Phat Bike Build

[itsmedc65]

@JKB how about an update?
I came cross this build and your recumbent build a while back but just skimmed back thru them today.

Any progress on the fairing?
Kingfish reported an improvement with a small fairing on his http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24094
And he did some Aero work on the rear as well.

Any tests at 12s?

Weather has been nice in the southeast, have you been racking up the miles?

 

[jkbrigman]

@JKB how about an update?
I came cross this build and your recumbent build a while back but just skimmed back thru them today.

Any progress on the fairing?
Kingfish reported an improvement with a small fairing on his http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24094
And he did some Aero work on the rear as well.

Any tests at 12s?

Weather has been nice in the southeast, have you been racking up the miles?

Hi itsmedc65 - thanks for asking! It's helpful to know people are looking at the build thread. I'll share some quick information with you now then more, hopefully this weekend, when I've got some test rides done.

Weather here has been hit-and-miss lately: sometimes bitter cold, sometimes temperate, sometimes rainy. We had a nice, steady rain all day today, even though temps have been moderate.

Here's a quick list of four items I can tell you about:

First: No tests at 12s yet, but will do that soon. I am not optimistic that it will improve things but I have to test to be sure.
Second: I have the "small scooter windshield" installed on the bike. It looks a little bit more scooterish and I don't like that, but it merits a test. I listened to a story from a scooter-riding buddy who says he gained 5mph at 30mph when he added the same size windshield to his scooter, so I figured it's worth a try. I also intend to make a trunk enclosure for my rear rack that will act like a tailcone.
Third: I have swapped out the stock "old man beach handlebars" for a nice flat handlebar. It gained me a lot of space on which to mount stuff and I got back the original handgrip that I had to forfeit on the prior stock handlebars when I added a throttle.
Fourth: I installed the Crystalyte HS3540 on the bike and it stretched out the Sapim 13GA butted spokes. I have to re-true the wheel before I can test.

I'll update soon and include pics: the bike looks a good bit different with the flat handlebar and scooter windshield.

JKB

 

[jkbrigman]

@JKB how about an update?

Any progress on the fairing? Kingfish reported an improvement with a small fairing on his http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24094
And he did some Aero work on the rear as well.

I have the "small scooter windshield" installed on the bike. It looks a little bit more scooterish and I don't like that, but it merits a test. I listened to a story from a scooter-riding buddy who says he gained 5mph at 30mph when he added the same size windshield to his scooter, so I figured it's worth a try. I also intend to make a trunk enclosure for my rear rack that will act like a tailcone.
I have swapped out the stock "old man beach handlebars" for a nice flat handlebar. It gained me a lot of space on which to mount stuff and I got back the original handgrip that I had to forfeit on the prior stock handlebars when I added a throttle.

Two things right quick:

1) I got the new regen braking levers installed. I had to swap out the connector and apply some heat shrink to bind the two wires together so they would be easier to route in the split plastic cable loom. I am amazed by regen braking! It's smooth, strong and effective, plus you get to recover some power! On a 3 mile loop, I regen'ed .05 Ah, which ain't too bad. Scaling that up, I'm predicting 1/2 Ah returned for a 30 mile run as a minimum. I'm expecting to double that to 1 Ah over a 30 mile run. That would be roughly 70 Watt-hours or about 3.5 miles added range. 5% is nothing to sneeze at and 10% is freakin awesome.

Lest you doubt my numbers, know that me, the bike and all equipment are roughly 330 lbs all-up. 250 of that is me, 60 of that is the bike and 20 of that is work laptop and tools. With that kind of weight, regen is a huge help. It's you 145lb flyweight guys that get nothing out of regen.

2) The new flat handlebar is installed and has been a tremendous improvement, offering much more room on the handlebar for all the attachments we must add to our ebikes. The former handlebar was a curvy "old man hybrid" handlebar. The new one is a flat MTB handlebar and it has made possible attaching the windshield, restoring the original handgrips to the bike and giving a place for the throttle.



Yes! I have been testing the windshield and I can offer the following information:

• 
  - My first impression is that the bike "feels" more efficient with the scooter windshield.
  - I need to do longer-distance testing to see if I can generate clearly differentiated measurements with the fairing vs. without.
  - The bike is very much more comfortable to ride in cold weather. The windshield truly improves cold weather comfort on the bike.

Any tests at 12s?

No testing at 12s yet, but that's one of the items on the agenda. To remind those who might only be reading this post: The Crystalyte HS3540 provides so much speed in the 26" wheel that I'm wondering if it makes sense to drop the battery voltage. I would get lower top speed but can I achieve better throttle control and range?

