BPM kit build thread

peasjam

Pedelecer
Feb 25, 2011
89
0
Hello,

So, after getting lots of great advice on kits from people here I have been waiting around for my order from bmsbattery to turn up.

On Thursday the first part arrived! So I am starting this build thread with the aim of helping others by sharing my build experience and perhaps providing a chuckle to those that already know what they're doing.

Impressions of BMS: Nice enough, extremely slow to process order although I was prepared for that. I took just over six weeks from date of order for the first packages to arrive, and the motor itself is looking like arriving a week after that.
Communication was reasonable, I had two separate requests for motor spec info the last of which was over a month after the order was placed. To be fair to them they were super-quick after this when I expressed concern at that point that the order was taking a long time.
The only other minor grumble was that they asked for extra shipping costs to be covered as presumably the cost of sending stuff around the world had increased in those six weeks. It wasn't a huge amount, but still...

This is the bike I'm fitting the kit to (though looking much less new nowadays); a Cannondale Bad Boy 8:

I have upgraded the front disc brake to 203mm (from 160mm) and will be fitting some chunkier tyres (perhaps cyclo-cross) to offer a bit more ride comfort given the extra weight

Here is what arrived on Thursday:

48V 16aH LiFePO4 Battery and all the kit parts for a front mount BPM kit (excluding the actual the motor and wheel which landed in Coventry on Friday so should be with me this week).

First impressions:
The charger is bigger than I was expecting, but feels solid and well built.
I assumed the battery came in an aluminium housing, which as you can see here it doesn't...
Replacement brake levers (for regen) feel cheap and are very, very heavy. I have hydraulics anyway so hadn't planned to use them. I would like to try and enable regen braking on my hydraulic levers at some point.
Pannier rack feels cheap but won't fit my bike anyway (my fault, turns out my frame doesn't have the required mounting points).
Haven't had a look at the twist throttle yet...
Instructions... well yes... the piece of paper you can see has the briefest of descriptions for each terminal on the controller but that's it. I'm hoping that the having the motor in front of me will trigger some kind of moment of clarity.
Peddle sensor is included.... but I think I'm going to leave it off to begin with.


I think I've found the solution to my immediate problem - that of mounting the battery.

is good for weight up to 9kgs which is enough to hold the battery.
I'm pairing this up with:

I think this is just long enough to accommodate the battery though it will be a tight fit, and has plenty of extra height for my work shirt and jeans. It's also fully waterproof. It's more than I wanted to spend if I'm honest, but I think it will be a neat solution in the end.

There isn't much more I can do until the pannier bag and motor turns up, so until then...

Matt.
 

banbury frank

Banned
Jan 13, 2011
1,565
5
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
 
D

Deleted member 4366

Guest
Good luck with your build and I hope your motor comes soon. I'm still waiting for my latest kit, which has already been shipped after very many requests for more information and, like you, I had to pay an extra $22 for shipping. I think they underpriced the BPM motor because my previous one from them was a lot more expensive.

You should fit the pedal sensor. It's much better to ride the bike with it. I came from motorbikes, so I was expecting to only use the throttle, but I very rarely use the throttle now. If you have the bottom bracket and crank removal tools, it's a five munute job to fit the sensor and there's no downside to it that I can think of. It's actually easier to fit the sensor rather than the throttle as you'll probably find out later. Looking forward to seeing the results.
 

vhfman

Pedelecer
Oct 5, 2008
144
0
Look forward to reading and seeing more of your build project, hope it goes smoothly Matt.

It seems like there are one or two of us waiting for BMSBattery deliveries. I have a BPM rear motor and a few more components supposedly on their way to me. I received a shipping link for BMS on the 8th April, but I could never see any detail of the shipment using the link. So I’ve emailed Jack Xie, and they have given me another shipping link, which also does not work at the moment. It looks like I will be waiting a little longer.

I must say BMS have been quick to reply to my questions. But I don’t think they carry much stock as they must get things in after the order is placed. I haven’t been asked for any more money, just the original P&P charges. It could be that happens when they do eventually ship the stuff!

Just interested what size charger that is? It looks like a 900 or 1200W. You must want the ability of a quick charge !

Chris
 
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Rab C Nesbitt

Pedelecer
Aug 15, 2008
96
0
Best of luck with your project Matt - looking forward to seeing it unfold beautifully.

You're putting the electrics onto a smashing bike - the Bad Boy's a good 'un but as you've noted, it will be missing a few bits and pieces to bolt on kit that we take for granted on other hybrid/commuter bikes.
Regards

Rab
 

wurly

Esteemed Pedelecer
Aug 2, 2008
501
9
Yeovil, Somerset
Nice looking bike. I have a Marin urban commuter bike looks like that. I reckon you should get the hub sprayed matt black before you fit it. The second rack will look better too. It's a shame the battery doesn't have an enclosure, because that could bolt directly onto the rack and you could put the controller and wiring somewhere else. I used a tiny triangle frame bag for the wiring on mine. I think i would enquire about getting an aluminuim encloure folded up for that size battery. Do you know anyone who works in a sheet metal shop?
Good luck.
 

Scottyf

Esteemed Pedelecer
Feb 2, 2011
1,403
-1
I'm also awaiting an ebike kit from bms battery. A bpm 350w 36v kit with controller and the normal bits. In the end i'm not sure if they sent me a front motor or rear. Always fast to communicate although don't always get the question. Still i.ve not paid any extra if they do send me a rear. I just said to make sure to send one laced in a 28inch wheel.

