2WD (Two-Wheel Drive) FAQ

[Kingfish]

Wow, KF!

Did I count correctly, and did you carry 13P 15S with you? Assuming 5Ah per lipo, that would be 3.6kWh....

The total was 5S1P 5Ah LiPo x 3 = 63V => @ 26P = 130Ah = 8.2kWh. Range varied depending on conditions. I never did get a fix on what this was over flat level ground.

For commuting, it's just the Triangle @ 63V 30Ah which is enough to go 50 miles @ WOT, though probably could squeeze 80 miles if I took it lightly (but then... why?)
~KF

[Alan B]

Kingfish, why do you think the 5V regulator was the problem with the throttle dropping out?

[Kingfish]

Kingfish, why do you think the 5V regulator was the problem with the throttle dropping out?

The problem consistently occurred when demanding WOT after bottoming out on a descent or rising out of a curve towards an incline; at maximum load. The Front had power (driven by the “primary” controller which provided the 5V supply) however the slaved Rear would drop out. If I feathered the throttle then the issue would not display. I don’t think there was enough current to push the signal to the other controller in those conditions due to sag. Maybe the 5V supply in the “primary” needs a bigger cap. Maybe it’s the 12V supply to the 5V regulator that needs the bigger cap; I don’t really know for certain cos I’m not an EE and don’t have the chops to debug the circuit properly.

Beefing up the skinny wiring to the throttle though would reduce resistance, just as shortening the cable.
~KF

[Alan B]

The current required for the throttle is so small I suspect something else was going on.

Ground Differentials on 2WD Controllers

My concern is the voltage drop between the two controller grounds. How much resistance was there between the controller PC board and the junction where the current split.

Not sure you want to discuss this in your FAQ thread, though it is on topic.

Take an example, assume:
[list=]
* 50 amps battery current to the primary controller
* 20 milli ohms from controller pcb to current split point
* 50 x 20 = 1000 milli volts of drop would then occur from the split to the controller ground.
[/list]

This 1 volt of drop would RAISE the ground potential of the throttle and the main controller compared to the junction point. This would also raise the +5 and the throttle output by the same amount.

Now this would increase the apparent throttle voltage to the secondary controller (that is not yet drawing much current). Which would tend to cause it to accelerate and 'catch up'. So on the surface it seems somewhat opposite what happened, and self correcting.

However, what if the throttle input to the secondary controller exceeded the max allowed input and caused it to go into 'shutdown'. Most controllers will reject a too-high throttle input value as a 'fault'. At WOT there is very little room to 'overdrive', so it would not take much voltage differential to cause it.

Feathering the throttle would allow the secondary controller more time to catch up at a lower throttle voltage before it was driven into cutoff. As it draws current the voltage difference between the controllers will be reduced as both of them will have a similar drop from the junction to the controller ground.

It is very important that the controller grounds be referenced together and have very low impedance between them if a common non isolated throttle is to be used. Or use an isolation amplifier to re-reference the throttle signal to the local ground on the slave controller.

Could this have happened to KF's setup?

[hjns]

It is very important that the controller grounds be referenced together and have very low impedance between them if a common non isolated throttle is to be used. Or use an isolation amplifier to re-reference the throttle signal to the local ground on the slave controller.

Could this have happened to KF's setup?

Hi Alan,

I am working towards a 2WD setup now. I can always try the dual-Hall-single-throttle solution, but I am interested in hearing how you would re-reference the throttle signal to the local ground on the slave controller. How would you do it?
thanks!

[Alan B]

It is very important that the controller grounds be referenced together and have very low impedance between them if a common non isolated throttle is to be used. Or use an isolation amplifier to re-reference the throttle signal to the local ground on the slave controller.

Could this have happened to KF's setup?

Hi Alan,

I am working towards a 2WD setup now. I can always try the dual-Hall-single-throttle solution, but I am interested in hearing how you would re-reference the throttle signal to the local ground on the slave controller. How would you do it?
thanks!

