Cross-Canada by Ebike

[EVnow!]

Justin you're a dynamo and an inspiration!

I was out of the loop and had no idea you were fielding my tech questions from the road, to wit:
******************************
Aug 11, 2008 at 12:37 AM, John wrote:
> I measure 0 to 3.65V swing as I depress the throttle and the wheel spins.

You should not be seeing 0V when the throttle is off, so there is
something suspect about either the measurement or the throttle.
Justin
******************************
Sure enough, eliminating the throttle (replaced with a temporary jumper with momentary switch between "5V" and the "throttle" signal lines) revealed the source of the maddening intermittent cut-out to be the throttle. I've ordered a new one.
Thanks for all you do on all fronts!
John
ps. Your photo shows 9Ah LiFePO4, 24Ah LiPoly, and 8Ah NiCad;
the bi-line says: 37V 26Ah lithium + 36V 8Ah NiCad.
?? Fuzzy math?
Do you run each pack till it's done then switch to the another, mix chemistries in parallel, or switch to a series boost to 73V at times?

[justin_le]

Hi John, glad to hear your problem's been solved (or at least identified).

ps. Your photo shows 9Ah LiFePO4, 24Ah LiPoly, and 8Ah NiCad;
the bi-line says: 37V 26Ah lithium + 36V 8Ah NiCad.
?? Fuzzy math?

Good eye. Those are what the nominal cell ratings are. But the 24Ah of LiPoly is only delivering about 19Ah in account of minor balancing and BMS issues, so the real world capacity of all 4 packs generally works out to about 36 Ah. I should have said 37V 28Ah of lithium, not 26Ah, that's a typo.

Do you run each pack till it's done then switch to the another, mix chemistries in parallel, or switch to a series boost to 73V at times?

I both discharge and (surprisingly) charge them all in parallel. This only gets the NiCad to about 85% charged. If I really want to get to 100% charge on the NiCad I'll separate it from the lithiums and charge it with the NiMH charger for a proper dT/dt based cutout. If you have multiple packs, it always makes sense to drain them simultaneously rather than in sequence, and right now with the 4 batteries there is almost negligeable voltage sag from loading. If the pack is at say 39V unloaded, I can draw 25 amps and it might drop down to 38.5V or so, then I can do -15 amps of regen and it might go up to 39.3V. It's really nice having this stiff of a power source.

Justin

Justin

[docnjoj]

Hey Justin! How do U run all those different Ah batts in parallel? U must use Shottkys, but dont u get say when the small packs are fully drained?
otherDoc

[hejo]

Are there any news about the new tiny controller?
How does it perform?
Chances to launch it ?
Price?
I want two of them asap
Greetings and good luck, Justin

[hejo]

My Dream-Team :

The new controller, the CA (either with bluetooth functionality of USB cable)
The Iphone as bike computer, display, programming / setting interface.... and of course GPS navigator, movie / music player.....

http://www.youtube.com/watch?v=rcdEFE9a1vY

[billvon]

Hey Justin! How do U run all those different Ah batts in parallel?

Not to answer for Justin, but on my bike I just run the 7ah Ni-MH and the 10ah lipo's in parallel. They share power pretty effectively; no diodes required. I can even charge them that way.

[EDWIN]

HELLO JUSTIN
If you need a place to recharge and sleep.I have spare room you can use. I am in central Winnipeg so it should not take you to far of your route.
edwin

[The7]

A group of seniors with average age of 64 are doing their cross-Canada by bicycles in nearly three months since 2008 May 26.

Justin, you may have to wait for another thirty plus years to beat them.

[The7]

Hey Justin! How do U run all those different Ah batts in parallel? U must use Shottkys, but dont u get say when the small packs are fully drained?
otherDoc

Don't think that the re-gen will function if there is a diode in series with the battery because the diode will block the charging current.

Maybe Justin have his geniuos way of doing so!?

[MitchJi]

A big part of this trip is to field test a number of components in a seriously demanding manner, and the regen motor controller is chief among them. This unit is quite a few years in the making, I think I'm at PCB revision number 12 or 13 now.

