Life, maintenance & repairing of geared hub motors

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Choudhary
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Life, maintenance & repairing of geared hub motors

Post by Choudhary » Feb 20, 2017 2:34 pm

Namaste. I am based in delhi, india. for the last 6 months i have been playing with the concept of ebikes (relatively new in India). I have made 2 bikes till now: 1 semi recumbent & 1 upright. I have used mxus geared front hub motors in both & am happy with the result. I have tried the best selling bikes here in india (hero, hullikal, volta) and the experience was pretty much the same. They are not not very big or heavy, not very noisy, look sturdy, don't heat up. I think their pick up / acceleration could have been better ( i have tried 24v & 36v setup).
Now, i plan to start selling ebike kits here in india. But a big concern that came up was motors life. The mxus people provide 2 years guarantee & say the average motor life is 3-4 year. That, in my opinion, is too less. A user can't possibly expect to change the kit 3 years down the line. That does not happen in automobile sector, and this is pretty much the same industry. I believe the 3-4 years must be the life for gears, which i think should be easily replaceable. I know these are one of the cheapest option market available in the market, but i feel mxus has good reputation. So is this life standard for geared motors?
What are the ways to keep it going for longer? Is replacing gears etc. tough or expensive?

Has anybody else faced similar issues with other geared motors like q100 or q75, or other 250 watt geared motors.

Thanks.

spiros
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Re: Life, maintenance & repairing of geared hub motors

Post by spiros » Feb 20, 2017 3:49 pm

I'm not an expert I have start to studying Ebikes principles from some days but from what I've understood till now the life time of your motor is in straight relationship with the way that you treat it. More gently you are more years you will go through. I have some friends that burned motors after 10 times of riding but others that go on years with the same things.
Anyway a good principle it could be adding at motor low watt controller so you will not stressing it. I think that a gently used gared motor cal be alive for more than 4 years.

Jon NCal
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Re: Life, maintenance & repairing of geared hub motors

Post by Jon NCal » Feb 20, 2017 5:03 pm

There's small direct drive hub motors now. Would those not work for your usage and last longer?

Choudhary
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Re: Life, maintenance & repairing of geared hub motors

Post by Choudhary » Feb 21, 2017 12:38 pm

spiros wrote:the life time of your motor is in straight relationship with the way that you treat it. More gently you are more years you will go through.
True. but as a seller, I am preparing for the worst use case. what happens when the motors are exploited to their limit. do their gears strip off? or something else happens. I talked to the company people and they said that the speed sensor dies in 3-4 years & it is easily (and cheaply) replaceable. as for the controller, i think thats a good idea. but i am using a 7-15amp controller at 36v. Isn't this already mild? I feel the speed drops to 20kph on flyover inclines.

Jon NCal wrote:There's small direct drive hub motors now. Would those not work for your usage and last longer?
The motors I am using are $50 & $60 each. I think the DD motors are generally expensive. Can you suggest any decent DD motor in sub 100usd range? People here in India don't really spend a lot on their bikes. :)

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Re: Life, maintenance & repairing of geared hub motors

Post by Jon NCal » Feb 21, 2017 12:47 pm

In that price range, the 9C clones (heavier motor) are available.

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MadRhino
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Re: Life, maintenance & repairing of geared hub motors

Post by MadRhino » Feb 21, 2017 6:29 pm

Well, if you don't plan to do service and repair, you would be better with DD motors. They are simpler, and can survive abuse much better. You need happy customers, either because you give good service or because they have no problems. If you sell cheap geared motors, you will have to stock spare parts and honour garantee.
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Choudhary
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Re: Life, maintenance & repairing of geared hub motors

Post by Choudhary » Feb 22, 2017 9:27 am

Jon NCal wrote:In that price range, the 9C clones (heavier motor) are available.
That actually sounds good. I read somewhere that most of the DD hub motors are actually 9c clones. But i still couldnt find any in sub $100 range. Can u share a link for this :)
MadRhino wrote:Well, if you don't plan to do service and repair, you would be better with DD motors. They are simpler, and can survive abuse much better. If you sell cheap geared motors, you will have to stock spare parts and honour garantee.
Servicing can't be avoided in this industry :). I do plan to stock parts & provide servicing / repairments. I just don't want it to my headache (or expensive for customers).
But I do get your point about DD motors. Can you suggest durable, light powered DD motor?

