APL's V4 Cruiser Build.

You could make it boost a little more it sounds like.

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Yea, that's the next step of course. :wink: But I'll stick with the 2.5Kw for a while and see what kind of stress it puts on the parts.
It's only able to deliver that amount for a second or so, because the bike gets up to speed so fast that it stops demanding power.
Only thrilling for a short moment,.. but I get to throttle it on every launch.

Still, it's fun to tweak the circuit, and I should make it easier to do so. Are the two 10 ohm resistors going to see any heat as 20 ohms across the shunt?

What if a person soldered the divider wire directly to the manganin center? Or better yet, make a slider on it so it's adjustable.
(just a thought, maybe simpler)

I'm assuming that the closer the divider gets towards the input lug, the more the output increases? Guess I'm not completely sure what's going on here.

Nice one. I'd never have guessed a controller that size would be shipping with such a low default power setting. Makes me wonder if you could have had luck fiddling with the settings over the comms header.

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Yea, I wonder if all these were set up this way, or if I just got the lemon,.. now I have to buy another one to find out. :lol:

Comms header; I'm not familiar with the MSU internals, .. never fooled with them, but think I saw on the manufactures specs, some kind of internal CAN bus communications form that accesses pin out settings.

Dunno if I've said this before, but my biggest concern with your design is the tiny cogs on the drive chain.

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For sure, larger cogs would be a good move. As the power goes up, I worry more and more. The thought of doing the walk of shame pushing this beast down the road is not good. I take a chain tool and lots of chain along, but the freewheel is my biggest concern,.. going to have to buy a spare and some removal tools and take them along.

(Yea, I'm not to good at video, but I'll start working on it.)

The shunt wires are probably around 1 milliohm total. You could place a tap right on one of the shunt wires if you wanted a 1 part solution (just a wire). Right, the closer you place the tap to the B- terminal, the higher the limit. At some point something could blow up.
At full current, the shunt will be seeing around 0.1v, so a 10 ohm resistor won't see any heat. You could use tiny ones. If you want to add a pot to make it adjustable, it can be a tiny one also. It's handiest if the setting can be controlled from the handlebars so you can change while riding.

It's strange is came with such a low limit. Either the programming was messed up or there's a wrong part on the board somewhere.

All's well that ends well, and I learned a lot, like how to control a controller, instead of the other way around. :|
I don't mind changing out resistors, just curious about the shunt connection,.. probably hard to solder to anyway.

I did get around to connecting a push button to the three speed 'high' mode, and was completely amazed that the controller mod
also doubled the high setting output! It acts just like a turbo now, even has a little lag,.. but takes off from 30 mph to 40 mph like a rocket! Wow, I've got a 40mph single speed! :thumb:


Well, I've been busy draining the last battery charge with the new set up, and have to say that this bike is totally fun now!

I've been "noticed" in the small sleepy town that's near by, and it's only a matter of time before there's a confrontation of sorts with the local law. So I guess I have to cool my heels and move on to the city across the way,.. an e-bandit on the run. 8)

Did you get any power readings in the high mode? It takes quite a bit of power to go 40mph. The button or 3 speed switch on the handlebars is great. Also good that nothing blew up during the test.

Keep an eye (well, hand, actually) on the controller and motor temps. Things can heat up pretty fast at those power levels. Good air flow is key.

I am happy for your success APL, and grateful to all who helped you! I am curious how many watts get you to 40mph. My recumbent is about 1750 watts from the battery for 40mph, if memory serves.

Double checked this morning, high speed setting only seems to work with 'completely' full throttle,.. strange.

Anyway, after 30 mph, when I push the button, it takes about 1400w at first and whips up to 40 mph at about 800 -900w at end cruise.



Not easy taking a picture with all that going on, but I used my red neck-cruise control, (Velcro strap), to lock the throttle.
Strap has a little give to it, so even that was difficult. (I'll get an acceleration video, once I figure out exactly how.)

Battery is drained down a bit, so full charge will be interesting, with a bit more power and speed. (I'll try that next)

I felt around for heat and didn't find much, controller is about hand warm, and the motor is the usual 'warm' but not hot.
It's pretty brief, so I imagine the internals are getting hot faster than the heat sink is showing.

Took a couple more pictures of the bike,.. but in 'direct sun' never seems to be a good idea.




