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Post Info TOPIC: 3 way fridge from inverter...


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3 way fridge from inverter...


Why don't people run the 3 way fridge at the 240v ac setting off an inverter, from the house batteries that are being charged by solar and dc to dc charger while travelling?

Aussie Paul. smile



-- Edited by aussie_paul on Sunday 11th of February 2018 04:19:31 PM

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They draw about 20 amps depending on size ? It wouldnât take long to flatten your house batteries . Unless you have a lot of solar .. Gas is the most efficient . 12v / 240v is basically short term . ESP 12v ..

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There would be no problem doing this if your solar is capable, but the power consumption is high and installing sufficient solar would be excessive for normal use.
No reason why you could not do it while driving.
But why would you not run it from 12V instead if you wished to run it not on gas?

Cheers,
Peter

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Some people do just that, but you need to remember to switch the fridge to gas when you stop so the battery isn't drained excessively. By using a DC to DC charger and powering the fridge that way on 12v the fridge gets the full battery voltage it needs to function properly while driving but automatically switches to gas when you stop driving if you add a fridge switch.
We have a couple who actually run their 3 ways fridge on 240vac 24/7 from the their solar and battery, but they have a lot of solar and a very large lithium battery pack. Eventually they plan to swap out the 3 way for a household inverter fridge so they didn't want to mess around with fridge switches and remembering to switch the gas on/off etc.

T1 Terry

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First off, let me state I am not electrically qualified in any way, nor am I saying what other people do is wrong.

I would seriously question running any devise on 240 volt whilst driving without some sort of very clever failsafe electrical switch off devise.

Once the tree has been hit or the van has rolled over the inverter will still be putting out 240 volts and if the wiring insulation has been compromised the potential for electrocution to ones self or emergency workers could be possible.

As I said, I am not electrically qualified but it seems possible. At least it is worth looking into the safety aspects.

 



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Run through a RVD .,

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KAYOS wrote:

First off, let me state I am not electrically qualified in any way, nor am I saying what other people do is wrong.

I would seriously question running any devise on 240 volt whilst driving without some sort of very clever failsafe electrical switch off devise.

Once the tree has been hit or the van has rolled over the inverter will still be putting out 240 volts and if the wiring insulation has been compromised the potential for electrocution to ones self or emergency workers could be possible.

As I said, I am not electrically qualified but it seems possible. At least it is worth looking into the safety aspects.

 


This is a common mis-conception that often comes up in these type of forum threads so I'll try to explain why such a problem can not occur.

If one wire from an inverter is in contact with the metal body work it is no different to when the RV is connected to mains power because there one wire is connect to the earth wire back at the switch board and that earth wire is connected to the metal body work, that then makes that wire the neutral.

If 2 wires come in contact with the metal body work it becomes a short circuit and will trip a circuit breaker or simply over load the inverter and it will shut down. If some one touches a bared section of each wire yet it has not touched the metal body work to cause the circuit to trip, then and only then could there be a risk of electrocution.

For this reason it is always advisable to use an RVD on an inverter power supply because any contact from either wire will trip the RVD faster than an RCD would trip so even less bite would be felt. The alternative is to wire the inverter as a earth/neutral system and then the RCD already wired in the van will trip if the active wire comes into contact with the metal body. The problem with this option is the inverter supply must be switch via a double pole break before make type switch so the mains supply with its own earth /neutral link does not see a second earth neutral link and see it as a fault and trip the mains supply.

Needless to say, all this type of work should be carried out by an electrically knowledgeable person and they would already understand the principles involved. 

 

T1 Terry 



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Paul, how far are you travelling each day?

When we had the Eagle, we used to cool it down before leaving home, pack two or three of frozen water bottles in the bottom section with frozen food in the freezer section & close the door. It was a 90L fridge & acted well as a big esky.

This way we could drive to either Rockhampton or Emerald from Townsville & still have a cold fridge.

With our Discovery, we cool it down first & use the 12v feed as it is a bigger fridge. I reckon if we got stuck, we could revert to the "Esky" again.


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Warren-Pat_01 wrote:

Paul, how far are you travelling each day?

When we had the Eagle, we used to cool it down before leaving home, pack two or three of frozen water bottles in the bottom section with frozen food in the freezer section & close the door. It was a 90L fridge & acted well as a big esky.

This way we could drive to either Rockhampton or Emerald from Townsville & still have a cold fridge.

With our Discovery, we cool it down first & use the 12v feed as it is a bigger fridge. I reckon if we got stuck, we could revert to the "Esky" again.


 Hi Warren, the question was asked out of curiosity. I always cool the fridge before we leave home.

Aussie Paul. smile



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aussie_paul wrote:

Why don't people run the 3 way fridge at the 240v ac setting off an inverter, from the house batteries that are being charged by solar and dc to dc charger while travelling?

Aussie Paul. smile



-- Edited by aussie_paul on Sunday 11th of February 2018 04:19:31 PM


 Hi Paul 

You are loosing power , "efficiency losses ," every time you convert ,so why not run on 12V with adequate sized wiring

And the Dc/DC charger  may not have much left over to charge the house batteries

What Size DC/Dc charger?

