My Electra Cruiser project

General Discussion about electric bicycles.
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teklektik   10 GW

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Re: Need help ordering MAC kit

Post by teklektik » Dec 12 2013 10:18am

psychonurse wrote:...for my 26" electra beach cruiser.
No disc brakes.
I plan to use either a 36v or 48v lithium battery.
psychonurse wrote:Yes, I have lots of stops and starts. I currently have 36v 12A.H. battery. Would like get a controller that will allow me to upgrade to a 48v 12A.H. down the line. I like having more low end torque. Not really interested in going real fast. If the bike can get to a top speed of 25mph that would be sufficient for me.
psychonurse wrote:My tire size is 26x2.125
psychonurse wrote:Not a lot of hills in my area.
Lots of clear requirements -good!

Some folks don't like plots, but here's some stripped-down results that might help if you can plow though the post...
Here's a quickie run in the Grin Tech simulator comparing the Mac 8T and 10T at 36v (well, really 38.4 which is likely your mean running voltage):
MAC8T-10T_36v.png
MAC8T-10T_36v.png (129.27 KiB) Viewed 1610 times
So what does this mean? Well - the run was done using BMC V2S and V2T motors which are similar to the MAC 8T and 10T. The speeds at the bottom are the max that you might expect and you can see the 10T will not make 20mph on 36v. The little red circles show where the motor power curves (red) intersect the load line (black) which shows how much power is needed to push the bike to any given speed - this is where the max speed number came from (intersect means motor power = power needed to push the bike). The blue oval shows the off-the-line torque and the 10T has a clear advantage but the 8T is good as well and the gap diminishes with speed. With a bit of headwind or a slight grade these Wide Open Throttle (WOT) speeds will fall off.

Here's what you might expect after upgrading to a 48v battery:
MAC8T-10T_48v.png
MAC8T-10T_48v.png (138.08 KiB) Viewed 1610 times
Quite a bit zippier. Of course, you don't need to run at full throttle, and having some speed headroom so you can run at 75-80% throttle is nice.

Along those lines, here is one last run on your present 36v battery comparing a 10T running WOT and an 8T at 73% throttle so that its speed matches that of the 10T (the two power curves intersect the load line at the same point - red circle - so both motors are delivering the same power):
MAC8T-10T_36v_sameSpeed.png
MAC8T-10T_36v_sameSpeed.png (116.75 KiB) Viewed 1608 times
There are some extra tables from the simulator at the bottom with a few interesting results highlighted: the motor efficiencies, battery power (consumption), and range are essentially identical. They actually would be identical but this was as close as the throttle adjustment resolution allowed matching the speeds. So - if you get an 8T, it will give you about the same range, etc for steady running as a 10T if you back off the throttle (Ahhh - there's the rub!) at the cost of reduced torque on the low end - and of course, it will go somewhat faster if you are feeling frisky. The small blue circle shows the difference in torque at 15mph. There is not much difference so the pickup or acceleration if you goose it at 15mph will be pretty similar.
  • IMHO your present 36v battery pretty much puts you in the 8T bracket to be able to comfortably run at 20+mph. This motor puts you in good place at 48v regarding your 25mph goal.

    As far as the rim is concerned, since you have a 26x2.1, I think the Alex 24 CNC looks good. This would let you go up to a balloon tire later if you wish (26x2.35 Big Apple, Fat Frank) to cush out the ride and enhance the cruiser look (also should roll a little easier).
The upgrade kit is a few bucks more and would improve motor efficiency a trifle, but since you're not flogging the build (no hills, modest voltage, no Cycle Analyst(temp sensing)), it's not a huge return. So - you might be looking at this:
MACrec.png
MACrec.png (5.13 KiB) Viewed 1608 times
The 9FET controller is speced to get a little headroom for the 8T when you eventually upgrade to 48v (read the EM3EV comments).

In addition to the usual torque arm and C-washers, I might recommend that you pick up an ebike tester which will be a big plus in the future. Optionally, you might ask Paul to add some extra connectors to the order to match the controller and motor to make the tester connection easier. You can affix these yourself or get some assist. With the tester outfitted with connectors that match your build, you can plug it in and get answers in just a couple of minutes.
Visit Grin Technologies at www.ebikes.ca
Build Thread: 2WD Yuba Mundo V4

psychonurse   10 W

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Re: Need help ordering MAC kit

Post by psychonurse » Dec 12 2013 6:07pm

WOW! Thanks so much Tekletiik for that comprehensive post. I really appreciate the time you put in for me. I feel much more comfortable now that I have something to compare.

