E-bike Control Systems—Which is the Best for You?
There has been lots of talk and controversy about E-bike control systems lately. That is no surprise to me as ever since my first ride on one back in 1994 I’ve had them on my mind. A lot of what I do deals with evaluating control systems, reporting on them and giving feed-back to the E-bike makers on how to program them better. Just in case you aren’t sure, the control system of an E-bike is what makes the motor run (when and how strongly).
Right now there are basically three types of control systems with some variations. They are throttle only, pedelec and dual-control. Some other terms you will see here are half (grip) throttles and full (grip) throttles, hall sensor, torque-assist sensor, ECU (electronic control unit) and true pedelec. I will try to explain each one as they come into the storyline. In addition to the actual control system type, we will find that the way they work, the time lag they offer and the amount of surging they have all figure into the equation and how comfortable you will be riding any particular E-bike.
As I’ve reported before the first E-bike I rode had no ECU. It had a simple three position toggle switch with off, low and high settings. To be just a little technical, the low setting connected the two 12 volt batteries in parallel (12 volts, at double the battery’s rated Ah), and the high setting hooked them in series (24 volts—full power). It was jumpy and not well controlled, yet at the low amount of power the motor added to the bike (old school motor and batteries), it was not too bad and quite fun to experience.
This was sufficient to run the bike yet some of its issues needed to be dealt with. For one, sometimes you wanted more or less assist from the motor. With only two power settings and off, that was all you got. Two, the switch was subject to internal arcing (metal contact damaging sparks) as it made electrical contact that would ruin the switch in a fairly short time. It was obvious that electronics were needed to bring the E-bike into the future.
Before long the E-bike designers added a ECU and a throttle to allow proportional motor control (throttle only control). This means if you twist the throttle (or push the thumb throttle) 30 percent, you get thirty percent of the power (and so on from 0% to full power). There is no lag or surge in these systems unless you initiate it yourself. These are still found on many E-bikes because of its simplicity and lower cost. Plus some makers are shying away from pedelec and dual-control systems until they become more refined.
With a throttle only control you are in charge of the motor’s power. There is no other system on-board that might add power when you don’t (or do) want it. In some ways it is the safest way to go, yet make sure you get one with the half-grip throttle not the full grip one. With a full grip throttle (motorcycle type) it is much easier to make the motor come to life by mistake when just grabbing the bike to move or mount it. I have seen riders fall from this happening.
Throttle only E-bikes control allow you to continually chose the amount of assist the motor adds to your ride. Under most conditions you want to give about half of the drive power with your legs and half with the motor. It doesn’t take long to get a feel for using the throttle to make your ride more fun and comfortable. One bad thing about this system is you have to hold the throttle (hand-grip or thumb) all the time you want power. This can lead to a fair amount of hand fatigue, especially on the longer rides.
Throttle only E-bikes might seem like they use your available power more efficiently, but that isn’t always the case. It is easy to add more power than you might need at any given time. Plus, although the option of not pedaling at all (motor scootering it?) might really appeal to you (a true pedelec will not allow this), it uses your battery’s power up at a very quick rate. My own eZip (a Currie Technologies E-bike) has an extra switch that you can engage so the motor won’t come on unless you pedal. It is still throttle only, yet that switch can help extend your battery range if used.
Next up is the pedelec. A true pedelec only powers up your motor when you pedal. The pedelec control system can be combined with the addition of a throttle to get a dual-control E-bike (which makes it not a true pedelec, more about that soon). True pedelecs are what you will see in Europe and other places because of their regulations concerning E-bike control systems. A true pedelec can be considered a bike rider’s E-bike as it forces you to pedal with the bike’s movement. Many love this system, many not so much.
Lots of people say true pedelecs have close to zero sales in the U.S. because they force you to pedal to get the motor assist (us lazy Americans?). Here is where some of the controversy is coming from, and there is a movement in some countries to allow throttle only and dual-control E-bikes to be available and ridden. Although it might be considered almost motor scooter like to be able to use a throttle, if it is a bicycle, than any control system you chose to use should be available to you.
