SLA Lepton Review
I've owned an SLA powered Lepton scooter now for a couple of months. Having only had it since late fall, I've not had much time to log serious miles. I have managed to do some real world range testing in colder temperature and hilly conditions, and would like to share what I've found so far.
These features are standard, and directly out of the Lepton sales flyer which is available for downloading (pdf format) on the Zap web site:
Top Speed: 25 MPH
Range: Up to 20 miles
Great hill-climbing ability
Colors: Red, Black
Helmet & Charger storage under seat
Rear view mirror
"Economy" and "Performance" modes
On-board battery charger
Tires: 100/80-10 53L
Suspension, Front: Hydraulic forks
Suspension, Rear: Coil spring over shock
Ignition Key w/ security pass card
Warranty: Six month
DC, Brushless, Permanent Magnet
Max. Power 1,800 watts
Continuous Power 1,000 watts
Throttle Control: Variable - twist grip
Make & Type: Lead-Acid, AGM type
Amp-Hour capacity: (4) x 38 AH
Pack Voltage: 48VDC
Life Cycle: 200
Recharge time: (80% DOD) five hours
I have found that the performance of the SLA Lepton scooter is fairly close to the advertised claims. The top speed according to the manual I received with the scooter is actually 28 MPH, and this is the top speed that my speedometer indicates on the flat. This is 3 MPH faster than the sales brochure from Zap (above) indicates. The ability to climb hills is definitely there as I live high up in the northwest hills of Connecticut, and have had no difficulty in climbing any of the steepest hills here. The quoted 20 miles of range is very close to what I've found, (16.5 max to date using my "performance" mode driving stategy outlined below) and to be fair, my testing has been in less than favorable (i.e. cold, quite hilly) conditions.
I have found that "economy" mode will absolutely maximize the range that the SLA powered Lepton can achieve. I'd even go further to say that I could likely go further than 20 miles while in this mode. I believe economy mode achieves this by internally limiting the current drawn by the motor. This in turn limits the speed. While in this mode of operation, I've observed that all I need to do is drive with the throttle wide open as the Lepton controller automatically limits the speed/current draw of the motor. By contrast, "performance" mode simply allows the throttle to proportionaly control the speed of the scooter. (faster, more fun!) Because the Lepton is SLA powered, the batteries don't have a constant capacity at all discharge current rates. The capacity of the SLA batteries in the Lepton (most all SLA powered LEV's, actually) becomes less at higher discharge currents. While economy mode will indeed minimize this drawback of SLA batteries, I think it is too conservative. The speed gets unacceptably slow even on small inclines. What I've done is to study exactly what economy mode does and then drive in performance mode while mimicking the function of economy mode to a less conservative degree. My stragegy here is very basic. Hold around 20 - 25 MPH on a flat, 15 MPH on a small to medium incline, and 8 - 10 MPH on really steep inclines. I would only switch to economy mode if I thought I was not going to have enough charge left to make it to my destination. Another advantage of my strategy is that since I'm actually in performance mode, I can very quickly accelerate to fast speed should I need to due to a traffic situation.
The Lepton also has regenerative braking. This means that while the throttle is completely disengaged, the motor becomes a generator and dumps charge back into the battery while coasting. The regenerative braking on the Lepton is very powerful. In fact, it can be used as the primary means of braking. If used in this fashion, I've learned that it is necessary to at least lightly tap the brake so that the back brake light comes on. This shows people behind me that I'm indeed slowing down. One change I'd like to seen made here is to have the brake light turn on automatically while regenerative braking is active. Personally, I'm of the school of thought that more range can be realized by free wheeling down hill instead of dumping puny amounts of charge back into the battery while coasting. In all fairness, however, I'm certain that the Lepton designers intended the Lepton to be used in the more urban environment where stop and go driving would be more prevalent. In this case, regenerative braking may be an efficient means of getting the most range out of a single battery charge.
Driving Strategy in Real World Traffic
While 28 MPH is mighty speed amongst most current escooters, it's very meek speed when compared to even modest automobile traffic. One must adopt a different strategy when traveling with average traffic. The gas powered mopeds I've owned and operated in the past had about the same performance, so my Lepton traffic strategy is really borrowed from my moped experience. I tend to stay to the side of the road and only actually enter traffic at intersections where there are traffic lights or stop signs. The very good acceleration of the Lepton gives me more than enough speed and power to jump into/out of traffic where necessary. (easily superior to the sluggish acceleration of the gas mopeds) The only acception I make to this strategy is in those towns that have two lanes going through the center in each direction with a posted speed limit of 25 - 30 MPH. In this case, I tend to occupy the right-most lane with no difficulty. On narrow back roads, I always pay attention to who's behind me and try to make it as easy as possible for them to get around me. Sometimes this means speeding up to get around a corner so that they can safely pass me on the next straight or slowing down and pulling far over so that they may safely go around me. I see this as being courteous. It's been my experience that most car drivers see it this way too, and as such, don't get annoyed with me. In fact, most of them take a moment to focus on the "neat factor" of the Lepton!
