Electric Motorcycle Primer “InsideEVs Style” – Part 4: The Rest
We’ve made it this far into it – the ride, the drivetrain, the batteries – there’s got to be a lot more to it, right? Actually, not really. An electric motorcycle is still a motorcycle, and does a bike by any other name ride so sweet? (ed note: Apologies to Bill Shakespeare. He rode a Vincent, we’ve heard.) Let’s talk about some of the details that are different than your gas bike, but not that different.
This seems to be one of the big questions whenever we’re showing, or even just talking about our bikes: does it have regen braking, how does it work, how much charge do you get back? To tell the truth, it’s not that big a deal.
Regen, or regenerative braking happens when, instead of the motor powering the bike, the bike is powering the motor. Remember back in Science class, if you give a motor power it turns, and if you turn the motor by hand the motor turns into a generator and gives you electricity? That’s how that works. When a motor is running in regen mode it makes electricity, and that is being fed back into the batteries. This sounds like a sweet deal. Free charging, right?
It is, but as usual, Physics rears its ugly head with some basic constraints. First, you’re not really getting a huge amount of charge from regen on a bike simply because the bike has such a small amount of mass. You’re still getting something back though, so that’s fine, but it’s not going to have a huge impact on your range. Next, there’s the issue of motor stress.
As you load the motor to accelerate, it generates some heat. If the motor is allowed to coast when it’s not pulling it can recover a bit, but if it’s being loaded in reverse, by generating power, it doesn’t get a chance to cool down. Most bikes on the market now have fairly aggressive air or liquid cooling partially as a result of these loads.
To do any effective braking, the motor has to have a load on it as well. To do predictable braking, you need a predictable load. That’s a little bit of a trick since you’re going to have a big load on the system if the batteries need a big charge, and a smaller load if they’re topped up. Newer models have this problem solved (we’re pretty sure it’s by shunting the loads), but the early bikes didn’t, and regen was either omitted or a little ragged – a problem when you’re talking about safety issues like braking.
Another challenge is the question of when and how the braking is activated. In all cases it has to be activated by some sort of switch or potentiometer, it doesn’t just happen, so do we want to have a lever that puts the regen brakes on, (the most basic method), or do we want regen to activate when you roll off the throttle, (as with most models today)? Even with throttle-activated regen, we want to be able to control how that braking is applied.
It’s far from a simple problem, and the result gives you several solutions – from the Vectrix scooter’s claim to fame, the first (and patented) regen throttle, to the Energica’s remarkably comfortable and controllable throttle-to-regen ramping that we talked about on our Bear Mountain story, that’s a combination of the VCU (Vehicle Control Unit) and the controller function. It’s a big piece of the puzzle, it’s a huge contributor to how the bike performs, handles and feels, it’s going to be a major aspect of how you feel while riding the bike, and it’s something you really need to experience for yourself.
Funny, after running our own bikes without regen it’s the one thing that we miss. Without regen braking the bike simply coasts, and it’s very hard to get used to. In Brammo’s specs, they comment that the regen braking is there partially to help balance the bike’s handling. Speaking with Rob Barber, though, one of the top motorcycle roadracers in the world, and pilot of the Ohio State Buckeyes entry to the Isle of Man this past year, he much prefers turning his regen off entirely. He wants to control his braking himself. With regen, you’re automatically applying braking to the rear wheel, and he, for the first time, can control precisely how much braking goes to the rear, and how much to the front, by eliminating the “motor braking” you get with both gas bikes and aggressive regen braking. Interesting.
Another common question is “How fast does it charge?” The answer to that is, it depends on your charger. Or chargers.
Every commercially available bike has some sort of charging system built in, and on-board the bike, and almost all of them offer charging options. The charging system is almost entirely independent of the drivetrain systems, so it’s a pretty flexible part of the equation, and though the manufacturers make a lot out of this feature, it’s really not that significant. They all need chargers, they all have chargers, and they’re not that special. Keep in mind, your riding habits are a lot different on a bike than a car – very often a “weekend warrior” will have the bike sitting in the garage for most of the week, and if that’s the case, you can afford to charge it at a slow pace.
