So, i reckon your motor rpm was about 245 @20mph. Do you know what rpm the code 12 is supposed to be?
BPM kit build thread
- Thread starter peasjam
- Start date
Good to see you have got on with the BPM build Scottyf. You say you had problems with the 7 speed cassette? I hadn’t realised that the BPM was designed for cassettes. I thought they had screw on freewheel sprockets. I wonder if the controller is programmable. I ordered the 12 Mosfets Universal controller.
Just looking at the winding codes and rpm I presume these are no load rpm. The speeds in a 26” rim would be:
• Code 10 is 310 rpm 24mph
• Code 11 is 285 rpm 22mph
• Code 15 is 206 rpm 16mph
You have a Code 12 which you estimate is 250 rpm; in a 700c wheel speed should be about 20mph.
I’ve had a bit of time this weekend, so I have been upgrading my front suspension mountain bike. Stripped all the components off the frame and rebuilt with a lot of new stuff; ready now for the BPM hub to arrive and get it laced into the rim.
Yes I am still waiting for my stuff to arrive from BMS battery. They say it has shipped but I have been unable to verify with the tracking number they gave me. I think it may require yet another email to stir things up!
Chris
Just looking at the winding codes and rpm I presume these are no load rpm. The speeds in a 26” rim would be:
• Code 10 is 310 rpm 24mph
• Code 11 is 285 rpm 22mph
• Code 15 is 206 rpm 16mph
You have a Code 12 which you estimate is 250 rpm; in a 700c wheel speed should be about 20mph.
I’ve had a bit of time this weekend, so I have been upgrading my front suspension mountain bike. Stripped all the components off the frame and rebuilt with a lot of new stuff; ready now for the BPM hub to arrive and get it laced into the rim.
Yes I am still waiting for my stuff to arrive from BMS battery. They say it has shipped but I have been unable to verify with the tracking number they gave me. I think it may require yet another email to stir things up!
Chris
D
Deleted member 4366
Guest
Just completed mine. I'll post some pics tomorrow because I've got some minor tidying up to do. I tested it with 37v lipos and I couldn't believe the power - loads more than my last BPM. This one is a code 12. Not sure what the last was, but this one has real pulling power. I took it to the 25% underpass hill that I use for testing and it just pulled me straight up as if it were on the flat. I built it to pull my trailer and it easily has enough power to pull it up the Welsh mountains. Very quiet too - and rolls well. I can't see the battery lasting very long with this power, so now I have a new problem to solve. I built a 44v lipo battery for this setup, but it was totally unnecessary because of the power from the 37v set.
I had two problems fitting the kit: First, as I said before, the free-wheel cluster was too long for the axle, so I had to make some spacers; one of the throttle connectors had the wire in the wrong place, so there was a mismatch in the colours - easily fixed by swapping the pins in the connector, but shouldn't have been necessary.
This controller has the cruise control, which'll take a bit of getting used to because it holds the throttle open after a few seconds use. I guess I might be able to use this to keep a constant low throttle opening to save battery power.
I had two problems fitting the kit: First, as I said before, the free-wheel cluster was too long for the axle, so I had to make some spacers; one of the throttle connectors had the wire in the wrong place, so there was a mismatch in the colours - easily fixed by swapping the pins in the connector, but shouldn't have been necessary.
This controller has the cruise control, which'll take a bit of getting used to because it holds the throttle open after a few seconds use. I guess I might be able to use this to keep a constant low throttle opening to save battery power.
I think the BMS states the size of the BPM as 137mm which is 2mm longer than the 135mm. Can this be the reason?
Great work anyway and Thanks for sharing.
Now you need to update your signature
I've had the same problem d8veh with the free wheel gears where by i.ve had to get some washers as the cassette was to long. Like you said though easy fix with the correct washers.
Its a very substantial motor which has turned the bike from assist to not requiring rider input. Its louder than the small front driving motor. However i reckon with a few hundred miles its will bed in and become alot quieter.
However hot of the charge its a right little beast. Even at 36v 20amp. However i believe its melted the wires from battery switch to my turnigy watt meter. However when i look at them my look ok which is strange. Will have to invest in a soldering iron and multi meter today to find the problem. Lets hope maplins is open on a bank holiday. As the solder on the switch has turned green and black. Guess to many amp's being pulled. If it is to much i can swap to the little controller to save range and battery
The cruise control is interesting but i've not hooked it up at the moment. To be honest i do that much stop and start it seems a bit pointless really.
My controller is the 450watt 9mosfet version. As others have said the bpm kit at 36v is powerful. I had my doubts. Can't imagine what it would be like at 48v. Either way you don't have to pedal.
Its a very substantial motor which has turned the bike from assist to not requiring rider input. Its louder than the small front driving motor. However i reckon with a few hundred miles its will bed in and become alot quieter.
