# Ring Inverter and Skybox



## RichardD (Sep 14, 2009)

I've got a 300W Ring Inverter I bought to power my Sky+HD box (55W max.) When I plug the box into the Inverter and switch it on the LED is not full brightness and flashes. I've tried switching the Inverter on first and the LED comes on full brightness but as soon as I plug the Skybox in it goes dim and flashes. I did get the Skybox to switch on once, but cannot get it to repeat.

I then tried a table lamp with a 60W bulb and this worked fine. It did produce the same results as the Skybox when I tried to switch it on by using the Inverter 'on' switch, but after about 6 to 8 flashes the unit switched on!

Anyone experienced any similar problems or has a cure??

Richard


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## ched999uk (Jan 31, 2011)

It might be worth making sure the connection to 12v is a good one. Remember at 300watts it could be pulling 25amps!!! I know you are only trying to run 55watts but you still need a good 12v supply. If you are using a cigarette lighter type plug it could be that that is not making a good connection.


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## premiermotorhomes (Feb 13, 2008)

Good afternoon Richard, 

On the basis you have tried a similar power item, then this should rule out the following two possibilities;

1) The 12V supply is not rated high enough to support the draw from the inverter and sky box

2) The inverter is faulty

This would mean that its quite possible that the sky box just does not like running on a modified sine inverter as some devices are sensitive to not running on this instead of pure sine.

Working on the basis that the inverter is 80% efficient then this would indicate a draw just shy of 6A.

Regards,
Chris


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## RichardD (Sep 14, 2009)

Hi Chris, I've had a response from Ring suggesting the same possible issue with the Skybox not liking a modified sine wave.

Is anyone else using a Ring Inverter on the new mini Sky+HD box?

Richard


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## premiermotorhomes (Feb 13, 2008)

We've installed many Sky boxes using the Ring MP75 inverter, and the only issue we experienced was interference on the display on a small number of occasions but the box did run.

There are of course several manufacturers of Sky boxes, so I can't say if some are more prone to not working from modified sine inverters. I would guess that as the boxes are becoming more advanced adding in Hard Drives etc that this would make the device more sensitive to to the power supply.

Regards,
Chris


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## teemyob (Nov 22, 2005)

premiermotorhomes said:


> Good afternoon Richard,
> 
> On the basis you have tried a similar power item, then this should rule out the following two possibilities;
> 
> ...


"This would mean that its quite possible that the sky box just does not like running on a modified sine inverter as some devices are sensitive to not running on this instead of pure sine. "

I would say that is the case for many electrical items. They will not operate off Modified sine wave. We had a ring inverter that ran many things it said it would not.

I now only use pure sine wave inverters.


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## RichardD (Sep 14, 2009)

Hi Guys, just tried the Inverter again and would you believe it the Skybox fired up!!! However, it was after 4 dim flashes of the LED and then it came on full and I heard the box HDD start up and then the internal fan.

Prior to this I fitted the croc clip connectors that Ring supplied and connected straight across the battery terminals just to check whether it might be a voltage drop caused by the Motorhome wiring and the cigarette connector which was limiting the voltage. Started up straight away with no dim LED flashing came on full bright and the Skybox whirred into action.

Not sure how sensitive these Inverters are to voltage before they don't work when we're off EHU. However, we have an EFoY cell which cuts in when the battery voltage falls below about 12.4 volts.

Perhaps I need to wiring in a 12v socket with heavy gauge wire going straight back to the battery terminals as currently I have got it going through the Rapido distribution fuse box.

Richard


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## ched999uk (Jan 31, 2011)

Inverters, even small inverters need a very good 12v supply. Remember that in simple terms the inverter is multiplying the 12v by 18 to get 220v.
So say you only have 11.5v at the inverter, that multiplied by 18 only gives 207 volts. So it doesn't take much voltage drop between battery and inverter to stop 220v equipment working.

As you say decent cable from inverter to battery via appropriate fuse (close as poss to battery). You also need to remember that although cable may be rated at 25 amps (300watt) it will drop voltage over distance. So it might be worth using a thicker cable if you need to go more than a meter or 2 between battery and inverter.


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## RichardD (Sep 14, 2009)

I've now taken the van off EHU and let the battery settle for a couple of hours and the battery terminal voltage had returned to the nominal 12.7/12.8 volts and the Inverter would not power the Skybox up this time. 

Looking at the Ring data, it quotes an input voltage of between 10 to 15 volts. 

Had no response from Ring yet!

Not sure what to do now!!!!

Richard


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## tulsehillboys (Jul 22, 2010)

Have you tried running the light first and then adding the sky box via a double socket - once running the light should be able to be switched off.


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## RichardD (Sep 14, 2009)

That's a good idea, I'll give it a go in the morning.

I've taken the van off EHU again and waiting for the battery voltage to settle so that I can try the croc clip cable directly across the battery terminals to see if this still works.

Richard


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## listerdiesel (Aug 3, 2012)

If the inverter runs a 60W bulb OK and is rated at 300W, it is possible/likely that the power factor of the load being applied is affecting the inverter, or the input voltage at the inverter is too low to give the required output.

The Sky box will need a substantial amount of initial power to get everything running from scratch, and if it is itself has switching power supply then it may not like getting a less than good sine wave out of the inverter.

The inverter is shown as being rated at 4 hrs continuous at 240W, so check on what the Sky box power supply says that it takes in power consumption.

Peter


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## RichardD (Sep 14, 2009)

Hi Peter, the label next to the mains in connector states 55W max.

Richard


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