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[Arnelon2]

Hello everyone Recently I decided to experiment when taking a usual 24km ride.
On the way there I rode as normal, keeping at the speed limit with gentle accelerations to get up to speed. In total that used about 50% battery, with an average speed of around 70km/h.
On the way home, I would alternate between accelerating and coasting with 0 regen. If the speed limit was 70, I would get up to 80 then coast back to 60 and repeat. This is obviously not a civil or safe way to ride, but thankfully the roads were clear at that time of day. The return trip only used 25% battery. The difference is so big that I repeated this test a few more times on other trips, getting the same result of twice the range, despite having the same average speed.

Here are the details on my bike and custom profile:
2018 Zero FX, belt drive, original 7.2Kwh battery pack
0% passive regen
100% active regen (foot brake)
0% torque ("0" is misleading, it's just more gentle than eco)
Started the test at 100% after a slow charge

Looking at the consumption when riding, I don't understand why there is such a huge difference. I remember reading here that this method of hypermiling was only really effective on Energicas. Does anyone know why this is happening?

[TheRan]

The first thing to consider is if you're testing by going somewhere and then coming back along the same route then there could be things on the way out that use more energy but that actually help on the way back, for example going up in elevation and heading into the wind versus going downhill with a tail wind. For an accurate test you'd need to do a loop riding with one method, recharge, then do the same loop with a different riding style (preferably on the same day for similar conditions).

The second thing to consider is your average speed, how long the loop took you. If you're accelerating slowly enough and slowing quickly enough when coasting then using the second riding style could result in an average speed below the constant 70km/h. However, even if you were just at 60km/h the whole time that wouldn't result in half the energy usage so there is some other factor at play.

[Specter]

A few other things to consider as well.
The battery / range calculation is just an estimate.  Many things can change that estimate.

How is the range exactly calculated?  Are they just metering KW used / KM burnt on?  Are they looking at battery voltage? which the discharge is not exactly linear.  If you started right after the charge, the voltage is going to be way high, and a lot of that voltage is not really an 'energy dense' voltage, so it will really drop in the first half KW/hr used or so.  That will skew the reading of how fast you are burning the battery.

Also temperature of the battery will play on voltage and watts/kg of battery, so once the battery is warmed up from the trip / the sun shining on it, the temperature now being 85 .vs. 55 in the morning etc that can affect it as well if you charged and it sat overnight and cooled as an example.

As THeRan suggested, if you can do a loop, or just one complete trip, riding one way, repeat a few times to get an average, note the weather, wind etc for comparison.  THen do the complete trip a few times riding the other way and see your net results.

TBH the only time regen really helps is on an intentional braking, because otherwise it just saps energy you spent to get up to that speed, and while it puts it back in the battery, it's not at 100 percent efficiency.

Aaron

[Bodo]

The most energy efficient riding is -idealistic- without braking or decelerating at all. Second most energy efficient is coasing to decelerate; ie. lifting off the accelerator early enough.

Regeneration only harvests a fraction of acceleration energy (even if all BEV marketing hypes it), so avoiding deceleration as often as possible and using coasting instead of regenerating should most energy efficient.

[Arnelon2]

Thank you for your replies, I'll do several more tests on my next round trips to the gym while implementing your suggestions. This will hopefully give a more accurate comparison. The initial question still remains through. Assuming the difference in consumption is real, albeit somewhat inaccurate, why does it exist?

[DonTom]

Hello everyone Recently I decided to experiment when taking a usual 24km ride.
On the way there I rode as normal, keeping at the speed limit with gentle accelerations to get up to speed. In total that used about 50% battery, with an average speed of around 70km/h.
On the way home, I would alternate between accelerating and coasting with 0 regen. If the speed limit was 70, I would get up to 80 then coast back to 60 and repeat. This is obviously not a civil or safe way to ride, but thankfully the roads were clear at that time of day. The return trip only used 25% battery. The difference is so big that I repeated this test a few more times on other trips, getting the same result of twice the range, despite having the same average speed.