One way is to use an Instrumentation Amplifier:

http://en.wikipedia.org/wiki/Instrumentation_amplifier

[Alan B]

Perhaps a better choice is a difference amplifier. Here is one example:

http://cds.linear.com/docs/Datasheet/1990fb.pdf

[hjns]

Perhaps a better choice is a difference amplifier. Here is one example:

http://cds.linear.com/docs/Datasheet/1990fb.pdf

Thanks, however... these amplifiers are way beyond my electric knowledge and skills....

And I am really trying to understand why these amplifiers would get rid of the voltage differences between the two grounds of two different controllers, unless one would connect the ground as V+. But if you do, which ground is than connected to the battery ground?

[Alan B]

They use magic.

Sorry.

In a way, they measure the voltage on the master side, send a message to the slave side, and generate a voltage on the slave side that has the same value but is relative to the slave controller's ground. So the ground difference is not eliminated, but the throttle signal is correct with respect to the slave ground.

The problem is the grounds on the two controllers will be shifting around depending on the battery current. This shift is not large if the controllers are well grounded but could still be many millivolts due to the significant currents involved. This gets added to, or possibly subtracted from the common throttle voltage as seen by the controller chips. Another way to think of it is to measure the differences in grounds in real time, and add or subtract this from the throttle signal to the slave controller.

Using two separate halls on one throttle is a great way to go if you can match the positions and get the same value from both outputs.

[Fishmasterdan]

1 wheel drive= Grin
2 wheel drive= Permanent smile and giggles.

Seriously;
I have burned out SEVERAL motors and ESC's over the last few years .
I have not been able to burn out my 2wd set up. Dual halls throttle, Cell man made the whole package and it just plain works.

My personal opinion;
2wd if you want a motorcycle. To heavy to be a fun bicycle.
1 wheel drive for assist. Keep the weight down.

[hjns]

I used method's method to create a twinsensor throttle. Posted my results here: viewtopic.php?p=501963#p501963

Next steps will be to create a twin-3-speed-switch, a common shunt for the CA to measure current, splitting the main power to both controllers, add a key switch, fuse, motorped EU approved lights, and approval from the Swiss cops that I can drive my 2WD on the roads....

[John in CR]

1 wheel drive= Grin
2 wheel drive= Permanent smile and giggles.

Seriously;
I have burned out SEVERAL motors and ESC's over the last few years .
I have not been able to burn out my 2wd set up. Dual halls throttle, Cell man made the whole package and it just plain works.

My personal opinion;
2wd if you want a motorcycle. To heavy to be a fun bicycle.
1 wheel drive for assist. Keep the weight down.

Best 2wd post yet. Assist, what's that?....Isn't that when my motor(s) gets bogged down and I assist it via the pedals?

[Kingfish]

Assist via pedals
Funny you mention that: I would say “yes”. Going through the analysis of my next 2WD incarnation I’ve considered having pedaling as an option rather than a requirement.

I would also agree that as a bicycle mod, 2WD creates an experience closer to moped and motocross that is certainly EV-grin worthy! You are right: Adding a second motor will increase the frame weight by another 14-20+ pounds, and that too is a good point of discussion.

Let’s talk about weight:
As a cyclist, we work very hard to shave off grams & ounces from our frames, all of which factor against us when beginning from a standing-stop, climbing hills, and endurance. Depending on use, a typical complete bike assembly weights between 26-40 pounds before rider & accouterments.

As an electric bike, we give up double that at the onset due to the mass of the motor, the controller, the batteries, the wiring, and the minimal accessories to go just 20 miles. I recall fretting that my first commuter battery pack was about 9 pounds and thinking THAT was heavy! And I could feel the difference in the way the bike handled when I strapped on the 13-pound extender: If I pedaled aggressively it was possible to go 50 Seattle-miles on a charge (using LiFePO4). For a noob coming from the bicycle world, this extra weight was difficult to accept, although the electric augmentation that came with it is so enticing, well – it’s only weight and within a few weeks our muscles will adapt, our chests will expand, our arms and hands become stronger, and our senses – become more alert.