What  Brand & model number is the fridge?

 



-- Edited by oldtrack123 on Wednesday 14th of February 2018 11:55:27 PM

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oldtrack123 wrote:


 Hi Paul 

You are loosing power , "efficiency losses ," every time you convert ,so why not run on 12V with adequate sized wiring

And the Dc/DC charger  may not have much left over to charge the house batteries

What Size DC/Dc charger?

What  Brand & model number is the fridge?

 



-- Edited by oldtrack123 on Wednesday 14th of February 2018 11:55:27 PM


Hi Peter, I was really asking out of curiosity. My 12v fridge situation is working well since I double the wire size to fridge. I think the dc to dc is 20 amp. After I asked the question the icecream disaster happened.biggrin The fridge is Dometic RM 2554. Ordered the element so I can fix it next week.

Aussie Paul. smile



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I ran the fridge through the inverter as we came home. The house batteries were down to 12.3!!!!! That answers that then. biggrin

Aussie Paul. smile



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aussie_paul wrote:

I ran the fridge through the inverter as we came home. The house batteries were down to 12.3!!!!! That answers that then. biggrin

Aussie Paul. smile


 Proof of the pudding ,so to speakbiggrin



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oldtrack123 wrote:
aussie_paul wrote:

I ran the fridge through the inverter as we came home. The house batteries were down to 12.3!!!!! That answers that then. biggrin

Aussie Paul. smile


 Proof of the pudding ,so to speakbiggrin


 Yep. biggrin



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aussie_paul wrote:

I ran the fridge through the inverter as we came home. The house batteries were down to 12.3!!!!! That answers that then. biggrin

Aussie Paul. smile


Did you have a DC to DC charger operating at the same time? If yes then I'd be double checking the DC to DC operations, if not it does show just how much charging happens via a direct connection and no DC to DC charger eh biggrin

 

T1 Terry 



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T1 Terry wrote:

Did you have a DC to DC charger operating at the same time? If yes then I'd be double checking the DC to DC operations, if not it does show just how much charging happens via a direct connection and no DC to DC charger eh biggrin

 

T1 Terry 


 Actually I did not check the DC to DC was working Terry. I am still connected so will have a look.

Aussie Paul. smile



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aussie_paul wrote:
T1 Terry wrote:

Did you have a DC to DC charger operating at the same time? If yes then I'd be double checking the DC to DC operations, if not it does show just how much charging happens via a direct connection and no DC to DC charger eh biggrin

 

T1 Terry 


 Actually I did not check the DC to DC was working Terry. I am still connected so will have a look.

Aussie Paul. smile


What did you find Paul? Can't remember just which DC to DC unit you have so can you refresh my failing memory please biggrin

 

T1 Terry



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T1 Terry wrote:

What did you find Paul? Can't remember just which DC to DC unit you have so can you refresh my failing memory please biggrin

 

T1 Terry


 Here it is Terry.

DC.JPG



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The fault light is on so the charger is not functioning at the moment, is that correct? If it really does pump out 20 amps @ 14.0 plus voltage it would have no problems powering the fridge element as well as a bit left for battery charging, but maybe the fuse selection wasn't up to the task or the unit itself was up to the constant load.

T1 Terry

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T1 Terry wrote:

The fault light is on so the charger is not functioning at the moment, is that correct? If it really does pump out 20 amps @ 14.0 plus voltage it would have no problems powering the fridge element as well as a bit left for battery charging, but maybe the fuse selection wasn't up to the task or the unit itself was up to the constant load.

T1 Terry


There is not a fault light on it Terry. That pic not very clear. I ran the batteries down a bit and started the tug. These are the 2 pics before and after reaching cut of voltage. Not sure of amps being put to batteries as I seem to have a fault with the amp meter. Job for tomorrow. biggrin

Aussie Paul. smile

 



-- Edited by aussie_paul on Tuesday 20th of February 2018 10:01:02 PM

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Ah, orange light is multi colour LED that turns green when it senses fully charged, I mistook that for an orange fault light. What voltage did the battery reach before it dropped into float when the unit determined fully charged was reached? Because these units do not have separate voltage sensing leads, often a battery type with a higher end of absorption stage voltage needs to be selected so the battery does actually get closer to fully charged.

 

T1 Terry



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T1 Terry wrote:

Ah, orange light is multi colour LED that turns green when it senses fully charged, I mistook that for an orange fault light. What voltage did the battery reach before it dropped into float when the unit determined fully charged was reached? Because these units do not have separate voltage sensing leads, often a battery type with a higher end of absorption stage voltage needs to be selected so the battery does actually get closer to fully charged.

 

T1 Terry


 This explains a lot Terry.

Next, the voltage drop running the fridge on 240v though the inverter!! I could not get a charge amount on the amp gauge from the tug through DC to DC. Checked wiring AND found I had not connected the DC to DC earth to the battery shuntnodisbelief

http://thegreynomads.activeboard.com/t64398771/bloody-hell-again/

Aussie Paul. smile

 



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