KD 600w China Grid Tie Repair

Today We Repair the KD 600w Grid Tie Micro inverters that arrived defective from China
If you have one of these inverters that does not synch to the mains & just flickers between st & fault led than you will need to replace both PC817 optocoupler ic's located near the AC socket & adjust the threshold trimmer to allow the inverter to start up as close to 10.8v as possible.

[@yongfeng1346]

I got a defective product from aliexpress from china, it have same problem like the video ,after i see the video , i do the same and it come alive, thank you to share this valuable information to me ,thank you

[@stephengaudette581]

I know this is old but Great Job dude

[@pulesjet]

Do these things take the battery down to the 10.8V limit ?

[@tripbyte]

Cool thanks die sharing. I have the 60 volt max version.. and with bad days i have 33 volt open. But when it get his ballast its down to 27.volt Should try 2 panels in serie?

[@chroschi]

hey i have an old GTI 600w they have problems to start and produce energy it shows error for maybe 2 minutes before they starts to work. And within the day the inverter shuts off several times. What could wrong with them? Thanks

[@gr0nis]

I have a 22V-60V, 600W, grid tie inverter (looks similar to yours). I have a problem that in low light condition, the DC side under voltage protection kicks in while mppt is working, and it faults. If I go under 8Watts or so in production, the MPPT algorithm basically triggers the under voltage protection the first thing it does. How can I make sure that the panel still works in low light conditions with such an inverter?

[@colingill9317]

I've got an inverter that blew 2 of 4 igbt transistors. I replaced them and tried like you with 2 x 12v batteries from a ups. It seems I had output runaway, as the transistors have shorted again, hmmm, any ideas. It's a powerjack gt 1200, cheers

[@dicasdodiaadia3645]

Muito bom amigo!! fiz os procedimento e deu tudo certo, meu equipamento esta funcionando 100%. Muito obrigado pela dica.

[@farmsidney]

Carlos Augusto Carlos, o seu modelo era o mesmo do video? 110v? Eu estou com um de 220 e não vi esse problema. Embora eu ache que ele fique piscando toda hora.

[@dicasdodiaadia3645]

Olá amigo! O meu modelo é 200V e no início estava apresentando o mesmo problema intermitente e foi agravando ao passar do tempo, fiz os procedimentos e agora esta funcionando perfeitamente.

[@farmsidney]

E vc substituiu por que peça? To pensando em olhar esse detalhe no meu. Viu a necessidade de corrigir fator de potencia da rede?

[@dicasdodiaadia3645]

Oi amigo, troquei os mesmos componentes explicados do vídeo e em relação ao fator de potencia a minha rede não tem necessidade.

[@arturandrade8185]

Good afternoon. I disassembled my inverter just like this one. could you tell me what are the mosfets (DC) RF2, RF3,RF4,RF5, RF6, RF9 I threw them away and I can't remember what they were. Or do you have a schematic of the inverter? In advance grateful.

[@ekiskaliburnirvana9047]

Optocoupler inputs need a reverse diode for reverse voltage protection.

[@tripbyte]

I bought in 2015 dec. a China grid inverter, - It is a 600 watt type for 36 volt pannels. There are 7 panels on it with total 600 watt. They are all parallel. After a few day the group of the inverter was shut down. Inverter also defect. I was measure the mosfet of the ac side. 1 was defect. Bought at the local parts 4 new and change 2 of the first AC side.Also i use new coolingpasta. Today the inverter is working oke. But i;m still knowing that the China Mosfets are also cloons..SO these can give problems after a few months. Now i change them for higher quality the inverter will work better and longer. Still have to at a better cooling fan on the side. Heat wil make the stuff crap

[@aaronespinoza3160]

Where do You buy spare parts?

[@abdullaruzny6156]

My same grid tie inverter after running get changed to faulty in a sequence even after changed AC MOSFETs

[@MarcosEduardodaSilva]

someone find the schematics from this inverter and can share???