The benefits of a true pedelec are many and the draw-backs are important too. These bikes get the best battery range because you are adding to the motor’s power with your own. Plus high-end electronics on the torque-assist pedelecs (still to be explained in a minute) add to that. One thing that can be bad news is that in a pinch when you need a burst of full power to get you moving, the motor may not respond in kind. Also in that instant when you start to move, a little power at the right time can add to your balance and confidence on the road. Some pedelecs and dual-control bikes don’t have these features.
A true pedelec can work the speed regulation wording to allow more speed than 20 mph. The U.S. regs and the California regs say an E-bike cannot exceed 20 mph by ‘motor power alone‘. So you can see if you are pedaling along with the motor power then a higher speed is ok. The Stromer Platinum I am riding right now (supplied to me for testing by NYCeWheels) and the Specialized Turbo (I tried recently) are two true pedelecs that fit above the scope of the 20 mph reg and can easily go 28 mph as long as you pedal strongly. Of course any E-bike can go faster than 20 if you pedal hard enough, but the motor will power down at 20 (give or take a few mph).
Pedelecs can add some danger and uncomfortable feelings to your ride. They can add more power then you want at a time you don’t want it. Plus the lag time before the motor turns on and turns off can cause some feelings of worry too. This brings us to the subject of how a pedelec works, the different sensing systems that work them and how to decide what is best for you.
In the more simple pedelecs, a hall effect sensor at the bottom bracket (pedals) tells the electronics when the pedals are moving. It doesn’t sense how fast you are pedaling or how hard, just the fact that you are indeed moving the pedals. As a side note, it also knows you are pedaling in the right rotational direction, you can’t fool them by pedaling backwards. Once the ECU senses the pedal movement, the ECU goes into its routine. Depending on the way it is designed and programmed, some work better and are safer than others.
Most have several levels of power you can select on a display panel or with some push buttons on the handlebars. Anywhere from 2 to 6 levels, with 5 seemingly being the norm. You might see some E-bikes with an analog knob that you turn to make the adjustment. So when you pedal, the motor automatically comes to that power level and stays there as you pedal. When you stop pedaling the motor turns back off. It’s that simple, or is it?
An off setting for the pedelec control is important in my mind, as sometimes you don’t want the motor to kick in, you just want to pedal your bike. You can turn off the entire system to simulate this mode, but on most E-bikes that will turn off the display and you won’t get speed and distance info from it. Plus if you decide you want assist, you will need to turn it back on and wait for the initializing sequence (which on some bikes requires you dismount and make sure the bike is fully stopped).
As I just stated above, as you start to pedal on a pedelec bike, the motor comes on automatically to the level setting you have chosen. Most bikes have a default mode, so when you first turn on the control system, it sets the level to a fairly low power setting. As good as a pedelec control system is, I think you can see that if you are in a high power level setting and you are going slow, stopping or turning, having the motor come to full power can be quite unsetting and possibly even cause a fall or worse.
To combat this and to help avoid other problems, most all E-bikes, especially ones that are pedelecs, have safety motor cut-off switches in the brake handles. This means if at any time you feel the motor is too powerful or you just don’t want power, a quick pull on the brake will electrically turn it off. A small pull is enough, you don’t have to pull so hard the brake itself actually comes on. It is to your (and your dealer’s) advantage to make sure these switches are installed, correctly adjusted, and working as designed. (And just so you know, a malfunctioning switch can keep the motor from running—a common reason your E-bike’s motor might not run) (E-bike troubleshooting 101).
I am well past my normal article length—my apologies—but this subject is important to me (and you), so I will continue without splitting it into two (or three) parts—thanks. And by the way, I have left out my normal barrage of photos so you can concentrate on the text.
Two more problems (or pluses) with pedelec systems are power lag and surging. Most all E-bikes (pedelecs) will have a time lag between the time you actually start to pedal until the motor powers up—and the from time you quit pedaling until the motor powers down. Each maker has their own reasons for setting it they way it is. A very short time lag is usually best. Yet some time lag is needed so the motor doesn’t come on too soon, or run too much. A long lag (some as much as 3 seconds, but most just over 1) before it comes on can make starting out much tougher. A long lag before the motor turns off can cause you some worries as you slow. There is no perfect setting for everyone’s needs, that is just one more reason I tell everyone to test ride the bike you want quite a bit before you buy. They are all different and what feels good to one person might feel unsafe to another.