Weather has been nice in the southeast, have you been racking up the miles?

We were bitter cold in the southeast in January. This past weekend and past week, we had a couple days that got into the 40's (F) where it was dry enough for me to do a couple short test runs. I even got in an errand run to the sub shop to pick up two sandwiches!

I am trying to get to the point where I can do some true cold-weather commuting with the bike, however, it might be a good time for me to outline what things are wrong with the bike that I am fixing right now. Some of the problems are a little informative:

Fixed: CA bolt - The bolt holding the CA to it's handlebar bracket was just too short and the nut would not stay on. After losing that nut, I finally got to the hardware store and bought a replacement stainless bolt and locknut for the CA. I also added some washers to help keep the CA from being floppy. Unfortunately, the bolt I ended up with isn't metric, but it's plenty up to the job of holding the CA on it's bracket.

It's on my to-do list to conjure up a new mounting bracket for the CA, something similar to what ebikes.ca has produced that works with solid handlebar stems. This would free up more handlebar space, centrally mount the CA and give the CA a more solid connection to the bike. (The one ebikes.ca made requires the more modern quill/stem arrangement. My bike has a plain old fashioned "gooseneck". I tried to convert to the more modern format but it's impractical.)

Next To Check/Fix: There is a bad mechanical wobble in the wheels. I fear the sealant has hardened in the tubes. If true, I'll have to remove the tubes and throw them away. Dang! UPDATE 12 Mar 14: The sealant hasn't hardened but it has gotten thicker. Simply riding the bike improved the wobble to the point that it's now "no factor".

Next to Check/Fix: Recall that the Crystalyte HS3540 stretched out the Sapim 13GA butted spokes. I found a new LBS with quicker turnaround and lower pricing and got the wheel re-trued. Bad News: the LBS is advising replacing the Crystalyte wheel with something else, so I'm looking at Alex rims. UPDATE 12 Mar 14: I've got about 80 miles on the Crystalyte rim and it's holding up now. But I have a very good used DH rim waiting in the wings if needed.

UPDATE 12 Mar 14: Regen brake handles absolutely kick ass! Everything I reported above still holds true. Braking is smooth and tapers off nicely to the stop, and I'm getting back way more energy than I expected - I can get 3% back if I'm good at anticipating upcoming stops! I'm using a set of brake pads I was prepared to replace soon, and I'm optimistic that regen braking is going to help them last much longer than they would have otherwise! You are really missing out if you have a hubmotor but aren't using regen braking!!!

UPDATE 12 Mar 14: Tried a test run with NO PANNIER and the difference in the way the bike handles and cruises is amazing. I can actually feel the lessening of the wind resistance and the one-sided out of balance weight feeling is gone with the pannier off. It truly is right that you want the weight in the bike as low as you can get it, and preferably in the frame, center of the bike!

Next to Do: Still in the process of building a truing stand for myself that can handle the heavy motor wheel. UPDATE 12 Mar 14: I have the parts cut and ready for the stand but not built yet. Not as urgent now that I have a close-by LBS that will true the wheel for reasonable cost.

Also note to self: Keep looking for a trunk bag that sits on top of the rack to replace the panniers. Trying to find a trunk bag laid out inside just like the pannier is, isn't going to be easy!

JKB

 

[neptronix]

alex rims are great rims. go for it.

 

[jkbrigman]

alex rims are great rims. go for it.

I'm ready for a "great rim". I don't think I got a new wheel, I think this was a crapped-out used one. It's been nothing but trouble from day 1. My 9c rim was flawless compared to this sack 'o carp.

UPDATE 12 Mar 14: Had the wheel re-trued by a different LBS. It's not perfect, but after 80 miles or so, it's holding up. I have yet to make a complete commute run with the wheel but I'll try that as soon as the weather improves. If I can get another 500-1000 miles out of the rim, I'll count myself lucky.

 

[Kinni420]

Taxes are coming up and Im going for the Alex DM24 26 36h on that back wheel with 13g sapim spokes. Im up to 10 spokes busted. I dont think the DX32 26 36 is much of an improvement for the extra 50 bux.

Going to this bike shop here to rebuild my wheel correctly. From experience, building a motor wheel isn't your every day run of the mill spokeing.

http://www.salvagetti.com/wheel-building-service/

 

[jkbrigman]

Taxes are coming up and Im going for the Alex DM24 26 36h on that back wheel with 13g sapim spokes. Im up to 10 spokes busted. I dont think the DX32 26 36 is much of an improvement for the extra 50 bux.