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Re: Need help ordering MAC kit

Post by cell_man » Dec 13 2013 6:36am

Excellent info from Teklektic as always, he's my first port of call when I'm lost with the V3 CA, as i often am... Do you fancy answering my emails in your spare time? :)

Just a quick FYI, as i think there is sometimes a bit of a misunderstanding about what best represents the various Mac windings on the Ebike.ca simulator. I believe the 8T Mac is very similar to the V2-Sp, but the V2-Trq is more like the 12T than the 10T Mac IMO. The 10t has an approx no load of 310rpm @ 36V, the 12T approx 260rpm no load at 36V. The V2-trq is approx 285rpm at 38.8V according the simulator, so more like a 12T Mac. The closest match to the 10T Mac in the Ebike.ca simulator IMO, is the 26" V2 Ezee, I believe it has approx 310rpm no load at 38.9V according to the simulator, so possibly, slightly slower than a 10T mac at 310rpm at 36V.

The attached data is for the standard Mac, the upgrade are typically have about 3% higher Max efficiency. I really must get that data to enable a comparison.

Thanks
Paul
Attachments
12T-36V.pdf
(45.92 KiB) Downloaded 76 times
10T-36V.pdf
(46.06 KiB) Downloaded 84 times
8T-36V.pdf
(46.09 KiB) Downloaded 123 times
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teklektik   10 GW

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Re: Need help ordering MAC kit

Post by teklektik » Dec 13 2013 8:31am

cell_man-
Thanks for the clarification on the 10T/12T... your rpm analysis makes good sense.

The whole BMC/MAC correspondence has gotten fuzzier with the advent of your newer upgraded MAC. I'm actually thinking that the upgraded versions with thinner laminations are closer to the BMCs than the plain vanilla MACs. It would be good to get at least your mainstream 8T/10T into the simulator. Having the full profile of efficiency and heat dissipation would be useful. It generally takes two motors to Justin to get one in - one for the destructive test and one for the shelf for future retest - so, unfortunately 4 motors would be sort of a noticeable expenditure... (but it might cut down on the emails! :D)

Anyhow - thanks for the words of encouragement and the PDF info - I think I see a little Excel exercise in my future! :D
Visit Grin Technologies at www.ebikes.ca
Build Thread: 2WD Yuba Mundo V4

psychonurse   10 W

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Re: Need help ordering MAC kit

Post by psychonurse » Dec 13 2013 3:04pm

I forgot to ask you guys if the MAC kits are simple to install? My last kit "ampedbikes" was pretty foolproof. The connectors where all matched up so it was impossible to make a mistake when doing the connections. Are MAC kits like that? Color coded or matched up connectors for someone with little electrical experience. I plan to order the "upgraded kit" offered. I may like to have a C.A. and according to them makes it an easier install. I'm still a bit hazy as to the controller. They cost difference is so little I would like to order the 12 fet 40amp 36-52v irfb3077 controller. Just incase I get power crazy down the line. Would this controller work with a 8t or 10t kit with my exsisting 36v 12 a.h. battery? Paul from em3ev wrote a e-mail stating "8t may be too fast and 36v battery may struggle with a small controller. 8t better matched with a 30amp controller. Am I correct that all the controllers work basically the same and that the higher the amp and fets the more powerful battery you can use? I appreciate your patience with me. I wish they had a electric bike book that is for the noobs like me that explains in lamens terms so I can understand the theory. No one has published anything you guys might know of have they? Thanks again for input. Mike

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spinningmagnets   100 GW

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Re: Need help ordering MAC kit

Post by spinningmagnets » Dec 13 2013 3:30pm

The 3077 FETs in the recommended controller are more efficient than the common 4110's. The extra efficiency means that they run cooler per the same amount of current, and heat is the enemy. The only restriction is that the maximum voltage of battery that will work with the 3077's is about 60V. If you think you may want to run 72V-100V in the future, then it's better to buy the 4110 FETs to make the controller "future expandable".

As to a 6-FET/12-FET...the 12-FET is physically larger and can flow more maximum current. There is the concern that if you have a controller that can be programmed to allow 40A, then you will do that now, and that will stress your 12-Ah battery very much (possibly leading to an early battery death). If you have plenty of room for the 12-FET, it should handle just about any commuter E-bike that you build now or in the future. The 6-FET is good for 20A continuous and 30A peaks, plus...it is so small, it can be somewhat hidden and stealthy (if that's important to you)

If you are using the 50V battery, the 10T should provide around 26-MPH or so. The 8T would be faster (30-MPH?), but would also draw higher amps when it's at a low speed and trying to accelerate. It is the higher amps that might hurt the battery, controller, and motor due to heat.

