Categories
wvc-600 crap

WVC-600 micro inverter repair: number 5

This is a followup about the fifth inverter that stopped working (and melted).

wvc-600 without caps
wvc-600 without caps

After removing the caps, we can see the amount of heat they must have gone through. No wonder why they blew up.

failing wvc-600 burned mosfet
failing wvc-600 burned mosfet

I’ve also desoldered and replaced one of the input mosfets, because it seems much darker than the others.

failing wvc-600 with heated traces
failing wvc-600 with heated AC traces

On this picture, we can see that the AC traces of the circuit board are too thin. They have heated up and started to burn.

WVC-600 strengthened circuit board traces
WVC-600 strengthened circuit board traces

So I’ve added to copper wires and solder to the AC traces on the back of the circuit, and to the Mosfets traces as well.

WVC-600 repair capacitors
WVC-600 new capacitors

Here is a view of the inverter with new branded low esr caps (Nippon Chemi-Con). They are ten millimeters taller, so I had to put some spacers between the case and the fan.

wvc-600 air cooling mod
wvc-600 air cooling mod

Here is the finish repair and mod of the fifth wvc 600 solar micro inverter, with the burn parts removed and replaced: input capacitor capacitors and connectors.

wvc-600 mod holes for air cooling
wvc-600 mod: holes for air cooling

Now it’s back in production and runs fine, apart the “MPPT stuck” problem that I still have to figure out, and the efficiency that is still crap. The temperature goes up to 31°C with two 300W pannels, compared to 45°C with only one panel before… and much more than 100°C with two panels!

19 replies on “WVC-600 micro inverter repair: number 5”

Great site! Like you I’ve got 7 inverters only 3 of which now work (one of which I repaired). I had them for 3 or so years as they slowly progressively failed. Maybe they lasted because they were only paired with 250W panels? Who knows. I’ve now repurposed one to work off a 36V battery bank and provide power at night. But, boy did it get hot! Even with the front and back cover off The side heatsinks were almost too hot to touch. Inspired by your site I’ve put a old 12V computer power supply fan on the front and drilled some holes to let air in. It stays a lot cooler now. Maybe it will last long enough for me to afford a proper hybrid inverter, we’ll see. Happy to supply a photo of the mod for your blog if you want.

Nice colling system… would like also to implement the to my inverter. Could you tell me the fan specifications and where I can soldar the fan power supply? From the pictures I cannot get it. Thanks.

Great idea on the colling system for wvc inverter! I have a wvc-1200 and would like to do the same colling system.
Where are you connecting the fan? Are you using a 12V or 24V fan? The fan shutdown ar night?
Thanks in advance.

Hi, the fans I use are 12v. I’m connecting the fan directly on the board, there is a small power supply that can be set with a variable resistor. I don’t know about the wvc-1200 but you can find it easily, that’s where the electrolytic caps are (small ones) near a regulator. One should have 12v, and another one 5v. I’ve soldered the fan connector directly on the cap.

My dear owners of a china micro inverter, I have a WVC-1600, on the board is printed WVC-1400(R4 A4/22-06-2021). All these devices will sooner or later die of heat death due to the lack of active cooling. That’s why I tuned my device shortly after buying it to extend its lifetime. The following was done: 2x aluminum heat sink profiles glued on the back, also 3x aluminum heat sink profiles glued on the front. Also on the front, 2 large slots were milled into the cast aluminum lid. These slots are located between the aluminum heat sink profiles. 2x 120mm PC fans (12V 0.5A) with 3000rpm were screwed on these aluminum heat sink profiles. They receive the power from a separate power supply with 12VDC 1A. The fans are connected to a thermostat controller with speed control. The thermal sensor is mounted outside the device. The WVC-1600 is connected to a wifi current measuring socket (myStrom). The inverter is switched on at 06:30 in the morning and switched off at 18:30 in the evening. No power consumption at night. So that the Chinese no longer notice everything, yesterday I have removed the Wifi/Bluetooth module. This means that there is no longer a cloud connection to China. The app “Cloud intelligence” can be deleted after this conversion, no one needs.

I’m hoping for a long life for this inverter.

