check out the new remote control Jockey Wheel SmartBar rearview170 Cobb Grill Skid Row Recovery Gear Caravan Industry Association of Australia
Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Inverter for fridges


Member

Status: Offline
Posts: 9
Date:
Inverter for fridges


Hi, this is my first post, I have been reading and soaking up information for a while, but now I need some help, I will be leaving in a week or 2 and want to make sure the refrigeration is reliable.

I have a Lvyuan DX-GAC1000W, and I have used it on a Chiq 200 litre 2 door fridge, and a Westinghouse freezer, it works fine.

So I decided to get a backup just in case, but they no longer make them, and the new model, an F1000P won't start the freezer, or fridge. So I bought what I thought was a  Lvyuan DX-GAC2000W, but turned out to be an F2000P and even the 2000 watt model won't start the freezer.

So my question is does anybody know which brands models etc will start refrigerators.

I can't keep buying door stops.

Any help would be greatly appreciated.



__________________
aj


Senior Member

Status: Offline
Posts: 485
Date:

If you have a 1000w inverter that will start the fridge and freezer, and a 2000w which wont I would seriously question the quality of the inverters. The reviews on them are not great also.

Have you tried testing with different appliances to see what load you can actually draw?

A few of us have Giandel inverters and I have had mine for a few years now.  I thought I had an issue with it a few weeks back but it turned out that a circuit breaker was causing the issue.  

Good luck



__________________


Guru

Status: Offline
Posts: 7403
Date:

Our 340L Westinghouse is rated at 0.57amps 240v, so about 137 watts.

 

So on 12v allowing for inefficiencies let's say divide by 10 = 13.7amps

 

Can't imagine that your fridge is any worse. There are people here running their fridge off a small Victron inverter.

 

I think you have some other issue.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 4706
Date:

Before you buy an inverter contact the supplier and ask:

"Will your ABC inverter run my XYZ fridge?"

And unless they answer positively don't buy it.

Victron products are expensive but they are very well engineered and I have little doubt Victron would support you in the event you have issues.



__________________

 

"I beseech you in the bowels of Christ think it possible you may be mistaken"

Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland



Guru

Status: Offline
Posts: 4706
Date:

Whenarewethere wrote:

Our 340L Westinghouse is rated at 0.57amps 240v, so about 137 watts.


 Fridges, generally, require a significant "start-up" current to get the under-load compressor running - maybe 10 times the running current.



__________________

 

"I beseech you in the bowels of Christ think it possible you may be mistaken"

Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland



Guru

Status: Offline
Posts: 7403
Date:

Never noticed on my Waeco fridge while testing & jotting down figures. Probably watched my clamp meter over 500 times when the fridge compressor started. Never saw a single spike.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 7403
Date:

From another thread:

 

Gundog wrote:

I have been using a Samsung 228l DI fridge in the van for almost 5 years now, it's paired with a Victron 350Va Inverter, when mains power is not available. Would I ever consider a 12/24v or 3 way fridge, never in a million years.


 



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 4706
Date:

Whenarewethere wrote:

Never noticed on my Waeco fridge while testing & jotting down figures. Probably watched my clamp meter over 500 times when the fridge compressor started. Never saw a single spike.


Digital metres generally sample around two of three times per second, try watching your Waeco fridge on a digital storage oscilloscope via a current shunt and you will observe quite different behaviour.



__________________

 

"I beseech you in the bowels of Christ think it possible you may be mistaken"

Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland



Member

Status: Offline
Posts: 9
Date:

Thanks, I was just looking at a Giandel inverter on eBay and the power switch looks like it might be a momentary action soft switch, like you get on laptops etc.

When you push the switch, does click in and out or does it just make contact when you push the button ?

The reason I ask, is I switch the current inverter externally, so it turns on and off with the fridge.

I just found one that uses a rocker switch, thanks again.



-- Edited by unusedname on Monday 14th of November 2022 07:52:31 AM

__________________
aj


Senior Member

Status: Offline
Posts: 485
Date:

It is a little push button switch.  It also has a remote switch with a 3 or 4 metre cable so that if the inverter is located in a concealed space it can be easily turned off.  again this is a simple push button switch.

Tim



__________________


Member

Status: Offline
Posts: 9
Date:

Cool.



__________________
aj


Guru

Status: Offline
Posts: 1942
Date:

unusedname wrote:

Thanks, I was just looking at a Giandel inverter on eBay and the power switch looks like it might be a momentary action soft switch, like you get on laptops etc.

