Currie converted to eZee rear motor

[c_4]

I've had my Currie iZip for a couple of years now and have really enjoyed it, particularly the hill-climbing torque available, but the loud outboard motor always makes me self-conscious when riding.. I've blown both the front and rear tires once (repairing a blown rear inner tube in the field is a very daunting proposition due to the outboard motor), worn out a couple of sets of rear wheel bearings (the wheel really needs to be replaced next), a chain (and you need an extra long chain: a standard 7-speed change is about 6 inches too short) and the freewheel is looking pretty worn this year, so I bit the bullet and bought one of the ebikes.ca eZee rear motor kits to replace the Currie outboard motor.. I chose the eZee kit for a number of reasons: first and foremost, the fact that it was sold by ebikes.ca- Justin has an impeccable reputation for standing behind his products, secondly, I wanted something that could take advantage of the space on the Currie bike frame for the battery pack and possibly the box on the frame for the controller, and finally as a geared motor, it would hopefully have a similar level of torque for hill climbing, but also a slightly higher speed on the flat, but without the loud and conspicuous whine of the outboard motor.. The fact that the kit is not just a motor and a rim, but comes with a high quality Schwalbe tube and tire was also a nice bonus.

First of all, controller installation: it takes a bit of fiddling and careful twisting and shoving, but the eZee controller fits perfectly in the box at the base of the bike frame that the Currie controller went in.. Only concern is with overheating on long rides, but my solution is to drill a couple of holes in bike frame box and mount a couple of these

.. They're heat pipe memory coolers but basically, I'd carefully straighten the heat pipe, insert it through the hole and attach the heat pipe to the top of the controller box..

The only issue with the controller is that all the cables are *way* too long for a rear motor installation- you don't need anywhere near that length of wire whether you use the provided eZee battery bag or do as I did, and retrofit it into an existing e-bike frame.. They should offer this kit either with shorter cables, or with bare ends and just a bag of connectors for you to install yourself.. I ended up having to cut and splice all of the cables coming out of the controller to make them shorter..

Motor installation: very easy, drops right in. Only issue was on the anti-rotation washer which interferes with the rear derailleur mount, but a bit of work with a file on the washer allowed it to slip right into place.

Battery installation: the eZee battery is slightly shorter and much slimmer than the original Currie battery, and it also uses a narrower mounting rail , so I fashioned a new mounting rail from 1/8" heat formable Kydex plastic and bolted that in place of the original Currie rail. I also opened up the battery and re-routed where the power cables come out: they now come out about the middle of the case, routed in the gap between the two internal cell groups.. The connectors are protected by a shroud that I fabricated out of 1/16" Kydex..

Other controls: the battery meter is kind of pointless; I'd prefer a lighted throttle instead.. I know Justin's opinion of e-brakes is that they are unreliable and not required, but mine have worked fine for the last couple of years, and I personally feel safer having the connected, so I had to figure out how to hook up the e-brake levers of the Currie.. Turns out it was actually quite easy: hook one end of the brake up the the Cycle Analyst throttle override line and the other end to ground.

How does it ride?? Well first of all, just getting rid of the heavy outboard motor and lead-acid battery makes the bike ride so much easier.. On power, it has noticeably *less* low end torque than the Currie, which is actually saying a lot because the Currie only runs 24V.. Once it gets going though, its torque output improves and its top speed is significantly higher.. Today, I rode against a 20 kph headwind uphill and the eZee really struggled; if I had to call it, I'd say that the Currie's top speed against a similar headwind up the same hill was actually *better* than the eZee.. Overall, it's still a very rideable bike and I'm very pleased, particularly at how quiet the motor is... I do wish it had more low end torque, but I'm happy with the top speed and don't have any intention of overvolting or overamping especially as this has the possibility of destroying the plastic gears- I don't need the extra torque that badly.. I may still get a metal gear just in case- anyone know if the BMC gear is the same as the eZee and who has these for sale?

 

[WonderProfessor]

Question: You complain of less low-end torque. Are you pedaling to get started from a dead stop or are you using the motor to do all the work?

(This may be a very stupid questions as the Currie may be a motor-only bike with either no pedals or so heavy that most people do not bother to pedal.)

Thank you very much for this review. I have been seriously contemplating the eZee motor with a 48 volt, 20 amp-hour battery for a 20-mile (33 kilometer) one-way commute. Would love to hear more about your initial perceived quality and your actual future reliability experiences with this motor.

 

[c_4]

I am pedaling to start off, but even with the extra human effort, the lack of low end torque is very noticeable; the Currie could also be pedaled, but in this case, the motor has a simply amazing amount of low end torque (again, at only 24V) and could easily start you on your way from a dead stop with no pedaling at all, but it's an outboard motor that is also quite loud..

On the eZee, If I don't pedal at all, the motor groans and growls and gets moving very slowly (I've only done this a couple of times as those gears are nylon and I don't want to risk damaging them, although this only seems to happen if you overvolt the motor- 48V is probably the highest voltage I'd ever attempt with this motor unless I replaced one of the gears with a metal one)..

