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[MostlyBonkers]

Last night I had a rare opportunity to find out what I consider to be the baseline range for my 2014 Zero DS(P).  It was late and all the roads were clear due to the Coronavirus.  I have a familiar route around the roads of Hertfordshire and thought it was time to do my worst!

With reasonably good tyres, it's difficult to spin the rear wheel in dry conditions on tarmac.  I've enough experience on the bike that I can comfortably hold the throttle wide open at all speeds.  So that's what I did.  I had no regard for the motor temperature, which soon rose above 110C where thermal management starts to cut the power.  I just kept the throttle pinned as much as possible and let the bike use as much energy as it could.

The result was that I arrived home with 6% SoC and 42.3 miles on the clock.  I'd call it 41 miles in reality as the odometer overstates by roughly that amount.  The SoC rose to 8% by the time I had parked the bike.  I guess we could be generous and say the bike could manage 45 miles at full chat.  Maybe 50 until it died as the BMS would restrict power significantly for the last few miles. 

I think I achieved what could be considered the worst case scenario.  The only other test I'd like to do is to replicate this on the motorway.  I'm sure the bike would settle at 75-80mph with full throttle applied.  It would be interesting to see if the energy lost to drag at a constant high speed would be more than that lost to acceleration and braking on country roads.  My gut feeling is that the range would be further on the motorway simply because the motor and inverter wouldn't get chance to cool so maximum power would be reduced for all but the first 30 seconds or so of the run.

I'd love it if manufacturers we forced to report the worst case scenario for range.  Tested in cold conditions with a big and heavy rider, like me at 16 stone and causing lots of aerodynamic drag.  After all, what's the point of having a sporty motorcycle if you have to ride it moderately in order to get 80 miles of range?  We might as well be riding a 125cc petrol bike equivalent in that case.

I think this becomes even more important the more performance a bike offers.  Many DS or S owners are likely to ride moderately and only use maximum power when overtaking.  An SR, DSR, SR/F or SR/S owner will want to have some proper fun on theirs.  I'll bet I could drain a ZF14.4 power pack even more quickly on any of those.  Especially the latest models that have better cooling and twice the power and torque of my old DS.

Time is also a consideration.  If I was to take an SR/F or S on a track day, how many 20 minute sessions could I get out of it? My guess is two at most, by which time the battery would be into thermal management.  That would also affect any charging that was attempted.

A lot of this is academic though.  Zeros are road bikes designed to be ridden sensibly on public roads.  They are very well engineered to do that.  After all, you wouldn't expect much more than 20 miles per gallon from a superbike on a track day when it could manage over 40mpg on the road at reasonable speeds.

I just thought I'd mention that Bugatti Veyron empties its 100 liter fuel tank in 15 minutes when trashing it. So riding a Zero so hard it goes into thermal slowdown, and thinking that that is somehow "true range", does not make sense to me.

By the way, riding a 2014 Zero into thermal management is very easy when having a bit of fun on the twisties.  The motor overheats very quickly and the challenge becomes finding opportunities for it to cool down. Going through villages is good for that.

[MostlyBonkers]

Knowing how far you can got flat out on the freeway is helpful as a lower bound.

-Crissa

Yes, thanks Crissa.  It can certainly help when planning and illustrates how much high speed affects range.  A good example of why we should never trust manufacturers' figures.

[princec]

Why no fans fitted to the motor? Hm.

Cas

[MostlyBonkers]

Why no fans fitted to the motor? Hm.

Cas

More to go wrong. Zero's design philosophy is to keep it simple, as much as is possible. I wholeheartedly support that.  Also, I'm not sure increased airflow would make a huge difference.  The bottleneck in heat transfer is probably internal and has something to do with the conductivity of the materials used.  There's also an air gap between the rotor and the stator, which never helps...

Overheating was mitigated somewhat in more recent model years by developing a new motor that used internally mounted permanent magnets.  This significantly reduced the eddie currents that build up in surface mounted magnets, those eddie currents generating heat that can be difficult to dissipate in the rotor.

I once tried spraying water on the motor to try and improve the rate of cooling. I don't think it made any difference!

On a day-to-day basis, overheating isn't a problem. It's only when pressing on a bit that the motor enters the thermal management zone.  It's certainly not enough of a problem to make me want to upgrade.

