BPM kit build thread

[Scottyf]

Jay, yours must be a monster running a 500w 48v motor.
What battery / controller combo are your running with it?

BMSbattery just emailed to tell me that they have actually sent me a rear motor for the price of the front.
Seems like they had not got any fronts in stock.

I'm happy as long as I get it.

 

[brueh]

BMSbattery

I just ordered three motors (Cute-C07, Q100 and Bafang SWXK5) and two controllers and a few other bits from BMS battery so I will follow yout thread closely. Looking forward to receiving the goods. Not looking forward to the wait though...

 

[peasjam]

So last night I was having a look at how the battery was going to fit. It's pretty big and heavy... the challenge is going to be getting it sitting as far forward on the pannier rack as possible to stop the front end from becoming too light. I also want to ensure that the least amount of stress is being placed on the rack as I can as it's a seat-post mount version. The rack is rated to 9kg load, the battery is 7.5kg according to the BMS website.

The pannier bag only arrived today (and it looks like it might *just* be a bit too small....) so I was really just mapping things out in my head:

While I was at it I also checked the thickness of my front drop-outs - a chunky 7mm. I'm still going to make my own torque arms though.

Exciting times this morning, I collected this from my post office:

Rather annoyingly there are no washers or nuts with it. It's not the end of the world, but you'd have thought they'd supply them. Have to go into town tomorrow though so will pick some up then.
Initial impressions are that it feels well built. Spokes are fairly meaty and all nicely tensioned, the rim is not too bad quality either.

More as it happens....

matt.

 

[Deleted member 4366]

`With my BPMkit, all the washers and wheel-nuts were in a little plastic bag inside the main box.

 

[Fordulike]

peasjam, how close to BMSBATTERY's stated dimensions of 90x180x350mm is the battery and how snug does it fit on the rack?
BMS quotes 8.5kg, have you weighed it yet?

 

[AndyOfTheSouth]

Good luck with your project.

I agree with NRG, though, it's a mismatch. That bike calls out for a lightweight motor/battery combination or being left as it is. If you do fit the motor, it is essential to use a torque arm, otherwise there is a risk of damaging the fork drop outs.

Instead, why not use a cheap, steel framed bike from Halfords and save the Cannondale? Great looking bike, by the way!

 

[Cyclezee]

Good luck with your project.

I agree with NRG, though, it's a mismatch. That bike calls out for a lightweight motor/battery combination or being left as it is. If you do fit the motor, it is essential to use a torque arm, otherwise there is a risk of damaging the fork drop outs.

Instead, why not use a cheap, steel framed bike from Halfords and save the Cannondale? Great looking bike, by the way!

I second the comments made by NRG and Andy. The Cannondale a very nice looking lightweight bike and would be better suited to something like a stealthy Cytronex kit when that becomes available.
The relatively heavy BMS kit would be better suited to sturdy an inexpensive MTB.

 

[vhfman]

peasjam , assuming you are still building onto the Cannondale Bad Boy. I was looking at the battery mounting arrangement you are using; and wondered if you could suspend the battery in the frame triangle, with some form of frame bag. This would distribute the weight much better than having a heavy battery hanging on the back of the seatpost. I know it would spoil the lines of the bike but you might find it rides much better with the weight in the wheelbase.

If you are interested I rather think that the seatpost rack you are using may be close to its weight limit. You say the one you have is good for 9Kg. According to BMS battery the 48v 16Ah battery weighs 8.5Kg in their spec.

This Axiom weighs 760g, and is stated to have a capacity of 15Kg, which could give you a little more leeway. With a large unsuspended weight going over bumpy roads could put too much stress on the seatpost & rack.

Chris

 

[Deleted member 4366]

My rear BPM kit arrived today: Yippee! I didn't have to pay any duty. Everything was present and correct. This time they sent me a slightly different controller. It's marked 36/48v 500w, which is handy as I'm going to use 44v lipos.
I just had one small problem fitting it, which I'll mention in case anyone else gets the same: the shaft didn't come far enough out of the free-wheel centre so that the anti-rotation washer couldn't sit against it's shoulder and when I did up the wheel nuts it locked the free-wheel. I had to make some special washers by drilling 10mm ones to 12mm so that they would go inside the free-wheel and keep the anti-rotation washer clear. Now all is OK. The only thing that I can think of that cause this is that the free-wheel thread didn't allow it to be screwed on far enough. Anyway, it was a pretty easy fix once I figured out what the problem was.
I'm building this bike specially to tow a heavy trailer, so I got the high torque low speed version. It'll be interesting to see how it goes up hills.