Going to this bike shop here to rebuild my wheel correctly. From experience, building a motor wheel isn't your every day run of the mill spokeing.

http://www.salvagetti.com/wheel-building-service/

Dude...I'm with you solid on the wheel rebuild. I'm sick and tired of putting up with a wheel that falls apart every 500 miles....I see guys out running way more power than I am, their wheels staying solid as a rock. I'm ready to get some good wheel and ride....

 

[jkbrigman]

Hero_004 has suggested a couple times that I try 12S now that I have a motor that can spin a reasonable RPM on 50VDC, versus needing 18S (72v) like the 9c 2810 does, to make a reasonable speed.

He's got a good point: going 12S would clear up several problems presented by 18S: need for dedicated chargers, difficult balance charging and more choices for DC-DC converters at 12S/50VDC instead of 18S/72VDC.

Most importantly, the whole pack has to be broken down to balance charge. I literally disassemble the pack to do that, and I've had no-end of trouble doing that. I've blown up balance connectors 3 times doing that (forgetting to un-series-connect the high power leads). I've GOT to fix that, it's foolish to still have that problem with the ebike.

So I cut my pack by 1/3rd and gave 12S a try. It works OK with the Crystalyte HS 3540. Top speed at 12S is somewhere around 31mph. Not bad, not bad, but the motor will make almost 40mph on 18S.

Now here's the interesting thing: over a course I've run before, my AVERAGE speed increased while my MAX speed dropped. I'm theorizing that it's because the controller is designed to work with 12S/50V and not specifically designed to work with 18S/72V. (and/or that there could be "ringing" or distortion in the motor drive waveform that wastes power. But that's just a theory...)

Look for more feedback on this soon. I can't make a final decision until I try making the commute on 12S.

In the meantime I'm also considering 24S. I could series-connect two 12S packs in series to get 24S. I could break the two packs down to parallel so I could balance charge on the Hyperion. Plus I could charge the whole pack with either one or two 50VDC supplies. But I will have to swap out the controller to try 24S. More money I'd like NOT to spend on the bike just yet....

 

[jkbrigman]

Completed a test run with the Phat Bike against a headwind and the windshield definitely helped. I saw improved power consumption on the CA vs. no windshield and it was far more comfortable on the bike with the windshield than it is without! I don't "have numbers" yet. I need to do a very long test - a commute test - so I can get numbers that are easy to interpret and average out error. I might change my tune about the windshield in the dead of summer when the heat is at it's worst, but for right now, in the cold part of March, that windshield is GREAT.

UPDATE 21 March 2014: We got one day of warm weather here so I took the ebike into work this morning. CA showed 31.56 miles for the inbound trip.

The scooter windshield appears to be very effective. I had a 5-10mph headwind THE ENTIRE WAY IN and I am sure I would not have had enough power to finish the trip without that scooter windshield! I added a plastic tote behind the seat that's shaped like a tailcone. I am convinced both the windshield and the tailbox made the difference in being able to get to work at all on 18S3P against a 10mph headwind.

The power it took to get into the office was the same as I'm used to seeing, about 680Wh, but I was able to go very fast the whole way: I averaged 21.3mph and peak speed was 43.7mph on one downhill.

So, despite the BAD headwind coming into the office, I made it on 19Wh/mile which is my "normal, no headwind" efficiency, at very high speed - over 21mph average! Total ride time was 1 hour, 28 minutes, which is about right.

 

[jkbrigman]

Completed a 100km commute on the Phat Bike today. Quick comments:

- the scooter windshield ROCKS. Needs some adjustment but it's effective and well worth installing on the ebike. Noticeably improves comfort and efficiency.
- the "tailbox" seems to have helped, but I can't be sure.
- removing the pannier seems to have helped
- running 70psi in the Schwalbe Marathons

Here's the stats:
Total Distance: 64.00 miles/100km
Max Speed: 36.9mph/59.4kph
Avg. Speed: 22.8mph/36.7kph
Time: 1 hr, 26 minutes
Total Current Draw: 9.983 Ah
Total Power Draw: 701 Wh
Efficiency: 21.7 Wh/mile/13.6Wh/km
Regen: 1.6%, Regen Ah: 0.1693 Forward Ah: 10.152 Net: 9.983Ah
Amp Min: -11.3 Amp Max: 17.97 Vmin: 63.9

I've been learning that gaining an extra MPH on the AVERAGE SPEED is very, very difficult. The only way to increase that number on a fixed commute route is to increase your speed, dramatically, in the long distances between stops. I was running a "typical" speed in the open spaces of about 28mph to average 22.7avg MPH over the 32 miles home. This was perceptibly much faster than the prior configuration of the bike, in which I was able to run a "typical" speed (not average!) of about 23mph.

