The eZip Trailz has been a perennial survivor at the bottom of the lists of factory E-bike models for sale to the public for years, due to their low price. I haven’t been a fan of them…until now.
Just to be clear, they didn’t suddenly improve the quality of an “entry level” E-bike…the bicycle part of this model is still the same as it was before (steel frame, no disc brakes, etc). Without the electrical kit, this bike is typical for the $99 bicycles found in the “big box” stores that most shoppers are familiar with when they need to buy laundry detergent and new socks for the kids. The reason that this is news is because…this “mild assist” E-bike has upgraded their battery from Sealed Lead Acid (SLA) to lithium.
The previous price was $449, and the new price with a lithium pack is $749, a difference of $300. The voltage is still around 24V, so this is still no hot rod. So…what’s the problem with SLA? They are bulky and heavy for the amount of Watt-Hours (WH) that they supply, but the worst part…is how fast SLA wears out. SLA remains the battery chemistry with the cheapest purchase price, and as a result…they are still frequently chosen by consumers who are new to E-bikes.
Some have stated that even if the battery does wear out in only three to six months, they will have saved up enough money by then to buy an upgraded battery. Maybe so, but my experience and research has shown me that the extra cost of a factory E-bike (over adding a E-kit to a bicycle) is usually paid by a customer who doesn’t have the experience or desire to mess with wrenches and soldering irons.
The previous battery was ten Amp-hours (10-Ah) in size, but…that’s not the whole story. SLA is kind of odd in that, in order to get the maximum life from them (short as it is), you should only use the top half of its range. If you run a SLA battery down to only having 10% left in it (its State Of Charge, SOC) on a regular basis, its life will be measured in weeks instead of months. So the big and heavy 10-Ah SLA pack is only useful for 5-Ah of range!
The second reason I never recommend SLA is that if you leave it discharged (even at 50%, like a careful consumer), then the un-coupled sulfides from the sulfuric acid will slowly begin to crystallize. Each time you do that, a little bit of its capacity is lost. This is why SLA batteries need to be charged up immediately when you are finished with a ride. If you commute, buy a second charger and charge both at work and at home.
If you let a SLA pack sit in the garage over winter, it will slowly self-discharge…and sit discharged until you dust it off in the spring. Then, when you plug in the charger, it simply won’t take a charge. When you take the batteries to a shop, their tester will verify that the SLA battery which you have only used a few time is indeed…un-fixable. The stock lithium battery in the new 2014 eZip Trailz Commuter is NOT likely to be made from high current cells, but even with the modest 9.6-Ah size, it should be adequate for the stock 15A controller.
The Currie Electrodrive
Currie remains one of the largest E-bike and “stand up” E-scooter retailers in North America, simply because they have continued to produce and support the eZip Trailz line. In the early days of the eZip Trailz, you could even sometimes find new units at $300 for the 24V SLA battery model, using the previous model motor (with loud straight-cut gears). The older eZip Trailz have developed a following by second owners because once the SLA batteries died, many of the first-time E-bikers simply sold the bike “as is” for under $100.
If you can get one of these older E-bikes for that price (and you live where it’s fairly flat), you could swap-in a larger motor, a 36V controller using 20A, and a 36V battery for a very affordable price. This basic drive unit has proven itself over the years to be well-sorted and reliable.
The only truly custom quirk is that this drive unit requires a freewheel on the left side of the rear wheel. In order for that freewheel to avoid unscrewing itself, it must use left-handed threads (LHT). The rear wheels’ proprietary hub should last a lifetime, but the freewheel does eventually wear out, requiring replacement. Here is a 7-minute video from Currie Technologies about how to remove and replace the rear wheel for fixing a flat tire, which will be useful if you want to attempt some of the modifications listed below.
There are aftermarket LHT freewheels available, but there are very few to choose from. If you want a higher quality freewheel (like the White industries ENO), there are no LHT units to be had. If you buy an eZip Trailz, I suggest you also purchase an extra LHT freewheel as a spare. You might not need it for years, but they may be difficult to find when you most need one.
