low budget pocket rocket

[nonlineartom]

I picked up an 8T mac in a 20" wheel dirt cheap off a forum member, so I had to think of something good to do with it.

So I picked up a beat up BMX for £10, I've never ridden a BMX before so decided to use it as a regular pedal bike for a week or 2 running errands and I'm really pleasantly surprised, it accelerates like a bullet and with such low rolling resistance even with one gear It's way way more fun than my XC MTB bike.

I also picked up a 1500W Hua Tong controller for £15 off a forum member bringing the total cost minus batteries to under £70. I plan to run on 18S of lipo and run this motor into the ground.

View attachment 1

I opened up the motor and all looks good inside, hardend gears and lots of grease, perhaps I will drill the casing for ventilation (stupid idea right?)



Phase wires are now 10AWG using these block connectors for testing purposes

I spent a whole evening wiring up connectors to the motor and controller (I REALLY suck at soldering but I'm persistent) and decided to film my first attempt at getting the gears turning, I could have deleted the clip but I thought it was worth sharing my magnificent fail

You can almost hear the cogs turning in my brain as it dawns on me the epic fail I just achieved. :/

[youtube]A-Zo0LbY9hE[/youtube]

 

[Farfle]

DOH!! :lol: :lol: :lol:

 

[nonlineartom]

DOH indeed, or as we say in England ... "hmmm" apparently

So, at the risk of sounding like the perpetual n00b. Whats the easiest way to get this going the correct direction?

 

[www.recumbents.com]

Try flipping around two of the phase wires.

 

[gwhy!1]

play around with phase and hall wire combo's. I found with the hub motors that i have played around with even if the motor turns the correct way this do not always mean that the correct combo has been found, I always use a current meter and a tacho, sometimes the wheel will run faster than expected and draw nearly 2 times the current ( not good for your controller or the motor )

 

[liveforphysics]

play around with phase and hall wire combo's. I found with the hub motors that i have played around with even if the motor turns the correct way this do not always mean that the correct combo has been found, I always use a current meter and a tacho, sometimes the wheel will run faster than expected and draw nearly 2 times the current ( not good for your controller or the motor )

Yup. That's what we call a "false positive". There are 2 false postives for each 1 correct combo.

On sensorless, you can simply swap any 2 phase leads and it reverses direction. With sensored, you need to swap both a pair of halls and a pair of phase leads. Knowing which ones requires an O-scope and some skills. However, you can simply trial-and-error your way to finding the correct combo.

 

[Beachcruzer]

Bike is gonna be badass though. 70 quid well spent.

Looking forward to video of your triumphant return.

 

[nonlineartom]

Thanks for all the replies. I presumed the colour coding was standard as I use an almost identical Cell_man 12fet with the mac on my commuter so figured the colour coding would be just the same.

I wish the pins on the hall connector weren't so monumentally fiddly to remove and swap around. Nothing is ever easy.

Video update this weekend

 

[Philistine]

Can't wait to see it going. I was in the process of putting a 20inch 2805 on a 20inch Haro 1980s BMX I picked up, which I wanted to run on 20S. In the end I had a friend who had a more practical use for the motor, and the project never materialised. I can't say I wasn't a little bit worried about how I might die on it, I imagine it will be a lot of fun though.

When you ran the cell_man controller was the colour combo Blue matching on phase and halls, and yellow and green swapped on phase and halls? If not give that combo a try. That is the combo that works on my Lyen infeneon and a BMC (I would have thought the BMC and Mac would be same colour combos.

 

[nonlineartom]

This is brilliant, so far 3 different people have suggested 3 entirely different colour combinations for the phase wires!

I'm going to try David Silva (neptronix) solution first as posted on the ES FB group which is to swap blue and yellow. His logic being cell_mans infienon controller which looks like the lyen, has yellow and blue shrink wrap covering the yellow and blue phase wires to make them appear the opposite colours. Logic would suggest that swapping these 2 phase wires over on the Lyen will make it behave, which of course means swapping the hall wires too, which will involve a lot of swearing trying to release the tiny barbs on the connector pins to free them.

On a side note, will I need a torque arm with this? The axle is a VERY tight fit in the deep horizontal slot, it's flat aluminium plate and quite thick. It looks stronger and thicker than the universal torque arm I was going to add?

Ride video this weekend

 

[nonlineartom]

Neptronix wins!!!! blue and yellow phase wires needed reversing and now it spins in the right direction.

So all sorted yeah?

PAH like hell it is... video on the way.

At least I'm providing some comedy with this thread

 

[nonlineartom]

[youtube]tEoZc6L58Z4[/youtube]


It's mocking me now. The only thing I can think of is that the one way clutch bearing is back to front, even though this is a new motor and I haven't taken the clutch out at any point.

Anyone got any wisdom to share?

 

[nonlineartom]

Just dawned on me..... Is the wire supposed to exit on the drive side? this is the non disc version of the mac motor. Have I put the freewheel on the wrong dam side of the motor and put the whole thing back to front?

 

[Philistine]

On my BMC the wires come out the disc side (ie NOT the chain side). How did you get the free wheel on the disc side?

 

[nonlineartom]

SO the phase wires were right first time, and I've put the freewheel on the wrong side, sometimes my stupidity amazes even me. The disc side is threaded, with the same thread as a freewheel I'm guessing!

kinda wish I had a freewheel removal tool now...

 

[Philistine]

If you don't have the proper ebike freewheel removal tool (with the larger opening), you can just get a standard bike shop removal tool, and use a dremel with a carbide bit to widen the opening, that is what I did, took 5 minutes to do.

 

[veloman]

I got a kick out of these videos. I think I did something similar before.

Yup, time to flip the wheel around... and go back to original wiring.

 

[nonlineartom]

Done, getting a big of rub on the frame, need to put a washer in there to stop it grinding, but I can only stretch the dropouts using a scissor jack, removing the jack makes it return to it's original width (aluminium) and I don't want to over stretch and break the frame. I can't seem to widen the frame enough to fit it in with the washer and get the wheel in at the same time.

On the upside it looks absolutely bad ass.

 

[knoxie]

You will need a torque arm if that frame is ally, trust me My BMX still works 6 years now since I did this video, it was breaking spanners and shredding metal, if you dont it will snap your drops if they are ally, the one way bearings can go but they can be replaced but yes and ahem you had this the wrong way around but yes fit torque arms, you can see what it does on my video, crikey this is an old one!!

[googlevid]1721490376015071704[/googlevid]

 

[nonlineartom]

Yeah they are ally dropouts, really quite thick beefy bits of metal though (side loading axle) and a very tight fit but I'll fit a Lyen universal torque arm for now and then mig weld one of Docs torque arms in the future, I've already had the freewheel go in my 10T mac motor on my commuter.

All I'm missing now is a 14mm axle nut and I'll give it a test, should probably fit some functioning brakes too. What did you do for battery on yours?

 

[nonlineartom]

This thing is terrifying. Noisy as well, sounds like a formula one car in a box. Goes like a rocket. Taped everything up for a test ride today and it launches better than my X5 motor.

Next up I will put this motor on the trike and test it at 4kw. Has anyone ever drilled ventilation holes in a mac motor? or is that just stupid

 

[nonlineartom]

[youtube]_fQ35z2TcG8[/youtube]

note the complete lack of brakes at the end resulting in the good ole foot brake method. I need to make this thing a lot more refined before actually riding it properly.

 

[nonlineartom]

Mike has found a name for this machine. Its now called:

I.N.N.U....

I need new underpants