Dual Voltage Rig?

DrkAngel

1 GW
Joined
Dec 15, 2010
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5,300
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Upstate-Western-Southern Tier NY. USA
I have multiple ebikes, various are geared and voltaged differently.
Lately, I'm bored ... again!, the idea of multi-voltaging has perked my interest.

Dual voltage motor.
For example, running 22V 50Ah in town, (425w power - near 20 mph), would give me a very peppy eBike, while a quick battery rewire to 44V 25Ah, (850w power - 30++ mph assist), would give me great assist for high speed on the open road.
Battery "rewire" could be rigged into a single multi-contact switch or through multiple rigged electric contactors.
Would require a 22.2V - 44.4V compatible controller.
(I've started "componentising" my battery builds in 11.1V modules = 12.3V full charge)

(I am developing this as a method of best multi-tasking my electric motorcycle for city vs highway usage.
40mph at double the amps-acceleration - for in town
vs
80mph capability for highway use.)

More interesting is the idea of dual motors. (Brush motors required ... ?)
Running 44V through 2 motors "in series" would supply 22V to each motor for massive low speed torque.
Switching to "in parallel" would endow each motor with 44V, but with 1/2 the Amps.
Which would double the motor speed with a similar reduction in torque ... effectively giving a 2 gear electrical transmission. (Overdrive! ... ?)
48V SLA controllers match 44.4V Li-ion LVC nicely.

A multi-arm "shifting lever" could quickly switch between modes.
Re-routing power with electrically powered contactors would be very impressive.
 
Interesting idea. Maybe a 3 position switch, with a pre-charge resistor circuit on the middle position, to soften the change to the higher voltage?
 
How do you wire motors in series? I though you could only get the phase wires to be wired in parallel and that would split the amps the controller gave to each motor?
 
Trackman417 said:
How do you wire motors in series? I though you could only get the phase wires to be wired in parallel and that would split the amps the controller gave to each motor?
DC brush motors
44V neg to #1 motor Neg
# 1 motor Pos to #2 motor neg
#2 motor Pos to 44V Pos
Will "effectively" give 22V, evenly, to "matched" motors. (Full Amps!)

Same principle as running leds, light bulbs etc, in series.

Possibly ... you could do the same with brushless motors?
They would have to be solidly linked "in phase" - identically and solidly connected?
 
That's exactly how a power wheels kids toy works. Low is 6volts, shift to high it's 12 volts. The series parallel wiring is done at the switch. There is no controller, just straight pull off the batteries. They really rip with batteries that let the amps out, especially when they are overvolted. Zero to top speed instantly, not bad when top speed is 2.5mph (in low), but up that to 5 and they give the kids a neck snap! :)
It should work fine on the output of a controller with brushed motors, you would need a high amp controller without lvc though.
You could also do the same with your battery 22v 40ah, or 44v 20ah, and have 3 speeds with no controller. 11v, 22v, and 44v.

I think in the end you are best off with a single good brushless setup.
 
DrkAngel, As you know like you I tinker with the Currie motors. I've done the twin motors in series using 48v from a 20ah lifepo4 pack. Honestly, I wasn't all that impressed with the results. You would think that the stronger motor would simply be slowed down to the weeker motor and it was. But I found the stronger motor ran at 15% hotter. I found running a single motor at 48v was actually a better setup. BTW, I was using a 48v 50a controller. I am hoping to do the twin motor setup again but wire them in parallel using the 48v 50a controller. I should have tried this the first time before I dismantaled my setup. OOPs!!

Bob
 
DrkAngel, can you tell me how your Ezip 12T mod went? Did it work? What kind of performance gain, if any? Issues? Sorry to post here.....Thanks.
 
I've also wondered about the idea of a 2-speed setup (start in parallel then "shift" into series.) That is what the "White Zombie" e-dragster uses. It seems like it wouldn't be terribly complicated to put something like that together. However, it would require a pretty beefy controller. Maybe in a few years we will all have controllers with a 2-speed electronic shifter.
 
Dual voltage can be nice. Or dual amperage. I've done both at times, mostly during the experimental process period. Two controllers on the bike, allowing a swap between 48v and 72v by unplugging and plugging 3 plugs. Or similarly, 72v 20 amp to 72v 40 amp swaps. Just takes a miniute to make the swap, such as at the bottom of a monster hill.

I also popped back and forth between 48v and 36v on long tours. At the time I had one 48v ping and one 36v ping. I'd ride the 48v ping up the big mountain, then cruise flatlands on just 36v.

It can be very nice to have various power, and or speed levels for various needs. The aim being mostly to ony use the minimum, saving the big power for when it's actually needed.