 

[Scottyf]

Good to hear d8veh. Mines also meant to be here very soon. Landed in cov and also got through customs. Happy days.

What wind did you end up getting then?

If its the 15 wind which is low speed high torque it should hit about 12nm of torque at 36v 9amp's at 15mph. I got most the stats from endless sphere.

 

[Cyclezee]

My rear BPM kit arrived today: Yippee! I didn't have to pay any duty

I don't want to put a damper on your joy, but the bill for import duty and Vat doesn't normally arrive with deliveries and can take a couple of weeks to arrive. Let's hope you are lucky

 

[Scottyf]

Doh, that means I might still be charged then.
My delivery was made yesturday unfortunatly I wasn't in.

I've looked at the tracker website to confirm the attempted delvieries but there has been no card or information on where to collect the items

Don't suppose anyone has any information on the depot or a number as the website has not proven useful!

Thank you in advance.

 

[Scottyf]

Its ok found out they are partnered with Parcel force for the UK.

 

[Deleted member 4366]

Its ok found out they are partnered with Parcel force for the UK.

Mine came by Parcelforce. The name should be on the card -normally with a map of how to get there!

I've never had to pay duty yet on Chinese stuff. When I did have to pay duty on USA and Japanese stuff, I always got a letter first and had to pay it before I got the goods, except one time I got it afterwards. I ignored it and never heard anything again, but it was only for a few pounds.

 

[Scottyf]

As i'm in an apartment you can't even post the card to get to me. Bit of a pain but if i sent it to work i'd never get it home. I'd have to taxi it lol. Or least drag it on the train.

Hopefully we wont be caught for customs lol. I had them write sample on the box just in case.

 

[Scottyf]

Picked up the kit this morning and tested it. Works with both my standard controller and new controller 20amp. Motor is the bpm in a 28 inch rim. Code 12.

Only problem i.ve had is getting the free wheel cassette off the old rear wheel. Ended up buying a locking tool from evans. Unfortunatly i brought a hyper glide locking tool and i need a uni glide. Which is mega annoying as i can't take the old one back.

Might just end up buying a new cassette. Anyway if anyones got an unlocking tool for a uni glide i'd be a happy bunny if you could lend it me.

Anyway bpm in physical size is huge compared to the baby bafang. Hope to get out on it soon.

 

[Fordulike]

Can anyone clarify that the BPM rear hub will happily work with a disc brake please.

 

[Scottyf]

Yes. My one is disc compatibale.

 

[Scottyf]

Evening All,
Been monkeying about on my BPM Build this afternoon. Anyway its virtually complete now.

Rear 36v Bafang BPM 350w (Code 12) - Laced into a 700c wheel
20amp controller

Controller is probably a bit to high for my battery (Only being 9ah rated at a max 2c).

Although I like the kit it is considerably bigger than the previous bafang kit I had. (Front driving QS...). The weight and balance of the bike has changed considerably.
On a test run the bike easily hit the 20mph barrier without me peddaling at all.

Now alot of this will be because the previous Kit I had was hindered by the 13amp peak controller.

Issues I had fitting the kit :-

Removing my rear cassette from standard wheel - Had to buy a uni-glide removal tool - Actually got a Hyerglide unit. So in the end took it to evan's to be removed.

- Correct spacing as the 7 speed cassette was slightly longer than the spacers given. This resulted in my pulling the frame a bit to get it all in without binding.

- Getting the correct wiring for my throttle - Trial and error but I got through it.

Other than that the axel is slightly thicker than the front driving motor and spacers are all heavier weight.

Front driving and pedel power definetly give more grip - Bpm can actually wheel spin on loose group - espcially with 35c tires...

Oh and I've managed to destrop the poor wires from the Sunlova rack to my watt meter so thus I have no power at the moment till tomorrow when I get a soldering iron and some thicker guage cables.

D8veh you where right on those poor cables at the back of the rack - Didn't take much to kill them at all.

anyway some poor quality pics...

 

[Scottyf]