When you push the switch, does click in and out or does it just make contact when you push the button ?

The reason I ask, is I switch the current inverter externally, so it turns on and off with the fridge.

I just found one that uses a rocker switch, thanks again.

-- Edited by unusedname on Monday 14th of November 2022 07:52:31 AM


 Hi smile

Just a comment on inverters to run 20V appliances like a fridge or freezer. Better inverters like Victron (and i have a couple of old Aussie made Selectronic inverters), that will go to sleep mode when not needed and automatically start up when a fridge switches on. They use miniscule power in sleep mode so can be left on all the time. They also have a good high short time rating for starting a fridge/freezer motor. In fact you might say they are designed to do exactly what you need them for ??? hmm Possibly worth paying a bit more for one of them rather than the cheapest ebay model !  

Jaahn



__________________


Guru

Status: Offline
Posts: 7403
Date:

Disclaimer: I just bought another piece of Victron gear.

 

One really doesn't want anything breaking down in remote areas. Personally I go for quality as it's cheaper in the long run.

 



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 7403
Date:

I know fridge motors do have a high start load, but there must be some electronics for a soft start on my fridge.

 

I have tried starting my fridge about 30 times then checking the min/max reading. My meter doesn't show any spike from the fridge motor starting.

 

I have tested a brief touch shorting a AA Eneloop battery. It's hard to guess how long, but let's say 0.1 second & the meter shows about 19 amps.

 

I have no idea how brief a spike Is on an electric motor, but I feel it's going to be at least 0.1 second to get going. 

 

DSC_1435_040030.jpg



Attachments
__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 4706
Date:

Perhaps your fridge does have some sort of soft start?

DC motors are close to a short circuit until they begin to turn and produce an opposing EMF so they will take a wadge of current for a short time at startup unless it it limited. Switch mode power supplies, which have a highly capacitive reactance, often use a thermistor to limit inrush current.

In any event you *should not* reply upon digital sampling meters to measure transient events for the reason I mentioned earlier. Someone use to sell a cheap-ish hand-held 'scope meter which only had a bandwidth of a meg two but was adequate for most hobby electronics. A few years back I bought a Chinese 250MHz DSO/meter via Ebay for about A$800 which has performed very well, I still have it in the caravan. A bit like a carpenter with his tools... I cannot bear to get rid of all mine :)



__________________

 

"I beseech you in the bowels of Christ think it possible you may be mistaken"

Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland



Guru

Status: Offline
Posts: 1942
Date:

Whenarewethere wrote:

I know fridge motors do have a high start load, but there must be some electronics for a soft start on my fridge.

I have tried starting my fridge about 30 times then checking the min/max reading. My meter doesn't show any spike from the fridge motor starting.

I have tested a brief touch shorting a AA Eneloop battery. It's hard to guess how long, but let's say 0.1 second & the meter shows about 19 amps.

I have no idea how brief a spike Is on an electric motor, but I feel it's going to be at least 0.1 second to get going. 

 

DSC_1435_040030.jpg


 Hi  Just for the discussion only I did look at the peak hold on that meter and it says AC A only so that might explain the lack of readings. 

"Peak hold function that can measure peak values such as starting current (AC A only)"

I was involved in measuring lots of currents and voltage in a testing lab for many years. Digital meters can hide lots of things if they are not fast. Indeed meters for general use can have averaging and zero supression to make them easier for general users. Hmm 

Jaahn

This is how they manually controlled the current inrush on larger DC motors on ships and other dc setups. Starting them with resistances  and then manually reducing the resistance over some steps in a short time to prevent the system being overloaded by the inrush current. The time depends on the load and the rotating inertia of the load.

Looks like they still make them in India

dc-starters-252.jpg

 

Hmm the ones I used in the past had no boxes covering the workings but they were 'only' 180V DC systems. I guess OHaS would not like them now.wink  

 



-- Edited by Jaahn on Thursday 17th of November 2022 06:55:40 PM



-- Edited by Jaahn on Thursday 17th of November 2022 07:05:22 PM

__________________


Guru

Status: Offline
Posts: 7403
Date:

Peak is AC for the top of the cycle, I was measuring DC. I bought this meter because it could do DC amps. I have a few other multimeters.

 

I hadn't really noticed it before but I can hear the compressor increase in speed substantially for the first number of seconds. So it does start quite slow.

