close-loop

solar_newbie20

I recently ordered a Nimtek MM5000w pure sine wave inverter.   I have been unable to find any user manual.  My solar system is 100% off grid, and uses a closed loop.  The house breaker has 3 connectors, pos and neg and a ground.  The inverter only has a pos and neg terminal. The technicians i emailed said that this inverter does not need a ground. There is no hub, or terminal, or lug nut.  However, without this connection my system is not working properly.  All the specs of the inverter match to what we need except how to close the circuit successfully.  This is probably a silly question, but any help would be greatly appreciated.  And i hope i explained this enough to help.  Thank you.

Lumisol

Contact the place you bought it from, I don't think they can sell that type of item without a user manual of some sort. Is there a PDF download address provided?
If you can't get that, I'd return it and look at something else.

Did the 'technicians' say how to get it to work properly?

BB.

What is your battery bank voltage and AH rating?

What is your DC wiring/fusing/breaker connections like? No "jumper cable clamps". Must be hard wired (bolted connections) from battery bank to AC inverter DC input.

A 5000 Watt AC inverter can take a lot of current--And if running at lower voltages 12 or 24 volts--Can take a huge amount of current.

-Bill

jonr

In other words, you need short, very thick cables with good lugs running from the batteries to the inverter.  I doubt your problem is related to grounding - what exactly is the problem?  Is there a problem at light loads?

Estragon

Just to clarify, the positive and negative terminals are for the big cables going to the battery bank. Is the "house breaker" for the AC wiring?

I found a picture of what I think is similar to your inverter and it appears to be made to have loads plugged dirctly into an outlet on the inverter, which will have hot, neutral, and ground (assuming 120v). A 120v outlet is normally made for 15a max (1800w) so don't just cut the end off a light extention cord and wire it to an AC panel!

Lumisol

It would be like the plug and play inverters and panels though, right? that should be safe. (sarcasm, do not try this at home.)

solar_newbie20

grrr...this is so confusing.  The house breaker has an AC ground lead, but the inverter does not come with anything for this to attach to.  That is the problem.  The manual they sent us is about the size of a pocket address book with 10 pgs in it.

mvas

Does the 24V DC Nimtek 5000 Watt Inverter ( see below ) have an 240 Volt AC Outlet ?
If yes, then do you use a 3 Pin AC Plug ( Hot + Hot + Ground Pin ) (see below) with a 3 wire cable?

If yes the, then the wires in the cable are as follows ...
Black wire  = Hot   (color in your country may be different)
Red wire    = Hot   (color in your country may be different)
Green wire = Ground <<< Here !

The entire metal case is usually grounded ( in the USA ).
This device does NOT appear to be designed to be "Hard-Wired" into an AC Breaker Box.
WHY do you think that not having the AC Ground connected is preventing your system from working ???

Estragon

@solar_newbie20

A description of your current setup would be helpful.

What is your battery voltage?
Is your AC 120V?
What are your AC loads?

A picture of the AC panel/breaker might also be helpful.

solar_newbie20

Mvas - that is a great idea. It does have that plug in. We are going to give it a try. Thank you.