[@danielalaptes9042]

buna, pot gasi la cineva schema acestui invertor va rog?

[@sangief17]

I’m having the same problem with the unit as well.

[@oramasdj]

Hi， I have a problem with some inverters of 600 watts 22-60vlts input, I bought the replacement trasistors 30NM60ND but I dont know the value of the zener diode with a blue label conected to STF30NM60ND ZD1, , ZD5,ZD3 AND ZD4 Please help me to know the volts and watts of those zener diodes to repair my inverters please!

[@darijomatijevic4352]

I have the same problem. Did you perhaps find out the values ​​of the Zehnerdiode? I would be grateful if you know.

[@oramasdj]

@@darijomatijevic4352 not at all, I still have the inverters waiting for repair in a box, now I have a 6000 watts, growatt series, 12 panels of 330 watts and 8 panels of 430 watts, conected in 2 series. Growatt=18 days= 532.6 kwh, with those 10 old inverters, with 2 panels on each one, I only used to get, max 22 kwh at a day.

[@ronaldhess1768]

Does anyone have part # for ac and DC mosfets for 600w grid tie inverters 10.8 - 36 volts DC input 110 v to 146v output ??

[@davidellenberger3852]

Don’t remember. My 230V one had 600V 20amps AC mosfets that were bad. Symptom was AC power error LED. A 6amp glas fuse (soldered) burned. Fixed by replacing all 4 AC mosfets and the fuse. First I replaced only the fuse. I only had one with slow reactance 6a which blew my 20A breaker as at least one AC mosfet showed 3 ohms across any leg.

[@davidojeda5529]

hello, i have the 1000w version of that inverter, but only stays on red light. i open it, and found a bad , AC mosfet, replaced it. and now, red and green lights wont turn.. i checked the A/C voltage input to the board, and also the switch... all mosfets DC and AC are fine. Any idea if it still can be repaired? Thanks.

[@MrRFoster2011]

did you check the AC fuse soldered on the circuit board? If I recall correctly on the 1000w KD it is a glass fuse that stands up on the board with black heat shrink tubing over it, on the 500w & 600w models the fuse is a small tan or brown disc about 1/2 inch thick soldered to the board, also check the wires to the AC socket at the socket connections & the wires at the led connections these aluminum wires are famous for breaking off inside the protective shrink tubing so you will have to remove the heat shrink to inspect the connections, if all is good there I would check the 3 or 4 double diode IC' s on the rail next to the AC mosfets, use caution as the tabs on those diodes will be charged & can give you a nice shock if you fail to discharge the DC cap bank before working on it.

[@davidojeda5529]

roger, i did not found any fuses. Could you pinpoint where the fuse is suposed to be? THanks man for replying.

[@MrRFoster2011]

if its the same board I worked on when the AC socket opening is facing you the fuse is just a head of the point where the black wire solders onto the board left of the 2 blue varistors near the right bottom side of the end transformer, it may stand up off the board & be tilted to the side it is inside black shrink tubing so you cant tell its a fuse until you cut the shrink tubing off, if you still cant find it let me know & I will upload a picture of it

[@nguyenhachi1163]

Can you show r47 =?

[@muhammadzeeshankashif5380]

Sir. I have an 1000w china car inverter. The 4 mosfet Hy1906c is dc Side located. Two of them will burn. Whenever i changed them. whenever 12 volt supply on it the mosfet again burning. I have removed all the 4 mosfet from pcb boards.and check the voltage. Reading is something like this Source to drain= 12v Source to gate = 5v Source is common to 12v battery negative point. Pls solve the problem. That how i Check out which component's. Regards Zeeshan

[@vrichmarketingrenewableene9418]

Sir, i have an issue in one of my cheap modified sinewave inverter..it beeps Fault whenever i draw large load like 500 watts and up from my batteries..i suspect the voltage sensor is damage..even i use other inverter to drive the load and the modified has no load..it will still beep for fault even it has no load, just turn on together with the other inverter with the Load on it.please share if you have idea on how to repair this..

