I own two rebrandet Axpert MKS 5K (64v) inverters.
In a parallel thread I read with horror about the problem with the quality of the outgoing sine wave form of the 64v version with 48v batteries (lead acid or 15s LFP) under certain circumstances.
I'd like to start a discussion on how to prevent such situations.
I'm located in Germany and we have 400V 3P AC grid. So one phase to ground is 230V AC. The tolerance is given with ±10%. So all devices should work with voltages between 207V and 253V.
The problem in the inverter is told to be the limited bus voltage. For a proper sine wave we need a voltage of:
I have seen these bus voltages on my inverter so far (5 month):output voltage × √2 + 12v
Code: Select all
# NumSamples = 205021; Min = 323; Max = 377
# Mean = 354,573980; Variance = 154,802743; SD = 12,441975
323 - 325 [ 10]: ∎ 0,00%
325 - 327 [ 16]: ∎ 0,01%
327 - 329 [ 59]: ∎ 0,03%
329 - 331 [ 111]: ∎ 0,05%
331 - 333 [ 1290]: ∎∎∎∎ 0,63%
333 - 335 [ 3070]: ∎∎∎∎∎∎∎∎∎∎ 1,50%
335 - 337 [ 5456]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 2,66%
337 - 339 [ 11887]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 5,80%
339 - 341 [ 13558]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 6,61%
341 - 343 [ 14194]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 6,92%
343 - 345 [ 13845]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 6,75%
345 - 347 [ 14172]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 6,91%
347 - 349 [ 10464]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 5,10%
349 - 351 [ 12837]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 6,26%
351 - 353 [ 10342]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 5,04%
353 - 355 [ 10076]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 4,91%
355 - 357 [ 4884]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 2,38%
357 - 359 [ 2565]: ∎∎∎∎∎∎∎∎ 1,25%
359 - 361 [ 859]: ∎∎∎ 0,42%
361 - 363 [ 1692]: ∎∎∎∎∎∎ 0,83%
363 - 365 [ 4489]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 2,19%
365 - 367 [ 11502]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 5,61%
367 - 369 [ 21228]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 10,35%
369 - 371 [ 18723]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 9,13%
371 - 373 [ 12887]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 6,29%
373 - 375 [ 4577]: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ 2,23%
375 - 377 [ 228]: ∎ 0,11%
My idea is to switch to 220V AC output voltage. I then only need 323V:
I'd like the experts to make some statements about the pro and cons.220V × √2 + 12v = 323 V
Will the inverter work this way and produce 220V output when the grid delivers 230V or more? I saw 241.3V on the grid.
I'm unsure if it is really bad for attached devices when the inverter switches from battery to grid with a voltage jump of about 20V (from 220 to 240V).
Thanks
Lars