The security card feature is a very nice anti-theft device. With this feature, the Lepton cannot be operated with just the ignition key. After the ignition has been turned on with the key, the Lepton looks for the security card code. It will not run until it has "seen" this code, which is accomplished by simply sliding the security card into the provided slot. Once done, the Lepton will finish "booting up" and will then operate. At this point, the security card may be withdrawn. It is not needed again until the ignition has been turned off again. The only thing I don't like about this feature is that the ignition key switch and security card slot are more than 6 inches apart. This makes it impossible to keep the security card and ignition key on the same key chain. This increases the chance of loosing the security card. I would almost prefer a simple switch for the ignition and rely on the security card alone for anti-theft protection.
The Autonomy mode on the Lepton yields an estimation of remaining range left. This display is updated every 15 seconds or so based on the last reading of battery voltage under load. (I think) This figure will go down while climbing up a big hill and will go back up when going down hill. When the Autonomy has reached around 9 miles remaining, the battery status light on the Lepton console blinks. When the Autonomy has reached around 6 miles remaining, the battery status light stays on solid. It is at this point that the driver should consider getting to an outlet. I found this feature to be terribly inaccurate during the first few cycles of the SLA batteries. After about 5 charge/discharge cycles of the Lepton SLA batteries, however, I've noticed that this display has gotten far more accurate.
There is a very nice, roomy, lockable storage trunk with built in reflectors that mounts on the back luggage rack of the Lepton. This trunk is currently available in flat black only.
There is a small faring also available for the Lepton escooter. I'm seriously considering purchasing this to cut down on the windchill effect during my cold winter rides!
For those like myself that purchased the SLA powered version of the Lepton scooter ---- fear not! It is possible to upgrade to the new Evercel Ni-Zi (Nickel Zinc) batteries. The upgrade consists of purchasing the Evercel 48V 38AH battery module along with a new charger designed specifically for the Ni-Zn battery chemistry. I have spoken with the Evercel people, and have been told that under equal conditions, I can expect a 50% to 80% range increase with these batteries! This is because the Ni-Zn batteries are 50% of the weight of the SLA batteries with the same AH rating. Additionally, the Ni-Zn batteries maintain virtually the same capacity even at extremely high discharge currents. That's a very big advantage over conventional SLA batteries! I'll be sure to let EVFinder know what results I get when I perform the upgrade. In order to find out more about the upgrade, I suggest that SLA Lepton owners start by contacting the dealer where the scooter was originally purchased.
Overall, I've found that the build quality of the Lepton scooter is outstanding! The workmanship easily equals any gas powered equivalent I've ever seen. The superb suspension of the Lepton along with a very low center of gravity provides for a very smooth ride over less than favorable road conditions with very decent handling. The very comfortable seat also helps here. The sealed belt drive along with the enclosed body of the scooter should also provide for years of trouble free driving even in wet conditions.
I think that one thing really working against the Lepton with regards to the competition from other high end electric scooter manufacturers is the fact that the Lepton sales information quotes what I've found to be real world driving range. From a sales perspective, this can be a disadvantage when other manufacturers specify much longer ranges that were likely derived under laboratory conditions. The perspective buyer is going to go for the biggest range number they see in print. The Lepton folks should consider emphasizing that their range figure is a real world one in their sales literature. In general, it would be nice if the electric vehicle industry established a standard for measuring the real world range of their vehicles. At the very least, manufacturers should be required to explain how their vehicle was driven and under what conditions (hills, ambient temperature, ....etc.) to achieve the advertised range. That would be a big step in the right direction.
The Lepton is available for sale from two sources that I personally know of below:
1603 York ave (between 84th and 85th)
New York, NY 10028
Phone (800)NYCEWHEELS or (212) 737-3078
Monday to Friday 9am - 7pm
Saturday 11am - 7pm
Sunday 11am - 7 pm untill x-mass
One ZAP Drive
117 Morris Street
Sebastopol, CA 95472 USA
tel (707) 824-4150
order line (800) 251-4555
fax (707) 824-4159
People may direct any questions they may have about the Lepton to my email address above. I'll do my best to answer them.
Charles H. Blow