[@MrRFoster2011]

vrich marketing renewable energy does it still power the load ok while it is beeping or does it unable to power load & shuts down? how is the quality of your battery ?, a weak battery can drop current under heavy load while the voltage & current appear ok at start up or light loads & some inverters are too sensitive to this low current. if the battery load tests fine but the inverter can power light loads but not heavy loads you could check the DC power capacitors if any are weak or open you will not have full power output, also a bad but not shorted mosfet could cause less than normal power output. I have a APC smart UPS pure sine wave inverter that provides 950w AC, after a battery went dead during a power outage I put a charged one on but it has never sensed properly even after cycling, at about 200w it starts beeping & flashing a fault but the unit still runs on it does not run any hotter & it does not shut down & it still runs all the loads for the proper amount of time. I looked into it & they said the board needs to be replaced because the voltage & load monitor is not working correctly. my solution was to snap the beeper off the board with some vise grips to shut the thing up, so far so good, if it dies on me I will replace it.

[@vrichmarketingrenewableene9418]

hehehehe very helpful idea Roger..that's what im thinking.. the voltage monitor is not working properly since the other inverter do not beep.i tested it using loads and it trip when i reach about 600 watts and up. i'll just observe this since it can still power my computer.if it worsen then i'll follow your advice to check the capacitor and mosfet on the input stage.. thank you very much Roger.you're very kind.

[@vrichmarketingrenewableene9418]

it's the voltage sensor / voltage reference which misinterprets the voltage from the battery does sensing it low voltage..is it functional if i just remove the small board controlling the Beeper?

[@MrRFoster2011]

vrich marketing renewable energy some will run & others wont run with the beeper board removed, try it & see, if it will not operate you will have to either desolder the beeper from the board of just snap it off, if you snap it 3/4 of the beeper will come off & the base part of the beeper that remains on the board will no longer beep.

[@vrichmarketingrenewableene9418]

ok thank you very much roger

[@dicasdodiaadia3645]

Good!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[@alviovalenciagonzalia5028]

good day. I want to know how and where to measure the 10.8v

[@MrRFoster2011]

Alvio Valencia Gonzalia you should measure it at the DC input connector terminals, the proper way to do it would be to connect it to a adjustable output DC power supply of at least 5 amps, set for 11V output then adjust the trimmer on the inverter board until it will start at around 11V if you do not have such a power supply just use a 12V battery that has not been on float charge & has been ran down a little.

[@alviovalenciagonzalia5028]

Roger Foster thanks

[@alviovalenciagonzalia5028]

Roger Foster my inverter jumps from stable to error. I could do about it

[@MrRFoster2011]

Alvio Valencia Gonzalia at the inverter power terminals with a DVM you will either need a drawn down battery to get close or a 10 to 15A 30V DC adjustable power supply to do a precise calibration.

[@MrRFoster2011]

Alvio Valencia Gonzalia did you replace the opto couplers as shown in the video ?

[@tripbyte1]

Now i have a next problem... When i connect the 230 Volt the inverter will not start... Also the DC side make a shut ... Have to figer out what now is defect...

[@pakjokohartono]

While connected to dc and ac, measure the voltage on the 3 electrolyte capacitor, if less than your dc power input, just replace the elco.

[@tripbyte]

pakjokohartono found it. The DC side has defected fets.

[@abdullaruzny6156]

If anyone can share the schematic diagram of KD-GTI-600W is much useful to troubleshoot

[@danielalaptes9042]

a.ti gasit schema? ma intereseaza si pe mine!

[@darijomatijevic4352]

I have the same problem. Did you perhaps find out the values ​​of the Zehnerdiode? I would be grateful if you know.