Since 2009, all eZips have used the quieter helical gears in the reduction. Previous eZips used a motor that is much louder, with straight-cut gears (Model MY1018Z) .
The gear-reduction should be dis-assembled and cleaned out once a year (or whenever it gets noisy). Re-grease it with synthetic automotive high-temperature disc-brake bearing grease. Any brand of this type of grease is acceptable, and it is widely found to be consistently cheap and high-performance.
The 2014 eZip motor is brushed (model XYD-16 from 2010 until now), and also…the electromagnetic coils (that are energized by the brushes) are the part that spins, so…it is called an “armature” instead of a stator (The word “stator” comes from the word “stationary”). There are four long permanent magnets that are non-moving and fixed to the inside of the motor-shell. This style does NOT have a good heat-shedding path to the outside air, so care must be taken to not overheat it.
In the pictures above, the (24V / 15A) brushes and commutator have been damaged by using 48V at higher amps than stock. Brushed motors can be designed to operate with higher volts and amps (The Agni-R has been run at 96V), but brushed motors operate in a much narrower design envelope.
The location of the screws on the brush holding base-plate show that this motors’ timing was slightly advanced to improve power. If the screws were centrally located in the adjustment slots, the timing would be neutral, which would allow the motor to run in reverse, if it was being used in a different application.
If you remove the sideplate that holds the brushes, they can be awkward to re-assemble. Here is a thread on how to hold them back until you slip them back onto the commutator.
The stock brushed 24V controller (from 2010 and newer) has been found to operate fine on a 7S LiPo 29.4V battery pack (7S when charged to 4.10V per cell), but if you want to use a common 36V lithium battery as a performance upgrade (a 36V battery often starts out near 38V when fully charged), you will need a new brushed 36V controller.
The upgrade to a 36V controller and battery will provide 27-MPH on flat land (when coupled with the highly-recommended 13T drive-gear mod listed below). A LiFePO4 battery in an 8S configuration provides 29V when fully charged, and LiPo (not recommended for the inexperienced). Using 8S provides 33V if charged to ONLY 4.10V per cell, and that is too high for the overvoltage protection circuit.
Using 36V on a brushed 24V-rated motor seems to work well in the case of these eZip models. However, any modification to the stock system is a risk (and of course, voids the warranty on a new E-bike). I do not recommend using a higher amp controller on the stock motor, since higher amps produce a much bigger increase in the motor heat, compared to raising the volts.
If you already have a bicycle that you like, and your E-conversion budget is $900…you might be better served by the popular MAC 10T geared hub at 48V. However, if you already have an eZip Trailz that has run well at 24V for a few years (but now has a worn battery), you can swap-in a larger motor and also a higher amp 36V controller at the same time for much less.
Currie has used these same motors on a popular line of young-adult “stand up” scooters. As a result there is an aftermarket parts catalog on the internet with larger motors and higher volt/amp controllers that drop right in, as replacement parts. A popular vendor for eZip upgrades is “The Super Kids”.
Do NOT use the stock eZip XYD-16 motor at 48V. Many have tried, and it leads to rapid brush wear from arcing. One builder fried the motor in only 8 minutes of use (even though others insist that they have done this for a very long time with no issues). This is the reason that DIY experimenters like brushless motors so much. The common 9C hub motor is brushless, and has been run on every voltage between 24V and 111V, with no damage.
Hot Rodding an eZip
The stock eZip provides 16-MPH from 24V, which is the European speed limit for an unlicensed E-bicycle. The eZip also has a magnetic wheel speed-sensing pedelec mode as an option, so the motor would be energized by pedaling (without using a hand-throttle). The modifications listed below allow you to run up to 20-MPH while still using 24V, and 20-MPH is the US legal speed limit (if you don’t want to get a moped license).
Changing the stock 20T freewheel (located on the left side of the rear wheel) to a Left-Hand-Thread (LHT) ACS 16T will increase the 24V top speed to 20-MPH, and although there is a decrease in torque when you are under 10-MPH, the torque is actually better at the speeds above 10-MPH. When using this mod, always pedal along with the bike when starting off to reduce amp-heat to the motor until you reach 10-MPH.