 

But I had noticed previously that the fridge once basically started, it is at about 2.7 amps & after about a minute settles at about 3.8 amps & the compressor going faster, using 4 x 26AH batteries, sometimes together with a trickle charger for some of my testing.

 

So there seems to be a lot more going on than I previously realised in this fridge when it starts.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 1467
Date:

Waeco fridges with 12/24v DC compressors are actualy 3phase motors with a soft start. The Electronic box on the side of the compressor does the work. This is the start current for BD35F Waeco compressor 3.31A peak & run 3.24A.WAECO START UP CURRENT..JPG



-- Edited by DeBe on Tuesday 29th of November 2022 04:18:19 PM



-- Edited by DeBe on Tuesday 29th of November 2022 04:19:34 PM

Attachments
__________________
D.L.Bishop


Guru

Status: Offline
Posts: 1467
Date:

FRIDGE on 12V.1.JPGFRIDGE ON 12V.2.JPGFRIDGE on 12V.3.JPGLG.1.JPGLG.2.JPGCURRENT RUN 49 Watt.JPGIf you seriously want to run a domestic fridge on 12V DC, then use an inverter fridge. This is what i run an LG fridge of 12V DC in emergencies & they are a soft start. & i use a 600W Giandel pure sine wave inverter.



-- Edited by DeBe on Tuesday 29th of November 2022 04:48:59 PM

Attachments
__________________
D.L.Bishop


Guru

Status: Offline
Posts: 7403
Date:

I found this on the Danfoss compressor (text from attached image).

 

' The BD compressors are fitted with a brushless direct current motor which is electronically commu- tated by an electronic unit.

The electronic unit is delivered separately and must be mounted on the compressor, please see instructions page 20. The electronic unit must always be connected directly to the battery poles or power supply unit terminals. For the protection of the installation an external fuse must be installed in the power supply cable close to the battery or power supply unit. Establish a special wiring for the BD power supply using direct one-piece cables and avoid to use the existing wiring.

If the chassis is used as a conductor, a proper connection between cable and chassis must be estab- lished.

Wrong polarity applied to the electronic unit does not destroy the unit, however, the compressor does not work.

If the compressor is planned to be stopped for a longer period, a main switch can be installed. The switch must have a contact system rated min. 20A, otherwise the voltage drop over the contacts will cause the battery protection to cut off the compressor earlier than intended. '



Attachments
__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 1467
Date:

DANFOSS  101N0500 Block diag.jpgDANFOSS 101NO500.JPGDanfoss 240V-12V Controler.2.JPGDANFOSS BD35F RUN.JPGDANFOSS BD35F. RESTRAINING TAB.JPGThe compressor is actualy 3 phase star winding. This is one i cut open because it would not run. The center termination of the star winding was open circuit. Once fixed the compressor would run, i now use it to test the controler modules.



Attachments
__________________
D.L.Bishop


Guru

Status: Offline
Posts: 1467
Date:

DANFOSS  101N0500 Block diag.jpgDANFOSS 101NO500.JPGDanfoss 240V-12V Controler.2.JPGDANFOSS BD35F RUN.JPGDANFOSS BD35F. RESTRAINING TAB.JPGThe compressor is actualy 3 phase star winding. This is one i cut open because it would not run. The center termination of the star winding was open circuit. Once fixed the compressor would run, i now use it to test the controler modules.



__________________
D.L.Bishop


Guru

Status: Offline
Posts: 7403
Date:

So it will run in reverse if you swap 2 phases.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 1942
Date:

Whenarewethere wrote:

So it will run in reverse if you swap 2 phases.


 Probably true. But what is the point as most reciprocating piston compressors just pump the same running either way. It will not suck the gas out of the wrong port wink  Possibly the lubrication may be affected though.

Thank you DeBe for some useful interesting facts about what looks at a quick glance like a totally different simple system. Hmm aww

Jaahn 



-- Edited by Jaahn on Thursday 1st of December 2022 06:31:51 PM

__________________


Guru

Status: Offline
Posts: 1467
Date:

DANFOSS. BD35F INT MOUNTS & OIL FEED.JPGIt will posibly run in reverse, but probably not wise as the oil is picked up by to bottom of the hollow crank shaft. Which probably has a spiral inside to draw oil up & out the top to lubricate the conrod & piston.



Attachments
__________________
D.L.Bishop
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us
Purchase Grey Nomad bumper stickers Read our daily column, the Nomad News The Grey Nomad's Guidebook