Here are the details on my bike and custom profile:
2018 Zero FX, belt drive, original 7.2Kwh battery pack
0% passive regen
100% active regen (foot brake)
0% torque ("0" is misleading, it's just more gentle than eco)
Started the test at 100% after a slow charge

Looking at the consumption when riding, I don't understand why there is such a huge difference. I remember reading here that this method of hypermiling was only really effective on Energicas. Does anyone know why this is happening?

Do NOT waste your time looking at "range left"! It is not worth your time to even look at. It assumes nothing will change in every km ridden, when it is often the opposite conditions such as going into the wind than with the wind or up hill and then downhill. It is calculated every ten KM for your current conditions ONLY. That makes it 100.0% totally meaningless, IMAO.


A lot of power can be wasted with regen. Such as on a hilly freeway. Best then to not have any regen at all. The bike slowing down will waste a lot of energy for getting up the next hill.


Regen is great for city stop and go traffic. Every time you MUST slow down, regen is very helpful. When slowing down is NOT a must, you want no regen at all. Too much energy is then wasted.


Figure out how many KM you can go per KWH on level ground no wind and adjust from there.  For here in the USA, I use 7 miles (11km) per KWH to figure out my range and I can adjust for hills and conditions from there. That will be MUCH closer than the useless "range left".


-Don-  Reno, NV

[Specter]

DT - how does a hilly highway with regen hurt your overall mileage?
If I want to go 70 MPH, I twist my throttle until the bike is going that speed, then hold it there.  (ideally on flat ground), if I am going up hill I might need to twist it a tad more to get it back there, if I am going down hill and get lucky and the grade of the slope exceeds friction losses and I am accelerating, then I can either let it speed up a bit, and let that pull me thru the next hill, until I hit the threshold of my throttle and need to put power to the train again,  or dink off the throttle a bit and let regen eat some of that excess speed back into the battery.  If you are using it properly, regen is not really like a vampire sitting there on your power bar.   Yes there are some losses but they are really negligible IMO.  If you are on that hilly highway, and don't want to activate your regen, then tweak your throttle a tad here and there so as not to pass the threshold where it would activate.. just IMO.

Im not saying this to be an asshole, or disrespectful to you, but genuinely interested in your perspective.

FWIW, Regen gets a ton of hype, and sadly, most of it is bullshit.  It's not going to double your range for most people bla bla.  AT best, it recovers part of ONE acceleration, at the point in time that you would brake, and NOT glide to a stop.  If you are in the city with a bunch of stoplights every block, stop go stop go, then yes regen instead of hitting the brake can help a lot because every time you'd hit the brake.. IF.. you can regen stop instead, it's putting that inertia back into the battery, instead of burning it off as heat on your brake pads and disc.

A lot of it is mental.  If I am doing 85 MPH and I see brake lights ahead of me and go oh dammit, and just let off the gas fully, and let the bike pump regen brake power at about  16 KW into my battery for 15 seconds or so, yah it's a nice little *tap* but the overall energy back to my battery is NOWHERE near what it took me to get TO 85 MPH to begin with !  I really wish some of these Manu's and Dealers would stop with the regen Porn.

I'll admit, it's nice to be able to regen stop and only use brakes for like the last 5 kph / mph or so, so you have control of the stop and are not just lolly rolling along flailing your legs, but at the end of the year, it's not like you can take your calculator and finagle the energy saved to go on a cruise to the Bahamas !

Aaron

[DonTom]

DT - how does a hilly highway with regen hurt your overall mileage?

I already explained that, but I will try again.


If you're slowing down going down a hill because of high regen (there is no regen if you do not slow down), and right away you have to go up a hill, the bike slowing down will waste A LOT more power than your regen can recover.


Regen is great when you MUST slow down or stop. Then you're gaining a little of that lost power back. But if regen is being activated on a freeway, it means you're slowing down, which is a big waste of energy. You will recover less than 10% in regen of what you just lost from the slow down when you need more power to make it up the next hill, or to return to the original speed.


