The eBike thread

unkel

Got the kit in the post today. Unfortunately no time to look at it until after the weekend, looks like.

SCOL

unkel wrote: »

Got the kit in the post today. Unfortunately no time to look at it until after the weekend, looks like.

What kit did you buy ? I still don't know if I should go for a back wheel kit or mid Drive.

unkel

See a few posts up, the Bafang BBS02B mid drive kit. From Germany, so no bill for VAT / customs. About EUR400 including shipping, this includes upgraded colour display, gear sensor and lights. Pretty good deal.

SCOL

It look like a nice kit, I might order one also.

Are you going to build a battery ?

unkel

I buy and build all sorts of batteries. Probably going to use a pack made up of cheap overstock hover board batteries (that have BMS included) for this one. 52V (14S) is what I plan to use to give it up to about 1.5kW :cool:

John Hutton

SCOL wrote: »

It look like a nice kit, I might order one also.

Are you going to build a battery ?

I bought the 17.5ah battery from them and it seems very good

YFlyer

Lumen wrote: »

Boards has a strict policy on not encouraging illegal behaviour, it's nothing to do with the mods, it's a site wide policy. Mods have to enforce it.

Yet cannabis and cocaine use is often talked, and sometimes encouraged, on site.

SlowBlowin

YFlyer wrote: »

Yet cannabis and cocaine use is often talked, and sometimes encouraged, on site.

Imagine if this policy was enforced by all the mods, some of the great threads would have never existed like "I Think My Grinds Teacher Fancies Me". Its still there if any mod wants to do some banning/policy enforcement.

unkel

Grinding noise coming from the front hub motor on the fat bike when I accelerate hard. It's fine when I gently accelerate and no noise either way at top speed. Not surprising really after riding the bike hard with very soft tyres. And connecting a 30A controller and 59V battery (getting nearly 1.4kW) to that poor wee 250W motor, that was not designed for that. Something's gotta give!

I guess that's wear / damage to the nylon gears? I guess this is beyond getting a bit of oil in there? I guess I will have to replace the gears - with more substantial ones, made from metal? Are these all a standard size and does anyone have any link to where to buy them?

nokiatom

unkel wrote: »

Grinding noise coming from the front hub motor on the fat bike when I accelerate hard. It's fine when I gently accelerate and no noise either way at top speed. Not surprising really after riding the bike hard with very soft tyres. And connecting a 30A controller and 59V battery (getting nearly 1.4kW) to that poor wee 250W motor, that was not designed for that. Something's gotta give!

I guess that's wear / damage to the nylon gears? I guess this is beyond getting a bit of oil in there? I guess I will have to replace the gears - with more substantial ones, made from metal? Are these all a standard size and does anyone have any link to where to buy them?

i have the same problem when the motor is under pressure. i opened the motor and checked the gears...couldnt find any wear. so i dont know what the problem is

unkel

What else could it be though, surely it must be the gears? If they're not worn / broken, they must be skipping / slipping?

I opened the motor too, but only a wee bit to spray some silicone oil in. Didn't make any difference. I guess the next step is to disconnect the motor from controller and take the wheel out and then open the motor properly to inspect the gears / replace them

unkel

BTW if I rev the throttle with the wheel in the air, it runs smoothly, no grinding noise at all. So it's only when it is under (a lot of) weight / torque. Did a quick google and it seems common enough, some people have lived with it for months without it getting any worse. Checked on eBay and replacement nylon gears are only a few euro

Linky


But replacing them might not solve the problem at all...

nokiatom

unkel wrote: »

BTW if I rev the throttle with the wheel in the air, it runs smoothly, no grinding noise at all. So it's only when it is under (a lot of) weight / torque. Did a quick google and it seems common enough, some people have lived with it for months without it getting any worse. Checked on eBay and replacement nylon gears are only a few euro

Linky


But replacing them might not solve the problem at all...

i still go out and do about a 20 mile trip but its always on my mind that i might break down in the middle of nowhere so i have to be careful where i go

Joe1919

unkel wrote: »

BTW if I rev the throttle with the wheel in the air, it runs smoothly, no grinding noise at all. So it's only when it is under (a lot of) weight / torque. Did a quick google and it seems common enough, some people have lived with it for months without it getting any worse.

