4ldesign

Awesome! I would try all the thing you mention. Enough guidance to go one step further Thanks a lot again, you have been so careful to explain things that I would probably need to know in advance to do any reparation. Luis

That's what I call a nice reply! Thanks @Psy I guess my knowledge on electronics is not so good. I can understand most of your reply, however, I think I can´t identify some of the parts you mention, for example: -the 2 bars that connect from the MPPT to the mainboard. Are those "nut bars" that are connecting a small board over the cooling aluminium profiles? Is that part the one that could be burnt? (in addition probably to the rest of MOSFETs and their control). -Measuring Resistance and Diode (GS, SD, DS,...numbers) Probably the best would be to find someone around me with tech skills, in order to tell me honestly if make sense repairing this inverter or investing in a new one. Won´t you think? Thanks a lot @Psy Luis

Dear readers, due an error 01 I opened my VX3 3k 40a Axpert Inverter (small equipment for off-grid houses). I had seen that big fan was stopped and I replaced with a spare non-excellent Chinese that I had. After this, I connected the battery wires and the PV ones, but these last ones badly because I confused the polarity. A little explosion happened, burnt smell and I switched off all equipment. From that moment, next time, PV wires connected rightly, the inverter did not report any error notice. Simply, it didn't charge batteries from PV, logically. Surprisingly, the PV icon was on in the LCD and green led light blinking but with no apparent charge. I opened the inverter and I found a mosfet IRFB4110 burnt (the first from the PV to charge regulator row) leaving kinda 'explosion' backside, doing bond with other circuits. Because those circuits seemed to be previously bonded, I decided to leave them like that (I attach a picture). I had some spare IRFB4110 from another non-working Chinese inverter that someone brought, so I made the substitution of that mosfet. I tried to switch-on and, from that moment, the inverter didn´t hold the ON estate for long, after few seconds it did resets repeatably, starting over and over again. SO, I have done my last and wrong step, I decided to put a AC line to recharge the weak batteries. I had the doubt that was doing resets because the equipment had no enough energy to run (but had around 22.3V!). Another, but little burnt happened with the subsequent fried smell. Stopping system intermediately! Questions: How I assure that the PV mosfet line is working? I tried to check continuity from first to last and... from second to last it does but not from first. Has to be like that? I tried to remove the melted metal breaking that bond, but it seems that there is a circuit connecting in the board underneath. After the second burnt (AC power cord connected), where and what I would need to check? Now the inverter does not any error report but continues reseting over and over again. Thank you so much for being so patient for me and this issue so far. Luis from Mallorca (and very sorry for my poor English)

Not clear but it could happen when you have no right continuity to all parts. I had that problem and I could solve it, however, it happens to me the same from a bigger issue. Usually the inverter stops due safety reasons, does it switch off and on repetitively?

Rain continúes but closing the circle. I discovered that humidity was the cause. Now the problem to all nights stops is... The inverter doesn't read properly the battery voltage. Eg. Tonight stopped at 21.5v on screen, but reading directly the battery voltage with a multimeter is 23.3v. Before, during the recharging process from solar panels the voltage eventually starts to normalize, but without that input it increases the difference between inverter reading and real voltage. Any ideas? Thanks for reading.

Thanks Coulomb for experienced reply. I've checked that part and looks OK. Actually, I think I found the cause, the humidity excess!! The dehumidifier seems to work, now the inverter lights the display and charges fine, but the converter doesn´t properly yet. it seemed to work but last night went down again, went under 22.1v. I've seen this morning that the battery voltage was going slowly from 12v to 22v probably because they were almost empty. Now the system recharges slowly, because we suffer kind a rain storm and the solar panels don´t charge quickly, but looks to work better so far. Thanks for the attention!

Hello again, some updates I opened it and I discovered an amount of dust everywhere. Plus, with the rainstorm that we soffer now, because the humidity/moist is quite considerable, so, the dust was sticky somehow, even I could see some water condensation in the interior!!! So, the next thing I've done, clean it as good as possible with a brush and a vacuum cleanner and... now it's in front of my dehumidifier XO Do you know if it has any fuse that I could check? Thanks!

After a rainy night tonight, my 4 years old inverter stopped, no screen lights, no sound, nothing. I've checked the wiring, batteries voltage (22.8v) and disconnecting the COM's board, that stopped the inverter in the same way a year ago, but nothing! probably is another thing. Any ideas about what to check next? Thanks a lot from Mallorca! If you know someone around me that could help me, also super-welcome! Thanks again

Exactly! Thanks so much, these two parts were burn. A Valencian technician repared it and works fine again.

Hello to everyone, my quite new small inverter-charger VX-3 3K-40ª doesn´t run anymore after a short overconsumption, trying to run a demanding tool. I tried to start a tool that takes a big demand just at the start, my bio-chipper of 1kva, but after three beeps went off forever. This chipper usually needs to do few short runs in order to get all the required revolutions to chip stuff properly. When I start it I switch it on until i hear a couple of beeps, after trying 2 or 3 short go gets the terminal revolutions and works superfine for hours without any beep. I have cheched the battery status after all and it's continuously 24.3v, even when I try to switch the inverter on. The inverter display doesn´t do anything, no beeps nor sign at all. I have opened the inverter but I haven´t seen any burnt or broken part, it doesn´t smell either. Do you know if there are any fuses that I could check or other missing interesting things that I could try? Thanks so much for your assistance, this forum is incredible. Luis from the Resilience Centre of Mallorca

After reading your post, I tried with another comms board from another Inverter that I had at home. I checked and the two internal connections were the same, so I've tried but unfortunately doesn´t work. Also, I had checked the yellow film around the original comms board transformer and it looks good, however, the hot summer temps could likely overheat anything.

Excellent, thanks for all your information, this is the first that I will try!

Thanks a lot, I will try to check first if I can find the diode in a local electronics provider. However, I will keep in mind the solution you gave me. Cheers!

Hello to everyone, I just signed-up to this forum because I had exactly the same problem, the diode PJ705K RS1J just broke and burnt. Fortunately, the inverter works unplugging the comms-port-board, can I break something else working regularly with the inverter? It seems that goes good, what gives me the chance to continue working while I find a replacement. Does anyone knows where I could find a spare part of this board? I found a technician near Valencia, Spain, who can provide a replacement one for 80€ aprox, but it seems to be pricey for such a little board (and problem). Thank you so much for all the attention that a post here seems to create. Salud!!