BPM kit build thread

[Scottyf]

I never did that self learning thing. Just wired up the red black and white throttle controls. D8veh is right on the anti rotational washers. To be fair i have four on mine. Two on the inside, two on the outside

 

[peasjam]

I think the anti-rotation washers are supposed to fit in the inside of the drop-outs. I can't see one in your picture, With them in, the gap will be about 6mm less. The rest (if there is any) will pull in when you do up the nuts.

Yes the washer does reduce the gap a bit (I'd just got the wheel dropped in there to test clearances for my discs), but what is difficult to see in the picture is that the space recesses into the hub quite significantly. Where the dropout is in the picture is the narrowest it can be before the mounting bolts for the disc brake rotor start clipping the bottom of the fork. The total distance that needs packing out is maybe 15mm or so.

 

[Fordulike]

Yes the washer does reduce the gap a bit (I'd just got the wheel dropped in there to test clearances for my discs), but what is difficult to see in the picture is that the space recesses into the hub quite significantly. Where the dropout is in the picture is the narrowest it can be before the mounting bolts for the disc brake rotor start clipping the bottom of the fork. The total distance that needs packing out is maybe 15mm or so.

d8veh mentioned a while back that he found his pack of washers in the main box.
Are you sure there's not something BMSBATTERY supplied that will fill out that space?

 

[Deleted member 4366]

San Eagle's got my old front BPM, so I can't look at it just now. I'll have a look tonight if he's in. Normally, the disk should be close to the fork leg to line up up with the calliper so that any packing should be on the other side. The problem then is that the wheel becomes offset from the centre. I think that's how I left my last installation, but I think we got it pretty close to the centre on San Eagle's and likewise on my first installation but neither had disk brakes and I'm sure extra packing washers were involved. Your gap looks much bigger. Could you show a photo of the other side. There should be a large nut on the spindle next to the motor. If it's missing, that might account for that size gap.
Here's a drawing of how it should look. The gap behind the anti-rotation washer on the non-disk side is where the thick nut is on mine:
http://www.bmsbattery.com/303-436-thickbox/bafang-350watts500watts-bpm--motor-e-bike-kit.jpg

 

[Deleted member 4366]

It's just come back to me now that I've studied the drawing. I removed the big nut and used a couple of spacing washers each side behind the anti-rotation washers on the non-disk installations to make the wheel central because it looks like they've designed in a 5mm offset, which I guess the wheel-builder is supposed to take into account, but didn't. On the disk version, I pushed the callliper as far as it would go and then spaced that side of the motor to suit. Then I packed the other side with washers (without the nut - I don't think it does anything other than acts as a spacer, but I may be wrong!) and that left me with about 2 - 3mm offset, which I thought was just about acceptable, though not ideal.

 

[peasjam]

That sounds pretty similar to what I'm seeing. The rim itself is substantially off-centre when everything is aligned and spaced for everything to seat nicely, not rub anywhere and break callipers sit over the rotor.
I suspect the rim should be spoked to take this into account but it hasn't - the spoke angle from hub to rim (as you look at the wheel front-on) is the same on each side. With the motor construction as it is, it looks like the only way to get a centralised rim is to lace the rim with a slight lateral offset to bring the rim more central.
Still. What with not being able to get the damn thing working at all at the moment I'll worry about that later. I can always get it re-spoked as there is a cycle shop just round the corner from my office.

 

[Scottyf]

Agree with the above.I don't have disks so it was never an issue. However my rear wheel - although straight is off center to a standard wheel.

This meant alot of calibrating for the gears as I would not be able to hit the lowest gear and slip of the higghest gear onto the axel.

I did the same as D8veh and just packed it with washers. The nut i removed as it just a spacer from what I can tell.

 

[Deleted member 4366]

Still. What with not being able to get the damn thing working at all at the moment I'll worry about that later. I can always get it re-spoked as there is a cycle shop just round the corner from my office.

Did you check that the colour of the wires oneither side of the throttle connector match?

 

[Deleted member 4366]

I never did that self learning thing. Just wired up the red black and white throttle controls.

You mentioned earlier that your motor was a bit noisy. It may be because you're running in sensorless mode. Did you get the hall sensor version of the motor? If you did, you should connect the hall sensors. You have to put the pins in the connector in the same sequence as the one on the controller, then do the self-learning procedure and then it should be smooth and quiet like mine.

