BMC V4 motor

mikhogl · Oct 3, 2011

Were can i buy this motor? I live in sweden and i cant find it here. Do BMC have any homepage? Do you know if there are any lighter motor then the BMC v4 that can handel 1500W+ Im building ebike and i need it to be light and powerfull, The frame im building on is a Kona Downhill. I need the bike to have good torque and a top speed about 20-25mph on 44.4v

best regards

Micke

itselectric · Oct 3, 2011

mikhogl said:
Were can i buy this motor? I live in sweden and i cant find it here. Do BMC have any homepage? Do you know if there are any lighter motor then the BMC v4 that can handel 1500W+ Im building ebike and i need it to be light and powerfull, The frame im building on is a Kona Downhill. I need the bike to have good torque and a top speed about 20-25mph on 44.4v

best regards

Micke

Micke:
try ElectroRide
http://www.electric-bikes.com/betterbikes/bmc.html
or
http://www.ebikessf.com/catalog/42

The problem with BMC when try to push through either higher speed or higher amp, the phase wire start to burn out or gear start to break down. But talk to two vendors, find out their opinion of the limitation of v4.

But if you are looking for 20mph, a 30amp controller, with BMC V2-T, should be able to handle it well.

Ken

mvly · Oct 3, 2011

My guess is that these BMC V4 are the ones that HIPowerCycle offered for presale a month ago. Essentially it's better at handling more power. Not sure if the problems is really solved, but they have definitely gotten better.

mikhogl · Oct 3, 2011

Ok, sounds like i have to go for the crystalyte ht3525, but its over 7kg. Almost twice the weight of the bmc, the bike is going to be less fun... any other options? Mac? Or should i settle with less power? So hard to deside

oatnet · Oct 3, 2011

mikhogl said:
Ok, sounds like i have to go for the crystalyte ht3525, but its over 7kg. Almost twice the weight of the bmc, the bike is going to be less fun... any other options? Mac? Or should i settle with less power? So hard to deside

A BMC V2-S will meet your design requirements just fine. It can handle 1500w, it will give you the speed at voltage you are asking for, and it is lightweight. It is a good, durable, commuter motor, and the gears are much stronger now. The 1st gen gears sucked but they are long gone, the 2nd/3rd/4th gen gears are great. Get a V2 with the 4th gen gears because they are the strongest, but there are folks here who have run the 2nd/3rd gen gears for a long time without problem.

You did not ask to build an 8000w wheelie-happy hotrod, which as itselectric points out, the BMC is not a good candidate for. However, if you do want to hotrod the motor up a little, you can increase volts not amps to get more watts (W=V*A). Increasing amps increases heat, which the WINDINGS (not the phase wires) cannot handle as well as a DD (direct drive) motor. In addition, increasing volts decreases back-EMF at a given rpms, so you can get more watts into the motor at higher RPM and achieve higher speeds. I always seek to maximize Volts and minimize Amps.

Here is a build with a BMC V2T that moves 300+lb through very hilly territory, @28mph on 60v nominal:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24329&start=15#p413920

-JD

PS - I'm not sure that the 'V4' exists. The V4 I know of was a Direct-Drive motor, and "Betterbike$" is the only place I see listing them.

mvly · Oct 3, 2011

oatnet said:
mikhogl said:

Ok, sounds like i have to go for the crystalyte ht3525, but its over 7kg. Almost twice the weight of the bmc, the bike is going to be less fun... any other options? Mac? Or should i settle with less power? So hard to deside

Click to expand...

A BMC V2-S will meet your design requirements just fine. It can handle 1500w, it will give you the speed at voltage you are asking for, and it is lightweight. It is a good, durable, commuter motor, and the gears are much stronger now. The 1st gen gears sucked but they are long gone, the 2nd/3rd/4th gen gears are great. Get a V2 with the 4th gen gears because they are the strongest, but there are folks here who have run the 2nd/3rd gen gears for a long time without problem.

You did not ask to build an 8000w wheelie-happy hotrod, which as itselectric points out, the BMC is not a good candidate for. However, if you do want to hotrod the motor up a little, you can increase volts not amps to get more watts (W=V*A). Increasing amps increases heat, which the WINDINGS (not the phase wires) cannot handle as well as a DD (direct drive) motor. In addition, increasing volts decreases back-EMF at a given rpms, so you can get more watts into the motor at higher RPM and achieve higher speeds. I always seek to maximize Volts and minimize Amps.

Here is a build with a BMC V2T that moves 300+lb through very hilly territory, @28mph on 60v nominal:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24329&start=15#p413920

-JD

PS - I'm not sure that the 'V4' exists. The V4 I know of was a Direct-Drive motor, and "Betterbike$" is the only place I see listing them.

I concer on the quality of the gears. As long as you keep it greased up, it should not be a problem, The only problem you will have is the power you can put into it. I have a BMC V3 and I put 1500W into it and it's fine. You just need to know its limit. If you are going for an off-road build, I recommend BMC V2T. You will lose high end speed but it should make up for major torque. Just make sure you run it at 60V or above. Keep the current low and you should be set to NOT burn out your phase wires. If you really want top of the line hot off the press stuff, then go for the new one. I should be able to handle more power, but the same rules still applies. I.e. Try not to push to much power into the motor at low speed. The only thing that the new motor will give you is probably more top end speed since you can push more current without fear of the phase wires melting on you. Also the wider gears might allow you to apply more torque on start up without stripping the gears. But all these are speculation. I want to wait for hi-power cycle or other ES member here to do some reviews before I put down the money for it.