Hub motors are known for having comparatively low torque unless you are using high voltages (60v+).. I tried out a bike with a Crystalyte hub running 36V and it was a slug getting started, then the owner put on his 72V battery and then the performance was acceptable, but still sluggish compared to the Currie, and once going, its top speed was quite frankly too scary for me.. I wanted something that had high torque, but I didn't need a high top speed, nor the extra cost and weight of such a big battery.. I went with the eZee because according to the ebikes.ca simulator data, at the stock 36V, it is supposed to produce over 60 NM of starting torque, compared to a Crystalyte 408, which only produces 40 NM.. Even the big 5304 only gets up to 50 NM of starting torque at 36V; you need 60V+ to get the amount of torque out of an ungeared hub motor..

I think all the other brands of geared hub motors are probably exactly the same in terms of torque output as their gear ratios are all the same (5:1); the difference would be that these motors could probably handle a higher voltage and probably have a higher top speed and you'd still need to use a high voltage battery on them to get the high low end torque....

As to perceived quality, the eZee is definitely up there: very nice Weinmann rim and Schwalbe Marathon Plus tire as well as a Schwalbe tube, and what's more, the rim is "in-true" as well.. Most other kits come with a very cheap rim which is usually badly laced to the motor and out of true, and furthermore, very few other kits come with a tire, and those that do, come with a much cheaper tire/tube.. The controller is low current, but the self-diagnostics are very impressive- no other controller in the price range has this feature, which should come in very handy if you ever have to diagnose a failure- again, my only concern is heat.. The battery pack is very well assembled- high quality Phylion cells in stainless steel cases... The motor itself is nicely machined, lots of nice touches like the little metal shroud over the end of the axle to prevent wire damage if you run into something or the bike falls over- again, major concern here is the plastic gears are the potential of wear and damage.

 

[docnjoj]

I also noticed low torque at lower voltages with my Bafang. But at 48 volts with a metal gear it pulls almost as well as my chain-drive MY1018 (Currie system). It (MY1018) wins the pull contest, however! Very powerful on 36 volts, but too NOISY! Its now living with grandchildren on the Mongoose CX450 that it came from!
otherDoc

 

[WonderProfessor]

Much appreciated, c_4!

I'm getting closer and closer to settling on an eZee motor. The main reason I want to electrify my bike (as opposed to just getting a small motorcycle) is that I still want the exercise. My problem is that my average speed has dropped significantly in recent years because of my knees. If I could get something that would help me maintain an 18- to 20-mph average speed AND is as reasonably reliable as a Honda Rebel 250cc motorcycle (for example), then I would be in cycling nirvana. The nylon gears will wear out eventually but they should be easily replaced (assuming they are still available).

Again, many thanks for your help.

 

[el_walto]

My ezee kit at 48v 20A does not accelerate nearly as fast as my 5304 at 48V 35A.

With that being said, i prefer my ezee kit bike setup, it feels much more efficient and coasts awesome with the freewheel and a couple of marathon plus tires at 60psi

 

[GTA1]

My experience with this bike is that it is adequate if you disconnect the pedelec (instructions posted).

Otherwise, it is a very heavy bike to start riding in anything but the lowest gear --- which means remembering to shift down before every stop --- like a motorcycle or car with a manual gearbox.

I spoofed the Pedelec system to think it is always getting a "crank rotating" signal, and had no trouble using both electric and pedal power to start even in the highest gear.

The major improvements I am considering are:

- Front dérailleur and new crank set to give a taller low gear. At the top speeds on electric, you have to pedal pretty fast to keep up.

- Additional battery pack to extend range. Right now I am getting about 15km per charge (6 to 8 hrs to recover). 2 extra 12V-12A batteries would double that with a nominal weight increase.

I am not inclined to go the Lithium battery route as it is exorbitant (both to buy and to use --- they don't last that long).

Anyone have ideas how to mount 2 extra 12/12 batteries let me know!

- Modified Battery charger:

Instead of the stock charger, what about using a plain auto grade charger (12V, with roughly 3ah per battery charge rate)? It would be easy enough to rig up a charging circuit that charges each battery at 12V.

- Front Hub Motor

A real interesting mod will be to add a front hub motor (DC-Brushless) that can provide the mid-end and high end power and use the geared outboard motor to best advantage (low torque start).

At the same time, there can be a disc brake upgrade --- which a e Bike badly needs if it is to spend anytime at 25mph or so.

 

[WonderProfessor]

I am not inclined to go the Lithium battery route as it is exorbitant (both to buy and to use --- they don't last that long).

Now, here's some information that does not jive with the reported conventional wisdom of this and other forums. My understanding was that lithium batteries lasted the longest.

 

[c_4]

It depends on what the definition of "lasting" is.. Lithium batteries have a higher energy density than any other current commercial battery technology and will thus run your bike longer than a conventional battery of similar size.. On the other hand, lithium batteries have a shorter cycle life- in other words, they can take fewer charge/discharge cycles, and worse, they degrade with age even if you don't use the battery: regardless of whether you use it or not, whether you baby the battery or use it heavily, a lithium ion battery is good for only a few years after it' is manufactured..