Check the motor phase wires for bad connections, as this can cause the phases to become unbalanced and make motor noise.
By the way, its possible to reduce the current in many controller, by 'shaving' or reducing the shunt thickness.

unkel

nokiatom wrote: »

i still go out and do about a 20 mile trip but its always on my mind that i might break down in the middle of nowhere so i have to be careful where i go

Even if the gears would physically break, the motor should still freewheel and you can just cycle home?

Joe1919 wrote: »

Check the motor phase wires for bad connections, as this can cause the phases to become unbalanced and make motor noise.

I doubt it's a bad connection as the issue is not intermittent. It does not occur once at full power and neither does it occur if I gently accelerate (or run the motor with the wheel in the air). Also I crimped in the phase wires, I can check, but I'd be confident their connection is strong. Maybe not so much the hall sensor wires.

Joe1919 wrote: »

By the way, its possible to reduce the current in many controller, by 'shaving' or reducing the shunt thickness.

I could always stick in a 12A or 15A controller, these are cheap as chips. But I like the
high current (=high power)

unkel

Went to my bike guru and he spotted straight away that the outside diameter of the bottom bracket of my bike (Boardman Pro 29er) is bigger than the fitting ring of the Bafang kit. This bottom bracket setup is common on modern higher end bikes

So we won't even try to fit it. And as such, my kit is now for sale. Brand new, never fitted. With a full one year warranty. Anyone in here interested in picking it up (for close to what I paid for it - which is as cheap as you can possibly get this kit), PM me. I also got official "Bafang 250W" stickers from eBay for on the motor. Prefer to sell it in here, before it goes on to adverts.ie

And.... back to the drawing board. Maybe a rear high power geared hub motor 29" wheel...

loughside

Isn`t it a 68/73mm bsa screw threaded BB? Or just an oddball type?

unkel

No, the bottom bracket is fine on the inside, but the outer width is too big. Not a BSA type screw BB, but one that is fitted to most higher end bikes in recent years, press fit. It looks like it will fit with adapters and stabilizer bars, but I don't really want to go that route - it sounds far from ideal as I would plan to put several times the motor's rated capacity through the system

I think this is like my situation:

Linky

SCOL

I was going to fit a kit onto my Hybred Trek bike, would that kit fit onto it ? I'll take a few photo's of the bike a send them to you tomorrow.

unkel

Post a picture up here, so others can comment. I'm no expert! But a standard screw BB should fit the kit as is, with no need for any adapters or anything.

unkel

From Bafangusadirect:

Please note, bikes with Press-fit bottom brackets (PF30, BB30, BB86, BB92, BB95 and BB121) have larger diameters and will require an additional adapter in order to work with the Bafang Mid-Drive motors. Press-fit bottom brackets are typically found on higher-end (more expensive), newer bikes that were manufactured in the last few years.

Linky

if you are still unsure of whether one of our motor kits will fit with your bike please email us the year, make and model of your bike at info@bafangusadirect.com.

Done. Just to see what they come up with.

unkel

Idiots from China sent me a 36V charger instead of the 24V charger I ordered :rolleyes:

Urgently need a 29.4V (7S, 24V nominal) charger, would like to pick one up today. Anyone any ideas? These chargers are commonly used in entry level (foldable) eBikes and some scooters and hover boards...

unkel

Bought a cheap Specialized full sus MTB and fitted the Bafang kit this morning



Didn't realise the kit comes with pedal assist built in as standard. Could remove the throttle so. Also have a couple of official Bafang 250W stickers I might use. Must look into programming the controller (via the P750C display?) if that's at all possible so I could restrict the motor to 25km/h - ish.

Bike has very strong pick up, even in assist level 1 (out of 9), even thought the cassette is stuck in the highest gear. It needs a bit of a service, the cassette is pretty worn and the derailleur needs tuning. Should I go for some heavy duty cassette and replace the chain with a stronger one too?

loughside

Have a look at those KMC ebike chains,
you`ll find you dont need anything more than a 7spd cassette, even then the torque will be so great you`ll be changing up through the gears two at a time.
and get the programming cable, there`s loads of .el files out there to try, or just do your own

John Hutton

unkel wrote: »

Bought a cheap Specialized full sus MTB and fitted the Bafang kit this morning



Didn't realise the kit comes with pedal assist built in as standard. Could remove the throttle so. Also have a couple of official Bafang 250W stickers I might use. Must look into programming the controller (via the P750C display?) if that's at all possible so I could restrict the motor to 25km/h - ish.

