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[mistasam]

Whoa!  Sorry for making a post and bailing on all the comments 

To answer some questions.. for the first year or so I followed Zero's advice and kept mine plugged in at 100% at all times.  After that, I let it sit somewhere around 60% when I wasn't riding, and I try to charge up immediately before riding (that's the way most EV manufacturers want you to do it, so the battery gets to 100% but doesn't stay there very long).  My wife commuted on the Zero daily (before the lockdown) and we'd plug in around 30% and unplug at like 85-90%.  Nothing really scientific or timed though.  Also, I've taken the bike racing a few times, overheated the battery, and completely drained it to 0% to the point where it wouldn't even turn on.. so I haven't been THAT nice to it.

I guess a better way to measure how much our batteries have degraded is to check the pack's voltage at 100% when you buy the bike and check it at 100% after a few years.  Zero doesn't have "bars" that drop like a Nissan Leaf, so even if it's at 80% capacity it will still read as "100% full".

including the energy regained from regen allows someone to travel using more energy than the 100% capacity of the battery.

This ^ sums up what I meant.  If you can go 50 miles using a full battery, regen might make it possible to go 55 miles.  It's more obvious in a big heavy car, but it still helps our Zeros in certain situations.

Thanks again for watching, everybody! 

[talon]

A heavily degraded battery will still charge to the same voltages, in fact, they will get there quicker! Range test with no regen on, a full monitored external charge, and then reading the logs is the tried and trued method I have heard of.

My range when I purchased my brand new 2016 SR in Feb 2018 was more or less 70 miles at 70 mph. It was a little less in the cold perhaps, untested because I didn't want to end up stranded due to a cold battery. Then after a few more cycles my capacity likely increased slightly. A few months later I installed a cheap Spitfire windscreen. I then noticed 80 miles at 70 mph and it hasn't changed since.

[talon]

It's not confusing and it's not saying that, all it's saying is that with regen you can utilise more than 100% of the energy capacity of the battery.

There we go again with the non-conservation of energy! If you believe that, I can tell you about a recently black hole observation where the particles shoot out "faster than the speed of light."

I'm not saying the battery can hold more than 100% of its capacity, which is obviously impossible, but rather that including the energy regained from regen allows someone to travel using more energy than the 100% capacity of the battery.

To make it simpler let's use an actual battery capacity instead of 100%. Say we have a 25 MJ battery (roughly what a 7.2kW/h Zero is), without regen you can only ever use 25 MJ of energy to move the bike on a single charge. With regen you might regain a megajoule or two which can also be used to move the bike, so the total energy you have available to you is greater than 25 MJ or 100% of the battery capacity.

Alright, I'll bite into this thread de-railing. No, it is improper to say you have any more energy than what you started with. The correct way to phrase this is that you can re-purpose energy you would have wasted as heat in the brakes. The 25MJ is all you get. Coming to a stop by braking wastes some of it, regen puts it to better use only if you had to stop anyway. Coasting always should be more efficient use of your energy (at low speeds) unless you need to slow down or stop. Regen technically causes less than 100% of your bike's full energy capacity to go towards doing useful work due to conversion losses (anecdotal but I believe you can get <=60% of your energy back from climbing a hill/storing your electrical energy into potential energy due to gravity*).

*exact number depends on a lot of factors

[Crissa]

Ya know, yes, you get to re-purpose energy, potential or battery.

But the comparison to a no-regen system is that you end up with more energy to spend.

-Crissa

[Crilly]

For the most mileage on a charge, coasting first, then regen, then braking .  Period.

[talon]

If you were watering a garden and collected some of the water you spill, technically you get to pump it again, sure. The amount of water that goes through the pump is not as significant as the total amount of water used (energy capacity) compared to the total amount of garden watered (range). Saying you can pump 30 gallons from your 20 gallon tank is not as helpful or significant as saying more *of the original 20 gallons* will make it into the garden, but no more than 20. "You end up with more +[of the] energy to spend." The "of the" is so important for clarity.

[TheRan]

No, it is improper to say you have any more energy than what you started with. The correct way to phrase this is that you can re-purpose energy you would have wasted as heat in the brakes. The 25MJ is all you get. Coming to a stop by braking wastes some of it, regen puts it to better use only if you had to stop anyway. Coasting always should be more efficient use of your energy (at low speeds) unless you need to slow down or stop. Regen technically causes less than 100% of your bike's full energy capacity to go towards doing useful work due to conversion losses (anecdotal but I believe you can get <=60% of your energy back from climbing a hill/storing your electrical energy into potential energy due to gravity*).

*exact number depends on a lot of factors

No, the total energy expended would be more than 25MJ. If it wasn't then the range would be the same without regen as with it.

