Imiev measured data

[Malm]

Today I made some measurements with Canion:

When charging, beginning at 75% SoC:
At 80% - 575 Wh reg (at the end of 13:38)
At 85% - 1,154 Wh (at the end of 27:12)
At 90% - 1,765 Wh (at the end of 41:21)
It seems difference slightly goes up as we add more 5% ?????

15% = 1,765 it means 100% = 11,77 kWh (if the value goes up every 5%, from 0-100% the value should be slightly lower). I think very consistent with the 11,65 kWh that I think my car established that can get in a maximum charge.

But when discharging, I'm seeing values of kWh out every 5% SoC a little higher. 628 Wh between 65% and 60%. Strange.

[me68]

For me, only batterie capacity out is interesting. This is the reference of battery condition.

Input is not so interesting, because ist's more efficient to load with 230V/16A as with 110V/8A. So you have to check efficiency of charger also. That's interesting for the money you have to pay for driveing the car, but not for available battery capacity/conditon.


Martin

[Malm]

But if I am seeing the Wh reg by CAnion, that should not be affected by the efficiency of charging, I think. And Wh reg never should be more then the Wh out. Don't understand this.

[me68]

Please do i test, as i have done. So we can see your battery capacity.

Martin

[7circle]

Could the display segments be measures of Ah not wh?

[Malm]

So me68, do you me to go to something like 0% of SoC and then see what it charges until its full? That's what you want?

[me68]

So me68, do you me to go to something like 0% of SoC and then see what it charges until its full? That's what you want?

No, not to 0%, only near to. I do it from 100 to 2%.

I'm interested in the capacity you get out. So do a long trip please and show us a screenshot from Trip Timer.

Martin

[Malm]

But my 0% can be better then yours 5%, so don't makes sense to me that you ask me to go to 2% instead of 0%.

[Malm]

I will go to 0% if the car let me do it.

[me68]

Ok - fine! Optional screenshots from Batt Status & Batt Temp from the beginning of the trip and also from the end of the trip. Also Amps History and Speed History from the end of the trip. So we have a close look to what's happened.

Martin

[Malm]

I know how is my car. It's simple: It have 15% less capacity then in new, but it does everything like it has 27% less capacity then in new.

So when it charges 100%, it will only charge in the battery 11,6 kWh, instaed of the 13,6 kWh that it really could. And then, at 100%, voltage of cells will be 4,08 V and not the 4,11 V that we should expect. If I try to do a second charge, normally it will go to 4,10 V (take 0,5 kWh more fro,m the wall) And another thing, it will stop at 0,0% with voltage of the weakest far from 2,75v (the real 0,0% SoC).

This happen because it miscalculated its real capacity this winter, when temperatures were much lower then normal here in Portugal.

The challenge,for me, is not to find what is happening with my car. I´m sure I know it. The challenge is to make you believe in what I think.

[offgridQLD]

So Malm,
        What your saying is you can for example discharge (measuring through Canion) -5000whr from the battery. Then put the car on charge and let Canion count back up again but it won't stop at 0000kwh when 100% soc. Instead for example it will stop at +400whr. Showing more charge in than out.

5000whr out but 5400whr in .

There could be a number of reasons for the discrepancy. One could be the how the energy is measured the current shunts could be less accurate at low amperage its not easy to have a device that measure's 50,000w loads down to say 100w resolution acuratly at both ends.

Another could be balancing your bleeding/ballencing off energy at the battery that most likely has allready been measured as whrs into the battery by Canion.

Never asume things are accurate until you can prove they are.

Kurt

[offgridQLD]

I just notice 628whr out 575whr for 5% discharge / 5% charge . That's the opposite to what I thought you might see if energy was lost in balancing.

Though my first theory could still be viable. As you discharge at a much higher rate than you charge at and accuracy could be out given the power range that needs to be meassured .

Kurt

[Malm]

"Though my first theory could still be viable. As you discharge at a much higher rate than you charge at and accuracy could be out given the power range that needs to be meassured."

It´s a possibility, the car getting wrong the values because a problem in accuracy.

[me68]

5000whr out but 5400whr in .

There could be a number of reasons for the discrepancy.

Hello Kurt!

Don't forget cell chemistry has also an efficiency of maybe 90%. So you lost energy on loading cells - this energy get in heating the cell during loading. The other point is cell balancing, but i do not know how many energy will be lost therefore. It depends on the drift of the cells. Maybe this is almost very low energy.

Martin

[Johny]

[offgridQLD]

Yes I agree with that 100%. Discharge loads are way higher than charge loads unless your fast charging so cell efficacy would varie.

Perhaps one test could be to discharge 5% on canion using the heater or AIrconditioner and measure whr's for 5% . Then compare them to charge whr's for 5% . As the charge and discharge loads will be more comparable.

Kurt

[me68]

Hello Kurt!

The heater and airconditioner do not use constant amps.

For me, it's only possible to calculate charging efficency comparing energy out from battery, measured with caniOn and energy in, measured with a energymeter at your plug. I use a Ferraris-energymeter in my electrical cabinet.

Have a look to spritmonitor.de for my measured data from the plug.


Martin

[offgridQLD]

I understand the heater and air conditioner are a variable load. I'm not suggesting using the heater to calculate a fixed load. Just method to discharge your battery vs driving it. All whr measurements in and out through canion in whrs. Remember canion is a bidirectional meter and Malm was asking why his whrs in and out don't equal zero after discharging then recharging 5% capacity using canion as a bidirectional whr counter I was attempting to explain why.

What I was getting at is the heater load might be variable 0 - 5000w but its a lot better than driving the car around town to reduce the battery by 5% (on canion) as real world driving is variable 0 - 50,000w!

when you compare that to the charge rate 2200w.

Heater on 0 - 5000w vs 2200w charge rate

Driving car 0 - 50,000w vs 2200w charge rate

As you can see any different efficiency in the cells due to charge /discharge (C rate) will be much less using the heater than driving the car.

Take lead acid chemistry for example a 100ah battery can become a 50ah capacity battery if discharged at 1C. Its called perk effect in lead acid. lithium isn't effected like this to the same extent but it still is defected by C rate some what.

Kurt

[g4qber]

Something weird just happened. Soc was 94%. Then dropped to 90%
Will post pic later.
Using clipper creek 15 amp unit
15/16 bars

[Malm]

Was it charging when it did that???

Of course it was (sorry). So it was at 94%, the it finds that it have more space to charge, and then recalculated is SoC. That happened to me until last March. Now it does the opposite, finds that there is not space for more and recalculates SoC up.

That is not unusual to me. It just find, in that moment (94%), that it could charge a little more then 6%, and takes it back to 90%.

This is a sign of some degradation. Now it is not getting anymore the SoC correctly (like mine). A new i-MiEV rarely miss its SoC. In a i-MiEV with more then 10% degradation, it will happen many times. If I am correct, you should be loosing bars when the car is off by one hour with SoC between 35%-65%. Take attention by canion how SoC behaves with time.

[g4qber]

yes while charging after about 2 hours.

[g4qber]

eventually got to 95.5%
and I couldn't wait any longer.
had to get home.
as previously mentioned, I seem to be getting 96.5% charged.

[Malm]

And it will go to only 96% or 96,5%? That happened to me a lot (until march).

[Malm]

One second. Missed for one second. I knew, 96,5%. Like mine, until march.