misleading for new forum members and those who had no option to perform tests themselfs.

I have done acceleration tests myself. And never had any better acceleration from a standstill with a slow motor when both slow and fast motors were fed as much power as they wanted to pull. I have done 10 ft and 100ft acceleration tests with 35mm, 40mm and 50mm stator motors. Fast wound 40 mm and 50 mm stators are pulling considerably more than 200 A on a hard start though. If current is limited, slower winding may give better results than a fast winding that is not fed enough power to achieve its full torque.

 

[john61ct]

If you have no idea than context makes no sense to you. Pronounce the word and find if sound assimilates to something meaningful to you.
Appearantly word is: pulls. It can be substituted with other words like thrust but even with correct spelling it might be complicated.

I am trying to also help you improve your English.

Pulls does not fit there, but maybe acceleration or power have something to do with what you intended.

 

[minde28383]

Exactly how it is. Fast wounded hubs needs lots of amps to achieve similar thrust, also small diameter light wheel helps too.
Mostly folks have Kelly's Sabvotons or some similar cheaper controllers in 80-150 amps range. Also batteries in frames mostly are 18650 in 100 - 300pcs which have certain limits. Depending on cells and controller, most frequently they will find that slow wounded motor accelerates more dynamically with max power they can feed that hub ie might be what most are after. And this is more a rule than exception. Nevertheless all hubs are ok. There are compromises everywhere.

 

[minde28383]

If you have no idea than context makes no sense to you. Pronounce the word and find if sound assimilates to something meaningful to you.
Appearantly word is: pulls. It can be substituted with other words like thrust but even with correct spelling it might be complicated.

I am trying to also help you improve your English.

Pulls does not fit there, but maybe acceleration or power have something to do with what you intended.

If one wants to improve some android auto correct than you are welcome but no need to pretend that can't understand. Did not sounded good intension initially so I bet you don't want to improve anybody.