There are a few things this controller does which have been IMO long overdue in the ebike scene:
1) Programmable limits : All of the controller parameters such as maximum battery current, maximum motor current, low voltage cutoff, max regen voltage etc. can be set to whatever value you like within the limits of the controller. With this 6 mosfet version, the battery current limit can be set from 0 - 30 amps, the motor current limit can be set from 0 - 45 amps.
2) Completely Waterproof: The entire controller is potted in epoxy so there is simply no possibility even of water damage. It can be run entirely submersed, in fact the controller would like that for the great heatsinking.
3) Small Size: This thing is about 1/10th the size of the Crystalyte 35A motor controllers so it can actually mount discretely on the bicycle.
4) Proportional Regen: When the regen switch is activated, then the throttle controls the intensity of the regen braking. The regenerative braking is motor current (hence torque) regulated, and you can set the maximum regen motor current in software.
5) Pulse by Pulse Current Limiting: You can short the output motor leads and run the controller full throttle and not blow a mosfet. Nice feature to have when the axle spins out and severs all the motor leads.
6) Current Throttle: The throttle input directly controls the battery current and hence the vehicle power. If you have the battery current limit programmed to say 20A, and ride half throttle, the controller will deliver 10A of power regardless of your speed.
7) Sensored and Sensorless: If there is a hall cable connected it will run as a sensored motor controller, if there are no hall signals present it operates sensorlessly. If the hall senor was initially connected, and then fails in the middle of your ride, the controller will detect this and switch over to sensorless mode without loosing a beat. I don't really need to say much more for people to know what this means for reliability!
8.) Overtemperature Protection: Rather than shutting down when the controller gets hot and leave you stranded on a hill, the controller automatically scales back the motor current limit value as the heatsink warms up, so it will protect itself from getting too hot while at the same time never cutting out completely.

There are a few more things too, but I think that sums up the important ones.

Hi Justin,

I hope you are enjoying your trip! Please drive safely!

No hurry on responding to the following, please wait until its convenient to reply.

It would be nice (IMO) if there were (like the Heinzmann) Overtemperature protection for the motor as well as the controller. Users could mount a temperature sensor on the motor and there could be a plug for it on the controller plus the ability to adjust the settings.

Cruise control would be nice also.

Can you give us a ball park estimate of when it might be available?

Two more controller related questions (if someone other than Justin knows the answers and wants to reply please do so):
Does Sensorless (#7) mean this would work with RC motors?

I don't understand the implications of Current Throttle (#6). If someone would explain this I would appreciate it.

Once again have a great time (if you decide to return via the S. F. Bay Area please let us know).

[justin_le]

I would like to know all the bike and non-bike related supplys that you have taken with you for the trip.
bike tools, spare tubes,parts, bike lock? etc

I've got all the standard fair of bike repair parts, plus a lot of ebike specific stuff like a multimeter, soldering iron, spare connectors and wiring etc. Non bike stuff is just a sleeping bag, a Hennessey Hammock, and a few changes of clothes.

Have you had any flats? Do you think your original tires will last?

I had one unexpected flat early on, there was nothing that punctured the tire but the tube got a hole on the inside that is against the rim, which was due presumably to improperly set rim tape which allowed the sharp edge of a nipple hole to be exposed. Since then the mechanic at the Power-In-Motion store in Calgary kindly re-outfit the wheels with Schwalbe Marathon Plus tires and these puncture resistance inner tubes that are like 1/8" thick, so right now the tires are nearly bullet-proof.

How are you getting back to Vancouver with the bike? Be careful of cannibalism if you take Greyhound back.
What are your plans if your bike irrepairably breaks down in the middle of nowhere?

The tentative plan at the moment is to take the train back to Vancouver, gives me a few days of rest to reflect on everything. The bike will be taken apart in Halifax and I'll only be bringing the essentials back with me, like the batteries, hub motor, and Xtracycle parts.

As far as irreparable breakdowns, that'd be part of the adventure! I can't imagine many things that would stop me for more than a day or two. Bicycles aren't that complicated. -Justin

[justin_le]

Are there any news about the new tiny controller?
How does it perform?

I'm quite pleased that so far the little controller has been doing just fine. I still get a bit nervous drawing a continuous 30A on long ascents, but the worst of those are over and right now on the prairies well it's pretty easy going for all systems involved.

Sounds like a great little controller! Have you considered adding phase advance? With phase advance I think you'd have a controller that could do anything.

Phase advance is really easy to do, but it doesn't make any improvement with the low commutation frequency ebike hub motors (unless you consider reducing the efficiency and increasing current draw an improvement). That's more something that comes into play with the 10,000+ rpm RC motors.

It would be nice (IMO) if there were (like the Heinzmann) Overtemperature protection for the motor as well as the controller. Users could mount a temperature sensor on the motor and there could be a plug for it on the controller plus the ability to adjust the settings.