Good luck on the build

neptronix · Oct 3, 2011

I put 2300w in short bursts, 1700w constant into my MAC and the BMC v2/v3 should be able to handle that... for the most part, they are identical on the inside.

Both the BMC and MAC gears have improved greatly as of late. Neither of them should be particularly problematic.. besides, you can order spare gears down the road. I have yet to destroy my original, non-reinforced gears.

BMC V4's '10% higher efficiency' claims have yet to be verified.

Really either motor will be fine.

Oh and with the controller problems, you should check out cell_man's new infineon controllers. They really smooth out the operation of the MAC motor, and i'm sure the situation is identical with the BMC unit. ( they may be so similar that they actually have the same stator. But they both have the low resistance issues that reak havoc on normal, unmodified infineon controllers )

cell_man · Oct 4, 2011

The BMC V3 is a high speed motor, you'll see not far off 30mph (48kph) on 36V in a 26" wheel, I would imagine the V4 will be very similar, The Mac 6T does about 46kph on 36V. A slower Torque Motor like the V2T or the Mac 10T would be better choice for roughly 40kph on 48V, or even the Mac 12T if you only want about 20mph 32kph on 48V. If you keep the current sensible in the 25-30A region and have just a little mechanical sympathy, I can't see you having any problems with the slower wound motors, your requirements are not high.

cell_man · Oct 4, 2011

oatnet said:

That's a plush ride you've got there JD, full suspension and springs in the seat too 8) Looks really nice and bet it rides as good as it looks, like someone I used to know.... :mrgreen:

mikhogl · Oct 4, 2011

I guess both bmc and mac has a high torque motor. How much does the mac 10t weight? Can i fit any brake on the mac?

Best regards

gensem · Oct 4, 2011

mikhogl said:
I guess both bmc and mac has a high torque motor. How much does the mac 10t weight? Can i fit any brake on the mac?

Best regards

about the same... 4.3kg I think.

dennyt · Oct 4, 2011

From http://ebikessf.com/node/143 :

BMC V4 motor is a direct drive/gearless BLDC motor with dimensions identical to its geared predecessors. We are still in process of testing it; this section will be updated with testing results as soon as they're available.

gensem · Oct 4, 2011

LOL.. A mini DD from BMC? Thats is bound to suck.
If im not mistaken they dropped the DD design.

neptronix · Oct 4, 2011

That's outdated information. This is a geared hub. They scrapped the plans for the DD.

mikhogl · Oct 5, 2011

okok, Does anybody know if it is possible to order BMC (V2) in europe? Or Mac?

neptronix · Oct 6, 2011

Dunno who sells the BMC in Europe.
Cell_man sells MAC motors direct out of China and ships internationally though.
Dunno if China shipping + import taxes to Europe are expensive but the MAC cost about half the money so that helps i'm sure.. lol

Philistine · Oct 6, 2011

I thought the main benefit or upgrade on the BMC V4 was that they had upgraded/fattened the phase wires. And as the phase wires were always the weak link in the BMC V3, that is an interesting prospect to have as an upgrade.

Personally I think the BMC is an awesome motor, really light, and freewheels really well. My only complaint about it is that I have never been confident to run it higher than 48v/40amps. But even having said that, the performance is so good that I get about the same top speed on 48v with my BMC V3 that I do with say my 9c 8x8 on 20S.

mikhogl · Oct 6, 2011

neptronix said:
Dunno who sells the BMC in Europe.
Cell_man sells MAC motors direct out of China and ships internationally though.
Dunno if China shipping + import taxes to Europe are expensive but the MAC cost about half the money so that helps i'm sure.. lol

¨
I saw cell_mans hompage, looks really interesting with mac. But im not sure that i cam fit my hayes brakes on the mac. maybe ill order one and see if the brakes fits.

thaks for the info!

oatnet · Oct 6, 2011

mikhogl said:
But im not sure that i cam fit my hayes brakes on the mac. maybe ill order one and see if the brakes fits.

Every Disk-Compatible hub I've seen comes with the same ISO 6-bolt pattern. If your brakes aren't compatible with the Mac, they aren't gonna work with any hub motor... I have bought from cell_man (MAC) and Ilia (BMC)and had a good experience with both.

That's a plush ride you've got there JD, full suspension and springs in the seat too Looks really nice and bet it rides as good as it looks, like someone I used to know....

Thanks CM! My first full suspension build, with 8" travel on the Boxxer World Cup front fork... very plush and very solid indeed. The Pelican case bolted to the front forks has 1kw of the a123 prisimatics I bought from you, enough to to 100 miles - at 11mph. :lol: The bike is much more maneuverable and balanced with the battery weight off the frame and over the steering. 8)

Did you know that HK LiPo is only 15% lighter than those a123 prisimatics?