Now we throw in another motor to complete the architecture: Twice the torque to the ground. The economies of efficiency begin to go by the wayside because a person that accepts this additional weight understands that they are improving the performance with a penalty, just as if I were to bore out the cylinders and drop in oversized pistons on an ICE. We add more batteries to compensate for the loss of distance, and this is not a 1:1 exchange: It’s closer to the inverse/cube-root function where the first and second doublings are profound, but then the weight of more battery additions are in fact their own flaw, and we’re back to counting grams & ounces.

If we’re talking about just bicycles modified for 2WD, then the weight limits of the frame and the safety of the experience comes about rather quickly, especially if the rider has a large body type: The effects of weight create self-limiting configurations that have their best utility in commuting and sport where the distances & duration are reasonably short.

These past few weeks I’ve been working at the other end of the weight problem: I need to go the distance at speed for hours. I can find/make a frame to handle the weight & speed. The problem is how to charge it at the end of the day. But this is a conversation for a slightly different 2WD application. Regardless – weight factors large, and the way to reduce that is to increase the efficiency of the system as a whole by examining the components. During that process of discovery, everything must be suspect to improvement.

Yikes, another novella! I’ll stop now to brew another pot.
<mmm> Fresh cup! KF

[sangesf]

I believe all your posts depend on the predication of having a single battery..

From MY experience.. If you're using 2WD AND the appropriate BATTERIES.. It is WAY more efficient than a double motor / single battery setup.
(The point being, that with 2 motors / one battery, you're pulling twice the C-rate as opposed to only one battery.. (especially if you're using only one throttle). In the case of a dual motor / dual battery setup, your using much less current to accomplish the same as a "single setup" and creates much more efficiency)

Again, this is MY experience and as always.. YMMV.

From one of my tests, I've found that if you pull only .2C from a battery as opposed to 2C from a battery, you can get (up to) an additional 11% (depending on size and type of battery) battery capacity. (This was using a 60Ah Thundersky battery setup)..

Questions/Comments/Queries, welcomed!

[miuan]

Nice KF, keep it comin'!
How much kWh do you need to charge and how quick? What cell IR?
If lipo, have you considered splitting the giant pack into more parallel groups that can be joint in series for charging? This way you could go the ghetto way of rectifying mains voltage and using a bulb as a current limiter.. never worked for me, but hey that's a serious hack for serious challenge.

[Kingfish]

Sangesf, is the single-battery comment directed towards my way? If so I’ll try to answer: I use arrangements of 5S1P to create battery assemblies. They are all the same make & model, I don’t mix chemistries, K.I.S.S. Thus, I can evaluate the “whole” battery assembly as one, having 2C charge, 15C discharge. But then I run with a large capacity and experience a voltage sag of 0.4V at WOT which I think is fine and good for two motors. (I hope that was helpful). And I’m with you on the observation: Pull easy and the batteries will be of less trouble. Mine get physically beat-up over time so I doubt I’ll ever see 1,000 cycles. Not complaining, just observing; we make the bed we sleep in.

Miuan: The next bike design is targeted at twice the speed and twice the distance. Allow me to shed a bit of light on what I have learned between the two cross-country trips I’ve made:

• P0 eBike was FWD, 9C 2806, 37V 10S9P. I had a crappy charger experience (issues documented and resolved in time for next year). Went 550 miles in 3.5 riding-days, longest was 173 miles with some opportunity charging (twice). Speed was about 24-26 mph (need to double check), and I could cruise at 29 mph on a flat easy enough. Me and the bike weighed 350 lb.s; batteries were 23 lb.s.
• P1 ebike is 2WD, Ebike-Kit (might be 2807-equivalent), 63V 15S26P. Had a better charger that used about 1kW/hour, and took roughly 8-9 hours to recharge my whole assembly. Farthest on a single charge was 165 miles of California Hwy-1 between San Rafael and Fort Bragg (hilly, windy, curvy). Average speed that day was closer to 23 mph (not worthy of bragging rights, but I got there), though I could easily cruise at 32 mph and could climb hills without any issues (other than what has been documented). I took 4.3 times more batteries to go about the same distance as last year, except that I had the pleasure and power of climbing hills without resorting to downshifting in most cases, and I towed a trailer with 50 pounds of additional gear on board (not counting batteries). Me and the bike: 450 lb.s, with 100 lb.s of that in batteries.
• Next bike: Proposed – is a 2WD electric motorcycle (someone coined eMoto and I like that term). Mathematically, the motors are designed to handle 75 mph, though realistically 65 mph is more fitting: Need to be able to travel on the freeway without getting run over. Minimum distance is 300 miles with average weather. Hence, twice the speed & twice the distance means 4X the batteries… optimistically. 5X would be better. Aside from weight, which is now 400-500 pounds, we have to find a way to charge it! The bike can’t come into the motel room like before; I have to go to RV Parks or EV Charging Stations (hey dnmun, you got yer ears on?). I spec’d out the “road trip” and 300 miles is barely making time for where I want to go. 300 miles / 60 mph = 5 hours in the seat. Now let’s flip this around and look at it from the other end of the telescope.

Most RV parks offer 30/35A service, and about 40% have 50A service. I need to consider 50A hookup, and here’s why: Let’s say I’m running 4X the batteries I ran this last summer. That’s 4 X 8kWh = 32kWh. My present charger uses about 1kW and is 88% efficient. This is plenty safe for motels. However the next pack will need an industrial-strength upgrade/replacement to keep up. In other words, the available charging infrastructure limits the practical size of the battery assembly.

Now we understand the limits: 8 hours (sleeping), 125 VAC, 50A service commonly available at 40% of the RV parks around the country (which BTW, vary from $11-35/day; much cheaper than motels – and the power is free). 125 * 50 = 6250W/hour MAX (likely theoretical at best), and 8 * 6250 = 50kW. Frankly, I’d be happy with 32 to 40 kWh if for nothing else but to keep the weight and the cost down.

Anyways, this is how I think about batteries and weight. Imagine now given all of this, that weight is not our friend, and that it is a drag (literally) on our system. How can we reduce that weight and improve our performance (aside from going slower)

Am I drifting off-topic? 2WD systems have a lot of potential beyond just bicycles.
~KF

[Alan B]

Just a note on continuous power ratings - 80% of rated - so 50A * 80%.

Note also that a lot of parks have separate 30A and 15-20A breakers and outlets, so you might set up your chargers that way. Again 80% rule applies.

[sangesf]

My observation was directed at anyone thinking of 2WD..
Your original FAQ was basically saying that 2WD is inherently ineffecient, when in reality, it really depends on the setup...
As an example...
Using a single motor, of let's say, 36v 30a max controller on a 36v 15Ah battery and then comparing it to two of those same motor/controller combos on the one battery/one throttle, and then saying it's inefficient is true...
However, if you took the same motors/controllers and hooked up two 36v 15Ah batteries and used two throttles, so that you can vary the load (re:torque) between the two motors and therefore needing less load (re:amps) on each motor respectively, your using less power (re:c-rate) to accomplish the same "pull" as a single battery setup.
Best way to explain is my experience.....
On my original bike, I had a 36v 20a controller and a 36v 15Ah battery... Best I was able to pull out of it was 21 miles at a 20mph avg speed. I then bought a second 36v 15Ah battery to double my range.. So 42 miles was about it... The VERY FIRST trip I made once I added a second motor and used the second battery in tandem, I was able to achieve 60 miles.. There was NO way I was gonna eke out an extra 10 miles from each battery separately on a single motor setup. The factors involved were these...
1.) Having two motors helps with original take off from a stop, not needing as many amps from each battery. (As opposed to a single motor setup)
2.) Keeping 20mph speed is a LOT easier on the 36v motors when there's two to help share the load.
3.) In relation, the entire system as a whole is just easier on the batteries.
(There's no reason to beat up your batteries, you MEANIE!)

As I said before, YMMV, but that has been my experience...

[Alan B]

KingFish, you never responded to my hypothesis on why your slave motor cut out under hard acceleration:

The current required for the throttle is so small I suspect something else was going on.