The time lag and automatic motor control part of a pedelec can be bad news when slowing for a stop too. As you slow you normally downshift in preparation on restarting in a low gear. On all, except bikes with internal rear geared hubs, you need to pedal while slowing to allow the chain to move to the lower gear. So, as you pedal to downshift the power comes on. Not a good combination. If you have your hand on the brakes (as long as the bike has safety motor cut-off switches and they are working), then the motor will stay off and all is well. Often you are coasting to a stop without the brakes, so the motor could surprise you. Add in the time lag or the control system being set in maximum power level and the surprise could be bigger.
Now, the best system of all (when programmed correctly and in a safe way) is the torque-assist sensed pedelec. Although this is the cats meow, when programmed wrong it can be a kitty nightmare (dangerous). On these bikes there is a very sensitive weight-load sensor (usually mounted at the rear drop-out) that can tell precisely just how hard you are pushing on the pedals. Combined with a programmable micro computer to assist the ECU, it works the best and costs the most. It can be harder to diagnose and repair too.
I call them intelligent control. I love the bikes that have these and have ridden many. Of all I have tested and tried, the only two I can recommend so far are the BionX (an E-bike conversion kit–and also available on more than a few E-bikes) and the eFlow (distributed by Currie Technologies). On many others I have ridden, I have felt like I am much more intelligent than the bike and know the possibilities of an uncomfortable rider are certain. Injury and worse is a issue that bothers me too. Let me point out why.
A torque-assist controlled bike makes you feel like your legs are supercharged. The power comes on smoothly and seamlessly as you pedal at different leg power levels. They all (almost) have a way to set the sensitivity (power levels), sometimes marked eco, city, touring and power. Often they are just marked 1-2-3-4. The thing here is in the programming of the system, some are great, some not as much.
So what makes one better than the other? The good ones are set so the motor will not come to life until the bike has reached some basic speed (1 to 3 mph it seems). If it isn’t set this way then just putting your foot on the pedal when stopped can make the motor start to go. A mistaken turn of the throttle can do the same. Plus, if you are pushing the bike backwards and the pedal arm jams on the kickstand, same deal. Some have surging power or not enough power levels (steps) so the motor seems to surge (back and forth through the different power levels) as you ride. If nothing else, they are wasting the power you need for that long ride. Worst case scenario is the bike causing you to fall or pull you into traffic or some other dangerous situation (it has been close to happening to me on more than one occasion).
Some makers want the power available to you even when the bike is stopped. They say that it can help you attain momentum and allow you to gain balance as you push off to move. This is true, as I have mentioned it in the above section about throttle only E-bikes. Yet, even if you need to get to a small amount of forward speed before the assist kicks in, it allows both of those abilities just fine. I’ve ridden both types on tons of miles and can confirm that. I recommend strongly if you get a E-bike with torque-assist sensed control, get one where the motor won’t try to run when the bike is stopped.
I have written much about these problems that torque-assist E-bikes can have. Check my ’opinions’ category for more articles about control systems and torque-assist control systems. When they are right, they are truly the best you can ride. More and more E-bikes are coming out with a torque sensed control systems and I’ve ridden plenty of them recently, but still only two companies (that I know of at this time) are programming them in a smart, comfortable and safe manner,
Dual-control E-bikes. I think you can now see that this means to combine a throttle and a pedelec system (either hall sensor or torque sensed controlled) to get an E-bike with dual-control. This makes for really the best system you can have. The truth is that not all are set the way I like, something I continue to push for with the E-bike makers is for them to listen to my desires for a smooth and safe control system. When everything is right, the pedelec part works smoothly, with little lag and no surging, and the hand throttle is available for use (up to full power) at any time for motor-scootering or a burst of maximum motor assist in traffic.