I took mine for a longish ride today to get an idea of range. I did about 15 miles with the pedal assist only and discovered some interesting things that I wasn't expecting. it appears that the controller is cleverer than me because I can't quite figure out what it's doing. It appears that the amount of power that it gives is proportional to cadence (perhaps in steps) until about 12 to 15mph, so it must be in speed-limit mode with the pedal sensor. When I went downhill, the most power showing on my meter was about 40w regardless of speed. I guess that the controller is using the hall sensors to gauge the speed. Going uphill was a bit weird because I had to change down to increase the cadence and then the power caused the bike to accellerate - increasing the cadence until I had too much power, but when I changed up, it reduced the power so that I slowed down again. consequently, there was a lot of gear changing to keep a steady speed uphill without using too much power. The most power I saw on the meter with the pedal sensor was about 750w compared with 1300w with the throttle. When I got back my 37v lipo had used about 5 aH and was showing 38.5v, so had a bit left. The journey was down Ironbridge gorge, up the otherside and then return, so lot's of very steep climbing, which was totally effortless with this bike.
So, final conclusion is that it's better than I first thought, and much slower when using only the pedal sensor. Range on normal roads with 10aH would be about 20 - 25 miles. The throttle is loads of fun, but drains the battery very quickly and is handy when you have to pull out onto roundabouts quickly. It'll pull any tub of lard (like me) up very steep hills.

 

[Scottyf]

To be honest as long as it works and the cruise control is a nice feature.

More annoyed by the fact my rear tire got a puncture today. Not through the tire but the stem looks like its rubbed and caused a hole! Not good at all.

 

[NRG]

I took mine for a longish ride today to get an idea of range. I did about 15 miles with the pedal assist only and discovered some interesting things that I wasn't expecting. it appears that the controller is cleverer than me because I can't quite figure out what it's doing. It appears that the amount of power that it gives is proportional to cadence (perhaps in steps) until about 12 to 15mph, so it must be in speed-limit mode with the pedal sensor. When I went downhill, the most power showing on my meter was about 40w regardless of speed. I guess that the controller is using the hall sensors to gauge the speed. Going uphill was a bit weird because I had to change down to increase the cadence and then the power caused the bike to accellerate - increasing the cadence until I had too much power, but when I changed up, it reduced the power so that I slowed down again. consequently, there was a lot of gear changing to keep a steady speed uphill without using too much power. The most power I saw on the meter with the pedal sensor was about 750w compared with 1300w with the throttle. When I got back my 37v lipo had used about 5 aH and was showing 38.5v, so had a bit left. The journey was down Ironbridge gorge, up the otherside and then return, so lot's of very steep climbing, which was totally effortless with this bike.

Hi d8veh, remember these controllers and motors are voltage controlled, some have a steep speed ramp up when using the pedelec only mode and others have a more progressive speed ramp. So cadence can have quite a dramatic effect on the feel of the bike depending on the controller.

It would seem the controller you have has a gentle ramp so as cadence drops due to a higher gear being selected the speed drops off.

The original and E-crazyman controller I have on the Alien GSII have very short cadence ramps and therefore have no noticeable speed drop when changing gear.

Also, depending on the controller the throttle, if fitted, may give more speed than the pedelec alone. This is not because there is more power but due to how the controller is programed and how much voltage the controller feeds to the motor in the two modes.

 

[Deleted member 4366]

Hi d8veh, remember these controllers and motors are voltage controlled, some have a steep speed ramp up when using the pedelec only mode and others have a more progressive speed ramp. So cadence can have quite a dramatic effect on the feel of the bike depending on the controller.

It would seem the controller you have has a gentle ramp so as cadence drops due to a higher gear being selected the speed drops off.

The original and E-crazyman controller I have on the Alien GSII have very short cadence ramps and therefore have no noticeable speed drop when changing gear.

Also, depending on the controller the throttle, if fitted, may give more speed than the pedelec alone. This is not because there is more power but due to how the controller is programed and how much voltage the controller feeds to the motor in the two modes.

Yes, Looks like I've got the one with the more gentle ramp. I'll try it on my normal commute and see how it goes, Battery range is my biggest concern because I like to go long distances. Maybe it'll be ok with only the pedal sensor. We'll see.

One other problem with the throttle: If you 're manoevring the bike, when not sitting on it - like walking it in/out of a parking space - with the controller switched on, it's easy to inadvertently open the throttle a little, which causes the back to kick forward, leaving you holding the bike upside down and anybody nearby in danger of injury. I've done it several times already - luckily, not in public

 

[peasjam]

I think I've tracked down the source of my problem:

Voltage reading battery-side of the plugs 48.4v. Other side is 18.5v. So, a dodgy connection in one or both of the terminals going into the blue cable.
Going to dive out at lunch today and get a straight replacement for them as they're kind of rubbish anyway.

Other things:
I checked the plug wiring for the throttle and the ground/signal wires were the wrong way round. This is how it came:

The white (throttle-side) and green (controller-side) are the signal wires, you can see they're not correct.

The battery level wire from the throttle isn't currently being used (which is kind of irritating, I mean why supply a throttle with an indicator and then not utilise it in the kit?). Anyway, to get this working do I just need to supply it with a positive feed from the battery or will I fry the thing doing that?
Also, the other two unused wires are for the red button. I guess this is for a mystery feature on a different controller? Does anyone know what this can be used for?