Now I'm needing to concentrate on the brakes, the last rotors I bought suck, and aren't even round so I cant get full pad contact.
Cheap rotors, and definitely sketch,.. and a 100lb bike at 40+ mph needs a lot more.

Going to upgrade to Magura MDR-P 220mm rotors first, and some 4 piston calipers next.

That sounds great. I think you have the grearing dialed in perfect.

The button behavior is strange but still useful.

Brakes are important. I always had problems until I started using Jagwire organic pads. Not the grabbiest but I like everything else about them, especially no squeaking.

Beautiful. And nice weather for it wherever you are. You must be pleased with this result!

Your power per speed seems very low. 800 to 900W for 40mph is much less than I'd expect. Your cycle analyst set up right?

Maybe now is the time to stop caring and start enjoying cruising about :lol:

I second this, but didn't want to say it first
At 40 mph (direct drive) the simulator estimates 1640 battery watts for a semi-recumbent and 2850 battery watts for an upright mountain bike. If you can verify the speeds with GPS on your phone, that means your battery is quite healthy Enjoy using that awesome machine now that it's summer!

That sounds great. I think you have the gearing dialed in perfect.

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For sure, the 20T/36T is right on at 30mph, and I'm happy with that. Draws around 200 - 400w most the time on the flats and I get
about 50 miles off a 10P battery, so that's all good.

The speed button is just frosting on the cake, and I have no use for it,.. but sure is a thrill from time to time and gives me 40 mph bragging rights. It's dangerous towards the 'end' of the charge though, because those 5+ second burst's at 1 to 1.4Kw really dig out the battery. I found out where the LVC was yesterday, (52v), and wound up pedaling home.

Your cycle analyst set up right?

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Well, not exactly,.. I replaced the Grin shunt with a 100A aftermarket shunt, and it's about 60w off, I wanted to wait until the system was settled in before calibrating the CA, and have been just mentally compensating. Not far enough off to make much difference though.

But to be sure, I have the digital display that came with the new shunt, and can hook that up to compare the two. (Will do.)
I've been using this CA for over three years now with Grin shunts, and I'm pretty familiar with what 100 to 1500w feels like. I'm confident with what the CA is showing as "close".

At 40 mph (direct drive) the simulator estimates 1640 battery watts for a semi-recumbent and 2850 battery watts for an upright mountain bike. If you can verify the speeds with GPS on your phone,

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There's a speed radar in town that I'll see if I can trigger to confirm the speed. Otherwise I can borrow a buddies phone.
The simulator is interesting for a direct drive, that seems like a lot of watts. But you would need to change a few settings to get my set up for comparison, (if possible?)

The motor is a 4T, (13.6 Kv from Neptronics post), the wheel diam is actually 27", and of course it's a Leaf motor as a middrive at 60v or so.

I suspect that the 1.8:1 ratio and high rpm is the biggest factor, I don't know the actual rpm's but the calculator shows 700 rpm at 30 mph and 900 rpm at 40 mph.




The Leaf seems to be happy at those speeds, and spins right along at 700 rpm,.. I'm sure that at 900 with field weakening it's not so efficient anymore, but it's only for a few seconds, (I wouldn't hold it at that speed), so it doesn't really matter.

Anyway, I've got a fresh charge on the battery so I'll take it out and see what some max reading are, and check the mph speed if I can.

Sure thing! Here is a direct drive upright vs. mid drive upright comparison at 67 volts (16s hot off the charger), 13.6kv for the Leaf 4T, 27" wheels and 20t front 36t rear cogs. It would appear that the upright bike is voltage/gearing limited to 35.7 mph. It takes 1700 watts at the wheel to achieve that speed, and 2000 watts at the battery accounting for drivetrain and electrical efficiencies.



If we were to change the rear cog to 28 tooth and limit the controller to 45 amps, we'd pull 3000 watts when the battery is hot off the charger. This makes for a pure direct-drive vs. mid-drive comparison, which is essentially a gearing change of course.

Hmm, according to that, there seems to be about 1000w missing or added somewhere,. not easily misplaced.
Don't think the speedometer could be that far off either, but I have to check that out yet, I'll hook up the other wattmeter and check it against the CA to see if it reads any different.

