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[Fred]

What Linux-based dealbreaker comment?

[togo]

What Linux-based dealbreaker comment?

Oops.  Got my time sequences wrong.  "Both the chip and the Pi are a little OTT", and both are linux based, and over the top, that's what I interpreted as.  Sorry, crossed brain wires, ignore.

[Fred]

Shall we stick to taking about the charger? I've got no problem giving my opinion of various microcontrollers​ and SBCs, but I doubt that's of interest to everyone.

[Neuer_User]

Shall we stick to taking about the charger? I've got no problem giving my opinion of various microcontrollers​ and SBCs, but I doubt that's of interest to everyone.

Yes, I would also appreciate if discussions about the pros/cons of microcontrollers could be done in a separated thread.

Here, I am rather interested in the progress of the self-built supercharger.

[Skidz]

Did I mention yet mine is working nicely? Without an attached microcontroller? 

[Neuer_User]

Did I mention yet mine is working nicely? Without an attached microcontroller? 

Yeah, I programmed my two flatpaks yesterday. Will finish all cables today or tomorrow (depending on my time). Then either by the end of this week or beginning of next week (end of this week it's said to rain) I will do a first test charge here at work (they have a new charging station here free for employees).

That would be already awesome.

Then later I will (continue to) build the microcontroller, display, etc. I am still looking for the simplest solution to control both flatpaks, as the main goal for me for the controller is to limit charging currents.

[Fred]

I'm also planning to just update the output voltage and then leave it unless I find I require output monitoring. Not point adding complication unless you need it.

[Skidz]

It would be interesting to see stuff like charging current etc. but fiddling around with a bunch of Arduino's doesn't seem worth it imho Just set to 115.4V, and let the current limiter do it's job.

[Neuer_User]

It would be interesting to see stuff like charging current etc. but fiddling around with a bunch of Arduino's doesn't seem worth it imho Just set to 115.4V, and let the current limiter do it's job.

Yeah, in general I agree. However, my volt meter is showing 58.0V per flatpak now, so it's together 116.0V. Not sure, if the measurement is wrong, or the paks are really wrongly configured now. Before I changed the voltage, the volt meter was showing 53.6V, which seems to be the expected value.

[Skidz]

Don't forget it's a floating voltage, things tend to differ wuite a bit under load

[hubert]

The question which is unclear to me: do the flatpacks work in CC mode like a normal "charger"? Since remmie worked out a PID voltage follower, the answer may be "no" and therefore the voltage servo is there to mimic the CC while the flatpacks actually doing CV. Others said they do not need the arduino stuff, once the output voltage has bee set to 57,5V or so. This would suggest that the CC mode is possible.

I know that usually "power supplies" for computers, which are not chargers, can only stand CV, and as soon as the current demand exceeds the rated value, instead of decreasing the voltage, they shut down completely.

[wijnand71]

Looking at the datasheet of an 2HE, Eltek states:
48 – 56V: Constant power
40 – 48V: Constant current
I think a FPs behaves the same.

[remmie]

The flatpacks (2 HE and S) are CV, CC, CP (Constant voltage, Constant Current, Constant Power)

You don't need the Arduino if you use the flatpacks on a powersupply which can handle the full current the flatpacks demand.

Operation without arduino attached is : set them to 57.6 Volt (which is the maximum they can do) and when the pack voltage is lower they will output its maximum power or current depending on the voltage.

When the output voltage of the flatpack S is below 48 Volt the current is at it's maximum of 37.5 Amps. The lowest output voltage the flatpack can handle is 43.5 Volt. Combined with the max current of 37.5 A this means 1631 Watt of output power.

If the voltage is exactly 48 volts the power is 1800 Watt and the current 37.5A

Above 48V the current tapers down with the voltage to keep it at constant power. So at 57.6 Volt the max possible current is 1800/57.6 = 31.25

The arduino was initially used just to display the voltage, current and temperatures which were available on the canbus. And the supercharger was only meant for 11kW or 22kW 3 phase EV charge locations but WITH the arduino it can also be used on a regular 230V 16A mains outlet using 3500 Watt on it rather than the onboard power of 1300 Watt. This effectively triples the charging power from a single mains socket.

[Skidz]

Don't you think you could use the flatpacks off a 16a group? Theoretically the group should supply 3680W which would barely be enough..... mmmm.... let's blow a fuse for science

[Lenny]

Don't you think you could use the flatpacks off a 16a group? Theoretically the group should supply 3680W which would barely be enough..... mmmm.... let's blow a fuse for science

I've charged with 2 Flatpacks + FXS onboard (so ~4650W) on a single plug with 16A breaker for about 20-25 min, the breaker didn't trip. Although I guess it was pretty close. It happened due to a silly fault which I made.

Regular B16 breakers are quite tolerant for a slight overcurrent, because this is determined by heat. The fast shutdown in case of high overcurrents is done magnetic. See the diagramm attached.