On some you need to toggle a switch or display panel to allow one or the other (throttle or pedelec) to control the motor. I don’t like this as you can’t engage full power when needed if the settings aren’t right at that exact moment. Also, the need to take your eyes off the road and/or your hand off the handlebar to make the change in setting can add to a possible problem. This is one more thing I push the E-bike designers to think about.
If you are riding in pedelec mode, at a lower power setting, then just pedaling harder or faster might not give the burst you need to ride to safely. At that point the ability to hit the throttle for that rush of full power is needed. Most E-bikes with dual-control have this built-in, but some don’t. Part of the reason you have the motor assist is to be able to add full power when you need it. Make sure the bike you are riding can get full power when you need it without having to push some extra button or knob.
All this adds up to the fact that it is up to you to make sure the E-bike you are riding has a control system that works the way you like and in a safe manner. You can read the reviews (I have many here on my site), you can read the makers specs and info on their website and brochures or you can just hope the bike you get will feel right and safe. The only real way to choose wisely is to test ride the bike you are interested in, quiz the salesperson on all the functions, and think long and hard about all you’ve experienced on the test rides (making a list is not out of the question).
Buying a E-bike online or sight unseen could allow you to get one that doesn’t work well in all these respects. An E-bike is not so fast or quick (like a motorcycle) that a poorly functioning and programmed control system will throw you quickly to the ground like a wild horse, but it might keep you from being happy and getting the full experience you have paid for. You are getting one to smile, have fun, save money and help the environment. Plus there are so many other reasons to ride one. If you don’t like the way it works or feel unsafe, none of those benefits will come about.
I have given hundreds their first experience on an E-bike. Some E-bikes I test I will not let others ride because they are either unsafe or I know it will give them a bad experience. Even on properly functioning pedelecs I have had more than a few people stop right away and climb off, claiming they felt spooked as the power came on too severely. Most love the rush of power they offer, but for some it can be too much.
The one last thing about control system operation that I speak of often has to do with the biking experience level of new E-bikers. Many haven’t ridden a bike lately, much, or ever. These people need a smooth, safe control system more than others. I have massive amounts of time in the saddle so a finicky control system is something I can handle in stride. Then again a low mile biker, a aged biker or even a weakened biker will never be ready for a unexpected burst of power. These are just some of the reasons I lobby the E-bike designers and makers to do their job in such a way that a great E-bike is the result.
It seems there are more companies and brands of E-bikes than ever before in their history. New ones hit the market every week. Most are good, some are very good and others are not. It takes a team to design and build these. Every now and then I ride one and wonder what they were thinking. Even to the point of wondering if anybody even test rode it before it went into production. Do what you can to make sure you don’t get one of those.
Keep in mind too that these makers can up-date their bikes to work better (or worse) at anytime. New systems are coming out all the time. The torque-assist sensed E-bikes are generally easily reprogrammed as long as the maker decides to do so. Components such as ECU, displays and the such are routinely swapped out on the bikes coming off the assembly line for different reasons. The bikes I test and review are often different from the bikes on the sales floor near you. Many I ride are prototypes that are still in the final planning stages. Try your best to test the actual bike you will buy. If you need to order it, ride it long and hard before you sign on the dotted line when you go to pick it up.
Some first time E-bike buyers will opt to get an inexpensive or poorly made bike (maybe not by choice). As time goes on (if they realize they like what an E-bike offers them), they will start understanding what they like and don’t like about their bike and will start shopping for the E-bike of their dreams. It takes knowledge and experience to climb aboard an E-bike to evaluate the many nuances of them. That is part of what I do, to try to help you understand and gain knowledge of what the differences are and how they affect your ride and contentment as each mile clicks by on your odometer.
Thanks for reading, test ride before you buy, Turbo.
“The grace and charm of the bicycle lend added warmth and contour to the person of the lovers it joins.”—James E Starrs, The Noiseless Tenor.
Remember, you can see more of my E-bike pursuits on my Facebook page and You-Tube channel, titled the same as my bike blog here on WordPress—Turbo Bob’s Bicycle Blog.