I took the bike out with a crackling fresh charge today and it really made a big difference!
Floored it off the line and watched it climb over 40,.. to 45,.. and then to 50 mph! Used around 16 -1700w to do it most of the time.
Totally amazed, and makes me a member of the 50 mile an hour club. 8)

I was able to get a video of the ride, :thumb:, with a Go Pro I bought a few years back,. just got around to figuring out all the downloads, uploads, and web crap for it today. Youtube says pending yet, so we'll see, I'll post it soon

I think it might have got something a little hot in there though, because the throttle was kicking in and out when I got home. I tried it again a few hours later and it worked fine, so I don't know what that's about yet. Guess I'll leave the magic button alone for a while and see if it throttle-glitches anymore.

Well I don't know what the deal is with youtube, still pending, and I might have to try uploading again. This is why I hate video.
Took a video screen shot though, thumbs on the button,. this is why I like photos.

Your brakes are at least hydraulic, which I like. If they use this size of pad, try Shimano B01S pads and see if they give you more friction.

Finally got the YouTube thing figured out, only problem is the video quality is worse than the original copy and you cant see the CA numbers!

Oh well, try, try again. Next video I'll know better and try to show that better (My first Go Pro experience.)

[youtube]UNiXKc6JGyU[/youtube]

Did a little bike walk-around for the new viewers on the Tube, so just go to 1:35 to watch the launch.
At 1:40 I push the button at 32mph, and at 2:00 I hit 50mph at the house.

Sorry for another bad road-runner video,.. but I can only get better now. I want to thank everyone once again for helping me get the old beast this far. :thumb:

Looks like it really goes. You can't tell much from the sound on a video, but how does it sound in real life? It should be fairly quiet.

Yes, it's very challenging to make a video with a good view and also have the display readable at the same time.

I agree with some of the others that your speed vs. power consumption numbers don't seem quite right. It's easy enough to check your speed with a speedometer app for a smart phone. I have a free one. Or if there's a radar sign in your area, those are pretty accurate too. Calibrating a current shunt is not so easy. You have to either trust the labeled resistance or have some fancy test equipment to check against.

The bike is pretty quiet, other than the new front freewheel on the cranks that I just bought, sounds like a roller coaster, but I can't really hear it much until I pass something and the sound gets reflected back.

Mostly the wind is the main noise of course, and it's defining, I've tried everything to keep the wind off of my ears, but it always mutes the rest of the surroundings, so it's no good. You have to be able to hear the traffic.

I'll try moving the camera forward, which I should have done before I posted. Wanted to get the CA, 'and' the front view of the road, but wound up with missing both.

Well, on the original video I can take screen shots at any point, and it appears to show around 1700w for most of the time between 40 and 50mph, so that's more in line with what's expected. I'm thinking that the 900w I stated earlier at 40mph was a bad camera shot in a difficult situation, and the watts can fluctuate a lot faster than the MPH,.. I can't do everything at once.
I can double check that too.

But first, I'm going to check the speed with the radar, and hook up the other digital display that came with the 100A shunt I bought.
These two things will help shed some light on the situation, and I'll work on getting it ironed out.

I won't be pushing the bike that hard anymore though, 50 takes too much of a toll, and I think the throttle was cutting out on thermal overload, just my guess, since it hasn't happened again.
I like 30 and a little burst once in a while. It's true I'm a criminal now, but I'm not a maniac. (usually) :wink:

OK, I road it through the speed sign today, and the sign and CA both read 31 mph, so at least that part of the mix is spot on. :thumb: Checked it twice.

I'll try to check the CA/shunt accuracy next, but I usually take the week of the 4th off to see the family, so it'll probably have to wait,.. leaving in a few days so not much time to mess with it.

40-50 mph should be taking closer to 4,000w. I think there's some charts somewhere or the Grin simulator can calculate it.

I have a DC clamp-on current meter that I can use to spot check the shunt calibration. Otherwise you need a known to be calibrated shunt. Measuring your existing shunt's resistance is a bit tricky as you need a way to pump a constant current at a fairly high level to get a good reading and a calibrated amp meter.

The cheap 100 amp shunt I bought is suspect for sure, it's rated at .75mv, (here we go with the low levle Chinese stuff again.)
It comes with a meter though, and I plan to hook it up for comparison.

Grin Tech says 100A+ shunts are rated at 1.00 mOhm, and the small plastic potted CA Grin's are rated at 1.00 mOhm, far as I know.

