Magic Pie II Dual Drive

[GM Canada]

Its not as big an issue iof both packs are of equal size and age.

I have been using a paralell setup for a while with no problems, I guess I could eliminate the problem you are describing by just turing on one battery at a time. But I don't seem to have any problems. I monitor them individully quite often with the CA and never run low on voltage. My round trip to work is 20 miles and 2 48v12ah packs always have lots of power left when I get home.

Gary

[GM Canada]

EXPERIMENTAL

Use at own risk.




Here is what Ive done so far.

The regulators are switchmode.  Depending of the lil transofrmer their maybe isolation happening.

I cant be sure unless someone tests this.  


Once we have established isolation between the two packs there is no reason why one can not draw 25 amps  from each pack without it shutting down.

Thats some diagram, where do you find the time?

So Far all I have done is Paralled the brake to the second motor and the black and white wire from the throttle to the other motor. No other wires are going to the second motor yet. The rest is still theory. Hopefully I'll have more time on the weekend. I still want to get the cruise going. I don't have a pedelac or intend to use one.

Gary

[GM Canada]

One thing I would like to add here is that with 2 motors I can now go farther then with one. I cant quite wrap my head around this but when I did my daily commute I would leave home with 54.6 volts and arrive at work with 48-49 volts left. Now with dual pies I arrive with 50-51 volts left. Can anyone attempt to explain this without my head exploding from a details overload?

Gary

[MonkeyMagic]

Hi Gary

I agree with you with the extra range, but that was when I had it set on 48v.

I put it down to on a single wheel, up a decent hill it would struggle quite a bit to move and would have been drawing max current.
With the 2 going there is much less stress/current happening and I would say have more range.

Also I noticed on a flat not having to push the bike as hard, both wheels would be drawing less current compared to a single wheel doing all the work.

Can I ask if you have tried setting the wheels to different voltage settings in the software?

You would have noticed a post or 2 about my difference in speed/power from the voltage change in software setting. This is with the cast wheel. I have left mine set to 24v as the power is a massive difference compared to 48v, but on 48v it seems to 'wind' out alot longer to get a better top speed (maybe 5km/h max)

[Bikemad]

Can anyone attempt to explain this without my head exploding from a details overload?

I'm prepared to have a go, but perhaps you should have someone on standby ready to clear up the mess, just in case I fail.

Here goes, I'll start with the obvious:
If two motors are sharing the same load, each motor is only doing half the work of a single motor doing all the work.

Here comes the interesting bit:
If you look at a performance curve for these motors, you should notice that after a certain point, the efficiency starts to decrease as the load on the motor is increased.
Because both motors are now running with much less load on them, they are able to run at a greater efficiency level, thereby consuming less combined current than a single motor producing the same amount of power output.
So, if the dual motors are using less battery power to maintain the same speed, you should be able to go even further on the same  battery.

Gary, I'm guessing your head is still in one piece!
But if I'm wrong, my deepest condolences go to Gary's family, he was a good man and he will be greatly missed by all of us.



Alan
 

[GM Canada]

Great Explaination Alan and no crazy numbers and graphs to confuse simple minds like myself! So if I add two 20 inch pies to my trailor I will go even further. A quad Pie bike and trailor! That sounds interesting. Then I would have to get into setting the 20 inch wheels and the 26 inch wheels to match torque and speed. Im sure this is where it would get more difficult.

Anyway Im thinking or ditching the trailor I have now and getting a B.O.B. YAK 28 PLUS with the B.O.B. Bag. This looks like a more efficient way to go as it would narrow the trailor making it easier to go around potholes and manhole covers. Plus cut down on wind resistence. They also make one with a shock. But since I have a hardtail bike anyway I don't think this would be nessesary.

Im sure others make trailors like this but I can't seem to find any. Anyone else know of any?

Gary

[MonkeyMagic]

Gary! that Bob model is exactly what I want yay!
I was searching for 1 wheel bike trailer and what not without success

I'll have a look around but I don't think my pocket is as deep as yours... Do you keep these in your inventory? haha

Thanks mate

[GM Canada]

Hi Gary

Can I ask if you have tried setting the wheels to different voltage settings in the software?

You would have noticed a post or 2 about my difference in speed/power from the voltage change in software setting. This is with the cast wheel. I have left mine set to 24v as the power is a massive difference compared to 48v, but on 48v it seems to 'wind' out alot longer to get a better top speed (maybe 5km/h max)

Yes I have used the software. I have both wheels at 24volts. The torque is amazing! At 48volts the torque is way to low. I use a Cycle Analyst to protect the batteries. Even though they have build in protection I prefer setting the CA low voltage setting at 41 volts so the BMS cutout is never reached. Also I had to cut the regen on the front wheel to 50% as I almost wiped out the first time I applied the brakes. Regen on 2 wheels at 100% is way to dangerous.

Gary

[GM Canada]

I made the mistake of going to a local bike shop "just to have a look" at the B.O.B. Yak Trailors.

Gary

[Bikemad]

Looking good Gary, but will a 16" pie fit in it easily? 

I'm not suggesting you should try a tripple pie, I'm just wondering if it could be used as a self powered pushing trailer for a non powered bike.

Alan

[Bikemad]

Gary! that Bob model is exactly what I want yay!
I was searching for 1 wheel bike trailer and what not without success

I'll have a look around but I don't think my pocket is as deep as yours... Do you keep these in your inventory? haha

You'd need a really deep pocket for one of these:

                Total price is £1999 inc VAT!

(I'd expect the bike as well for that price.)

Alan
 

[GM Canada]

Looking good Gary, but will a 16" pie fit in it easily? 

I'm not suggesting you should try a tripple pie, I'm just wondering if it could be used as a self powered pushing trailer for a non powered bike.

Alan

Thanks Alan. I love the looks of the entire package. Last night I was having a few "pops" and sat there just looking at it. It's almost as interesting as watching a campfire.

I thought about motorizing the trailer, but really its not necessary as I have allot of power now. Using it as a push trailer may not be a good idea as either as the trailer frame is only rated at 70lbs. Using it to push 4 times that weight might crush the frame like an accordion!

Now I guess the next step is to remount the second battery on the front of my bike again as adding batteries to this trailor doesnt seem as easy. Also I miss the battery on the front as I was quite used to the weight.It gave it a "more like a motorcycle feeling".

Gary

[GM Canada]

Gary! that Bob model is exactly what I want yay!
I was searching for 1 wheel bike trailer and what not without success

I'll have a look around but I don't think my pocket is as deep as yours... Do you keep these in your inventory? haha

You'd need a really deep pocket for one of these:

                Total price is £1999 inc VAT!

(I'd expect the bike as well for that price.)

Alan
 

Wow thats some beer cooler, I could go camping for a week with that!

Gary

[Bikemad]

Using it as a push trailer may not be a good idea as either as the trailer frame is only rated at 70lbs. Using it to push 4 times that weight might crush the frame like an accordion!

That trailer frame can easily take all the force a pie could ever exert and a lot more besides. You'd have the rear tyre burning some serious rubber well before that frame would start to suffer!

Alan
 

[GM Canada]

See, now you have me thinking. I do have several ebikes and keep them all going for when I have freinds iver and we go for a group ebike ride. A push trailor with a battery would be handy for a friend that shows up with a bike and no motor.

Gary