What motor

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Sargenebike   1 µW

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What motor

Post by Sargenebike » Mar 20 2021 4:37pm

Hi, I have 36v Bafang 500w system on my fatbike. The motor is no longer as strong after 200hr as when new. Motor is brushless. I don't know how it's possible. Also the range is not good. I have 17.5ah battery with Panasonic cells.
With my other bike 52v 17.5ah 1500w hub I can easily drive almost 50km with one charge with good speed.

I want update my fatbike system. What is best option for that? I want power/torque but ofcourse the max speed should be also at least 50km/h.
Is there any good quality 3kw rear hub kits available for fatbike or should I get mid drive for example Bafang bbshd?
Thanks

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motomech   1.21 GW

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Re: What motor

Post by motomech » Mar 20 2021 6:49pm

Although motor magnets can weaken over time, it's a long process and very gradual.
What you are describing is something we don't really see here. What we do see is motors stopping altogether or start making noise or smoke on their way to not working.
I think you need to take a closer look at your pack.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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markz   100 GW

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Re: What motor

Post by markz » Mar 20 2021 7:15pm

I was thinking you cooked your motor, which means you cooked it real good or the you cooked it a little. Open up the cover plate and you'll notice the instant you cracked the seal, but do take it off and look at the windings. I dont know if I had reduced power, or flatlined power when I cooked mine. Just felt like mixed up phases, gittery at low speeds.

I've cooked a few motors in my time :oops: :oops: :oops:

Eastwood   100 W

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Re: What motor

Post by Eastwood » Mar 20 2021 11:21pm

Maybe you think it’s slower now because you’re using the 52V 1500W hub on the other bike?

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amberwolf   100 GW

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Re: What motor

Post by amberwolf » Mar 21 2021 12:22am

Sargenebike wrote:
Mar 20 2021 4:37pm
Hi, I have 36v Bafang 500w system on my fatbike. The motor is no longer as strong after 200hr as when new. Motor is brushless. I don't know how it's possible. Also the range is not good. I have 17.5ah battery with Panasonic cells.
The most likely problem is not the motor, but the battery being unable to supply as much power. Sometimes this is due to cell groups that arent' fully charged (imbalanced) vs the other cells. If so, then leaving the battery on the charger until it is completely balanced may fix it for a while. This can take anywhere from hours, overnight, to days, or much longer, depending on how badly imbalanced it is. If it's bad enough to take a really long time then it probably also has lost significant range, which also matches the other issue you describe.

If it isn't a balance problem, it is probably just pack aging. 200 hours of operation means probably a hundred charge cycles, which for some batteries is a lot, especially if it gets run down close to empty a lot.

Most likely you just need a new battery for it.

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Chalo   100 GW

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Re: What motor

Post by Chalo » Mar 21 2021 1:17am

If you want 50 km/h from a 500W system, then the problem isn't the system's.
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Sargenebike   1 µW

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Re: What motor

Post by Sargenebike » Mar 21 2021 3:47am

I have changed the battery maybe 2 years ago. It is used propably about max. 50hrs.

I have some hills in my city and i remember that it climbed faster when it was newer.
When driving in deep snow or something else like it the controller starts smelling and gets hot.
This has happened couple of times but usually I have to drive only on the road with this bike.



I want propably change the system for my fatbike. I want have a bike what can do what I want. What is most powerful hub or mid-drive kit what is good idea and safe to install for that?

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markz   100 GW

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Re: What motor

Post by markz » Mar 21 2021 4:43am

Cyclone makes a 30kw mid drive motor kit
You'll need a commercial account with Shimano, Micro or Sunrace to be replacing your bicycles drive train all the time.

Then theres Astro Flight motors if you want to go down that noisy route.

Or goldenmotor.bike

Or http://mymobilemms.com/OFFTHEGRIDWATER. ... 50hp-Motor

Question is, do you really want to go 90+mph on a bicycle?
Sargenebike wrote:
Mar 21 2021 3:47am
I want propably change the system for my fatbike. I want have a bike what can do what I want. What is most powerful hub or mid-drive kit what is good idea and safe to install for that?

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dogman dan   100 GW

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Re: What motor

Post by dogman dan » Mar 21 2021 6:02am

I have had similar symptoms to what you have, as a controller did a slow death. Since you say you can smell it, I suspect you might need a new controller.

The hot thing you smell could also be a bit of the wiring, or a connector that got corroded or otherwise developed a poor connection getting all hot. This can also impede the flow of electrons, resulting in a slowing down.

Look real hard. I mean really hard at that wiring, before you pop for a new controller.

LewTwo   100 kW

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Re: What motor

Post by LewTwo » Mar 21 2021 9:21am

Time marches on. A 2 year old battery should not have as much capability as a brand new battery. You can lose up to 15% capacity in the first year just due to the age of the cells and chemistry breakdown. Somewhat less for each additional year. When I was working in the IT segment we considered 3 to 5 year the max for laptop batteries. After that one had to keep the laptop plugged in or replace the battery. I have a six year old Golden Motor LiFePO4 battery that still works but I would not risk a very long trip with it.
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Sargenebike   1 µW

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Re: What motor

Post by Sargenebike » Mar 22 2021 2:23am

Yeah. I think I have to update my kit because I feel there is not any more power and range enough for me. Could be because my other bike is rated for 1500w. Or there is real problem in controller.

If I update the voltages I have 2 pieces of 36v batteries as an extra. One 10ah and one 17.5ah.
If connected I can get 72v out.
What is max. safe motor power what I could use with this type battery set up?

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