[DonTom]

It can certainly help when planning and illustrates how much high speed affects range.  A good example of why we should never trust manufacturers' figures.

Here is what I discovered after getting a new battery in my Zero 6.5 (which is now 7.2 KWH). My very slow speed range improved quite a bit, like taking a trip on a long unpaved road. Such as the 40 mile round trip  to Quitobaquito Springs with my bad battery last December. I had no problem with enough range on the bad battery as there was a lot of regen helping.

But my freeway range increased the most, by far, with the new battery.

I have a theory why.  When my battery started to go south, the slow speed regen SEEMED to be more than ever. I will see the SOC increase a FEW points on a long coast, unlike now that the SOC  doesn't increase at all (with the new battery) going down the same hills. This is because the battery was also charging three times as fast with the bad battery (perhaps was a third of the KWHs), so the regen would show 3 times more charge as well. But in reality, the regen was adding the same range as ever, it just has less battery to charge. But at slow speeds, the regen helps a lot when it's the same KW charge as ever, but with less KWHs to charge. Regen is  adding the same range to a bad battery as it does to a good battery.

The big difference in range that I now have with the new battery is most noticeable on the freeway and at faster speeds. 

Comparing my old battery to my new, I now can get about twice the range at slow speeds, but at least four times the range at higher speeds than before. Wasn't what I expected to happen with the new battery.

So when your battery starts to get old or starts to fail, expect to notice the BIG difference on the freeway and at higher speeds. The range difference  is not as noticeable at slower speeds, perhaps because of the regen adding the same range on a bad battery as on a new.

If you notice your SOC increasing more than usual on a long down hill ride, that could be an indication of your battery having less KWH than before. Just as with faster than normal charge times.  My bad battery was charging to full more than twice as fast than it should.

Anyway, that is my recent experience.

-Don-  Reno, NV

[MVetter]

Overheating was mitigated somewhat in more recent model years by developing a new motor that used internally mounted permanent magnets.  This significantly reduced the eddie currents that build up in surface mounted magnets, those eddie currents generating heat that can be difficult to dissipate in the rotor.

I once tried spraying water on the motor to try and improve the rate of cooling. I don't think it made any difference!

Just do what we did. Cut holes in the sides of the motor to force air through it. Debris/rocks get chewed up and spit out, no problem.

Do not actually do this. Or you could run liquid cooling like Arthur Kowitz!

[princec]

The existence of the air cooling fins on the motor suggests that there's definitely some merit to fans helping though. Probably quite powerful fans I imagine...

Cas

[MostlyBonkers]

It can certainly help when planning and illustrates how much high speed affects range.  A good example of why we should never trust manufacturers' figures.

Here is what I discovered after getting a new battery in my Zero 6.5 (which is now 7.2 KWH). My very slow speed range improved quite a bit, like taking a trip on a long unpaved road. Such as the 40 mile round trip  to Quitobaquito Springs with my bad battery last December. I had no problem with enough range on the bad battery as there was a lot of regen helping.

But my freeway range increased the most, by far, with the new battery.

I have a theory why.  When my battery started to go south, the slow speed regen SEEMED to be more than ever. I will see the SOC increase a FEW points on a long coast, unlike now that the SOC  doesn't increase at all (with the new battery) going down the same hills. This is because the battery was also charging three times as fast with the bad battery (perhaps was a third of the KWHs), so the regen would show 3 times more charge as well. But in reality, the regen was adding the same range as ever, it just has less battery to charge. But at slow speeds, the regen helps a lot when it's the same KW charge as ever, but with less KWHs to charge. Regen is  adding the same range to a bad battery as it does to a good battery.

The big difference in range that I now have with the new battery is most noticeable on the freeway and at faster speeds. 

Comparing my old battery to my new, I now can get about twice the range at slow speeds, but at least four times the range at higher speeds than before. Wasn't what I expected to happen with the new battery.

So when your battery starts to get old or starts to fail, expect to notice the BIG difference on the freeway and at higher speeds. The range difference  is not as noticeable at slower speeds, perhaps because of the regen adding the same range on a bad battery as on a new.

If you notice your SOC increasing more than usual on a long down hill ride, that could be an indication of your battery having less KWH than before. Just as with faster than normal charge times.  My bad battery was charging to full more than twice as fast than it should.