I've thought about that, but it's not so easy to retrofit a temperature sensor inside a hub motor, since the wiring needs to go through the axle and generally there isn't room for anything more beyond the phase and hall leads that already occupy that space. This is especially true with the common practice now of having the cable run through a hollow in the center of the axle, rather than a larger slot on the slide like Crystalyte.

With proper motor current limiting that this controller has, there really shouldn't be any need to have a temperature sensor inside the hub. Both the controller and motor are going to be heated by the same currents, and a temperature rollback on the controller overheating will also limit the motor heating. As the hub motors have considerably more thermal mass than the controllers, you are not likely to ever run into a situation where the motor is overheating and the controller isn't.

The heinzmann only has a bimetalic type of temperature switch, and the controller just cuts out when this is switched.

Two more controller related questions (if someone other than Justin knows the answers and wants to reply please do so):
Does Sensorless (#7) mean this would work with RC motors?

It means that it will work with brushless motors that don't have hall sensors. However, I did not design it for motors with really high commutation frequencies like RC motors. I haven't tested the limits yet, but I'd say an upper limit on the commutation frequency would be about 500Hz for sensorless operation. Take that number, multiply by 60, and divide by the number of poles in your motor to get an RPM value.

I don't understand the implications of Current Throttle (#6). If someone would explain this I would appreciate it.

In a typical ebike controller right now, if you apply the throttle part way from a stop, you'll get the full current limit of the controller flowing from the battery at first, then as you accellerate this current will go down until you hit your partial throttle cruising speed. If you then pedal the bike, the current will go down further, to zero amps, unless you press the throttle further.

With a current throttle, if you applied it part way, the current that flows from the battery pack would be in direct proportion to how far you are pressing the throttle, regardless of your speed, until you are going fast enough that the current is back-emf limited.

Chances to launch it ? Price? I want two of them asap

Can you give us a ball park estimate of when it might be available?

Just to clarify, the controller is still just a pet project of mine, so don't anyone hold their breath for this to show up at an ebike shop near you. There aren't any plans at all to manufacture controllers for resale at this point, though that may change in the future.

-Justin

[justin_le]

We'll I've come pretty far:

Map to SwiftCurrent.gif

Trip route as of Aug 15th

(95.76 KiB) Downloaded 1686 times

But boy when you look at the big picture, there is there still a long way to go!

To SwiftCurrent, big picture.gif

Damn large country

(120.26 KiB) Downloaded 1672 times

Trip stats to date are in the attached spreadsheet. Will be in Regina on Sunday.

The rolling hills and strong winds here in Sasakatchewan have actually given me pretty poor energy usage, so I'm generally only able to budget about 90km from a full charge, using more like 14Wh/km instead of the 12 I was getting through BC. The complete trip statistics are attached, I've used exactly $2.00 worth of electricity and covered some 1811km. It's actually going to be pretty close to get all the way on $10.

Justin

[Doctorbass]

Justin, Quebec is waiting for you here!

see that article in our newspaper... oh! they talk about you at the end of this article!

http://veloptimum.net/velonouvelles/8/ART/8aout/Soleil16p.html

Doc

[mikereidis]

In a typical ebike controller right now, if you apply the throttle part way from a stop, you'll get the full current limit of the controller flowing from the battery at first, then as you accellerate this current will go down until you hit your partial throttle cruising speed. If you then pedal the bike, the current will go down further, to zero amps, unless you press the throttle further.

With a current throttle, if you applied it part way, the current that flows from the battery pack would be in direct proportion to how far you are pressing the throttle, regardless of your speed, until you are going fast enough that the current is back-emf limited.
-Justin

It's not entirely clear from this explanation, but my understanding is that a traditional throttle is a power control. Ignoring aerodynamics, maintaining a constant torque/acceleration requires turning the throttle higher as your speed increases. This can be annoying, IMO.

With a current throttle, the position more or less sets the torque / acceleration. In theory, in a perfectly 100% efficient world with no wind resistance or other exponential resistances, a constant current will produce a fixed torque and acceleration. I.E your speed would increase forever, like a craft in space. In the real world of course, besides aerodynamics, the motor back EMF will rise towards the battery voltage and current flow will decline.

But at low speeds, current throttle = torque control and normal throttle = power control, more or less. I'm sure someone will correct any misunderstandings I have.

How well is this current control working on your trip ? Does it make it easier to maintain speed without adjusting the throttle ?

So Justin: Does it look like you'll be in Southern Ontario by Labor Day ? Or a bit later ? By rough eyeing of your route it looks like your 40% here already, but I imagine your speeds have increased on flatter land ?