-JD

cell_man · Oct 6, 2011

mikhogl said:
neptronix said:

Dunno who sells the BMC in Europe.
Cell_man sells MAC motors direct out of China and ships internationally though.
Dunno if China shipping + import taxes to Europe are expensive but the MAC cost about half the money so that helps i'm sure.. lol

Click to expand...

¨
I saw cell_mans hompage, looks really interesting with mac. But im not sure that i cam fit my hayes brakes on the mac. maybe ill order one and see if the brakes fits.

thaks for the info!

The thing to be aware of with the Mac and lots of other Hub motors is that there is not so much space for wide calipers. Hydraulic calipers may foul, the available space is only about 15mm. You could use washers to make more room and space off the caliper from the mount. The disk mounting is the standard type.

oatnet said:
Did you know that HK LiPo is only 15% lighter than those a123 prisimatics?

-JD

Yeah there isn't much in it, 132Whrs/kg I believe in the case of the 20Ah cells, which isn't too shabby. Ample discharge discharge current for anything this side of an EV dragster, excellent cycle life and safe too. Got lots of the 20Ah cells in stock now and built a few packs recently

neptronix · Oct 6, 2011

As for disc brakes i don't know much about hydraulics. To get the rear disc working on my MAC motor though, i had to use 2mm spacers. HOPE makes some spacers that work well.

an_ebiker · Oct 8, 2011

oatnet said:
mikhogl said:

Ok, sounds like i have to go for the crystalyte ht3525, but its over 7kg. Almost twice the weight of the bmc, the bike is going to be less fun... any other options? Mac? Or should i settle with less power? So hard to deside

Click to expand...

A BMC V2-S will meet your design requirements just fine. It can handle 1500w, it will give you the speed at voltage you are asking for, and it is lightweight. It is a good, durable, commuter motor, and the gears are much stronger now. The 1st gen gears sucked but they are long gone, the 2nd/3rd/4th gen gears are great. Get a V2 with the 4th gen gears because they are the strongest, but there are folks here who have run the 2nd/3rd gen gears for a long time without problem.

You did not ask to build an 8000w wheelie-happy hotrod, which as itselectric points out, the BMC is not a good candidate for. However, if you do want to hotrod the motor up a little, you can increase volts not amps to get more watts (W=V*A). Increasing amps increases heat, which the WINDINGS (not the phase wires) cannot handle as well as a DD (direct drive) motor. In addition, increasing volts decreases back-EMF at a given rpms, so you can get more watts into the motor at higher RPM and achieve higher speeds. I always seek to maximize Volts and minimize Amps.

Here is a build with a BMC V2T that moves 300+lb through very hilly territory, @28mph on 60v nominal:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24329&start=15#p413920

-JD

PS - I'm not sure that the 'V4' exists. The V4 I know of was a Direct-Drive motor, and "Betterbike$" is the only place I see listing them.

I agreed with this post (assume this is Justin who I work with). BMC V2 is a great motor. V4 is V2 but with better design, 10% more efficiency, and 3 windings.
BMC has no incentive to make V2 anymore now it has V4, but it is built on the successful V2 technology. Once V2 is gone it is gone, although some may
just call it the new V2, V4 is an appropriate name for it as it has several improvements.

neptronix · Oct 8, 2011

The V4 uses the same side covers and motor case.. how is it a brand new motor?

Any proof of the 10% more efficiency claim? That's a pretty bold one and no self promoting vendor of the BMC motors has been able to prove it.

Show me that the BMC V4 is a smoking hot awesome motor and i'll replace my MAC with one. Until otherwise ....

Kris B Krunch · Oct 10, 2011

oatnet said:
Here is a build with a BMC V2T that moves 300+lb through very hilly territory, @28mph on 60v nominal:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24329&start=15#p413920

-JD

Hey JD, I was talking to you a while ago about battery stuff. Anyways, I was gonna ask you about the pics in your build thread if you could post them again, really interested in how built a pack with a123 prismatic cells.
I haven't even got my first bike done but I'm already planning my full suspension bike next!!
Thanks

*Edit*
Ooops, disregard that, I just went back and saw that further down the page you reposted the pics. Thanks

oatnet · Oct 10, 2011

neptronix said:
The V4 uses the same side covers and motor case.. how is it a brand new motor?

I think the V4 is vaporware. Has anyone seen/heard anything about a geared BMC "V4" motor from anyone besides BetterBike for-sale post? BetterBike is not my preferred source for BMC info, and at their markups, definitely not my preferred source for product either. I bet they are listing the '2011 V2", with the new gears and double-phase wires, as a 'V4" model, and pretending it is a new motor. Wheras the V1, V2, and V3 have different windings, I'd bet the motor they advertise as 'new' doesn't change the windings.

-JD

BMC V4 motor

100 µW

1 kW

10 kW

100 µW

1 MW

10 kW

Administrator

100 kW

100 kW

100 µW

100 kW

10 W

100 kW

Administrator

100 µW

Administrator

100 kW

100 µW

1 MW

100 kW

Administrator

1 µW

Administrator

100 mW

1 MW

Similar threads