 

[jkbrigman]

Arrg. Trouble with hall sensor lines. Looks like the connectors I installed with needle-nose pliers are failing. Waiting on a proper crimper to arrive from China.

Until then, I've got plenty I can do....

- researching different battery configurations
- research and build a battery BOX...
- windshield adjustment and more testing,
- swapping out the innertubes. I'm pretty sure that now the goo inside the tubes has hardened.
- lube and adjust the pedal drivetrain

And then when the tool gets here: Rebuild and weatherproof the halls and phase connectors...

 

[tomjasz]

Excellent read. I have several scooter windscreens. I'm thinking the flyscreen, smallest, might be the most helpful design. Scooterists universally claim improved ride, comfort and efficiency with a screen. More!!

 

[jkbrigman]

Excellent read. I have several scooter windscreens. I'm thinking the flyscreen, smallest, might be the most helpful design. Scooterists universally claim improved ride, comfort and efficiency with a screen. More!!

I actually DREADED installing the scooter windshield because I don't want the bike to "look like a scooter" in any way. However, it's worked out pretty well so far. I definitely don't plan to remove it any time soon!

I think you will like it if you add a windshield to your Trek Pure build. With an upright, "european" riding position we have, we need all the aerodynamic help we can get on our bikes.

 

[pendragon8000]

sorry if i missed it but did you get the rim?
ive got 2 alex dx 32 26 36h rims from ebay, exported from U.S. $70 each all tolled i think.
i only needed to replace 1 after a drunk skate park session where i decided to show off and ride up some stairs. they are super tuff as far as bicycle rims go. hey look fairly nice to imo.
search ebay
edit
and skpokes from holmes hobies, 12g ... just dremel off the eyelets on the rim. should take you a few hrs to lace single cros.

 

[jkbrigman]

sorry if i missed it but did you get the rim?
ive got 2 alex dx 32 26 36h rims from ebay, exported from U.S. $70 each all tolled i think.
i only needed to replace 1 after a drunk skate park session where i decided to show off and ride up some stairs. they are super tuff as far as bicycle rims go. hey look fairly nice to imo.
search ebay
edit
and skpokes from holmes hobies, 12g ... just dremel off the eyelets on the rim. should take you a few hrs to lace single cros.

Hey PD8000!

I got some older, used rims from a buddy of mine that are pretty good - they are welded, not pinned. But I was very close to pulling the trigger on a couple Alex DX rims and still might, so I'll search ebay and take a look. THANKs for the heads-up!

I regret not just sending John Rob my Crystalyte motor and having him build up a wheel from it. I think I'd have a lot more miles on the bike by now if I had done so...

JKB

 

[pendragon8000]

sorry if i missed it but did you get the rim?
ive got 2 alex dx 32 26 36h rims from ebay, exported from U.S. $70 each all tolled i think.
i only needed to replace 1 after a drunk skate park session where i decided to show off and ride up some stairs. they are super tuff as far as bicycle rims go. hey look fairly nice to imo.
search ebay
edit
and skpokes from holmes hobies, 12g ... just dremel off the eyelets on the rim. should take you a few hrs to lace single cros.

Hey PD8000!

I got some older, used rims from a buddy of mine that are pretty good - they are welded, not pinned. But I was very close to pulling the trigger on a couple Alex DX rims and still might, so I'll search ebay and take a look. THANKs for the heads-up!

I regret not just sending John Rob my Crystalyte motor and having him build up a wheel from it. I think I'd have a lot more miles on the bike by now if I had done so...

JKB

well my new theory is buy it and enjoy it. both equaly improtant. but to buy it you need to honestly know its worth it. so in this case IMO its definately worth the $70 for rim and $100 for 12g sapim spokes and nipples. im am sure frm what youve shown youve done you could lace a wheel single cross. just copy from a picture or google it. so easy. it would be totally solid as a rock. not heaps aero dynamic but meh less flats and better handling.

good luck

 

[tomjasz]

Excellent read. I have several scooter windscreens. I'm thinking the flyscreen, smallest, might be the most helpful design. Scooterists universally claim improved ride, comfort and efficiency with a screen. More!!

