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Vladimir

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Everything posted by Vladimir

  1. I can confirm that the capacitors solved my problem. Prior to this mod, the output voltage in my parralel setup was fluctuating so much that the setup was useless (flickering bulbs, turning on UPS etc...), now everything works fairly stable. But I recommend foil capacitors (grid ones, motor capacitors etc..) I used initially 400V electrolytic capacitors but after few days they heated up and vented (terible smell). Now using foil capacitors - they are bigger, but do not heat at all and have much lower ESR. You need at least 5uF, the more, the better - but be carefull when they are charged.
  2. Thank you for sharing! Has anyone tried it already? When I was experiencing the flicker problem last year, I tried electrolytic capacitors 100uF/400V on PV input without any significant results. But I guess the electrolytic capacitors had a really high ESR, so maybe grid foil capacitors (X2 type)could be much better. My intermittent solution is that both PV strings (East and West) are connected only to one inverter using diodes. In this way, the parallel operation remains stable, but limits the max PV input to just one inverter.
  3. Hi, I did not solve the problem. I currently run only one inverter, which limits the output power to 5kW, the second inverter is used just as MPPT charger.
  4. @Coulomb, first thanks for your response. No idea... maybe the MPPT tracking brings some instability in the system. The new inverter came with 71.87 i thought this can not be much different from the updated 71.82 on the old models. I was affraid that a downgrade 71.87-> 71.82 was not worth the risk on a new device. Thanks for your recommendation I will order 2 parallel kits (at least they can be spares) Check current sharing components on the controll board (per post above)
  5. Update 2: I found a likely solution in the service manual. Unfortunatelly I am so busy I can fix in only after a week... will keep you updated.
  6. Update to previous post: It seems to be related to the Current sharing cables. During parallel operation, there is 0V on the cables (AC or DC) and no current (measured with a precise clamp meter). Likely cause: Burned parallel board Burned something else inside the inverter Faulty internal cables (the cables between inverters were checked previously) Or am I wrong? There is supposed to be some voltage or current on the "Current sharing cables", right?
  7. Hello guys, hello Coulomb, I have an issue with parallel 2x Axpert MK II (Easun Solar SMV II) 5KVA/ max450V solar. When both invertors are working and both invertors have solar input, the output voltage fluctuates, PV becomes unstable and every few seconds PV input suddenly drops to 0W and even light bulbs in the whole house can be seen flickering... Each inverter run as single works perfectly - both 230V output and MPPT charging With just one inverter turned on in parallel setup, both invertors work well as MPPT chargers, providing the 2x2500W solar input but the output is limited to just one inverter Parallel 2x5kW they give output up to 10kW -rock stable with no fluctuation but without solar, ... but when there is solar input on both of them, the system becomes unstable (fluctuating output voltage 210-240V, output power +-50%, and PV swings in the range 0- 5000W within a few seconds like a roller coaster... surprisingly it posts no error here, but the PV generation is flutcuating and output power almost unusable What I did so far - without any success: updated firmware from 71.50 to 71.82 (as posted on this forum, there was a discussion with unstable parallel Axperts) purchased a new inverter, tried Old1+New, then Old2 + New.... no change I blamed the current sharing cables, so I shortened them replaced with thicker cables and checked with continuity mode Tried new wiring - keeping all cables same lenght etc... checked the parallel connection etc. Tried removing the output circuit breaker and connecting the parallel outputs directly to minimize any interference Both invertors are connected to a single battery bank (400Ah lead carbon paralleled with 200Ah lifepo4 - well tested). Each invertor has a separate PV array (2x 2500W loaded panels around 200V - one slightly west and other slightly east. Any Idea what else can I do? Maybe there is a fault in the parallel board but no other way to find out than to purchase two new boards... which is quite costly. Or there can be any type of interference between PV arrays? Thank you very much for your help, any working solution will be rewarder. With kind regards, Vladimir, Czech Republic.
  8. Hi, I just had the same issue... a lot of smoke coming out, inverter display was flickering and turned off with some error. Result? Burned transformer on the communication board - Axpert MK II 450V The probable source of my error was short in the transformer likery caused by Raspberry Pi, which had poor isolation on the power supply (Cheap chinese 5V mobile adapter). So the USB cable could cause some power spike which developed in a shorted transformer... .... anyway removing the whole communication board resulted in fully working invertor... I just could not use monitoring.
  9. Same issue with 2x 5kW Axpert clone (EASUN SM II 5kW). In line mode, the power is very stable with 1700W load showing minimal fluctuations. But when I run on batery mode with PV (2x 3kW array. around 200V loaded) the reported load fluctuates from 1300 W to 2400W and notable flickering can be seen with light bulbs. Even the output voltage sees higher fluctuations 210 - 240V (in 230V system). The explanation by Coulomb seems reasonable, but is seems there is not much I can do.... I will try improving the current sharing cables - they seem thin and improving the output load wires from 4mm2 to 10mm2.
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