Ground Differentials on 2WD Controllers

My concern is the voltage drop between the two controller grounds. How much resistance was there between the controller PC board and the junction where the current split.

Not sure you want to discuss this in your FAQ thread, though it is on topic.

Take an example, assume:
[list=]
* 50 amps battery current to the primary controller
* 20 milli ohms from controller pcb to current split point
* 50 x 20 = 1000 milli volts of drop would then occur from the split to the controller ground.
[/list]

This 1 volt of drop would RAISE the ground potential of the throttle and the main controller compared to the junction point. This would also raise the +5 and the throttle output by the same amount.

Now this would increase the apparent throttle voltage to the secondary controller (that is not yet drawing much current). Which would tend to cause it to accelerate and 'catch up'. So on the surface it seems somewhat opposite what happened, and self correcting.

However, what if the throttle input to the secondary controller exceeded the max allowed input and caused it to go into 'shutdown'. Most controllers will reject a too-high throttle input value as a 'fault'. At WOT there is very little room to 'overdrive', so it would not take much voltage differential to cause it.

Feathering the throttle would allow the secondary controller more time to catch up at a lower throttle voltage before it was driven into cutoff. As it draws current the voltage difference between the controllers will be reduced as both of them will have a similar drop from the junction to the controller ground.

It is very important that the controller grounds be referenced together and have very low impedance between them if a common non isolated throttle is to be used. Or use an isolation amplifier to re-reference the throttle signal to the local ground on the slave controller.

Could this have happened to KF's setup?

[Kingfish]

Hi Alan

It’s possible that your hypothesis is valid; on the face of it, there is merit. We’d have to set up a way to test that in situ to be sure – and I would be happy to oblige if I knew how. EE is not my strong point; I am an E-M engineer, and I know a tiny wee bit about computers too: Although I could not register an opinion about your circuit, I could make fish animate across your screen

Regardless, like you - I feel strongly that the two controllers should be as close together as possible. I agree that every time there is a connector in line, the quality of the signal is at increasing risk. FWIW, I measured the throttle voltage between the two controllers and it was the same (and I repeated this test several times on several days), but then these were static tests without load; I couldn’t replicate the condition at the workbench. Perhaps with a dyno… (it’s on my Wish List).

The Sandman comith...
Z z z, KF

[llile]

This is a very useful thread. I am determined to build a dual front motor tadpole trike, for various reasons but also because I can

Obviously with dual matched front motors they'd have to be matched in speed and throttle and so on. Meh? If they don't match, I will just point the wheels a different way and go. It'll work even if it wears out one tire. I'd probably set it up so the batteries are amidships, right next to each other on either side of the frame, and make all the connections super short between them. Controllers also mounted close. With 'Bents you have a lot more room to put things where you want them, and since it is a custom frame, the options are endless.

Here are the questions I come away with:

1. One motor per battery, or two batteries in parallel? It seems it has been done both ways, which is best?

2. I'll be using a Cycle Analyst. Will I need two CAs, or one? ( I guess that depends on the answer about number of batteries..?) Two is more expensive, but that is still in the budget. Maybe two CAs check the health of both batteries? two CAs monitor individual motor power more closely, allowing fine tuning of match? I am still a little concerned about how to hook up the CA to this hack.

3. One throttle. Definitely. The controllers and batteries will be physically close, grounds will be heavy and short between the systems, throttle wires will be short and symmetrical. I guess if the throttle is powered from the cycle analyst there isn't a problem with the 5V power supply? If there is any interface electronics needed, can do. 5V Dc-Dc converrter if necessary to get the throttle working right. Instrumentation amp? Hell it is all 5V stuff, I might use a PIC or an Arduino instead of an instrumentation amp. I do that shit for fun anyway. But that seems overcomplicated. Can the throttle just be hooked parallel to two controllers or CAs?

4. I will probably be running at 72V. With a faring. I hope to build something with a 40 MPH speed on the flats. Don't tell the cops.