Usually, a steady speed will give the best range, such as when the cruise control is used.


-Don-  Reno, NV

[Zelidar]

I leave near the Alps (Europe) and, whatever the regen manages to put back in the battery (never more than 4-5%), I am glad I don't have to rely on heating my brake pads and disks in the heat of the summer. I have 53 Mm on my SR/F and the mechanical brakes still look like new. For me it is full regen all the time and I decide how much of it using the throttle. Coasting makes little sense over here, those curves are not far enough apart for that  .

[DonTom]

I leave near the Alps (Europe) and, whatever the regen manages to put back in the battery (never more than 4-5%), I am glad I don't have to rely on heating my brake pads and disks in the heat of the summer. I have 53 Mm on my SR/F and the mechanical brakes still look like new. For me it is full regen all the time and I decide how much of it using the throttle. Coasting makes little sense over here, those curves are not far enough apart for that  .

I also think the biggest advantage of regen is when going down curvy hills. It's kinda like having an ICE bike in first and 6th gear at the same time. Even better than a manual tranny when going down a curvy road.


High regen is also useful in city traffic.


-Don-  Reno, NV

[Curt]

I don't know what year your bike is, but the range estimator on my '16 FX isn't doing as well as it used to. When I leave with 100% charge, it drops precipitously to 90% after 2 miles, 80% after 4 miles, 70% after 6 miles. But then as it reaches 60% and 50%, it starts to decrease more slowly and the panic lets off. I'm going to want to do a full range test as the weather improves to determine the true remaining battery capacity. To your experience, maybe the same thing is happening; the range estimation is pessimistic at first, then progressively more optimistic.

[rgutt]

Not quite on topic but related to several of the previous posts, the best part about regen is that my brake pads will almost literally last forever. It should be noted that I've overwritten Zero's control of the Sevcon so I can apply full motor torque in regen to within the voltage limits of the battery. I ride quite aggressively (for street riding, not track) and only touch the front mechanical brake if I need max braking to turn off the highway quickly. I also have a solenoid inline to the rear brake caliper controlled by the Sevcon so that until the rear wheel has stopped, brake pressure doesn't reach the caliper and all rear braking is through regen.

[Specter]

That sounds like a good way to lock up a tire / skid / and potentially dump yourself if it's rainy or you hit some sand or something with that much regen on it.  Im sure it'll slow you down in a hurry and the bikes weight will push some KW back but I can also see too much making it start to get grabby too, which would be bad

Aaron

[rgutt]

Maybe it wasn't as intuitive as I thought, but my regen is controlled through a pressure transducer on the rear brake hydraulics. It's no more prone to skidding the rear tire than the mechanical brake. Moreover, because I put the transducer on the backside of the ABS pump, the ABS works through the regen.

[Specter]

Id think the pressure xducer is to throttle it depending on how hard you hit the brakes?  Maybe also a sensor to tell it to turn on or off, ok he hit the brakes lets enable regen throttling.  With that being the case, then it almost sounds like it's kind of relying on YOU to provide some sort of haptic feedback, ie ooh not so hard let me let off the brakes a bit, to tweak the regen.. unless it's also looking at RPM to see itself how much affect the 'braking process' is causing.

Regen to brake is not as simple as some might want to think it is, and if something is set wrong or malfunctions and you hit the regen harder than the locking point, no matter how much your mechanical may let the brake loose to keep from locking the tire, it will magnetically be held in place by the over powered regen.  I know this is not the proper term but, another thing, you over load it and you slip a pole, now very bad things are going to happen.

Maybe im out in left field or don't fully understand the process that is happening on your bike, but be careful that too much regen don't cause you a bad issue to contend with.  Yah on a perfect road, you stop really REALLY fast, on a less than perfect road, you slide.. now you are no longer in control of your destiny...

Just, please be careful tinkering with regen for critical braking.

Aaron