Inverter Charger VX3-M PLUS 3K stopped

[4ldesign]

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

[4ldesign]

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!

[Coulomb]

It probably has one battery fuse right near the battery terminals, but that rarely blows, even after a catastrophic short of the MOSFETs. 

Edit: but in this case, with no display etc, it might have blown that fuse. 

22.8V on the battery is very low. The Solar Charge Controller might still be working, though very unlikely. 

Edited November 12, 2021 by Coulomb

[4ldesign]

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!

[4ldesign]

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.

[Coulomb]

On 2021/11/16 at 1:15 AM, 4ldesign said:

battery voltage was going slowly from 12v to 22v probably because they were almost empty.

I hope that's not real voltage as measured with a trusted multimeter. 12 V total from a 24 V battery means total collapse of several cells, which you usually can't recover from.

18 hours ago, 4ldesign said:

Tonight stopped at 21.5v on screen, but reading directly the battery voltage with a multimeter is 23.3v.

Even 23.3 V is very low. I hope you are able to charge the battery soon.

It sounds like the humidity/moisture is affecting the resistors in the voltage divider that the inverter uses to measure the battery voltage. If you're handy with electronics, you could possibly fix this yourself. Look for a string of same-valued SMD resistors in series near the battery terminals. There should be two strings, one for the positive and one for the negative terminal. The exact same parts designators may not be used in your model.

Edit: the other ends of the voltage dividers are on the control board, if your model has one.

Edited November 17, 2021 by Coulomb