5. I ride a long way in rolling hill country. 2WD will be a good thing for those hills. Some are killer grades, short sections of 20% are encountered on most rides. 50 Mile round trip is also not uncommon. Battery requirements will be serious. I am thinking about two 30 AH batteries. Ping. Is that too much battery? This is 4X the battery I use now, at 20MPH same distance.

6. I'll still pedal. I love the feeling of exertion, I love being in shape, and it takes a good 1-2 hour workout to get there anymore. I hate sitting in a car, wishing I was getting some excercise. I'll probably cobble together a transmission that can still allow pedaling at 40MPH - maybe a 7 speed rear and a 3 speed intermediate hub. I've built crazier transmissions than that. Geared high, the pedals will be useless at normal non-Ebike speeds but who cares? I have never run out of juice before, due to good planning.

7. The other innovation I am seriously considering is a leaning frame. Front wheels don't lean, but the rear wheel, me, and the heavy batteries do lean. My friend has had his trike up on two wheels, doesn't sound fun. Leaning should improve cornering. But that is a whole 'nuther thread.

How about the 'lectric details, am I on the right track?

[hjns]

Hi Llile,

I do not have experience with 2WD yet, but I am building one, so I just wanted to share some of my thoughts. More experienced ES-members can correct me at will.

This is a very useful thread. I am determined to build a dual front motor tadpole trike, for various reasons but also because I can

Obviously with dual matched front motors they'd have to be matched in speed and throttle and so on. Meh? If they don't match, I will just point the wheels a different way and go. It'll work even if it wears out one tire. I'd probably set it up so the batteries are amidships, right next to each other on either side of the frame, and make all the connections super short between them. Controllers also mounted close. With 'Bents you have a lot more room to put things where you want them, and since it is a custom frame, the options are endless.

Here are the questions I come away with:

1. One motor per battery, or two batteries in parallel? It seems it has been done both ways, which is best?

Probably depends on the expected amps per motor and the c-rating of your batteries. As I use Lipo, I don't have to worry about the discharge rate, therefore, I find 1 large pack more convenient. Especially as I have rear- and front driven motors that are expected to draw different currents at the same time, using one pack leaves me with one worry less that there may be a difference in discharge between two packs. I guess the same counts for 2FWD, but less so, as the expected current should be more or less the same for both motors (unless you are driving circles or use different motors...)

2. I'll be using a Cycle Analyst. Will I need two CAs, or one? ( I guess that depends on the answer about number of batteries..?) Two is more expensive, but that is still in the budget. Maybe two CAs check the health of both batteries? two CAs monitor individual motor power more closely, allowing fine tuning of match? I am still a little concerned about how to hook up the CA to this hack.

I agree this is depending on the number of batteries, but more importantly, what do you want with it. If you use the CA only to monitor voltage, then there are much cheaper ways to do that. If you want to check the used Wh, then having two battery packs and two CAs means that you will have to do a lot of counting. It is one more reason to go with one battery pack, one stand alone CA with a separate shunt to measure current from the battery pack BEFORE the split to both controllers.


However, if you expect currents higher than 45A continuous, you may need a bigger shunt. I went with a 200A shunt from Ebay (expecting 100A per motor), which is on the high side.... better safe than sorry, though. To use it with my CA, I need to modify the CA (I have the DP) and recalibrate it for the new shunt. I am still working on that. If you get the stand alone CA, connecting the new shunt should be piece of cake.

3. One throttle. Definitely. The controllers and batteries will be physically close, grounds will be heavy and short between the systems, throttle wires will be short and symmetrical. I guess if the throttle is powered from the cycle analyst there isn't a problem with the 5V power supply? If there is any interface electronics needed, can do. 5V Dc-Dc converrter if necessary to get the throttle working right. Instrumentation amp? Hell it is all 5V stuff, I might use a PIC or an Arduino instead of an instrumentation amp. I do that shit for fun anyway. But that seems overcomplicated. Can the throttle just be hooked parallel to two controllers or CAs?

