John Phoenix

I have seen some kits with dual motors (front and rear). I reason that you cannot go twice as fast with two motors only the max speed each would give you and you would have to pull twice as much battery power. So, what is the advantage of having this setup?

Sangesf

Two motors = less amp pull as opposed to one..
They work off each other..
Here is my experience...
50% more range, less wear on the motors, etc...
I have 2 36v 20ah batts..
Each one gives me approx 28miles..
So that's 56 miles on 40 Ah of batteries on ONE motor...
When I hook them up to my two motors, I get 80 miles, given the 20mph I get either way...
If I go a bit slower (16mph) I get a max of 114 miles. (tested) on both motors.
That's 50-100% more traveling distance by using 2 motors.
(the cost of the second motor set and battery was my only original concern, besides the added weight.)

With two motors, getting up to speed uses less total amps as well as the added effect of momentum with the extra weight helps on continued riding.

I use LiFePo4's so the weight of those two probably weighs about the same as a 36v 20ah SLA setup.
With SLAs you prolly wouldn't get as good mileage.

That's my .02

P.S. If I removed the speed limiter on the bike I would get a few extra mph. Top speed on one motor is 23 and on two motors it's 25. (remember that wind resistance is a killer as you go faster.

edcastrovalley

[QUOTE=Sangesf;11782489]Two motors = less amp pull as opposed to one..
They work off each other..
Here is my experience...
50% more range, less wear on the motors, etc...
I have 2 36v 20ah batts..
Each one gives me approx 28miles..
So that's 56 miles on 40 Ah of batteries on ONE motor...
When I hook them up to my two motors, I get 80 miles, given the 20mph I get either way...
If I go a bit slower (16mph) I get a max of 114 miles. (tested) on both motors.
That's 50-100% more traveling distance by using 2 motors.
(the cost of the second motor set and battery was my only original concern, besides the added weight.)

With two motors, getting up to speed uses less total amps as well as the added effect of momentum with the extra weight helps on continued riding.

What kind of throttle(s) do you use. Can you use 1 throttle on two controllers?
I bet you can get vertical on the hills with your all-wheel-drive bike!

Sangesf

You can use one OR two throttles..
Don't know why you would only use one throttle. You CAN, but I like to use my cruise control(s) separately on both motors, so I personally use two.
If you use one throttle, both motors run at the exact same speed and power. I like to tailor my speed and power on the motors independently.

Sangesf

I live in south Florida and there are no hills whatsoever.
Range is my main concern...
I will ultimately change one of the 20AH batteries to a 40AH one, because I would love to get over a 150 mile range.
I run low wattage motors (250w), because I don't need power or speed. The lower wattage motors give me extended ranges, hence the current 114 mile max range.
With the total 60ah of the batteries, I should be able to hit 150 miles doing 20mph.

alfonsopilato

Impressive numbers!
Also, since you're using two throttles you're using two controllers. You've basically set up your motors as two individual systems. Very interesting and thank you for the insight as to how that would work out.
Cheers!

FunkyStickman

[TimTaylor]

More POWERRR!!!! Arg arg!

[/TimTaylor]

As long as you have the space and money for batteries, go for it.

Sangesf

99% of the time, you would need two controllers, because the motors use hall sensors and need to be setup separately, otherwise the controller would have no clue how to move the motors correctly.

Sangesf

The best part about two motors is in the fact that if one fails for whatever reason, you have a second one to rely on.
Perfect example of this is my recent experience. The front motor on my bike crapped out (failed hall sensors) when I was 32 miles away from home.. If I didn't have the second motor, I would have had to either have to call someone to pick me (and my 120lb bike) up or walk!
I'm currently having my front motor replaced, and as soon and I have the money to purchase the higher AH'd lithium batteries, I'm either going to go replace one of the batts (with a 40ah) or both batts with a 100ah one and either run the controller's power in parallel OR change the batt to a 48v 100ah and run the controller's power in series.
I'll have to ask around and see if anyone knows which is more effecient, 36v in parallel (36v on both motors) or 48v in series (two motors at 24v each)

dumbass 

OK, I have tried the twin throttle setup on my twin motors but found them very clumsey on the handly bar. And trying to mechanically link them together was a supper PITA and really made for a crapy look. Can you post some pics of your twin throttle setups?

