Harbor Freight Inverter Schematic Diagrams

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N11778

Joined Dec 4, 2015
174
I have been using several of their inverters for powering small Air Conditioners(6000btu) , Refrigerators, Pool Pumps,etc. from my solar panels. They have been doing well except for the cheep fans they quit and a couple resistors get to hot.
I have replaced (EBAY "mynewfan") all the fans with ones with ball bearings.
Also the resistors that get hot with larger wattage ones.
They have been running for 3 years or more with no problems and they are very Inexpensive.
I made a control system from a keyence PLC that controls everything so I am not tied to the grid.
The reason why I drew the Schematics of the Inverters is I blew a few of them up with my automatic controls design.
I repaired all of them and they still work fine.
I am attaching the diagrams In case someone else is interested in repairing them.
Be advised there are mistakes in the diagrams, I found several. Try following a double sided board Yuck!
But their better than none or a poke with a sharp stick.
 

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Lestraveled

Joined May 19, 2014
1,946
Cool
You don't see many schematics of inverters. All of the inverters I have repaired, I have had to "wing it", as in no schematics.

Thanks for posting these.
 

strantor

Joined Oct 3, 2010
5,187
I don't need these, but I would like to recognize your awesomeness. Thank you for posting this.

If ever I need a big inverter, I'll choose the one i can get schematics of, which i guess now means harbor freight, thanks to you. HF should compensate you for your advertisement, and for having the good sense that they don't, to publish friggin schematics! Why wouldn't they do that? Is their circuit so special? Is it revolutionary? Would they lose the market by publishing it? NO! Everyone makes inverters. That made in China inverter design was probably ripped off from someone else anyway.

Well I'll cut the rant short, thanks again!
 

GopherT

Joined Nov 23, 2012
8,012
I don't need these, but I would like to recognize your awesomeness. Thank you for posting this.

If ever I need a big inverter, I'll choose the one i can get schematics of, which i guess now means harbor freight, thanks to you. HF should compensate you for your advertisement, and for having the good sense that they don't, to publish friggin schematics! Why wouldn't they do that? Is their circuit so special? Is it revolutionary? Would they lose the market by publishing it? NO! Everyone makes inverters. That made in China inverter design was probably ripped off from someone else anyway.

Well I'll cut the rant short, thanks again!
They probably don't publish it because they ne er had one. They just went to some tradeshow in Hong kong and said, I'll take 10,000 of those if you put this HF logo on it.
 

Lestraveled

Joined May 19, 2014
1,946
I have a 1000 watt Xantrex inverter that I burnt up and repaired. Xantrex is a big brand name, but still no schematics available. The electronics industry wants you to "buy new" instead of repairing. Remember the corner TV repair shop, long gone.
 

wayneh

Joined Sep 9, 2010
16,155
They are all modified sine wave.
And isn't modified sine wave just a glamorous way to say 3-step square wave? My inverter puts out a square wave but with a brief zero-voltage in between peaks. Hi-zero-low-zero and so on. I'm pretty sure that makes it a modified sine wave.
 

Brownout

Joined Jan 10, 2012
2,390
And isn't modified sine wave just a glamorous way to say 3-step square wave? My inverter puts out a square wave but with a brief zero-voltage in between peaks. Hi-zero-low-zero and so on. I'm pretty sure that makes it a modified sine wave.
Yup.
 

Joy Smith

Joined Jun 22, 2016
2
Thank You soo much! I run 4 of these units for daytime only apps. I like them because they go to sleep then wake up with the sun. Most don't. Obviously the time bomb is R50, R118 and R119. I kept some going for years by just cutting a big hole in the top cover and installing a 4" 12V fan hooked to it's own small PV panel. Yes, the fans suck,and I had the fan controller go out on one. When the resistors burn you can't read them, so I am very grateful to get the values from you. I have several units in the scrap pile I will go back to and try to repair this winter. We are a solar dairy so summer is busy. Is there anything else that dies when these resistors go? I'm guessing not. Yes, I have been too lazy to open a new one to read those resistors!
 
Awesome.

If you like doing these I have some single sided boards you can do for me. I'll pay. I do have a parts list, but not electronic at this point. Possibly some mirrored pics that I could get scanned. Physical parts not required.

Thanks.
 
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