Why not just back off the throttle? Indeed why not, it's how I ride more of the time now. But at times, in places, a lower powered full throttle can make using less power easier. That is because a high power 3000w bike is hard to ride at 200w level because the throttle wants to go straight to 400w. While a 400w bike is easy to ride at 200w.
 
elpq35 said:
DrkAngel, can you tell me how your Ezip 12T mod went? Did it work? What kind of performance gain, if any? Issues? Sorry to post here.....Thanks.
Good news - bad news.
The 12T mod, combined with 16T mod, works nicely ... as far as I could take it.
30mph was attainable.

Unfortunately, my old decrepit body is a bit past it's prime. It was not able to maintain it's portion of the "assist" for any prolonged period, 30mph with only 485w motor, (25.9V), assist overtaxed my left side. "Hot" weather might improve circulation, allowing "sustainable" high speed. A tucked racing position might also be enough but my bad wrists-elbow are limiting, perhaps modded aero bars would help me.

Come Spring, My Haro Express Deluxe, with 16T mod and 44.4V, (48-11T human & 832.5w electric), will be making it's debut as my 30mph "sustainable" project.
 
Hummm?

A little searching on this forum will find you a schematic of how to switch 2 batteries from series from series to parallel with a relay.

Then look for a schematic showing you how to change the low voltage cut off in the controller by changing a resistor. I would wire that with a relay too, then you could change both with the same switch.

I found both of those mod's here on Endless-Sphere when thinking of doing that for a Mobility Bike (that thread is down the list a bit). I finally decided that it would not do me much good with the local cops, so more or less gave up on the idea. However, it is definitely doable from the technical viewpoint.
 
I have tried this. 24s 3p that was switchable to 12s 6p, and Lyen had set for me a 24 fet controller that was switchable to those 2 voltage setups. I have found after all that I was using 24s all the time anyway, and a 3 speed switch is more than enough for me if needed at all.

So it is perfectly doable, but not practical unless you are willing to sacrifice a lot of the performance to gain some efficiency. Now I use a modular battery system, making it quick and easy to carry 1, 2 or 3p according to the range that I need. This is making the weight and performance of the bike optimal for the ride.
 
Just ordered up a 20-72V Brush Controller - $31.49 shipped!
20-72V 30A 1200w rated.

$(KGrHqF,!k0E-ir-MST5BP6KL3ot!w~~60_1.JPG


Looks like it will shoehorn into the eZip rack, as an oem replacement.

Limitations ...
25A continuous
limited to 600w @ 24V ... ?
no brake disconnect
no connectors
shipped from China ... couple weeks?

Considering the price ... no problem ... for me!
Nice project item!
Can't go too far wrong ... ?

My previous "project item", price reduced!
Waterproof!, heatsinked!, indestructible?
24-60V 500-1000W Motor Brush Controller for Electric Bike Bicycle & Scooter - $45.50
$T2eC16V,!)sE9swmZv57BQPFIMwT8!~~60_1.JPG


Oh! ... Going the other way.
I had to get a 12V 30A controller - $13.58 to play with!

$(KGrHqZ,!hoE83w0d-5OBPc)CJ22Hg~~60_1.JPG


I have a quantity of 12V cordless drills waiting for some application.

Self-powered wagons? Twist throttle on handle. Helps pull up hills. Sit in wagon and cruise.

Low speed friction drive for bicycle?
 
DrkAngel said:
Just ordered up a 20-72V Brush Controller - $31.49 shipped!
20-72V 30A 1200w rated.

$(KGrHqF,!k0E-ir-MST5BP6KL3ot!w~~60_1.JPG
Received controller.
Is labeled as "12V-36V".
Complained to sender, and received promise of an immediate replacement - no return - no charge!

While , them sending me the wrong item, is a minus, a no hassle free replacement encourages me towards their being "reputable" with the hope of their products being of reasonable quality.

Of course I can find a use for the free 12-36V controller.
Possibly mislabeled ... I might pull apart and check the rating on the "caps".

Oh! 9 days to ship from China.

Update! - Compatibility of various multi-voltage controllers - verified cap voltage!
DY-1 has 50V caps 12-36V, possibly 44.4V@4.1V per bank = 49.2V ... not 72V capable!
DY-2 has 50V caps 12-36V, possibly 44.4V@4.1V per bank = 49.2V ... not 72V capable!
CK-1 has 80V caps 20-72V ... 72V capable!
 
Re-rigged a Forward reverse switch as a 24V to 48V shifter.
2 - 24V packs, "shifted" from parallel to serial .
Switch does disengage all power in "neutral" center position.

* Important to remove bus bar on left side between #2 and #5 for Serial Parallel
24-48V.JPG

Available at - EBike Toolbox - Bargains! $
 
this is the same type of setup i am going to tun on mine, i am going to use 6x6 cell batterys but doubled up to give me 60v for cruising around and long range, and then i can switch to 24s or even more for speed runs :D i was just going to use a 240v breaker switch to flick it from one to the other.
adam
 
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