Bike has very strong pick up, even in assist level 1 (out of 9), even thought the cassette is stuck in the highest gear. It needs a bit of a service, the cassette is pretty worn and the derailleur needs tuning. Should I go for some heavy duty cassette and replace the chain with a stronger one too?

Good man.

Via the display go into the password settings bit (can't remember the actual name but you'll see it)

Password should be 1919. Will let you set speed limit and wheel size. No need for cable.

I've never used the throttle, don't see the need.

Joe1919

John Hutton wrote: »

I've never used the throttle, don't see the need.

A few places I have found throttles useful.The first is if you are stopped and the bike is stuck in the higher gears, it can be hard to get going on PAS. The second is when you are in a lower PAS setting, perhaps sparing battery on a long run and are suddenly chased by dogs. I have also found throttle useful for walk assist on very steep ramp. But the above are based on experience with low power hub motor. Are things different with higher power kit?

unkel

John Hutton wrote: »

Good man.

Via the display go into the password settings bit (can't remember the actual name but you'll see it)

Password should be 1919. Will let you set speed limit and wheel size. No need for cable.

I've never used the throttle, don't see the need.

Cheers, just programmed via the display, was indeed very easy. Pleasantly surprised that you can change the settings to digital and not analogue clocks. They looked a bit tacky to me in the pictures. Also pleasantly surprised that there is a setting for 52V batteries. Wasn't clear from reading online. The biggest chance I made was change the assist levels down from 9 (ridiculous) to the minimum of 3. And of course limit the speed to 25km/h. Ish

I guess there is a lot to say for complete kits. The only fabrication I had to make was cut off the connectors for the battery and crimp on a male XT60. Everything else was just click and play. The complete opposite of what I had got used to.

John Hutton

unkel wrote: »

Cheers, just programmed via the display, was indeed very easy. Pleasantly surprised that you can change the settings to digital and not analogue clocks. They looked a bit tacky to me in the pictures. Also pleasantly surprised that there is a setting for 52V batteries. Wasn't clear from reading online. The biggest chance I made was change the assist levels down from 9 (ridiculous) to the minimum of 3. And of course limit the speed to 25km/h. Ish

I guess there is a lot to say for complete kits. The only fabrication I had to make was cut off the connectors for the battery and crimp on a male XT60. Everything else was just click and play. The complete opposite of what I had got used to.

Yeah it's a handy enough set up I thought. Did you fit the cut off brakes? I have them spare, I have drop bars so I fitted an inline cable sensor instead but curious what the brake levers are like.

I bought a battery from the same supplier and they were just bullet connectors so I could plug it straight in, didn't need to change anything.

I think you'll really enjoy it once you get the gears sorted, it will haul you up anything.

Re the KMC ebike chain, I bought one but haven't fitted it yet. They are expensive enough but I'd say without the throttle perhaps not necessary. I'll fit it once my current one breaks.

I'd like your thoughts on the difference between peddling a hub motor and this motor with them turned off, ie of this mid drive is easier.

unkel

I did fit the cut off brakes. I feel you do need them for safety with the PAS. Not so much so with throttle only. The quality of them is fine, they are better than the old ones they replaced. The bike is a 2008 full sus Specialized Epic that I bought off adverts for the princely sum of €150

The bike strangely did not have a front derailleur fitted (but it did have two front chain rings). Which is grand as I would have had to remove it anyway

It needs a new rear cassette though, the current one is worn. Maybe I will go with just a standard one and keep the chain (which looks newish). Be sensible with how to use the bike (and no full throttle from standstill) and see how I get on...

Joe1919

unkel wrote: »

And of course limit the speed to 25km/h. Ish

I think the 'ish' is +/- 10%, so I think its OK to set to 27.5 km/hr and still within the spec?

D.1 Generalities (EN15194)
This Annex gives guidance on how to measure the power at the wheel.
The maximum power which the bicycle gives assistance may differ by ± 5% of the power indicated on the label described in Clause 5. During a production conformity check, the maximum speed may differ by ± 10% from the above-mentioned determined value. The test shall be performed without pedalling using only the electrical assistance system (the test bicycle shall be prepared accordingly).

PS The regulations have been revised recently and I cant get a copy without paying, so I am presuming that the tolerance is still the same.