On the subject of the throttle, I mentioned the issues I had mounting it on the right-hand side. Here it is mounted on the left:

You can see the body does intrude a fair bit over the grip, I'll have to see how this is over a long ride and find another solution if it's a pain.

Still don't think I can fit the crank sensor

The notched ring you can see that buts up against the crank arm is static relative to the frame, there really isn't anywhere to mount the ring even if I bore out the centre of it. The other side is much the same...

So, hopefully get some new plugs today and get them soldered up tonight. Fingers crossed that sorts everything out.
I am enjoying doing it, though the family don't allow me much time with it. It's definitely not a plug-and-play product though.

Matt.

 

[Deleted member 4366]

The battery level wire from the throttle isn't currently being used (which is kind of irritating, I mean why supply a throttle with an indicator and then not utilise it in the kit?). Anyway, to get this working do I just need to supply it with a positive feed from the battery or will I fry the thing doing that?
Also, the other two unused wires are for the red button. I guess this is for a mystery feature on a different controller? Does anyone know what this can be used for?

To get the the battery indicator lights to work, you only need to supply it with battery voltage. I hope you got a 48v throttle otherwise the lights will be on all the time(if they don't blow).
The switch on the throttle is for putting the controller into standby mode so that you can pedal without power (if you had connected the pedal sensor). It would still be worth wiring the switch so that you don't flip your bike when you're parking it. It's easy to inadvertently open the throttle whilst moving the bike when your not on it. You get an instant flip and end up holding it upside down with the back wheel in front. To wire it up, you take the pink (could be thin red) that's normally attached to the thick red power lead to the controller, and send it to the switch and then back to the 48v +ve battery wire. When it's energised with 48v the controller will give power; when not, it won't.

I can see the problem with the pedal sensor. Your bike's too high spec for it. They fit better with the square type.' I seem to remember one guy managed to get the sensor mounted and then stuck magnets directly to his chain-wheel to save space. You can get the little magnets on Ebay and superglue them in place, but you must fix them the right way up, so you'd need to check the magnet disk with a compass to find out the orientations and make a similar pattern.

 

[peasjam]

To get the the battery indicator lights to work, you only need to supply it with battery voltage. I hope you got a 48v throttle otherwise the lights will be on all the time(if they don't blow).
The switch on the throttle is for putting the controller into standby mode so that you can pedal without power (if you had connected the pedal sensor). It would still be worth wiring the switch so that you don't flip your bike when you're parking it. It's easy to inadvertently open the throttle whilst moving the bike when your not on it. You get an instant flip and end up holding it upside down with the back wheel in front. To wire it up, you take the pink (could be thin red) that's normally attached to the thick red power lead to the controller, and send it to the switch and then back to the 48v +ve battery wire. When it's energised with 48v the controller will give power; when not, it won't.

Excellent, thank you for the info! Still have one major hurdle though, I still can't seem to get anything working...

I've fixed the bad connection by replacing the supplied plugs with a three pin kettle-style. This gives me 48.4 v all the way to the controller.

With power connected to the controller I get 5.1v readings on the power wires. Where I should be seeing 5v feeds on various red/black wires I'm only getting 0.1 volts. My orange switch on/off wire has a live feed. I'm a bit of a loss... again... starting to turn slightly from fun project to pain in the backside.

 

[kitchenman]

Hi

peasjam

You now have a Supper battery and Charger

Witch size BMS did you order in the battery pack

Witch motor did you order

and where about in the UK are you
I would like to help you put the kit together

are you forks alloy or steel or carbon

Frank

What does a BMS do? (Added BMS size, and fork type to my list of thi
ngs to think about when deciding on a kit

 

[Scottyf]

battery management system. Basically a small pcb that has certain settings like low voltage cutoff, high voltage cutoff, also helps balance cells when charging. There for safety really. Most brought ebike batterys come with them fitted.

 

[kitchenman]

I would also be concerned about front wheel drive with the BPM at 36v let alone 48v. Why did you go for a front mounted motor? I wish you luck with the build (nice bike BTW) but I think you have the wrong motor and wrong bike for the kit you've ordered.

Whats the concern NRG re: 36v for front wheel hub? Is that in general? or just the BPM motor?

 

[Deleted member 4366]

A couple of suggestions:
1. Check again that you've definiteley got 48v on the orange(?) switch-on wire and that your 48v power leads are the corrct polarity
2. You have to do the self-learning procedure before it'll work: You connect the white wires; switch on or connect power; open the throttle, whereupon the wheel will turn slowly; switch off; disconnect power; switch back on again and it should go.

I would have thought that before this you would already have 5v on the throttle unless it's waiting for the white wires to be connected.

 

[kitchenman]

battery management system. Basically a small pcb that has certain settings like low voltage cutoff, high voltage cutoff, also helps balance cells when charging. There for safety really. Most brought ebike batterys come with them fitted.

Thanks. Any chance of a photo? If you get a battery from ebay or buy the cells and make up packs like some members do .... do they have to buy the BMS pcbs and then wire them in?