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[enaef]

Hi
With FW 19 my impression was, that SoC on charging was not 'very true'.
Being on the road in need of new power it my be crucial to quite exactly know how much you really have in the tank.

Now I observed it closer - documented and calculated it in two different situations:
At home 3 phase 16A 230V with JuiceBooster2
At an official 22 kW charging station with a simple Type 2 cable.

After a BMS-failure and complete depletion of the battery the battery is quite new:
~ 2600 km when I did 'my thing' at home (exactly 1 month before today)
~ 5000 km when I did it at the charging station today

Attached you can find the results in PDF (as I can't upload Excel-Files).

'Method'
I observed the SR/F display and took a picture in case of changing readings.
Times I took from the picture time stamp.
To calculate what was going in in kWh I took the kW-Display readings multiplied by the time since the last change of ingoing kW.

I calculated sort of a 'real SoC' by adding up all the rest of ingoing kWh. As base I took the 12.6 kWh nominal battery capacity.

There IS A RELEVANT difference between disply-SoC and the calculated SoC.
In short:

AT HOME:
Display SoC / Calculated SoC
81 / 69.8
92 / 78
98 / 82.5
100 (first time) / 84

The last 16% SoC (after reaching Display-SoC of 100%) need 24 minutes


AT THE CHARGING STATION 22 kW
90 / 80.6
95 / 84.6
98 / 87.2
100 (first time) / 88.8

The last 11.2% SoC (after reaching Display-SoC of 100%) need 27 minutes



That confirms my observation, that the 'range promise' will not hold, if I cut the chargin too early because of high SoC on the display.

I don't know the influencing factors for this charging behaviour. Temperature will certainly be one of it. Both chargings were in warm temps.
How much the quite new battery influences things I can't tell ecactly. My dealer told me, that the BMS would need some charging cycles with the new battery in order to adjust things/calculations.

If I did things the wrong way you will tell me ... :-)

[Crissa]

That definitely sounds like faulty charge state history.

I wonder if there is a way to purge the saved data on the mbb?

-Crissa

[Mooseman]

What I would expect is that if you charge at let's say 6 kW, a 12.6 kWh battery should charge a little less than 47.6% SoC per hour, provided the 6 kW remain constant. Why a little less? Because the chargers are not 100% efficient and neither is the charging process itself.

The charging setup you mentioned implies that you are not in North America.

For some odd reason I can't see the pdf you mentioned. Care to elaborate how much power was used to charge the bike or how you did the calculation?

[enaef]

Yes, the setup is in Switzerland.

The time it takes to charge was not the (main) concern in my post. Main concern is the displyed SoC compared to what's really in the battery.
(On the road ofcourse it's good to know how long the cell balancing will take and how much is going in in this time. Charge rate before the beginning of the cell balancing is no concern; if it's warm enough and the charging station communicates well with the SR/F it's always ~11.6 or 11.7 kW going in. Cold or very hot temperatures are another story.)

One of the pdfs is (was) allready there.
Here is the second one.

Calculation of 'real SoC'; Example of one SoC at one specific point in time:
=100-(SUM(K38:$K$114)/12.6*100)

K38:$K$114 being all the Excel-cells containing the 'kWh-bits' going in after that specific point in time until the SR/F shuts down on its own (after finishing cell balancing).

Calculation of the 'kWh-bits':
Example: 20 seconds at a rate of 9.7 kW means 0.054 kWh going in (9.7/60/60*20).
Each time the amount of displayed kW changes, the time tifference since the last change will be taken into account and the new bit is calculatet.
In the case at the charging station I documentet 105 such bits, starting at 86% SoC at the SR/F display with the rate of 11.7 kW going in (shortly before cell balancing / reduction of charging rate starts).

[electrictwowheeler]

Using 12.6 KW battery capacity is probably not really accurate because I doubt that we can actually use all the rated capacity. I don't know exactly what voltage the individual cells are charged to. I would assume around 4.15v or somewhere above 116v pack voltage. Does anyone know what the individual cell voltage is when the BMS cuts power? I would guess around 3.4 based on other EVs I have had. To get the rated 12.6 KW capacity the cells would have to be discharged to 3.0v usually. This is speculation on my part not having the actual cell specs. If you recalculate using a lower capacity will the calculated SOC be closer to the displayed SOC. My 2020 SR/S came with firmware 17 installed and now I am using 19 and I see no difference in SOC behavior but then I don't usually watch the bike charge. I do notice that the dash will display 100% SOC around the time the charger starts to cut back the charge rate. I am in the US and charge at level 2 stations at 5.8 KW (displayed) and if I get back to the bike before the charge completes I just unplug at 100% SOC displayed because letting it go till it shuts off doesn't get me much more range compared to the time it takes. It's probably at 98 % actual capacity so what the heck. My observation is that the SOC and miles to go functions work pretty well. It will never be perfect. As long as the bike doesn't shut down before the indicated SOC reaches zero % all is good. I plan my charge stops to have at least 20% left. I have never run it below 12 % and that was after 90 miles traveled when I changed my planned route to a slightly longer more scenic one. I was still showing 15 miles range left. Thanks for spending the time to record these interesting observations which help us to better understand how these wonderful bikes function.

[enaef]

electrictwowheeler why do you doubt that the 12.6 kWh can be used?
According to the Zero website 12.6 is the Nominal capacity = the amount of usable energy.
Max capacity given by Zero is 14.4 kWh.