In regards to coasting, I'm not saying that using regen instead of coasting would be more efficient. We're talking about using regen instead of braking, when you have no option but to slow down. If you can make a trip without ever having to touch your brakes then sure, having no regen would be the most efficient usage of energy, but that doesn't happen in the real world.

[Curt]

No, the total energy expended would be more than 25MJ. If it wasn't then the range would be the same without regen as with it.

Ok, now that's even more directly wrong and anti-physical, the notion that one could expend more energy than exists.

Sam spoke some truth above: with regen you can go more distance on the same amount of energy (55 vs. 50).

Mathematically:
   Distance (mi) = Capacity (Wh) / Consumption (Wh / mi)
"110% of the battery" implies that that when Distance goes up 10%, Capacity has gone up 10%.
No. Capacity is a constant. Rather, adding regen decreases Consumption.

Consumption varies with terrain. "110% of the battery" imagines it doesn't, hence why it's not a valid way to think about it. The integral of Consumption over Distance equals energy used, and is bounded by Capacity (14.4 kWh).

[TheRan]

No, the total energy expended would be more than 25MJ. If it wasn't then the range would be the same without regen as with it.

Ok, now that's even more directly wrong and anti-physical, the notion that one could expend more energy than exists.

But it's not more energy than what exists, some of the energy (from regen) is regained from what was originally expended. If you measured the energy output from the battery over the single charge you would find that it is greater than the 100% capacity of the battery.

When you ride the bike not all of the energy from the battery is used to drive the bike forward, some of it is lost as noise, some as heat, and some in braking (more noise and heat). None of that is useful work, however regen allows you to take some of that braking energy and put it back into the battery to be reused. It's not creating new energy.

[mistasam]

Adding regen doesn't decrease consumption. It adds back to the battery.

Remember that electric mining truck that would drive uphill empty, load up, then drive down full? It CREATED more energy than it used, because it was heavier while it was using regen. That's the kinda thing I was referring to, on a way smaller scale.

[mistasam]

Also, Tesla regen is so strong that you can tow them to recharge the battery at 50kW. I know Zero regen isn't anywhere close to that but I'd imagine if you towed it long enough, it would do the same.

[Curt]

Adding regen doesn't decrease consumption. It adds back to the battery.

Remember that electric mining truck that would drive uphill empty, load up, then drive down full? It CREATED more energy than it used, because it was heavier while it was using regen. That's the kinda thing I was referring to, on a way smaller scale.

Regen does decrease consumption, to the point where it's negative. The way I figure it, every term has a clear meaning in raw numbers, and anything else is merely a colorful interpretation.

Electric mining trucks do not "create energy!" We all know that. It's imprecise to say that they do. Large amounts of potential energy are being added to it and converted. If you expand the discussion that way, then I can allow the motorcycle to start on a hill with an empty battery. It gets to the bottom then makes it another mile. I say "wow, it got infinity percent of the battery!"

[Curt]

But it's not more energy than what exists, some of the energy (from regen) is regained from what was originally expended. If you measured the energy output from the battery over the single charge you would find that it is greater than the 100% capacity of the battery.

Capacitors store energy too. There is a capacitor in your cell phone that oscillates through 1V at several MHz. If we look only at the energy going out of the capacitor, that thing puts out 1.21 gigawatts a minute!

[mistasam]

Haha ok.. let's call the motor a generator then, because that's what's happening.  The motor is used as a generator to put power into the battery.  We're not creating energy out of thin air, but the power you're adding to the battery wasn't there before.  It's new power, gained from rolling down a hill or coming to a stop.  Charging while riding, if you will.

So like someone said above, the capacity you use on a ride with regen turned on is MORE than the battery's capacity.  For example, using 10.5kWh from a 10kWh pack.

[talon]

You can say that the capacity you use on a ride with regen turned on is more than the battery's capacity. It can be misleading though in the same way I can correctly say regen always wastes energy that *could have* gone towards range. Or saying the range with regen on is lower than what you could get without regen for any given capacity. These are all perfectly true statements but they sound conflicting because we aren't being careful.

These need to be qualified and are not practical ways to express the system physically. For instance, if your bike can travel 100 miles and gain 6kWh, you should mention that you were starting on a hill and not climbing it again so everyone understands that the total system energy that got you there came primarily from gravity and altitude rather than your battery pack. This is a huge communication issue and I'm sure it irks many of our inner physicists to see people reasoning (at least semantically) they have more energy introduced in a system without getting it from somewhere.

We all agree on the conservation of energy and that regenerative braking does not violate it, correct? If you have 10kWh in all forms of energy ("total energy"- specifically potential energy due to gravity and electrical), you can only go as far as 10kWh can take you.

Here is my problem and solution:
"...including the energy regained from regen allows someone to travel using more energy than the 100% capacity of the battery." *ONLY if you had more energy to start from a hill, otherwise it's the exact same energy amount as the 100% capacity of the battery. If you don't mention the hill it is a problematic statement.