The 'Dual' in the Crown. My Pocket Rocket Dual Mini Bike... <<KAAAH.....BOOM!!>>

[Andrew]

 

 

It's been blood sweat and tears!...  and a lot of swearing, but it's finally finished


Specs:
Photos show my fully loaded dual GM 250Watt Mini Motor Bike.
54volt 20Ah Lithium ion Battery pack
x2 GM Magic controllers. Currently set to 10 amp continuous, 20 amp peak.
26" mountain Bike Build with Avid BB7 disc caliper brakes, Schwalbe Big Apple Tyres 26x2.35

What can I say?
The bike is really light and nimble compared to my Magic Pie bike. The frame bag contains the two controllers, all the wires and the battery pack. Positioning of the pack is a dream come true keeping weight distribution very balanced and centre of gravity low.

I started today with a test drive with the controller set to 36 volts, Current 6A cont., 9A peak......  This was rubbish, i'd rather burn out the motors than use the bike at those settings, there was no power at all. At this setting it just made pedalling a little easier, it would be just as easy to carry the bike on my shoulder and walk
The magic controllers are set to 10amp cont and 30amp peak as default on the mini motor kit, so I'm hoping that 10cont and 20peak will be ok.

The setting at present is 10A / 20A peak , 48 volt.   This was more like what I was hoping for. The hill climbing is comparable to when I ran one Magic Pie although you don't feel the torque/pull as you do on a pie. These motors 'just' made it up the long steep hill near my home, the hill is in two halves, with a small dip to regain momentum half way up. The motors made it to the top but I assisted very briefly without any muscle effort.

The motors are very quiet and discrete and just what I need for city centre riding as well as long distance cruising in the sunshine It's actually nice to have an e-bike which isn't all aggressive and all or nothing like my Dual Magic Pie.

I have no speed or meter readings yet,  but they will be posted here very soon.

Sorry for the over exposed washed out photos from my phone....






















Hopefully more feed back soon, including my better half's small light weight build.

Andrew

[GM Canada]

Looks Great Andrew!

Very stealthy! I like the way the motors blend in with the disk brakes it looks really good. Very few people will ever notice its electric unless you are not peddling at all

Gary

[Sangesf]

That is F-in awesome looking stealth.
Awesome job!

[DirtyGinge]

Hey Dude, she is looking nice and tidy.....sweet indeed.....have you got the screwdrivers back out of the wall where you threw them ??

How's the performance on one wheel ( I mean you did Sarah's bike first right )

[Andrew]

hey Dude, she is looking nice and tidy.....sweet indeed.....have you got the screwdrivers back out of the wall where you threw them ??

Hows the performance on one wheel ( I mean you did sarah's bike first right )

Believe it or not I started on Sarah's bike to keep her sweet, but one thing led to another and my bike build took over as we awaited a frame bag for her bike

I've just now this second test ridden her bike with one front mini motor and the 54v/10ah battery you made me.  Her bike is set the same as mine on 48v and 10A cont, 20 peak.   The bike 'assists' you when pedalling but really lacks luster on its own, but that's all she wanted.  
I will try and do a couple of uphill runs with the watt meter on, and also tie on my sat nav to get some accurate speeds and get some stats up for both bikes.

As for screwdrivers etc, I took over the spare bedroom for about 5 days and poor old Sarah has got up every morning to find more soldering in front of the TV in the front room.  

[DirtyGinge]

Indeed our other halves are patient lol

I'd be careful doing non assisted hill tests on one motor......the chances of stripping it get higher with just one motor and 500W input.......anyone else got experience of the overcurrenting of the mini motor ?

To be honest that will be what I use it for , assistance as opposed to power......I must admit I was really tired of the weight of the 2 pies.........one seems to be a nice mid point, specially with the power brought up

[MonkeyMagic]

haha I think my bike is the likely reason why I don't have a mrs at the moment

Hey Andrew is that your 'donor' bike you got for free?? cool bananas

**Ginge LOL you keep posting seconds before I do haha nice work

[DirtyGinge]

yup, its a bike posting frenzy lol......

so who else is planning their second / third / fourth electric bike ?

[MonkeyMagic]

I don't care what people build as long as they use one of these bad boys




lol

[Andrew]

Hey Andrew is that your 'donor' bike you got for free?? cool bananas

Not completely free, the frame was bought brand new for £50.00 on eBay.  Bottom bracket, headset, brakes were the main other outlays.  Handlebars, forks, crank, seat donated. Some parts I had lying around.


Anyway here are some stats....

just tested my bike

54v at 10 amp cont, 20 amp peak

928 watt peak  
19.04 amp peak

that's all I can pick up at present from the turnigy watt meter.

On the source side it also reads 44.6 watt hours and 0.912 Ah, not sure about this are these measurable with distance/time?  or do I need the 'load' side figures?

I will not be doing any non assisted hill starts or even flat starts if I can help it

[Bikemad]

54v at 10 amp cont, 20 amp peak

928 watt peak  
19.04 amp peak

that's all I can pick up at present from the Turnigy watt meter.

On the source side it also reads 44.6 watt hours and 0.912 Ah, not sure about this are these measurable with distance/time?  or do I need the 'load' side figures?

Andrew, the "Source" and "Load" on the watt meter are used to indicate which way the measured current flows (Source= Battery, Load =Motor).

If it was wired in the opposite direction, you would only measure current going into the battery from the motors (Regen current, which should be zero in your case).

Presumably the 19.04 Amps peak is for both motors, but as you have different voltage motors, one is probably drawing more current than the other.

I don't care what people build as long as they use one of these bad boys

That would be far too restrictive, you should insist they use at least one, but more would be much better!

Alan
 

[MonkeyMagic]

I totally concur lol

[GM Canada]

indeed our other halves are patient lol

Mine's not, it only takes a day and I get "take the f'n thing out of the living room! And clean up all those bottles!"

I must admit I was really tired of the weight of the 2 pies.........one seems to be a nice mid point, specially with the power brought up

Ahhh but when you run dual pies and no battery weight, the center of gravity is low and it's really a different ride! I'm lovin it!

Gary

[Andrew]

I maybe living on borrowed time with the amps, perhaps I should turn down the peak amp?

 I have a 42 tooth chain wheel up front and a shimano freewheel 28 -14 tooth cog and I surprisingly run out of gears which tells me I must be doing 20mph.  I have yet to GPS the bike for speed.

The bike is too fast at present as I do stil want to be able to pedal with a little effort.  


Anyways, heres's some more piccys...


Sarah's bike..


Todays "His and Hers"  bikes and an off road test ride....








We got back home after about 90 minutes of riding and went straight to the shops to buy Gel cushioning seat covers

[DirtyGinge]

A couple of points chaps.....

a...Andrew...are you sucking in the tummy in those photo's

b...Sorry Gary, didn't mean to be sales prevention......dual pies were great, but at my work I had to go up about 6 steps.....went like this...grab bike, lift bars, hit thtottle by accident, graze shin etc etc....

I must admit the dual pies give a lot more balance to the bike...I really do have to consider weight distribution when accelerating up hills etc....

c...I thought about one of those big motors on a Sinclair C5......then I sobered up....but hey....that's the bug