As expected on my side: If I use 10 kWh for example in my calculation for the total capcity, the gap gets bigger (not smaller). Must be, as the amount of kWh going in is the same, which makes a bigger portion of a lesser capacity.

You are right, normally it doesn't bother me, if I got 10% more or less. But there ARE situations, where I need the full capacity. Therefore I want to know what's really up in that case ...
If I see the display with 100% but actually it is only 84 or 89% - that matters on occasions ...

[MVetter]

electrictwowheeler why do you doubt that the 12.6 kWh can be used?

Because the battery, as listed by the bike, is 114 Amp hours (Ah). Multiply that by the nominal voltage on a Zero (102vdc).

11,628 Watt hours, or 11.6kWh. That's why.

[electrictwowheeler]

If you let the bike charge till it shuts off on it's own you will get the maximum capacity. If you unplug it when the SOC first reaches 100% but before it shuts itself off you will have a little less.  Knowing how far you can ride is another story. So many variables can affect range. I don't claim to understand your calculations as I am more of a hands on type of person. Maybe the best way to determine your range is to just ride the bike and see how far it goes in different conditions.

[enaef]

If you unplug it when the SOC first reaches 100% but before it shuts itself off you will have a little less.  [...]
So many variables can affect range. [...]
Maybe the best way to determine your range is to just ride the bike and see how far it goes in different conditions.

I rode the bike for >20'000 km - so - I think I got quite good an idea how far it goes in different conditions (temperature, topography, wind, riding mode, riding style, dry/wet road, ...)
It was my observation, that if I unplug just when the display reaches 100% I got not a little less (as you and 'everybody' states) but quite a bit more than a little less.
That's why I took the time to observe/document closely and tried to calculate.

My calculations seem to confirm my experience.
Also: If Morgan Vetter is right (and I have no doubt he is), the calculated gap is even bigger.

May be, it's only my SR/F ... I can't say.
Also, I can't say if I did things (method, calculations*) correctly; I'm no technitian / engineer but a nurse - so - I'm walking on unfamiliar turf here ...

* I have uploaded the Excel-file to the fb-group "Zero Motorcycles Owners Group". I think in this forum it is not possible to upload Excel-files.

[enaef]

Because the battery, as listed by the bike, is 114 Amp hours (Ah). Multiply that by the nominal voltage on a Zero (102vdc).
11,628 Watt hours, or 11.6kWh. That's why.

Thanks Morgan.
As written in my last answer: I'm no technitian / engineer but a nurse ...

Where would I find the 114 Ah and nominal voltage? (However, first I have to dive into the matter of battery technology in order to understand the matter. In ac I know that I have do multiply voltage by amps to get power (is power the correct physical term? In German = Leistung))

[DonTom]

. In ac I know that I have do multiply voltage by amps to get power (is power the correct physical term? In German = Leistung))

Yes, watts (volts times amps in resistive  loads) is power. In reactive loads it is called "apparent power" but is really no power at all. It's power wasted as it is reflected back to the source. Apparent power cannot power things, but it can destroy transformers by causing them to overheat by the reflected power.


AC & DC makes no difference with watts. But "apparent power" will only happen with AC.


Amps is current.


Voltage is the pressure that causes the current flow through a load.


-Don-  Reno, NV

[MVetter]

Zero does some things that I question. They also do some things very wisely that I support. Let's talk quickly about their battery cells and how they use them.

As a general rule batteries have a minimum and maximum voltage in which they like to operate. In the case of these Lithium pouch cells made by Farasis they have the following characteristics:

32Ah cells, 3.65vdc nominal. Max 4.2vdc, min 3.4vdc

Those are the values if you want to stress the cells; there's a little more wiggle room if you want to delve lower into the pack. Zero engineers, however, decided they wanted to prioritize pack longevity. As such they decided to take a percentage off the top end of the battery max voltage and reduce it so the cells stay healthier, longer. We know that Zero batteries run in a configuration of 28S meaning 28 cells in series, and we know the max voltage is 116.4vdc.

116.4/28=4.157vdc meaning instead of letting the cells go all the way to 4.2vdc, Zero stops it at 4.157. You can also use this formula to detect the bottom end of the pack. 95/28=3.39vdc per cell which is well within the acceptable realm of the batteries.

The end result with the capping means they are ~28.5Ah cells as recognized by the bikes. Each "short brick" is made up of 28 cells with a 28.5Ah rating. 4 of them together make a Monolith that is 114Ah which is the current pack Zero uses.

[DonTom]

Zero engineers, however, decided they wanted to prioritize pack longevity.

That's because they  have a five year warranty on their batteries. Does any other motorcycle have a five year warranty on their batteries?


-Don-  Reno, NV

[Richard230]

Zero engineers, however, decided they wanted to prioritize pack longevity.

That's because they  have a five year warranty on their batteries. Does any other motorcycle have a five year warranty on their batteries?


-Don-  Reno, NV

Based upon my Zero ownership experience they could probably get away with a 10-year warranty on their batteries. 

[DonTom]

Based upon my Zero ownership experience they could probably get away with a 10-year warranty on their batteries. 

My DS 6.5 KWH battery crapped out in three years. Good news, it now has a 7.2KWH at no cost to me.


And what a nice difference in range. Noticeably better than when the bike was new.


-Don-  Reno, NV