Anyway, that is my recent experience.

-Don-  Reno, NV

I think regen is a red herring, DonTom.  In fact regen is best switched off for the off-throttle position in order to increase range.  Max regen is still useful when using the friction brakes, but conservation of momentum is what to focus on when trying to extend range to its maximum.

I think your bad battery was suffering from severe voltage drop, just as my ZF11.4 did when it was dieing.  It explains the poor range at speed: voltage drops more severely under load.

[MostlyBonkers]

The existence of the air cooling fins on the motor suggests that there's definitely some merit to fans helping though. Probably quite powerful fans I imagine...

Cas

Sure, a strong fan would help, but perhaps much less than one would expect and less than the effort was worth.

[MostlyBonkers]

Overheating was mitigated somewhat in more recent model years by developing a new motor that used internally mounted permanent magnets.  This significantly reduced the eddie currents that build up in surface mounted magnets, those eddie currents generating heat that can be difficult to dissipate in the rotor.

I once tried spraying water on the motor to try and improve the rate of cooling. I don't think it made any difference!

Just do what we did. Cut holes in the sides of the motor to force air through it. Debris/rocks get chewed up and spit out, no problem.

Do not actually do this. Or you could run liquid cooling like Arthur Kowitz!

Lol! And I thought I was bonkers!:-)))))))

[DonTom]

I think regen is a red herring, DonTom.  In fact regen is best switched off for the off-throttle position in order to increase range.  Max regen is still useful when using the friction brakes, but conservation of momentum is what to focus on when trying to extend range to its maximum.

At slower speeds which MUST vary a lot, regen is VERY helpful, so I am not sure what you're saying there. And there is never a real need to switch off regen as we can have it set to max regen and then use the throttle for NO regen at all. When you see no negative  or positive bars on the screen you have NO regen even with regen set to the MAX. Just don't use the "off-throttle". There is no real need for it, except for when stopping completely.

I think your bad battery was suffering from severe voltage drop, just as my ZF11.4 did when it was dieing.  It explains the poor range at speed: voltage drops more severely under load.

Of course it will drop voltage faster under larger loads. With new or old weak batteries.

Charge time was less  half the normal time to full with my bike with the old bad battery. The means less than half the distance as well. IOW, my 6.5 KWH battery was down to around 3 KWHs. Much like a NEW 3 KWH battery would be. Will charge faster, and will have a lot less range. But the exact same benefit (in distance)  from slow speed regen.

Since regen is mostly useless at higher speeds, there nothing is regained. There is much to regain at slower speeds when they MUST vary, as is the usual case at slow speeds, regardless if city or an unpaved road.

But a battery with half the KWH capacity will charge just as much (in added distance) from REGEN as a battery twice the KWH.

When my battery went south, it was obvious that the KWH dropped. Faster charging as well as less range proves such.

-Don-  Reno, NV

[MostlyBonkers]

I think regen is a red herring, DonTom.  In fact regen is best switched off for the off-throttle position in order to increase range.  Max regen is still useful when using the friction brakes, but conservation of momentum is what to focus on when trying to extend range to its maximum.

At slower speeds which MUST vary a lot, regen is VERY helpful, so I am not sure what you're saying there. And there is never a real need to switch off regen as we can have it set to max regen and then use the throttle for NO regen at all. When you see no negative  or positive bars on the screen you have NO regen even with regen set to the MAX. Just don't use the "off-throttle". There is no real need for it, except for when stopping completely.

I think your bad battery was suffering from severe voltage drop, just as my ZF11.4 did when it was dieing.  It explains the poor range at speed: voltage drops more severely under load.

Of course it will drop voltage faster under larger loads. With new or old weak batteries.

Charge time was less  half the normal time to full with my bike with the old bad battery. The means less than half the distance as well. IOW, my 6.5 KWH battery was down to around 3 KWHs. Much like a NEW 3 KWH battery would be. Will charge faster, and will have a lot less range. But the exact same benefit (in distance)  from slow speed regen.

Since regen is mostly useless at higher speeds, there nothing is regained. There is much to regain at slower speeds when they MUST vary, as is the usual case at slow speeds, regardless if city or an unpaved road.