Bob

Sangesf

They arent linked up together, there's one on either side o the handlebars..
One is a twist throttle, the other is a thumb throttle.
I don't understand the problem with two of them.

dumbass 

In my case I was using 2 half twist throttles mechanically linked on the same side of the handlebar. did this because I did not want a throttle on the same side with my Nuvinci shifter. I looked at it but felt it would be to much to deal with that way. Beside, I felt by linking them together it would ensure both motors were doing the same thing as closely as possible.
.

Sangesf

Problem is that there is a weight diffferencial on the motors, so they are definitely not using the same amount of power, unless of course, you have the Miata of the bike world with 50/50 weight distribution.
I have a single speed so I don't have a shifter, which obviously gives me more room on the handlebars.
I see where you would have a problem...
Here's the thing to do..
Use only ONE throttle and split each of the wires off of that throttle and connect each set of wires to the separate controllers.
It WILL work with no problems whatsoever.
The reason I personally can't do that is because I have a cruise control for each motor which sets the throttle voltage in one position, which means I can't set the cruise separately.

dumbass 

Without question we have different setups giving each of us a different challange. My setup is 100% balanced because both motors drive the Nuvinci. Therefore, a single controller would work great. In fact I actually did try it but no luck. I have been told by several people that it can be done and some had actually done it. But what happens when I try it with my controllers is which ever controller I turn on first causes feed back to the other. Bottom line I can only run one motor at a time. The only thing I came up with to correct this problem is to install diodes to prevent the feedback. But diodes will drop my top hall voltage therefore my top speed.

I am still considering just going to a single 48v controller instead of 2 24v controllers. But that would cancel some of the values of having twin motors. It's a winter project now. Find a way to use twin controllers and quite the motors 50%.

Sangesf

Just use one throttle on both controllers.. I don't see a problem

dumbass 

LOL, I explained the problem in great detail....IT WILL NOT WORK WITH MY CONTROLLERS

Sangesf

Actually, you didn't tell me why ONE throttle wouldn't work, you just said hooking up TWO mechanically was a problem.

dumbass 

Please re-read the part I re-printed in red. When using 1 throttle with 2 controllers there is a voltage feedback from one controller to the other. The controller detects this as a short and shuts down to protect it's self. This is why the first controller turned on will run but the second controller turned on will not. It's a built in protection. I have tried using the 5v from only one controller but that will not work ether. Of course that would defeat what I am trying to do even if it did. I have considered 2 solutions; 1) use a separate small set of batteries to create the 5v supply for the hall control voltage or 2) install a diode on each of the controllers 5v hall supply to prevent the backfeed. the problem is a diode looses about .5v or in this case 10% or more of the control voltage. This would significantly effect my top speed for both motors. Of course it maybe worth it because of the gain of running two motors when needed/wanted.

As I have said some people I have spoken to insist they have used 1 throttl with 2 controllers. I can only assume their controllers did not have the built in protect that is reading the voltage feedback.

****************************************************************************************
Without question we have different setups giving each of us a different challange. My setup is 100% balanced because both motors drive the Nuvinci. Therefore, a single controller would work great. In fact I actually did try it but no luck. I have been told by several people that it can be done and some had actually done it. But what happens when I try it with my controllers is which ever controller I turn on first causes feed back to the other. Bottom line I can only run one motor at a time. The only thing I came up with to correct this problem is to install diodes to prevent the feedback. But diodes will drop my top hall voltage therefore my top speed.

I am still considering just going to a single 48v controller instead of 2 24v controllers. But that would cancel some of the values of having twin motors. It's a winter project now. Find a way to use twin controllers and quite the motors 50%.