 

[GTA1]

Kilowatt hour for Kilowatt hour, measured in terms of installed capacity, Lithium batteries (any chemistry) will not last long as deep cycle (not starting) lead acid batteries measured in terms of the number of charge / discharge cycles it last before it has to be replaced.

Measured in terms of Kilowatt hour / $, Lithium batteries cost some multiple more than deep cycle lead acid batteries.

What Lithium batteries excel in is energy density, both in terms of physical size and weight.

When users refer to "Lithium lasting longer" they are referring to a larger capacity battery vs. a lead acid battery.

One other characteristic of Lithium is that it can be both charged and discharged faster than deep cycle lead acid batteries.

That gives a certain advantage in terms of acceleration when the motor draws maximum power, and also for people who wish to implement regenerative braking.

That is why lead acid batteries are moving in the direction of being paired (possibly with it built in) with supercapacitors, which can handle the surge load (both charging and discharging) and thus, greatly lengthening both battery life and the apparent power output of the battery.

If e bikes are not just hobbyist machines, but something which have to deliver to a price / performance level that makes them competitive as basic transportation that compliments the motor car, the costs must come down and performance improve.

That is very hard to do with a lithium battery chemistry unless there is a sharp drop in the price of lithium technology --- not likely anytime soon.

Hope that helps....

 

[swbluto]

There seems to be quite a bit of disinformation here.

It's true that conventional lithium technologies typically don't have a significantly different lifespan than SLA, but most bikers use LiFePO4 which theoretically has a cycle life somewhere in the high hundreds to a few thousands which is far greater than an SLA's typical 100 to 200 cycle life. I haven't seen such longevity with my battery pack but I've also abused it a bit, so my experiences would be irrelevant. Anyways, I'm distrustful of cycle life claims from lifepo4 that hasn't been verified (In my opinion, only a123 has actually been verified) especially concerning the discharge rates that EVs demand. So, with that notion, I'm postponing any significant battery expenditures until testing can be done.

 

[dogman dan]

Ok , it's just my imagination that I put 3400 miles on a lifepo4 battery last year with no loss of capcity that I can measure yet. These aren't the batteries in yer cellphone. The weight is a minor issue too, since my lifepo4 pack weighs 15 pounds, and enough sla to get me up the hill to home would have weighed about 70 pounds. With lifepo4, my bike really is able to replace my car. With sla, I can't reach a store that sells more than beer and lottery tickets.

 

[swbluto]

Ok , it's just my imagination that I put 3400 miles on a lifepo4 battery last year with no loss of capcity that I can measure yet.

It is, isn't it? I think I last remember you saying you've never actually measured the full capacity of the 20ah pack, it's just that it's never cut out on your sub-18 ah rides.

 

[Rassy]

I responded to GTA1 rather curtly on another thread where he was spewing some mis-information, IMO. The improvements he talks about for SLA may well turn out to be a good thing, but not only is this not yet available, as far as I know, but it would probably push up the price considerably. Plus, the same capacitor enhancements to a LiFePO4 battery system would also give you better performance with less weight.

 

[WonderProfessor]

Okay, so now we have a "dialog" -- I just love a good "dialog!"

This is from http://www.ecospeed.com/battsdet.html. They offer high-end e-bike kits designed mostly for recumbents. Either they are incorrect or some of the above posts are incorrect.

10Ah, 36V SLA -- 100/300 cycles (full/80% depth) -- 3 to 6 years -- $0.09 per amp-hour
10Ah, 38V LiFePO4 -- 1000/2500 cycles (full/80% depth) -- 4 to 10 years -- $0.03 per amp-hour

Disclaimer: I am in no way trying to foist myself as an expert. I am in the "sponge" mode where I am gathering up as much information as I can in anticipation of electrifying a recumbent this summer. Last week, I bought a used EZ-1 recumbent. This week, I ordered the first part -- a fairing which will help with wind resistance and act as a sound board for the bitchin' stereo which will be the second part to be added to the 'bent. (I already have the stereo. I bought 10 of them years ago when I first added a bitchin' stereo to my Gold Rush. They are 12-volt Yamaha computer speakers.)

 

[GTA1]

10Ah, 36V SLA -- 100/300 cycles (full/80% depth) -- 3 to 6 years -- $0.09 per amp-hour
10Ah, 38V LiFePO4 -- 1000/2500 cycles (full/80% depth) -- 4 to 10 years -- $0.03 per amp-hour

The real question is what is the actual life from real users using the cells in normal use.

That must include users who are not "professionals" who use it every day, but ones who e.g., may use the bike maybe once a week, forget to charge it, use it again and completely deplete it, etc.

All the normal abuse of regular users....

Under these circumstances, I do not believe in the credibility of the 1000 to 2500 cycle claim.

That many cycles would put the battery way to the top of any secondary battery (rechargeable).

Long ago, Ni-Cads had a similar claim of 1,000 charge cycles.... but actually few survived to that life.

I am willing to listen if someone can dredge up the science --- actual research / test that show life of LiFePO4 cells in conditions that reasonably approximate normal use.

Will someone step up and give us some facts?