But a battery with half the KWH capacity will charge just as much (in added distance) from REGEN as a battery twice the KWH.

When my battery went south, it was obvious that the KWH dropped. Faster charging as well as less range proves such.

-Don-  Reno, NV

It sounds counter-intuitive to not use regen unless under hard breaking.  I had regen set to maximum at zero throttle for the first 20,000 miles on my bike.  I liked it because I was mostly commuting in heavy traffic and it meant I didn't have to use the brakes much.  However, I knew that a few people here had disabled regen on the throttle and had it set to max when the friction brakes are used.  I finally got round to giving it a try and haven't looked back.  It results in an even smoother riding experience and regen can still be used with the light application of either brake.

With regards to maximising range, minimising the use of regen makes sense when you think about all the energy losses from using it.  Whilst Zero's drivetrain is very efficient indeed, it isn't perfect.  Energy is lost in the motor converting kinetic energy to electrical energy. It is also lost converting it from AC to DC and then some more is lost while putting that energy into the battery.  Similar losses occur as soon as you open the throttle and use the energy that was just stored.  In most situations you're better off leaving the energy in its kinetic form by conserving momentum as much as you can when riding.  That also leads to much smoother riding; coasting more and allowing wind resistance to slow you down.  If you Google hypermiling, you'll get a more detailed explanation of some of the methods used to increase fuel economy.  Car drivers will even put their EV into neutral to coast and prevent regen at times in order to maximise their range. I find that a bit extreme though.  It's easier on a Zero as you can just switch it off in the custom settings. 

Once you get used to riding without regen, you'll probably find it even more enjoyable. I highly recommend it.  You'll also realise just how much speed reduces when off the throttle due to wind resistance.  Even going down quite steep hills you'll notice that speed is maintained or reduces slowly.  Therefore the brakes are only needed on the steepest of hills and regen will kick in as soon as you start to pull the brake lever, so you might not even get to apply the friction brakes in any significant way.  Your brake pads will still last as long as they did before. 

Some people find it disconcerting to ride with no regen at first.  We're all conditioned to expect some engine breaking when we lift of the throttle.   Persevere a little and it soon becomes natural.  I'll even go as far as to say it might even improve your riding skills as you'll be looking further ahead and anticipating the road conditions more, rather than relying on regen to slow you down.  You might make swifter progress too, as riding smoothly is a key aspect of advanced rider training.  It makes you quicker overall, even though it seems you're riding Miss Daisy... ;-)

I hope that helps Don.  If you've got anymore questions or I missed something from your previous post, then please fire away and I'll do my best.

Oh, and I hope it goes without saying: Never compromise your safety for fuel economy.  It can be tempting to take corners faster than you might otherwise.  Don't, unless you're confident you can stop in the distance that's visible to you and you've got enough grip etc.

I don't want to sound patronising.  I put last paragraph in because I've been guilty of making that mistake myself...

[Crissa]

Even if you don't have regen on the throttle, you still have regen available with a soft tug of the brake lever.  It triggers before the friction brakes do.

-Crissa

(Edit: There was an m instead of a comma.)

[Richard230]

That is a great dissertation, MostlyBonkers.  Which I fully agree with.  But I wouldn't have been able to explain the advantages of coasting with no regen nearly as well as you did.   

[DonTom]

The advantage of REGEN is only when you MUST slow down or stop. Or else it is a waste of energy as you will never get back the power lost from slowing down when you have to speed back up. That's what I have been saying from the beginning.

At slow speeds, we often MUST vary speeds because of stopsigns,  stoplights, traffic. Same type  of thing often happens on unpaved roads. That is when we get the big gain from Regen.

There is never a reason to turn off regen unless you want to release the throttle all the way back. That is what I used to do. But since then, I discovered the regen can be set at the very max and have absolutely NO regen at all by using the throttle instead. Just have to get used to it.

I started doing this on my Energica because it has way too much regen even at the minimum setting.  When I once got used to using the throttle to control the regen, I set it to the very max regen on my Energica for all times, but rarely use it while riding except for when I must slowdown or stop.

And I ride in the custom mode at all times on my Zeros with 80% deceleration regen and 100% braking regen and I often use NO regen at all with these settings when slowing down just a little.

-Don-  Reno, NV