However hot of the charge its a right little beast. Even at 36v 20amp. However i believe its melted the wires from battery switch to my turnigy watt meter. However when i look at them my look ok which is strange. Will have to invest in a soldering iron and multi meter today to find the problem. Lets hope maplins is open on a bank holiday. As the solder on the switch has turned green and black. Guess to many amp's being pulled. If it is to much i can swap to the little controller to save range and battery
The cruise control is interesting but i've not hooked it up at the moment. To be honest i do that much stop and start it seems a bit pointless really.
My controller is the 450watt 9mosfet version. As others have said the bpm kit at 36v is powerful. I had my doubts. Can't imagine what it would be like at 48v. Either way you don't have to pedal.
D
Deleted member 4366
Guest
My latest build is now fully working. Thanks Caph for recommending the forks. They're brilliant. I've still got a few things to tidy up and a few extra bits to add, but here's a couple of photos in the meantime:
Donor bike Diamondback something or other £15
BPM motor kit £150
44v 10aH lipo pack £120
Rockshox dart 4 forks £70
Humpert Moon Cruiser bars £6
Steerer spacers £10
Rack from boot sale £2
Chain £13
Wattmeter £16
Scwalbe City Slick tyres £20
Total cost about £450 with a few other bits and pieces.
We tried it out today with the 44v lipos, which easily get it up to about 25mph. I think I prefer the 37v ones, which are a bit more sensible. For all those that want a bike for going up hills. This'll go up anything - shame it's not legal.
Donor bike Diamondback something or other £15
BPM motor kit £150
44v 10aH lipo pack £120
Rockshox dart 4 forks £70
Humpert Moon Cruiser bars £6
Steerer spacers £10
Rack from boot sale £2
Chain £13
Wattmeter £16
Scwalbe City Slick tyres £20
Total cost about £450 with a few other bits and pieces.
We tried it out today with the 44v lipos, which easily get it up to about 25mph. I think I prefer the 37v ones, which are a bit more sensible. For all those that want a bike for going up hills. This'll go up anything - shame it's not legal.
Nice set up, especially the doner bike (£15 quid!!!).
I might have to invest in some front forks like those as well, bumps are so big around here my hands have come off the handlebars on occasions.
How much power are you drawing at 25mph? Any pictures of the batteries?
I'm glad you are all finding the BPM motor such a success. When my little tongxin blows it's innards again i will have to join the BPM club.
I might have to invest in some front forks like those as well, bumps are so big around here my hands have come off the handlebars on occasions.
How much power are you drawing at 25mph? Any pictures of the batteries?
I'm glad you are all finding the BPM motor such a success. When my little tongxin blows it's innards again i will have to join the BPM club.
Managed to fix the battery. The wiring appears to be find at 20amp running through it. Battery must have had a loose connection and the fuse was blown. Replaced them put some thicker guage wires in the battery and more solder on the connections.
Anyway took the bike out down the canals. Completed 10 miles. Used the following:
4.3amp hours
20.3 amp peak
32 volt min
763 watt peak
So in 10miles i'd used up a similar amount of battery as i do with completing 18 mile round trip.
In short i'm using up about 60% extra of the battery compared the the previous kit. How ever i'm going at a considerably quicker pace compared to the 250watt 13amp kit.
If i was to continue using it i would really need to charge at work. How ever its much quicker.
Costs=
Bpm kit £150
Washers £2
Bullet connectors £4
Insulation tape and shrink tape £5
Starter solder kit £20
Multi meter £9
New spanners £8
Chain lube £6
Uni glide tool £10
Adjustable spanner £8
Ok alot of the cost was on tools and about 15 hours installation time which was no where near as straight forward as a front wheel build.
Most my time was took up removing the free wheel and setting up the derailer. Still its fun and you can get the bike to wheelie. Its also helped the ease some pressure off the front suspension.
The axels on the bpm where a perfect fit into the drop outs. I.ve used several locking torque washers to make sure the drop out's don't become damaged.
I think in the future i'll run a torque arm just in case. Will speak to an engineering place a friend works at to see if they can make me one. Unless there's any in the uk you can just buy?
All in all expensive and a long setup but happy about it so far.
Running at 48v would be a bit of a monster and i'd probably upgrade the brakes first. Now to use up my standard battery and then my next move will be to upgrade the battery. But for now i'm very happy with the result.
Anyway took the bike out down the canals. Completed 10 miles. Used the following:
4.3amp hours
20.3 amp peak
32 volt min
763 watt peak
So in 10miles i'd used up a similar amount of battery as i do with completing 18 mile round trip.
In short i'm using up about 60% extra of the battery compared the the previous kit. How ever i'm going at a considerably quicker pace compared to the 250watt 13amp kit.
If i was to continue using it i would really need to charge at work. How ever its much quicker.