Have fun with this conversion

Thanks for your reply.
Today I open one of the inverter sides and just by doing that I noticed a massive decrease of temperatura and a increase on the inverter performance!!!
Next step is to add fans to the system and would like to connect them to the board. I have 5v fans but have no idea which cap has 5v unless you send me a picture.
I was thinking connecting the fans to the 5v that are used on the 433mhz communication module. Do you think that will also work?

The cap that has 5V is just next to the regulator. You can see it on the 3rd picture, just above the blue transformer. On the other side the cap have 12V. It’s the wvc600 but it should be the same on the wvc1200. I’m not sure it’s ok to plug a fan here tho, depending on your fan consumption. The 433mhz module is near the regulator also, it will be the same to get 5v. Oh and there is an easier way to get 5v as well, there is a place where you can solder a connector (5 pins not populated, just above the 5v cap on the picture), pin 2 is 5v and pin 3 is ground.

Der Wechselrichter ist wärmetechnisch falsch konstruiert.
Die 2 inneren Langlöcher in den Alu Kühlprofilen,an denen die Seitenteile angeschraubt sind, unterbrechen die Wärmeleitung im Kühlkörper.Es ergibt ein Schwächung des Kühlprofils auf1,5mm !! . Abhilfe ist das ausfüllen der Langlöcher mit einem passendem Alu oder Kupferdraht (CuL Draht d=2,36mm)

Hallo Hans,
ich habe ein Problem mit einem SG700MD Microinverter und suche Hilfe. Vielleicht können Sie mich kontaktieren? Ich wäre Ihnen sehr dankbar!!

Mit freundlichem Gruß – Joerg

Hi Mika, I think it’s a mov (metal-oxide varistor). The circuit should work if you remove it. It’s designed to protect against overvoltage.

ciao a tutti ho un microinverter wcv600 ho un pannello da500 watt è possibile collegarlo solo su un ingresso o obbligatoriamente ne devo mettere due non superiori a 300 watt

Hi Claudio, you can feed 600W in one input because the two panel inputs are in parallel. BUT you have to check your panel voltages. The max voltage input of the wvc600 is 50V and the mppt works between 22 and 50V. Check your panel open circuit voltage (Voc) and voltage at mpp (Vmp or Umpp).

Hi, sadly I purchased a vevor branded 800w wvc unit before finding this blog. It’s been working well so far, but that’s most likely due to me having negative temperatures in my climate during the winter. I am planning to make some changes to improve cooling before any failures crop up, but was wondering if this modification has held up. I’d rather know if my time would be better spent elsewhere or if simply improving cooling really does resolve the failure mode. Thanks for your time!

Glad to hear I’m on the right track then Seb! My current plan was to strap some water blocks to the housing since mine is currently left outdoors (in the shade) and run some simple water cooling. Do you think this will be sufficient, or is the airflow a pretty strict requirement?

You can try with the water blocks and monitor to see if it’s not heating too much, but honestly I would go with the airflow. It also depends on how much you’re producing. I don’t know the 800W wvc model though.

Thanks for the iput Seb. I have noticed that my unit has been throttling its output (fluctuating between 59-58C reported in the app) despite having an ambient temperature of -7C. Given this, coupled with the fact that the unit is only slightly warm to the touch, I suppose a fan solution is the best course of action. Annoyingly I can’t keep my unit indoors, which means I will have to devise some form of enclosure for it I suppose. Thanks again for your insights! I will hopefully be able to follow up down the line

As a follow-up for posterity, I’ve removed the panels from my WVC-800 unit, leaving only the sides to which the FETs are mounted. I’ve added a 3D-printed bracket to mount a Noctua iPPC fan to cool the unit. This entire assembly was then installed inside a NEMA 4x enclosure using cable glands to bring power in/out without impacting the water resistance.

I’ve also added some additional components to monitor the enclosure temperature, humidity, and fan speed. All together, this is now allowing me to maintain a constant 800w output with enclosure temperatures stabilizing around 15C and inverter temperature reporting ~17C. This is with ambient temperatures of ~-5C; I will need to monitor this to identify if additional enclosure cooling is required.

My only remaining concern is humidity management within the enclosure. I have added some desiccant beads to try and keep it under control until I come up with a more permanent solution.

Leave a Reply

Your email address will not be published.