You may want to do this mod if the stock LHT freewheel has worn out, and needs to be replaced anyways. Also, the chain must be shortened if you go to a smaller freewheel. Be aware the chain is a very strong 1/8-inch style. Here is a discussion on how to remove these freewheels.
The other option is to change the stock 9T drive sprocket to a 13T found on the GNG parts page, and this is the easiest and cheapest way to increase the stock eZip Trailz speed. By changing from the stock 9-tooth sprocket to a 13T, there is also a small improvement in the drivetrains noise level. The very strong 1/8-inch chain must be lengthened if you switch to a larger drive sprocket. There is also an 11T sprocket on that same parts page for those who want to experiment with that.
If the only change you make is to swap-in the drive sprocket, the 13T should provide roughly 22-MPH at 24V, and the 11T would be about 19-MPH.
Like any common and small geared hub-motor, this power system is a “one speed”. The GNG company uses this same motor in a bottom-bracket located mid drive. I like that idea, but…the quality of the GNG parts is disappointing. If you’ve already bought an eZip Trailz, and the motor gets very hot on your local hills, I have two suggestions. Do NOT change the gearing (16T freewheel mod, and the 13T drive-sprocket mod). This bike will be a better hill-climber with the stock gearing.
This motor is not appropriate for steep hills. For that you need a mid-drive, and a motor that sheds heat well, but…if you already have the eZip Trailz, and are willing to mod it?
Staton-Inc had a flanged LHT freewheel, which allows you to attach a 27T chainring. This will dramatically lower the gearing, which also lowers the top speed of the motor-assist. If the stock 9T:20T gearing provides 16-MPH at 24V, the new 9T:27 gearing might provide 11-MPH. At that point, you could also raise the controller and battery volts to 36V, which would increase the power, and also raise the top speed to roughly 16-MPH.
If you live on flat land, you can swap-in a higher amp controller to improve the acceleration (20A?). This is because you will only use the higher amps for a few moments, and then while you are cruising along…the motor has a chance to cool down a little. On a long and steep uphill, using higher amps will destroy a motor like this. You can lower the gearing, and raise the volts (just a little), but…do NOT use higher amps on steep uphills. Pedaling hard during acceleration (or on a hill) is a huge help to a system like this.
I wanted to thank my friend Walter, from New York (endless-sphere.com member DrkAngel), for all of the data in this article. He has been a proponent of the affordable eZip Trailz line, and he has experimented for years to identify and record the viable and most cost-effective upgrades to these useful E-bikes. His master index of links can be found here.
The Currie Technologies company is one of the top three most prolific E-bike vendors in North America, and they are based in The Netherlands (sometimes called Holland). That country is very flat, and as a result they have a very extensive bicycle culture that has continuously been reinforced through history due to high fuel prices (currently around $8 per gallon).
The upright riding posture and “moustache” handlebars found on the eZip Trailz is a characteristic of the most popular commuter bicycles found in Holland. This posture takes the pressure off of the riders wrists (compared to the inclined forward “racing” posture found on many road bikes), but also shifts the riders weight onto the bikes seat. This is why the eZip Trailz has a suspension seat-post.
The simple style of this paticular seat post is not the best performing, but it is a big improvement over the common solid seat-post. For bikes that have a hardtail frame, we have been proponents of a serious suspension seat post for a long time. Even if you end up getting another bicycle, you can take the expensive seat-post with you to the new bike.
If you live where the commute is fairly flat (like Holland), this new lithium-powered eZip is actually a very good starter E-bike. The buyers who are likely to be happiest with this will probably prefer to not hot rod anything, or mess with alterations or upgrades. If you are very mechanically-inclined and enjoy working on things, there is a significant improvement in performance if you add a kit to your bicycle. But…if you are happy to simply get a little extra boost when you are riding, and 16-MPH is plenty of speed for you…it just doesn’t get any simpler than this model here…
If this E-bike interests you, be aware that some retailers will try to sell an older $499 eZip Trailz with a SLA battery for the Lithium price. Also, some retailers are asking $999, so shop around for the best deal.
Written by Ron/Spinningmagnets, August 2014