New Twizy, charging measurements (drawn power, charging status, cell voltage)

Hello everybody,

I made some measurements during a charge cycle, maybe will help somebody.
Test conditions:
-twizy charged in a garage, approx ambient temperature 15 degrees
-new vehicle, under 500km
-cell parameters recorded with pcan device from vehicle can bus, messages 0x557, 0x558, 0x55E
-power measurements made with a sonoff pow r2 device connected between twizy plug and power outlet

Charge precentage - Measured input power - Average cell CAN value - Calculated voltage:

begin charge at 56%
60%-2000w-0x31A-3.97v
65%-2000w-0x322-4.01v
70%-2000w-0x327-4.03v
75%-2000w-0x32C-4.06v
80%-2000w-0x331-4.08v
85%-2000w-0x334-4.10v
90%-2000w-0x338-4.12v
91%-2000w-0x339
92%-2000w-0x33A-4.13v
93%-1600w-0x33A
94%-1600w-0x33A
95%-1300w-0x33A
96%-900w-0x33A
97%-650w-0x339
98%-650w-0x339
99%-400w-0x33A
100%-400w-0x33A
end charge, display off, input power drops at approx 20-30W

that's very interesting, thanks a lot!

I ask myself for some time if it would be possible not to load the twizy to 100%, because mostly LI batteries don't like to be fully loaded.
Of course the Twizy has no setting for that (or do i miss something? OVMS?), a solution could be to stop loading when the current drops below 2000w for example.
Does sonoff pow r2 gives you control to stop the power when the power flow drops below a certain level?

Yes, exactly this is why I did the measurements, to find a way to stop charging earlier. The battery is mine, not rented, so I have every reason to try to protect it as much as possible.
My daily needs are approx 60% from battery (this around 0 celsius degrees) and I would very much like to use 30-90% or 20-80% instead of 40-100%.
Sonoff pow r2 does allow to automatically disconnect when the power drops below a certain level (which you can set) but it has to be configured and activated after you enable the device. This is because the twizy charger does not draw full 2kw of power immediately after connecting to mains, only after ~5 seconds. If the minimum power threshold is already configured into sonoff pow r2 device, during those 5 seconds after enabling device, the device senses less power than let's say 1500w or whatever threshold you set, and disconnects. If you configure and activate the threshold after charger begin to draw 2kw of power, there is no problem. I made a suggestion to sonoff design team to allow that parameter to be compared with an average value of power for several seconds instead of comparing it with an instantaneous reading. Let's see if they'll consider it.
But then there is a slight problem. Until 92%, the power is constant, around 2kw. When it drops enough so you can sense this with sonoff device, the cell is pretty much at its maximum level, 4.13v. I would have liked to catch a power drop at lower voltage, but measurements says otherwise. From 92 to 100%, it takes at least another half our with significant energy consumption and to be honest I don't understand where that energy is going, since the cell voltage stays at that level, plus/minus one LSB.

Hi pisoiu, you might consider reading the OVMS user manual:
github.com/openvehicles/Open-Vehicle-Mon...lt-Twizy/OVMS-UserGuide-RenaultTwizy.pdf