I actually DREADED installing the scooter windshield because I don't want the bike to "look like a scooter" in any way. However, it's worked out pretty well so far. I definitely don't plan to remove it any time soon!

I think you will like it if you add a windshield to your Trek Pure build. With an upright, "european" riding position we have, we need all the aerodynamic help we can get on our bikes.

Perhaps a small flyscreen style properly designed will almost get visually lost in the design. Then
again, looking like a scooter would suck.

 

[tomjasz]

I just read this. And thought of your ideas and tries with windscreens.

Article Summary
If you were designing a vehicle to be as aerodynamic as possible, it would definitely be counterproductive if parts of that vehicle actually moved into the oncoming wind. According to Los Angeles-based engineer Garth Magee, however, that's just what the forward-turning top sections of bicycle wheels do. His solution? Upper Wheel Fairings, which shield the spokes from the breeze. He claims that cyclists using his fairings can go up to 20 percent faster without any extra effort.

http://www.gizmag.com/null-winds-upper-wheel-fairings/31781/


"Under null headwind conditions, the wind is null at the bottom where the wheel is in firm contact with the stationary ground; and near the top the wind rises to twice the vehicle speed. By shielding the upper surfaces, the effective wind on the wheel is greatly reduced. And if a headwind is also present, the wind is reduced significantly more."

 

[WASYLBRYTAN]

I also discovered this technology last week and have been experimenting with it. It looks very promising. This is a picture of my e-bike with a very crude wheel fairing made from pie plates and duct tape. Crude as it is, it definitely gives me 20% improvement in battery range and 6% improvement in top speed in preliminary testing. This is definitely worth looking into and there is a lot of room for experimentation. https://scontent-a-sea.xx.fbcdn.net/hphotos-ash3/t31.0-8/10329718_625125934247705_7950162680216565647_o.jpg Bill

 

[jkbrigman]

Rode the Phat Bike into the office this morning - had a teeny bit of stuttering but probably because I've got the current limit set insanely low, at 10A for a total of about 730 watts. (The CA seems to respond a little slowly to current limits - I have a 2.25 version and I'm wondering if I can upgrade the firmware to the 2.3 version...)

Some things I'll be reporting on in more detail:

Distance: 32 miles one-way. (I'll cover that same distance again on the ride home.)
Avg. Speed: 25.2 mph
Sustained Speeds: About 30-31mph
Peak Speed: 38mph
Power: 730-680 watts.
Current Limiting: 10 amps
Start: Pack Voltage 18S/72v nominal.
End: 66 volts

This was a hugely successful morning commute that met a goal I've had since starting the build: I've achieved a "minimum desired average speed" of 25mph over the commute route. It required sustained speeds of 30-31mph to reach that average.

Travel time is now approaching the same time to make the trip in a car. I made the trip this morning in 1 hr, 18 minutes (door to door). Driving it in a car takes between 50 and 65 minutes depending on traffic. I am happily anticipating the commute home - being able to make steady progress on the ebike vs. sitting, stopped in traffic is an exciting idea.

Efficiency is "very good" at about 21 Wh/mile and I saw about 2.5% regen over the distance.

Key Factors:
Schwalbe Marathon Tires running at 70-80psi
Scooter windshield
Removed pannier, replaced with plastic tote on top of rack (picture coming of that tote - it's got a great shape)
Dieting, lost 40 lbs weight.
Better controller mounting keeps it in cooling airflow
Better battery harnesses offer unrestricted current flow, fewer connection points.

I'll update this posting with bike and CA photos later...

 

[tomjasz]

Well done, now I have another long thread to read. AND perhaps a future goal!

 

[jkbrigman]

Well done, now I have another long thread to read. AND perhaps a future goal!

Thanks man, I appreciate the good word! More in a little while...

 

[teklektik]

The CA seems to respond a little slowly to current limits...

Have you properly adjusted ItermMax/Min and IntAGain or are you using default settings?
This can make a very noticable difference...

 

[jkbrigman]

The CA seems to respond a little slowly to current limits...

Have you properly adjusted ItermMax/Min and IntAGain or are you using default settings?
This can make a very noticable difference...

Thanks for the tip teklektik - but how would I know what to set "IntAGain" to?

Downloaded the manual, read up on IntAGain, saw that it's going to take some testing and experimentation to determine the best value...

 

[teklektik]

Thanks for the tip teklektik - but how would I know what to set "IntAGain" to?
Downloaded the manual, read up on IntAGain, saw that it's going to take some testing and experimentation to determine the best value...