It will be 4 weeks in a few days from the first payment and order. But i understand lead times will always be around the 6 week mark. Just standard when getting items from the far east.

But thats a kit and a half you have there with a huge battery. You should be able to ride it like a scooter. Just be worried about how much power your sending through the front forks.
 

vhfman

Pedelecer
Oct 5, 2008
144
0
Matt, I was just reading your post again and noticed your comment about enable regen braking. You won’t be able to use regen with the BPM motor as it’s a geared hub.


Chris
 
D

Deleted member 4366

Guest
For those still waiting.: I didn't get the notification about the extra money until they told me that the shipment was ready to go.
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
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.
 

Scottyf

Esteemed Pedelecer
Feb 2, 2011
1,403
-1
Should be ok. But maybe a torque arm would be best to ensure the dropouts don't get mullered.
 
D

Deleted member 4366

Guest
I've just had another look at your bike after NRG's comments. You may have a prolem with the drop-outs on the forks. What metal and how thick are they? The anti-rotation washers that come with the motor are quite big and might not fit properly. If the drop-outs are steel and at least 5mm thick, you should be ok. If they're alloy and not at least 6mm thick, you should investigate different forks or more substantial anti-rotation arms.
 

peasjam

Pedelecer
Feb 25, 2011
89
0
Hey,

To answer a few questions that have cropped up:

I went for the front drive as the bike has a Shimano Alfine internally geared 8 speed rear hub which I'm fairly attached to. So, it was either front drive on this or buy another bike to build on to. Jury is still out on whether I jumped the right way or not...

I'll investigate a bit further on the drop-outs; I strongly suspect they're alloy (the rest of the fork certainly is). Seems like it's a bit tricky sourcing torque arms in the UK, so once the motor turns up I'll either make my own or buy one from overseas.
I'm not quite sure how much torque to expect from the kit. I live in Cambridge which is flat so have gone for a lower torque/higher speed motor winding. The intention is for it to assist maintaining a higher average speed rather than accelerating away or hill climbing. That said, I realise that especially with front hubs caution is advised.

My cranks are self-extracting type and easy to remove, so I'll do what has been suggested and fit the peddle sensor.

That's it for now, motor was released from customs yesterday so hopefully I'll have it for the weekend.
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
Hi Peasjam, I don't want to cause offence but I think you have gone with the wrong bike and wrong configuration.

The BPM is a big, heavy, powerful motor not really suited for front wheel mounting. Yes it will work but there is a risk of spinning out the dropouts and the motor will noticably affect handling and ride.

Also you will most likely need to change the gearing as it's is I think the bike will probably be under geared for the motor. What the bike is crying out for is to either be left as it is or for a small light weight, lower powered motor to be fitted to the front wheel.

Anyhow, I wish you luck, keep us informed of how you get on. BTW are you lacing the wheel yourself or is it pre built?
 

peasjam

Pedelecer
Feb 25, 2011
89
0
No offence taken. It's a bit of a journey into the unknown, worst case scenario I buy a second hand mountain bike and switch to rear-wheel drive while keeping the rest of my components. I'm taking the view that this is a long-term project to get involved in as much as anything so I'm comfortable with the idea that things might not pan out quite as expected.

I had wondered whether I'd need to go for a larger diameter gear at the front but will decide on that later. The motor is pre-built into a wheel, not really sure what quality to expect from the rim and lacing to be honest.
 
D

Deleted member 4366

Guest
Best is to try it first. How much you feel the weight of the motor depends a bit on the steering geometry. On one bike I tried, it made the steering really heavy, but it's perfect on Steve's bike now with down-hill type forks. As you say, if you find that it spoils the ride and the feel of the bike, you can always get a cheap (sorry- good value)) MTB off Facebook adverts - or wherever. Like NRG says,I think heavy duty suspension forks might be better. but try it with your present ones, and then we'll know. Having said that, I've just got a feeling at the back of my mind that you'll have problems fitting the motor to those forks, which might force you to change something.
 

Scottyf

Esteemed Pedelecer
Feb 2, 2011
1,403
-1
By the time the battery and rack is on the bike will beel more balanced. Although give a harsh ride though due to the increase in weight.

I don't think you've gone about it the wrong way at all. As long as you can get it to fit and maybe run a torque arm to be safe it should be fine.

I've gone for a Front BPM and despite what everyone says the battery pretty much limits my power (36v 9ah) so at best it would only chew through 648watt and after that would come the voltage sag. Realistc Watt's at peak will only be 600.

Obviously your battery is far bigger / better than mine but as long as you don't rope in to much amp's and pedal a bit before whacking on the power you should be fine.

The great thing about the the BPM motor is you can safely run it at a continous 750watt all day and some people on ES have been pushing 2000watt peak on the standard Nylon gears.

Either way the motor gives you a geat platform to build on.

Thats why I've chosen it.
 
D

Deleted member 4366

Guest
For anybody else waiting for BMSbattery stuff, I've just figured out that the tracking number search only works if you put the letters in the verification code in lower case - even though the code is in upper case!
 

Scottyf

Esteemed Pedelecer
Feb 2, 2011
1,403
-1
Took me a second stab at it to get it.
Still its on route! Hoorah!

Pedelec forum filled with BPM Motors...
 

jayuk

Pedelecer
Jan 20, 2010
62
0
Ive had my rear bpm for a while now, only clocked up about 200 miles, but i actually prefer using the bike for work now rather than my car.

Jay