# Inverter photo: positive/neg terminals?



## TheNomad (Aug 12, 2013)

Hi guys - to continue the saga of my inverter project, the secondhand Sterling 1800 watt inverter that I bought from ebay has just arrived.

The seller did say that it would come without any 12 volt cables to connect it up to the battery, as it had come out of his canal boat where it had been hard-wired in.

When I make up some 12 volt cables, they go through two holes in the inverter body, and then get attached to two threaded post terminals with nuts on, inside the unit.
Unfortunately these two posts don't have "+" and "-", and I can't tell which is the positive and which is the negative!

I'll try to attach a couple of photos of the inside of the inverter: please can someone who knows about such things give me an absolutely definitive verdict on which terminal is which...........many thanks!


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## TheNomad (Aug 12, 2013)

Here's a closer view of the inverter showing the terminal posts in a bit more detail..............


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## peribro (Sep 6, 2009)

What's the full model number of the inverter?


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## gaspode (May 9, 2005)

Looks to me as if the one on the long side is the positive (based on fuse locations) but don't take my word for it, wait for some other opinions.


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## readyforoff (Dec 28, 2013)

Gaspode probably correct. Positive at the fuses. Stick an ohm meter across it. Fuses out. One stud will be common to the input of each fuse.


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## TheNomad (Aug 12, 2013)

Peribro - I'm not sure what the exact model number is.
There's a number in red on the top that reads 021440

Here's a photo of the top of the unit:


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## rayrecrok (Nov 21, 2008)

Hey up.

At a guess one of the two connectors will be connected to the inverter framework somehow, and I would suspect that to be the negative, and if the other goes to the workings that would be the positive..

But who knows?..  

ray.


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## Steve_UK (May 18, 2012)

I think that I'd be tempted to contact the manufacturer...

http://www.sterling-power.com/contact.php

There doesn't seem to be a manual or data sheet download for your particular model as far as I can see.

Steve


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## listerdiesel (Aug 3, 2012)

The capacitor nearest the left-hand terminal has its negative side towards that terminal, plus as others have said, the fusing is normally in the positive line, so left hand negative, right-hand = positive.

Peter


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## listerdiesel (Aug 3, 2012)

The capacitor nearest the left-hand terminal has its negative side towards that terminal, plus as others have said, the fusing is normally in the positive line, so left hand negative, right-hand positive.

There is one other thing that makes it 100% that way, there is a position for an inverse diode between the two tracks, part D37 between the first fuse and the first inductor, If that was fitted and the polarity was anything else, it would blow the diode.


Peter


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## TheNomad (Aug 12, 2013)

Thank you to everyone for their help!

Peter, you're a star - can I just make absolutely certain that I understand what you have said:

So, when looking at my first photo: the terminal nearest to the cooling fan (which is on the left end of the unit) is the 12 volt Negative, and the terminal a little further to the right in the photo, on the longer run, with the row of fuses running alongside its run, is the 12 volt Positive?


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## listerdiesel (Aug 3, 2012)

Yes.

I'd also have thought that these would have have reverse polarity protection, but can't see anything that shows that it has.

Peter


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## TheNomad (Aug 12, 2013)

Peter, many thanks.

It does say on the top of the unit (I posted a photo of the writing there....you might be able to read the writing if you click on the photo to see an enlarged version) "reverse polarity protected"..........but I don't want to test that feature!


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## TheNomad (Aug 12, 2013)

Just a quick note to report that I fitted the inverter today and.....it works!

Big thanks are due to all here who helped with info and advice.


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## Mrplodd (Mar 4, 2008)

How pleasant to see someone posting a final update to an issue they have had  Doesnt happen that often !!!


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## listerdiesel (Aug 3, 2012)

Result!

Well done on getting it fitted and working, and, as Mr Plodd says, for letting us know what happened.

Peter


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## john107 (Mar 7, 2014)

*which inverter?*

Hi everyone, can someone please give me some advice as to what power inverter I should buy. I am thinking that a 1000w pure sine with surge of 2000w would be ok. to power a 220v kettle or a tv. I am a complete novice with the mh and any advice would be very welcome. TIA .John.


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## bigtwin (May 24, 2008)

*Re: which inverter?*



john107 said:


> Hi everyone, can someone please give me some advice as to what power inverter I should buy. I am thinking that a 1000w pure sine with surge of 2000w would be ok. to power a 220v kettle or a tv. I am a complete novice with the mh and any advice would be very welcome. TIA .John.


You need to indicate the wattage of the kettle you intend to use before anyone can answer your question.

However, unless your kettle is less than 1kW (unlikely?), a 1000w inverter is unlikely to be adequate.

Ian


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## philoaks (Sep 2, 2008)

*Re: which inverter?*



> Hi everyone, can someone please give me some advice as to what power inverter I should buy. I am thinking that a 1000w pure sine with surge of 2000w would be ok. to power a 220v kettle or a tv. I am a complete novice with the mh and any advice would be very welcome. TIA .John.


To be honest, IMO, you would be better off boiling a kettle of water on the gas hob and getting a TV that will run direct of the 12 volt leisure battery rather than trying to set up an inverter to run them.


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## Mrplodd (Mar 4, 2008)

I would agree entirely in respect of the kettle, however as far AS TV is concerned a 230 volt TV and an inverter will cost you much less than a 12 volt TV.


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## john107 (Mar 7, 2014)

*my previous post*

Thanks to everyone for the advice. I was given a 19inch tv and a 1000w kettle and they both work great with my 1500w inverter. I can use my laptop and charge my mobile at the same time. I'm very happy with the setup as it gives me the freedom to pretty much stay anywhere. Gotta love my Freestyle.!


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