Apologies for delay - good you found the stuff in the manual. Unfortunately, it's been a couple of years since I tuned up a V2 - some settings are a PITA compared to the V3... that said, here's some notes that might help:

Overview
The CA has a software controller that accepts two primary inputs: the desired current (set by MaxAmps) and the actual battery current (read from the shunt). It has a single output: a control voltage that is used to drag down the operator throttle voltage to limit the controller. It's important to recognize that the CA has no effect until the current limit is actually exceeded at which time the Throttle Override voltage begins falling to limit the operator throttle. This means that some overcurrent is inevitable - the trick is to minimize the time the required for the CA correction to take effect and to adjust the magnitude of the correction so that it is prompt but not so aggressive that it over-corrects and limits excessively - perhaps even causing surging or oscillation as it hunts for the target limit value.

When in normal limiting mode, there are two things that affect the speed and stability of this control:

• the 'closeness' of the CA bracketing of the operator throttle voltage (ITermMin/ITermMax) and
• the agressiveness of the limitnig correction (AGain).

ITermMin/Max
The limits for the control voltage are set by ITermMax and ITermMin - ideally, these parameters should closely bracket the operator throttle voltage range - this keeps the CA control efforts tweaked in to the useful control voltage range that will affect the operator throttle. However, this control range is actually a bit lower than the real throttle range - lowered by one or two diode drops depending on the controller CA interface - about 0.4v for newer 'Large Screen Compatible' and 1.0v for older 'V2 Compatible' interfaces (1 Schottky diode or 1 silicon and 1 Schottky diode respectively).

• For example, if the true operator throttle range is 1.0v - 4.0v and the controller is the new style then there is a single Schottky drop of 0.4v so we expect ITermMin, ITermMax to be set to about (1.0v - 0.4v) = 0.6v and (4.0v-0.4v) = 3.6v respectively. We want a little safety headroom so we jiggle the range open by 0.1 or 0.2v at each end giving a range of 0.4v to 3.8v.

In point of fact, ITermMin is generally not that important in simple 'limiting mode' (as opposed to 'Current Throttle mode') so setting it a little low (or leave at default of 0.0v) is not harmful. However, ITermMax is the normal output control voltage of the CA when no limits are in effect, so tweaking it as low as possible without interfering with normal operator WOT can speed response by minimizing the 'dead zone' that the CA must traverse before limiting attempts have an effect.

So - with MaxAmps set to a very large value to disable current limiting, reduce ITermMax until it begins to limit the throttle, then increase it 0.2v. This is best done by connecting/disconnecting the green ThrO signal lead with the bike on a stand, but you can monkey around on the road and do pretty well with some tests on a steep incline.

IntAGain
IntAGain is the multiplier or coefficient of the error between the two inputs - MaxAmps and Actual Current. Tuning this is largely a matter of trial and error but the general strategy is to increase it as much as possible without incurring overcorrection. This appears as a oscillation around the limiting value or in cases of very large values, a loss of power for some seconds after hitting the limit as the CA over-corrects and sends the limiting control voltage to a very low value. Values that are too small can allow currents significantly higher than MaxAmps as the CA is unable to reduce the control voltage quickly enough. This parameter is really the most important and getting it right is worth the time. Your riding situation will determine the best test procedure, but I find it useful to run up an incline to load the motor.

Also of interest for the CA V2:

• CA 3-speed switch
  You can hook up a two or three speed switch to the V2 'Vi' input and configure the Aux Voltage function = Current. This will cause the MaxAmps setting to be scaled according to the switch voltage e.g. 50%, 75%, 100% and the resulting value used for current limiting. This is much niftier than the simple controller 3-speed switch that effectively just scales the operator throttle voltage without regard to the programmed current limit. This is easy to build with a few resistors but is slightly non-obvious - post back if you want to do this. This is very effective - highly recommended.
  
  Current Throttle
  An alternative form of the 3-speed switch idea above is to substitute a throttle for the switch and wire the V2 to drive the controller throttle input. In this mode, the throttle rotation scales the controller current 0-100% of MaxAmps. This is equivalent to the V3 Current Throttle mode but requires a little more customization instead of just selecting an option. If your throttle is twitchy or hard to control, this is the way to go - turning the throttle tells the CA the current you want, and the CA adjusts the (twitchy) controller throttle as necessary to achieve that value. This is a very predictable and smooth feeling throttle - highly recommended.