Costs=
Bpm kit £150
Washers £2
Bullet connectors £4
Insulation tape and shrink tape £5
Starter solder kit £20
Multi meter £9
New spanners £8
Chain lube £6
Uni glide tool £10
Adjustable spanner £8
Ok alot of the cost was on tools and about 15 hours installation time which was no where near as straight forward as a front wheel build.
Most my time was took up removing the free wheel and setting up the derailer. Still its fun and you can get the bike to wheelie. Its also helped the ease some pressure off the front suspension.
The axels on the bpm where a perfect fit into the drop outs. I.ve used several locking torque washers to make sure the drop out's don't become damaged.
I think in the future i'll run a torque arm just in case. Will speak to an engineering place a friend works at to see if they can make me one. Unless there's any in the uk you can just buy?
All in all expensive and a long setup but happy about it so far.
Running at 48v would be a bit of a monster and i'd probably upgrade the brakes first. Now to use up my standard battery and then my next move will be to upgrade the battery. But for now i'm very happy with the result.
D
Deleted member 4366
Guest
Just over 28amps with 1300w showing on the meter at 47v. Great fun, but a lot more power than I wanted. I'll post some picures of the batteries tomorrow, when I get my camera sorted.
1300watt, must be a right little beast. Mines only hitting half of that and i already think thats loads or enough for a bike.
Guys on es that run 2500 peak out of the bikes must be like motor bikes but more scarey! Most motor bikes weigh in at 120kg+
If anything its made of appriciate the speed of a push bike and hitting past 25mph really is a scary prospect.
Glad your build went well D8veh!
Guys on es that run 2500 peak out of the bikes must be like motor bikes but more scarey! Most motor bikes weigh in at 120kg+
If anything its made of appriciate the speed of a push bike and hitting past 25mph really is a scary prospect.
Glad your build went well D8veh!
D
Deleted member 4366
Guest
Thanks. I haven't weighed it yet, but it's definitely lighter than my Sunlova, which is 29kg. Should have a range of about 10 miles, or maybe 20 with my other battery as well - not quite enough to tow my trailer to Presteign. I'll have to think again!
Yeah seems to be the only issue really with the kit. The additional battery use will undoubtably kill batterys life expectancy and range suffers quite a bit. How ever its expected.
Think i'd be lucky to get the 18mile round trip to work without charging the battery in between. Least to keep the battery from running to low. Not sure if the controller has a low voltage cut out since it can be used for 24v or 36v systems. In saying that the battery bms should kick in.
Bet at 1300watt it should wheelie quite happily.
Next on the xmas list will be a 14 or 20amp hour battery.
What controller are you using?
Think i'd be lucky to get the 18mile round trip to work without charging the battery in between. Least to keep the battery from running to low. Not sure if the controller has a low voltage cut out since it can be used for 24v or 36v systems. In saying that the battery bms should kick in.
Bet at 1300watt it should wheelie quite happily.
Next on the xmas list will be a 14 or 20amp hour battery.
What controller are you using?
Finally got some more time to work on the build after a hectic family-orientated Easter.
I have the motor mounted. I found a couple of issues; the first was that the drop outs needed a very small amount of filing to allow the axle to drop in.
Also, there is a very large space on the disc side which needs packing out for the drop-out to butt up against.
Really the axle could do with protruding a little more on this side as by the time the washers and bolts are on there isn't enough space left to fit a torque arm. In contrast, the other side has more than enough space...
The peddle sensor won't fit my bike - there isn't a suitable exposed piece of crank for mounting the sensor.
For the time being I'm mounting my battery in a small heli-ski rucksack I have. I've had a walk around with it and it actually doesn't feel too bad at all, and sprung-weight is always preferable to unsprung... Anyway, I shall see how it goes. I think really I will end up mounting the battery on the back in the medium to long term, but this solution allows me to crack on while I buy/build a suitable case.
I had some issues regarding mounting of the thumb throttle. The bulk of the casing impedes the down-shift of the alfine shifters rendering the gears unusable. This has forced me to mount the throttle on the left-hand side. The throttle body does slightly overhang the grip which may be a pain over the distance of a ride... I'll have to see how it goes and work up a solution if this proves to be the case.
I've had to do a small amount of wiring:
So, these are the connections I have available on my battery:
The green/red pair match the charger, so all good there.
The power-in connection on the controller is a three-pin plug:
So, I have removed the 3-pin from the controller and fitted a set of connectors that came with the kit which match the red/black pair on the battery. Essentially I've replaced the 3-pin on the controller with what you see on the battery (on a short extension cable so it'll reach to the rucksack).
I have also connected the small orange wire to the red power.
Motor is connected, as is the throttle, supplied brakes and peddle sensor. I connect the power and...... nothing. Not even a bang and puff of smoke to show I've done something wrong.
Charger reckons the battery is fully charged.