Some of the realities of chargers? Well, the biggest one is probably that speed and power carries a tradeoff of weight. While we love our big fast charger, it’s sitting in the garage. Our little, slow, light charger is the one on the bike, and it’s often only used to grab a top-up while grabbing a cup of coffee, or getting a full-day charge while parked at work (or overnight at the motel). Our buddy Terry Hershner, on his record-setting cross-country rides, figured out that if you have twice as many chargers you can charge in half the time. Four chargers do it in one fourth of the time, as in, a full charge in 15 minutes as opposed to an hour. The result? He’s carrying almost 180 lbs of on-board charging. Here’s what that looks like, under his aerodynamic fairing:
Clutchless Riding – Safety Concerns
Any rider with experience knows that you use your clutch to feather the power at low speeds. By combining throttle control with your clutch you can feed the engine enough gas to get into the power band but control the amount of that power that’s delivered to the wheel with your clutch. The flip side of this is, you use your clutch as an emergency “power cut-off”. If you’re moving slowly through obstacles and want to cut the power, the clutch is the first thing an experienced rider will grab, and it’s often by reflex. Throttle, and even kill-switches are secondary. An electric bike doesn’t have a clutch, and thus, doesn’t have this kind of emergency cut-off. It’s a tough reflex to overcome.
Think in terms of dirt-bike riding through the woods. How many times have you sort-of lost your balance and wanted to cut power? How many times have you done it with the clutch? How many times have you been unable to grab the clutch, because you’re wayyy off balance? If you’ve done any dirt riding at all we’re going to wager this has happened at least once, and the harder you ride the more this has happened to you.
What happens is you’re falling backwards and the bike is still pulling forwards. As you go in one direction and the bike goes in another, your hand, if it’s still on the throttle, is twisting it “on”. The bike goes faster, you fall backwards more. Normally the only thing to do at that point is to try to lay the bike down on it’s side, or, as it’s otherwise known, “fall off while kind of holding on”.
This is just an example, and yes, you can say you don’t ride in the dirt so it will never happen. Well, it can, and at such low speeds it’s particularly embarrassing, (we like to call it the “Clown Crash”) yet still hurts. Especially when you laugh. At yourself. Please don’t ask how we know.
Low Speed Torque and Spinouts
This is related to the clutch question, too. As we’re accelerating in less-than optimum traction conditions there’s a very real danger of spinning out the rear wheel. To a pro rider it can be intentional, useful and fun, to an experienced veteran it will surely get your attention. To a beginner it can be a “What the HELL just happened?” moment, as they pick their bike up off the pavement and check themselves for bruises. We’ve seen it more than a few times with new riders – both the crashes and the confusion. This would apply to any situation where there’s not great traction like sand, water, even ice on normal street riding, and it can happen astoundingly quickly. Much is made of an electric bike having “100% torque at 0 RPM”, well, this is one place where that can bite you in the butt if you’re not careful.
A few more details. On-hill parking: a funny little growing pain of electric bikes. You can’t put the bike into gear, so there’s nothing keeping the bike from rolling when you park it on a hill. Simple solution? A rock behind the wheel. Better solution? A parking brake, though to our knowledge nobody offers one.
Theft: not something we worry about much. Granted, all of them are new, flashy machines, but any thief with any sense at all is going to look at this thing, scratch his head, and move on to something he at least knows how to start, and can sell or part out.
Service and support: This is a big one. Buying a product that has a high degree of cutting edge sophistication means your average wrench down the street isn’t going to touch it if something goes wrong – maybe not even for routine service. The manufacturers are trying – both Zero and Brammo will, at some point, send a tech out to you, but the further away you are from their homeworld, the less likely that would be. It’s a concern, and for this kind of price, it can’t be taken lightly. The good news is we’re not going to need anywhere near the maintenance we need on a gas bike, but if something goes wrong, it can be tough getting it fixed.
Do we have you hooked yet? Stay tuned, in our next and final piece we’re going to look at how to look at the Specifications.
As an old friend is fond of saying, figures don’t lie, but liars (and Marketing Departments) sure can figure, and sorting out exactly what the bike can do from the numbers they give you can be a little daunting for the newbie. At this point, though, if you’re reading along, you’re no longer fall into that category, right? So let’s forge ahead to Part 5: Reading the Specs.
Catch up on the whole Electric Motorcycle Primer “InsideEVs Style” series:
Electric Motorcycle Primer “InsideEVs Style” – Part 1: The Ride …where in we talk about why we’re doing this in the first place. Because riding electric motorcycles is awesome.
Electric Motorcycle Primer “InsideEVs Style” – Part 2: The Drivetrain The bits and pieces, and how they’re different, but also how they’re the same as your gas bike.
Electric Motorcycle Primer “InsideEVs Style” – Part 3: Battery Care and Handling (the BMS) How a lithium battery pack is different than any battery you’ve ever owned.
Electric Motorcycle Primer “InsideEVs Style” – Part 4: The Rest … the other funny stuff about an electric bike.
Electric Motorcycle Primer “InsideEVs Style” – Part 5: Reading the Specs Wrapping up, using what we’ve learned by reading the spec sheets (and actually knowing what they mean).