To make life easier on the battery, you could either get a bigger battery, or switch to a higher-performance chemistry (Samsung 18650-20E?, LiPo, etc). I don't recommend LiPo if you are new to E-bikes, it's a complex subject to handle safely without fire.

psychonurse   10 W

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The final solution for Mac kit

Post by psychonurse » Dec 13 2013 10:26pm

Alright you guys. My head is spinning with all the data you guys supplied. I'm not complaining but my head is about to explode. Tell me I am making the right decision. I don't do big hills. I like a little low end torque and would like the ability to go beyond the 22mph governor in some kits once in a while. My bike is a 26" electra cruiser.No disk brakes. I plan to use my 36 V lithium battery.Plan to upgrade to a 48v battery in near future. Front hub motor. My choice is as follows. 9fet 30amp 36-52 V IRFB, 10T Mac motor, 26"ALEX DM 24 CNC wheel. The "MAC upgraded kit" as seen on orders@em3ev.com. Thanks for your input. Mike.

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Re: The final solution for Mac kit

Post by footloose » Dec 13 2013 10:49pm

Mike --
May have missed this in your other posts... but why "front motor"?
I have a 10T Mac, rear drive, 26" wheel. It's a pretty powerful, torquey motor.
And not particularly light.
Opinions will vary, and front mounting is a bit simpler, but I think it is overkill for front wheel.
Unless you have a compelling reason for front drive, I'd go with 10T Mac rear wheel drive.

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Gregory   100 kW

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Re: The final solution for Mac kit

Post by Gregory » Dec 13 2013 10:58pm

em3ev wrote: with a 36V battery pack (12S A123 liFePO4) in a 26" wheel .....10T - 32km/h (20mph)
So don't plan on exceeding 22mph unless you are going downhill, or you go straight to 48V or you get a faster wind.


1) x5305 Hub Motor in a 24" Sun rim with 10G spokes, Kelly 72601 controller, 74V 10Ah Turnigy LiPo 20C Battery and CycleAnalyst
2) Mac 10T rear hub in a 700C "comfort bike" 15S 5Ah LiPo, stock 28A Xie Cheng controller
3) 38" Longboard, Turnigy 6374, CC Mamba XL2 ESC

The Mighty Volt   10 MW

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Re: The final solution for Mac kit

Post by The Mighty Volt » Dec 14 2013 5:43am

Are MAC kits now being liquidated?

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dogman dan   100 GW

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Re: The final solution for Mac kit

Post by dogman dan » Dec 14 2013 8:49am

Made us look, that's for sure. I was thinking we'd see fire.

I bet his only brakes are a rear coaster.

I'd get the smaller controller. 30 amps will kill your current battery I bet. Otherwise, sounds good to me.

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Re: The final solution for Mac kit

Post by DAND214 » Dec 14 2013 11:21am

The Mighty Volt wrote:Are MAC kits now being liquidated?
Why would you think that?

Dan

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Re: The final solution for Mac kit

Post by psychonurse » Dec 14 2013 12:39pm

My only reason for doing the front was ease of installation. Is there any forum member in the Northridge /L.A. area that could help me out if I got stuck on the installation of a rear hub motor? If so I would definately go with the rear. No coaster brakes. Standard front and rear friction type brakes. So which one of the lower amp controllers would you reccommend that they offer? Certainly don't want to wreck the battery. Thanks. Mike

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Re: The final solution for Mac kit

Post by DAND214 » Dec 14 2013 1:01pm

psychonurse wrote:My only reason for doing the front was ease of installation. Is there any forum member in the Northridge /L.A. area that could help me out if I got stuck on the installation of a rear hub motor? If so I would definately go with the rear. No coaster brakes. Standard front and rear friction type brakes. So which one of the lower amp controllers would you reccommend that they offer? Certainly don't want to wreck the battery. Thanks. Mike
Does it have a shifter, 7 speed? If so be sure to get the freewheel when you order.

Dan

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footloose   10 kW

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Re: The final solution for Mac kit

Post by footloose » Dec 14 2013 1:19pm

Mike,

The EM3ev kits are pretty easy to install.
The wiring is pretty much all plug-and-play, and easy to identify what connects to what based on the shape of the connectors.
Installation of rear hub is not significantly harder than front hub, if you have reasonable bicycle maintenance skills.
Suspect if you run into problems, there is probably an ES member near you who could help.
If not, I've seen ES members offer some pretty great troubleshooting tips based simply on photos of the install problem.