Frankly I'm at a bit of a loss where to look. The motor is sensorless, so I have no connection for this going into the controller.
Any ideas? I am a bit stuck...
I have the motor mounted. I found a couple of issues; the first was that the drop outs needed a very small amount of filing to allow the axle to drop in.
Also, there is a very large space on the disc side which needs packing out for the drop-out to butt up against.
Really the axle could do with protruding a little more on this side as by the time the washers and bolts are on there isn't enough space left to fit a torque arm. In contrast, the other side has more than enough space...
The peddle sensor won't fit my bike - there isn't a suitable exposed piece of crank for mounting the sensor.
For the time being I'm mounting my battery in a small heli-ski rucksack I have. I've had a walk around with it and it actually doesn't feel too bad at all, and sprung-weight is always preferable to unsprung... Anyway, I shall see how it goes. I think really I will end up mounting the battery on the back in the medium to long term, but this solution allows me to crack on while I buy/build a suitable case.
I had some issues regarding mounting of the thumb throttle. The bulk of the casing impedes the down-shift of the alfine shifters rendering the gears unusable. This has forced me to mount the throttle on the left-hand side. The throttle body does slightly overhang the grip which may be a pain over the distance of a ride... I'll have to see how it goes and work up a solution if this proves to be the case.
I've had to do a small amount of wiring:
So, these are the connections I have available on my battery:
The green/red pair match the charger, so all good there.
The power-in connection on the controller is a three-pin plug:
So, I have removed the 3-pin from the controller and fitted a set of connectors that came with the kit which match the red/black pair on the battery. Essentially I've replaced the 3-pin on the controller with what you see on the battery (on a short extension cable so it'll reach to the rucksack).
I have also connected the small orange wire to the red power.
Motor is connected, as is the throttle, supplied brakes and peddle sensor. I connect the power and...... nothing. Not even a bang and puff of smoke to show I've done something wrong.
Charger reckons the battery is fully charged.
Frankly I'm at a bit of a loss where to look. The motor is sensorless, so I have no connection for this going into the controller.
Any ideas? I am a bit stuck...
Have you got a meter? i would check for voltage between the red and black from the battery first. Did you get a spark or flash? that would indicate the capacitors in the contrioller have charged when connected.
Is there a fuse on the battery pack...is that ok? The orange wire is for 'soft' switching the controller on and off, so while it is connected to the red wire the controller is on.
If everything appears ok, i would then disconnect the pedal sensor and brake switches and try to get some life using the throttle only.
Is there a fuse on the battery pack...is that ok? The orange wire is for 'soft' switching the controller on and off, so while it is connected to the red wire the controller is on.
If everything appears ok, i would then disconnect the pedal sensor and brake switches and try to get some life using the throttle only.
Last edited:
Can anyone give a heads up if there is the same issue with the rear hub BPM pleaseAlso, there is a very large space on the disc side which needs packing out for the drop-out to butt up against.
D
Deleted member 4366
Guest
If you want to fit the pedal sensor, there's two things you can do: 1. Get a longer bottom bracket spindle assembly - less than a tenner from Halfords; 2. file a couple of mm off the thickness of the pedal and fit the sensor on the non-chainwheel side. You'll have to turn over the magnet disk so that the shiny bits are away from the sensor.
The reason your motor won't run will probably be because of either of these: 1. The wires in the throttle don't match those of the controller. Have another careful look at the colours on both connectors. I think they just poked the pins in randomly. It was like that on both my throttle and pedal sensor. 2. Have you done the self-learning procedure? You have to connect the white connectors and then open the throttle a bit. After the wheel spins, you switch off and disconnect the white connectors and that's it. My guess is that your problem is reason no.1.
The reason your motor won't run will probably be because of either of these: 1. The wires in the throttle don't match those of the controller. Have another careful look at the colours on both connectors. I think they just poked the pins in randomly. It was like that on both my throttle and pedal sensor. 2. Have you done the self-learning procedure? You have to connect the white connectors and then open the throttle a bit. After the wheel spins, you switch off and disconnect the white connectors and that's it. My guess is that your problem is reason no.1.
D
Deleted member 4366
Guest
No, the measurement is exactly 137mm between the drop-outs. The problem is that the ant-rotation washer doesn't reach the shoulder it should sit on on the free-wheel side, so you need a couple of 10mm washers drilled out to 12mm to fit inside the free-wheel
D
Deleted member 4366
Guest
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.Finally got some more time to work on the build after a hectic family-orientated Easter.
I have the motor mounted. I found a couple of issues; the first was that the drop outs needed a very small amount of filing to allow the axle to drop in.
Also, there is a very large space on the disc side which needs packing out for the drop-out to butt up against.
Really the axle could do with protruding a little more on this side as by the time the washers and bolts are on there isn't enough space left to fit a torque arm. In contrast, the other side has more than enough space...
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