I know there's advanced settings on the CA to center out the shunts, and I need to access that yet.
Not sure how big a difference that makes overall.

All I can find on the CA shunt, from Grin instructions printout: http://www.realelectricbikes.com/Cycle_Analyst_V3_programming.html


It says;

"Range: The CA can be configured in a Low range mode appropriate for ebikes, as well as a High range mode intended for electric cars, motorcycles, and other large EVs.
Lo (W): This mode is intended for systems with shunt sense resistors that are in the 1-9mOhm range. Current resolution is to 0.01A and power is shown in watts.
Hi (kW): The high range mode is intended for high current systems that have shunts which are in the 0.1-0.9 mOhm range. All power units are shown in kW instead of W, and the current resolution is 0.1A. As well, all of the current and power feedback calculations are also affected by the chosen range mode, so an AGain of 50 in low range mode would be equivalent to 500 in the high range.
RShunt: The CA is only as accurate as the calibration value for the current sense shunt resistor. Most controllers with direct plug-in CA connectors have resistances in the 1.5-6 mOhm range, while the Stand Alone CA shunts are all exactly 1.00 mOhm. For high current shunts used in larger EV's, they will typically not rate the shunt resistance but instead show the current draw that causes a 50mV drop. So a 200A 50mV shunt has a resistance of 50mV/200A = 0.25mOhm.
Zero-Amps: Pressing the button here will take the present amperage readings as the œzero amps reference. After holding the button, you will see two voltages on the screen which are the outputs of the two current amplifiers. They should both be around 2.5V.
VScale: This is used to calibrate the voltage display. The factory calibration is about 31V/V. If you use an external voltage divider, you would set this to match the voltage scaling ratio".



I should invest in the Grin name brand 100 amp shunt, but had trouble finding one last I checked. Not sure if they actually make
it in house,.. probably not, but most sellers show a .50Mv shunt in the photo, and say it's a CA shunt. (confusing)

I also have a few of the original small 50A potted CA shunt that I can put back in there and check it with.
Although the wires are kinda small, and the shunt tends to get hot at the higher amps.

We shall get to the bottom of this somehow.

See what the included meter says with a known load. I believe you had a resistive heater or something during your battery creation. Then calibrate the CA to show the same wattage with that load.

I have 3 of these meters on bikes in my circle of influence. They're pretty handy and accurate enough. I have no idea if the shunt is actually calibrated to 75mV at 100amps, but the current readings measure just a tad higher than what my JBD Smart BMS's show.

Good to know that those meters are somewhat close to accurate, I have the same meter and shunt. Thanks thundercamel. :thumb:
So when I compare it against the CA reading it should at least get us a little closer to the truth.

Think I can hook them both in parallel to the shunt, so I can view both readings at the same time? Or one at a time?
I suppose I could try it both ways easy enough.





No time left though, I'm hitting the road tomorrow,.. back in a week, and enjoy the 4th everybody!

I believe they can be hooked up in parallel, since they're both just measuring voltage on each side of the shunt.

Yes, you can put both meters in parallel on one shunt.

Back in the sadel. :thumb:

The Magura 220mm rotors and Jagwire disc brake pads arrived while I was gone, so I spent the last few days wrestling them onto the
bike. The usual adapter fiasco ensued, but I think I have them pretty close and just need a little fine tuning.

Next up is a 4 piston caliper or two,.. but not in a hurry to spend the $$$, so we'll see how well the XT's work first.



I also started working on the shunt meter thing, got it mounted and piggy-backed onto the CA. Took it out for a quick test and found it to read quite a bit higher than the CA. In fact, rather unbelievably higher. So for now I don't know what to think.

I finally went into the CA advanced settings and accessed the shunt value, and found it to read 2.5 mOhms, which is way to much. (should be 1.0) The shunt is .75mv,.. so 100A/75 equals .75 mOhms. The CA only goes down to .763 mOhms in the settings, so I punched that in, and wound up with an extra 250w over zero on the meter.


I'm not really getting anywhere here.

So, what I'm going to do is go back to the original Grin 1.0 mOhm potted CA shunt, and re-set the meter back to the factory 1.0 mOhm and see if that zero's it out. I'll leave the other meter and shunt the way it is and compare the two of them when I'm done.

I might have to just shelve that 100A shunt and stick with the original CA one.