I am no electronics guy. Therefore, I went with the easy way out, as shown by ~Methods, and inserted another hall sensor into my throttle (see here). Took me 45 minutes. No high-voltage peak will mesh up my throttle signal.

4. I will probably be running at 72V. With a faring. I hope to build something with a 40 MPH speed on the flats. Don't tell the cops.

I guess that is 20S? Looks good to me, cause that is what I use now! On the flat, my HT3525 gave me 36mph. A faster motor (HS version) should give you more than 40 mph, but if you go that route, you will use more amps when hill climbing, increasing the risk of melted wires inside your motor.

5. I ride a long way in rolling hill country. 2WD will be a good thing for those hills. Some are killer grades, short sections of 20% are encountered on most rides. 50 Mile round trip is also not uncommon. Battery requirements will be serious. I am thinking about two 30 AH batteries. Ping. Is that too much battery? This is 4X the battery I use now, at 20MPH same distance.

I have no idea yet. Is also very much depending on which motors, max amps used, etc. You need to give us a bit more details about those, in order to give a better estimate. My rear HT3525 eats 20% hills at 20mph at 84V (20S lipo hot of charger) and between 20 and 30Amp. I guess, at a certain speed, you just need to 2kW energy to manage those 20% hills. However, with a consumption of 100Wh/mile, your mileage may vary.. Two 30 Ah batteries (72V?) sounds very heavy to me and gives you >4kWh. But with >4kWh you should be able to climb a 40 mile-long 20% hill at 100Wh/mile (assuming your motors don't melt). So, a 50 mile round trip sounds very manageable without hitting LVC.

6. I'll still pedal. I love the feeling of exertion, I love being in shape, and it takes a good 1-2 hour workout to get there anymore. I hate sitting in a car, wishing I was getting some excercise. I'll probably cobble together a transmission that can still allow pedaling at 40MPH - maybe a 7 speed rear and a 3 speed intermediate hub. I've built crazier transmissions than that. Geared high, the pedals will be useless at normal non-Ebike speeds but who cares? I have never run out of juice before, due to good planning.

Looking forwards to see that.

7. The other innovation I am seriously considering is a leaning frame. Front wheels don't lean, but the rear wheel, me, and the heavy batteries do lean. My friend has had his trike up on two wheels, doesn't sound fun. Leaning should improve cornering. But that is a whole 'nuther thread.

How about the 'lectric details, am I on the right track?

[llile]

I am no electronics guy. Therefore, I went with the easy way out, as shown by ~Methods, and inserted another hall sensor into my throttle (see here). Took me 45 minutes. No high-voltage peak will mesh up my throttle signal.

Oh so THATs what all this gibberish about throttle hall sensors is about. I never realized the hall sensor is how the throttles work. This sounds easy - two throttles in one. THe only problem is getting them both to make the same signal. It looks like yours were a bit mismatched, and with my dual motors integrated into the steering, I want a setup that matches as closely as possible.

If the throttle puts out 0-5V, it would still be easy to take a microcontroller and make it follow one signal input with two totally matched identical outputs. and also make sure it didn't mind being shorted out by the CA's throttle override. As long as there wasn't a ground bounce somewhere in the system that upset the signals, the two would follow. But I digress. If I decide to go this way I'll post all the details.

I'm still a little unclear how the Cycle Analyst interfaces with a standard motor controller, and how that motor controller interfaces with the various flavors of motors. Apparently some motors contain hall sensors as well, but I haven't quite figured out how the controller interfaces with them, nor how a non-sensor motor is different. Surely there is a FAQ around here that explains all the wires and nuts and bolts and signals. I've been looking into this but havent run across anything of sufficient detail yet. Can anybody point me to a good technical reference about this stuff? Once I get out of FAQ territory and into a build I will peel off a separate thread.

[hjns]

Maybe the CA manual is a good start?

[hjns]

It looks like yours were a bit mismatched, and with my dual motors integrated into the steering, I want a setup that matches as closely as possible.

Makes sense, but good luck. Alternatively, add some resistance, or just get two identical programmable controllers (Lyen comes to mind), and program them for matched speed to correct for any other interference.