On a different note, I was experimenting with batteries & here are observations (& doubts :D )
1. Bike 1 (Semi recumbent + 24volt setup) - VRLA battery 24 x 14ah. Total Range (throttle only) - 22km. The last 5km were miserable with the bike running at 15kmph.
2. Bike 2 (Regular upright bike + 36 volt setup) - Li battery (2C samsung cells). 37 x 6.6ah. Total range (throttle only) - Good speed till the end.
3. Bike 2 - To cut down the initial cost, i thought it wud be a good idea to keep a small battery option of range ~10km. So i tried a 2.6ah battery. But alas. It lasted 2km. I checked the voltage and it showed 39.5 volt but the controller wont accept it. So this meant that a small battery doesn't provide enough current even at 39v. In process of making new packs of 4.4ah & 5.2ah. will post the results. :D

Jon NCal
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Re: Life, maintenance & repairing of geared hub motors

Post by Jon NCal » Feb 22, 2017 1:07 pm

Just go on alibaba.com and do a search on "ebike motor" or something like that. Good luck!

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Re: Life, maintenance & repairing of geared hub motors

Post by LI-ghtcycle » Aug 20, 2017 10:02 am

Welcome to ES my friend!

I think what you are doing is great, I have a friend in India who is also into Ebikes, I am curious what are the laws concerning the size of the motors? All I see is 250W, is that because of more powerful motors being illegal or just too expensive?

As to your search for a sub $100 DD hub motor, a couple things to note:

A 9C DD hub motor is an excellent choice, but will be much heavier than a geared motor.

As a bonus, it will be capable of using much more power, the geared hub motors really are limited since they are geared to a specific speed at a specific voltage.

Also, you might try experimenting with 48V, you should find that your 36V systems will generally work with it, but you will need to use a DD hub motor in most cases to see the advantages.

Here is a possible suitable motor from Alibaba.com:

https://www.alibaba.com/product-detail/ ... b095eNd98h
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Re: Life, maintenance & repairing of geared hub motors

Post by spinningmagnets » Aug 20, 2017 10:49 am

I am under the impression that the majority of customers in India will be very price-conscious, so I imagine the most popular systems will be for lower speeds. High speeds require expensive equipment, and I really strongly recommend some suspension for higher speeds, for safety and comfort. For lower speeds this is less of an issue.

I read quite a bit, and I am under the impression that welding with steel is widespread across India, but...I suspect that heli-arc for building or repairing aluminium bike frames is less available. If this is true, then you would focus on a low-speed ebike with a steel frame that has no suspension. For the very affordable addition of a small amount of tubing, you can extend the rear of the frame to make a longtail cargobike, which I am certain would be very popular.

I believe that mopeds are very popular there, so a selection of moped rims and spokes should be available. For reliability and ease of maintenance, I would recommend a direct drive hubmotor in the rear. It should be a fairly large diameter motor, but mounted in a smaller wheel. A 16-inch moped rim will seat a 20-inch bicycle tire (just as an example of the size of wheel I am suggesting). If you are using a moped rim with angled spoke-holes, you can mount a common 9C/Yescom size of hub with a one-cross pattern.

Moped tires (at the heavy end of the bike) are very flat-resistant, and a moped rim of a certain size will seat moped tires, or a 20-inch bicycle tire. A DD hub is very reliable, and if you use a sensorless controller, you never have to worry about the Hall sensors failing. I would recommend a 36V battery over a 24V, even if customers want to save some money by getting the smaller battery.

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spinningmagnets
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Re: Life, maintenance & repairing of geared hub motors

Post by spinningmagnets » Aug 20, 2017 10:59 am

And maybe add a Rinsten spring for the seat?

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