Re controller. If you are planning to upgrade to 48V, I think the 9FET 3077 controller is a good choice.
I have one paired with a 50V / 12Ah / Samsung NCM battery, it works great.
Until you get around to upgrading from your existing battery, you could ask Paul to program max amps in the controller to something lower than 30A to help preserve that battery, then reprogram it yourself later when you upgrade.
Or you could just run it with stock programming, knowing that it will decrease life of your existing battery, thus giving you an excuse to upgrade battery sooner :wink:
http://em3ev.com/store/index.php?route= ... duct_id=79

Didn't see any mention of torque arm in your post. Don't skimp on that, get one.

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Re: The final solution for Mac kit

Post by mark5 » Dec 14 2013 1:56pm

psychonurse wrote:My only reason for doing the front was ease of installation. Is there any forum member in the Northridge /L.A. area that could help me out if I got stuck on the installation of a rear hub motor? If so I would definately go with the rear. No coaster brakes. Standard front and rear friction type brakes.
Installing a rear hub motor ought to be very easy. You can watch Hyena Electric Bikes kit installation tutorial, a 13-minute video below. It's what I used to learn how to install a Mac kit. You basically just pull out the old wheel and drop the new wheel-motor-freewheel assembly in. Not much different than what you'd have to do to fix a leaky tire.

If you have a quick release rear wheel now, you might order 1 or 2 Grin Tech C-washers from em3ev to make the rear wheel washer fit easier. You could get the C-washer from Grin Tech in Canada but you'll save $15 Canada Post postage for a $5 item. You really need only one C-washer if you'll need it at all but having a spare might come in handy some day. If you have a quick release rear wheel and the dropout is flat, without a dimple or depression that the cam locking assembly of the skewer rests in, you don't need a C-washer.


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Re: The final solution for Mac kit

Post by mark5 » Dec 14 2013 3:01pm

DAND214 wrote:
The Mighty Volt wrote:Are MAC kits now being liquidated?
Why would you think that?
Holocaust reference--Final Solution (to the Jewish Question).

psychonurse   10 W

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Re: The final solution for Mac kit

Post by psychonurse » Dec 14 2013 3:06pm

It took a minute for the penny to drop on the Mighty Volts pun. I was driving to play tennis and it struck me. Well actually more than a minute.

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Re: The final solution for Mac kit

Post by psychonurse » Dec 14 2013 3:10pm

Thanks guys for your excellent input. The video will be very helpful. Yes I have a 7 speed. Will definately order the freewheel and 2 torque arms for safety. I didn't know you can make adjustments on the controller. How is that done?

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Re: The final solution for Mac kit

Post by psychonurse » Dec 14 2013 3:14pm

Here's a picture of the bike I plan to put the Mac on.
Attachments
IMG_0288_2.jpg
Electra Cruiser 7d
IMG_0288_2.jpg (20.45 KiB) Viewed 1767 times

mark5   100 kW

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Re: The final solution for Mac kit

Post by mark5 » Dec 14 2013 3:50pm

Looks like there's just a plain nut on the axle--no quick release and flat surface on dropout--so there's no need for a C-washer.

Controller is programmed using a PC program and USB cable. You can buy the USB cable and get the program from em3ev if you later need to change controller settings.

[The extension bmp has been deactivated and can no longer be displayed.]


psychonurse   10 W

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Re: The final solution for Mac kit

Post by psychonurse » Dec 14 2013 7:08pm

Mark you have good eyes! Looks like I'm all set. Will order tommorow. What make of rack to hold the battery do you use? Thanks.

psychonurse   10 W

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48 v 12 a.h. lithium in solid slide in aluminum case

Post by psychonurse » Dec 14 2013 8:14pm

Hi, I have one of those 36v 12 a.h. lithium batteries that slide onto your rack and can be locked and turned on an off with a key. Can anyone recommend a supplier with a decent price and reputation that offers the battery in a lockable slide out format. This time I want a 48v 12 a.h. Thanks in advance.

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Re: 48 v 12 a.h. lithium in solid slide in aluminum case

Post by cwah » Dec 14 2013 8:27pm

Yeah I haven't found something like that yet
Help me find my stolen electric brompton: http://bit.ly/1a0vbBC and Bosch Sinus B3 http://bit.ly/1eV0WQz

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dogman dan   100 GW

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Re: The final solution for Mac kit

Post by dogman dan » Dec 15 2013 7:51am

Yep, a rear motor should install easy as pie on that motor. You should still get one torque arm, but a cheap one intended for the front forks should install very easy. No need to get the c washer.

I dont' know what voltage you will want to run, but the easiest controller on the battery will be the lowest amps offered. I think it's 25 amps? It will be plenty of amps for that bike, and still get you up some big ass hills.

People just have this tendency to go straight for the big controller, which is fine, if you go straight to the highest power batteries.

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