Can't get any regen with LDU, help! [SOLVED]

[Ev8]

Do people really connect a pot for regen? I would really love to have working pedal regen, and not adding any pots of paddles to adjust it. When it works well, there is no need for that.

As my pot2 shows value of 27, I changed pot2min to 0 and pot2max to 27 to overcome that, but there was no change in regen. Still always only 26kW regen power and pretty mild. I did not see any change to earlier setting, where I had 4095 for both (min and max).

The pot is used to vary the maximum amount of regen, It affects both off pedal and brake switch activated regen, to do without it you may have to pull the input high to +5v maybe place a current limiting resistor inline and set pot2 min=0 pot2 max =4095 then you will have 100% of your selected regen settings available.

Ps having a pot that proportionally scales the 2 regen modes is actually very useful In icy conditions

[mane2]

In my experience, this should be basically undrivable, the regen is that strong. I've got no clue what's going on here.

I also noticed now two times that when battery drops to 36%, some kinda limit hits. I get only max 35kW power out. My guess is that it's somehow related to voltage. I had to use that hidden parameter udcgain to lower the voltage that inverter sees, to match measured voltage (from terminals). I haven't had time to plot that yet, but I think the voltage be now wrong on the lower end, and goes to somekind of limp mode.

36% of battery in my case is about 243V (100% is 302V). I wonder if LDU itself has some additional limp mode if voltage is too low?

But not sure how that can affect regen... Or how to investigate that even?

[muehlpower]

Can it be that your udcmin and udcmax limit the performance or regeneration? Maybe you have cables that are too thin and too long, with a high resistance!

[mane2]

Can it be that your udcmin and udcmax limit the performance or regeneration? Maybe you have cables that are too thin and too long, with a high resistance!

If voltage is calculated wrongly, it might be udcmin and max - but my settings are correct to my setup:
"udcmin": 216,
"udcmax": 300,

I have 70mm2 cables, 10 tesla modules at front and 2 at back. Cables are short and those should be good. I get good power when accelerating, it's the regen that just does not work well.

Btw, related to voltage .. my uaux parameter, what should state 12V voltage, says 16V constantly, even though it's 13,6 or so. Could that be related? Or is that uaux param not working in Tesla boards? My Tesla charger board shows that correctly though.

[johu]

uaux doesn't work on Tesla boards.

Just set udcmax to 350 or so just to test of it's the culprit

[mane2]

The pot is used to vary the maximum amount of regen, It affects both off pedal and brake switch activated regen, to do without it you may have to pull the input high to +5v maybe place a current limiting resistor inline and set pot2 min=0 pot2 max =4095 then you will have 100% of your selected regen settings available.

Just checked the code related to this. If you have pot2min and pot2max set to 4095 (max), code will clamp the pot2 value between those. If it's not in range, it will be set to min value (4095). So no need to have pot connected or pulled high.

EDIT: There is also "DigitsToPercent" code related to pot handling, where it checks if min and max if the same value, and returns 100% if so.

[mane2]

I noticed that when I have D selected, firmware shows dirmode = Reverse. Could this play a factor here?

I wonder why it shows reverse, when motor is not installed in reverse. Inverter on the right, gearbox closer to nose, and motor on left. It this normal? Does firmware do something differently when in reverse?

[mane2]

Okay, I was now able to get proper regen. The issue was with fweak being 280 or so. Dropping fweak to 90 made the trick. Wheels lock when -100 regen used. That's what I supposed to happen. Setting that fweak lower, also gave loads of more power!

And then the sad part. I first put the regen to -30, then wanted bit more .. then put -60. Was super fun to see the car skid at 60km/h speeds. Then after first good acceleration, lifted the accelerator. Saw something like -40kW regen .. and all the sudden "click" .. and neutral. Firmware showed OVERCURRENT. I think the inverter is broken I'll start another thread with that, as this regen issue is now solved, but was replaced with another .. bigger issue.

[P.S.Mangelsdorf]

Okay, I was now able to get proper regen. The issue was with fweak being 280 or so. Dropping fweak to 90 made the trick. Wheels lock when -100 regen used. That's what I supposed to happen. Setting that fweak lower, also gave loads of more power!

And then the sad part. I first put the regen to -30, then wanted bit more .. then put -60. Was super fun to see the car skid at 60km/h speeds. Then after first good acceleration, lifted the accelerator. Saw something like -40kW regen .. and all the sudden "click" .. and neutral. Firmware showed OVERCURRENT. I think the inverter is broken I'll start another thread with that, as this regen issue is now solved, but was replaced with another .. bigger issue.

Did you power cycle and try to restart? I've hit the overcurrent limit with mine many times.

Also, yeah fweak being the culprit makes some sense; lowering does improve acceleration/launch.

[Ev8]

What mode have you got contactor control set to, you absolutely don’t want it to open contactors on an over current, it will kill the Tesla inverter

[mane2]

Yeah, I had contactor control set correctly, dcswon (tripmode = 1) after reading some horror stories, but what I didn't realize, was that BMS had default setting of 250A for charge limit. And when that hit, BMS opened main contactors. I verified with multimeter diode mode, it showed something like 0,27. So it's a goner.

[Ev8]

That’s a shitter, I feel your pain, sometimes we blow things up!

[mane2]

Yeah, I have new motor on a way. But as I have LSD swapped to the broken one, I was thinking if it would be easiest to just swap the inverter side completely? Anyone done that? I've been searching that from youtube for hours, but only video I saw was some youtuber loosening the bolts inside and then just mashing the inverter out as it didn't release and cutting the wires. I think what he missed was that the orange cover needs to be opened and undo the bolts there to free the phase bars.

[muehlpower]

Replacing the entire inverter is not a problem. There are two temperature sensors, the three lines to the stator and the temperature lines to the stator. Everything plugged or screwed. To access the screws for the heatsink you have to remove the busbars. You can reach the three screws for the stator cables after removing the small cover. You probably know about the LSD installation. You can see the location and number of heatsink screws in the third picture. You need an extension for the ratchet.

[mane2]

Awesome! Thanks! Looks like straight-forward job and way easier than pulling the LSD out and putting it into another.

[mane2]

Inverter/powerstage swapped and all good again. Thanks for help.

Hopefully this one lasts longer than 3 days

[johu]

Great Leave them contactors closed and you should be fine