[@freddenker9537]

This inverter from Ego-Worty (made by Kai Deng) look good but ... The inverters have no approval worldwide, they are not allowed to use ON GRID and I have in two years, 60% failure, no one lokal can fix these things ... I have dispute with the current Office for 1 year There is no brand name at the device, ... No Serial Number...NO TESTREPORTS I have bad experiences with these China-Micro-inverters and now buy an SMA inverter from Germany ... the Micro Inverter come in the trashm

[@peterb4450]

I mailed them in Germany. Simply said new model we do not support the old one. Thus you cannot buy components to repair as they promised !! I bought some on Ebay. The pcb components to my opinion a Arduino chip (US$1)+ siemens chip to make a sinus wave + mosfets (to forward more power) + LM for voltage + diodes. I suspect my Arduino chip died (software could be 'permanent' but they did not. The booklet supplied to repair is not the same as the PCB. When I ve time I ll look into it again.

[@ChristmasEve777]

Stupid naysayers... well the only concern I had was that, if you had a "600 watt" grid tie inverter and connected it to batteries, would it only draw 600 watts or would it exceed that if more amps are available (that's basically the only different between DC sources when you're comparing battery solar panels). But your video proved that the inverter did not try to pull all the power that was available to it. So, yes, you can use batteries :) Good to know.

[@MrRFoster2011]

Paul any GTI will only draw what is required to produce the output is is tuned for, quite often these cheap inverters have fudged specs to make them appear more attractive, quite often they are tested at the maximum or an unrealistic voltage to get that 600w or what ever, in the manual they recommend solar panels in parallel upto 700W more panels will not damage the inverter they will just be a waste. when using them with batteries it is mainly used to limit over voltage spikes from wind turbines and provide a more even power curve, also you may be able to get more power out of it because the battery will allow you to get close to the maximum input voltage, which most solar systems fall far short of. so for example if you have a grid tie inverter rated at 600w 10.5 to 28v DC you would probably only get 300 to 400 watts out because you would be operating in the 17v to 20v not the 24 to 28v at which the inverter was rated. if you connect two panels in series you will blow up the inverter because the no load voltage can exceed 40v DC the inverter will shut down over 28v & blow up over 30v so now you connect two 12v batteries in series for 24v & connect the two series solar panels, or more (parallel series pairs for more current if required) to the battery, this will act similar to a capacitor lowering the voltage to about 27.2 to 27.5v DC now you can connect to the grid tie inverter and you should achieve close to maximum output provided your panels are providing enough current to keep up with the inverter draw & your inverter cables are heavy enough to handle 40A DC. although you can use a simple setup like this your batteries will last longer using a 30 -40A solar charge controller using the load control to feed the GTI that way you can control the cut in / out voltage ore perhaps time shift to a evening time when you will use more power if you are not home during the day.

[@582herb]

@@MrRFoster2011 Just my 2 cents I have been retired out of the electronics and communications field for many years but in reference to the 600W GTI I can pump (tested by shunt) before the GTI terminals negative side and verified with a Victron charge controller , up to 700 watts at 19 amps into the 600W GTI but when I look at the AC output side (with an AC hall effect battery monitor) with the AC cable plugged into the wall outlet, and all I see is a maximum of 570 watts and 4.75 amps going into the AC outlet, then I look at the grid tied house PV system (Enphase) with productions and consumption CTs and I can verify that the AC input at the outlet is very close to what the hall effect monitor is showing. So IMHO, You are correct in your analysis. Thank you sir for clearing this up, now if i could get the 1000w GTI working correctly I'll be all set. Is doing the very same thing as many others, I will try the adjustment you talked about see if I can get it to stop erroring out every so often. The charge controller is set for 36 nominal so it's output is around 42 volts DC the 1000w GTI is supposed to take 45 volts, I'm thinking 42 volts is a little too much and it errors out when it goes above 42 volts and that happens occasionally but never seen ot go over 43 volts.