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Sorry for the sudden out burst mate, But I need to pick your brains,

I remember a while back you said that hooking a 12v fridge in to a 200/240v inverter will draw more Amps and was a waste of time because of a few factors like having to add the current drawn by the Appliance + the inverter,

So with that I have ordered a Generic version of the 12v KickAss meter and I also bought a good one that runs off 240v that you plug in the wall or inverter that measures/Logs KWh, and while running measures Amps, Time, Volts, Watts.

I am trying to work out if my little Cooler/Fridge would be cheaper to run if I did use the inverter because I know what you said about wasted power of using an inverter going from 12v to 240v but I got some really crazy figures when hooking this Cooler up to my charger and when I plugged it in to 240v it all went Nuts as in Mega Low figures which I know are correct,

By chance is there any possibility that you could work out what the current draw would if I ran the Cooler via the inverter if I gave you it's 240vAC figures ?.

Thanks Mate.

John.
 
Nothing is 100% efficient, you will loose when you use the inverter. You will also loose when you use a transformer. Just use the 12v straight from the battery and avoid the losses, even if they are small they will be greater than nothing. Ken.
 
Probably better to try and understand measurements in watts.
Lets say your cooler draws 5 amps @12v 5x12=60watts
Now if you ran a 60w appliance on 240 it would be 60/240=0.25A@240v +losses

A pretty good inverter will have a no load draw of 1amp@12v, so that is lost just having it running.
An inverter will use around 10% in the switching process as well.
So you'll use (from the battery to power inverter) 5amps+10%=5.5A +1A no load draw total 6.5A or 78W. 78/240=0.325A@240v ac
You'll use less power running it on 12V vs inverter.
1529444469_dcp4.jpg
 
Occasional_panner said:
Probably better to try and understand measurements in watts.
Lets say your cooler draws 5 amps @12v 5x12=60watts
Now if you ran a 60w appliance on 240 it would be 60/240=0.25A@240v +losses

A pretty good inverter will have a no load draw of 1amp@12v, so that is lost just having it running.
An inverter will use around 10% in the switching process as well.
So you'll use 5amps+10%=5.5A +1A no load draw total 6.5A or 78W. 78/240=0.325A@240v ac
You'll use less power running it on 12V vs inverter.
https://www.prospectingaustralia.com/forum/img/member-images/7956/1529444469_dcp4.jpg

Well my 300w/310 surge Inverter does have a No Load draw of between 0.9 and 1.0.

Using 240v My Cooler uses 16.2watts and has an Amp Draw of 0.102 amps Per Hour/ so I need to know what it all adds up In Amps on the 12v/Battery side of things to because of the very low amp draw on the 240v side.

thanks,

John.
 
Just hook that meter between the 12v Batt and the inverter batt input.
If the appliance uses 16w and you have a no load draw of 1 A(12w)
Then you'll be using 28w+ losses@240 will be around 0.116A
Or 2.3A +losses from the 12v battery
So running that for 12 hours will draw around 28AH
If you go down to max 50% depth of discharge you'll need bare minimum 60AH battery to operate it, but far better off with 100Ah
Don't get hung up on the 240v amps, if you are running the inverter from a battery you need to calculate the amps coming from the battery.

But since it's already a 12v device just run it on that and you'll use 16w instead of 28w.
 
Occasional_panner said:
Just hook that meter between the 12v Batt and the inverter batt input.
If the appliance uses 16w and you have a no load draw of 1 A(12w)
Then you'll be using 28w+ losses@240 will be around 0.116A
Or 2.3A +losses from the 12v battery
So running that for 12 hours will draw around 28AH
If you go down to max 50% depth of discharge you'll need bare minimum 60AH battery to operate it, but far better off with 100Ah
Don't get hung up on the 240v amps, if you are running the inverter from a battery you need to calculate the amps coming from the battery.

But since it's already a 12v device just run it on that and you'll use 16w instead of 28w.

Cool, Well done,

running it on 12v it uses 1.34 amps constant, Unless I turn it down a notch or two then it will cut out every 5 minutes or so and then cut back in again and it will do that in both 12v and 240v, but because of the amperage figures are I don't have a clue what it is doing.

My starter battery is a 115Amp/1000cca and I have 4 more exactly the same on order to run my fridges etc,

Thanks again.

John.
 
Ridge Runner said:
I am trying to work out if my little Cooler/Fridge

Is this the Waeco TCX35 from your other thread?

If I assume it is :rolleyes: :| the manufacturer claims 64W @240V and 46W @ 12V.

Input voltage (AC) 220-240 V
Input voltage (DC) 12/24 V
Rated input power (AC) 64 W
Rated input power (DC) 46W DC12V/50W DC24V W

I would guess that there is a step down transformer in there consuming power also.
 
Mr Magoo said:
Ridge Runner said:
I am trying to work out if my little Cooler/Fridge

Is this the Waeco TCX35 from your other thread?

If I assume it is :rolleyes: :| the manufacturer claims 64W @240V and 46W @ 12V.

Input voltage (AC) 220-240 V
Input voltage (DC) 12/24 V
Rated input power (AC) 64 W
Rated input power (DC) 46W DC12V/50W DC24V W

I would guess that there is a step down transformer in there consuming power also.

Yes it is the TCX-35

It only uses that 64w when you first plug it in and once it has cooled down it never does it again Unless you have it set to the MAX setting, on the mid settings it will switch on in the ECO Mode which is 16.2 watts and in the lower settings it will run in the ECO mode for 5 minutes and then shut off completely and after 4 or 5 mins it will kick back in to the ECO mode again and it will repeat doing that for as long as it is plugged in.
 
Sorry for the delay, others seem to have answered.

In simple terms, calculate your battery draw in Watts by multiplying V x A.

So if it's 46W @ 12 V that approximates just under 4 amps. (divide W x V)

Your 240VAC power pack uses 64W which is approx. 0.25 amps @240V not 12.

However, the thing most people forget when using an inverter is that the 240V wattage is similar when calculating the 12 V amperage. Sound confused, here are the simple math for both sides of the equation.

To produce 64 W of 240 VAC power from an inverter you divide 64 by the battery voltage of 12 = 5.3 amps then add another 10 or so % for efficiency loss of the inverter, of 0.53 = total of >5.8 amps. Given the 12V rating is 46W = <4.0 amps you are using nearly 50% more battery when running it off an inverter.

Not only do you have inverter efficiency loss, but pretty well all of the 240VAC power packs i.e. laptop, TV, fridges or coolers also use more watts to step down from 240VAC to 12 VDC.

Hope that helps, BTW I don't need the actual figures, the rating of the Cooler says it all :)
 
Thanks Mate,

the reason for the confusion is because the actual AC and DC figures when tested are a lot less, Their figures must be based on when it is first plugged in because they are way way OTT, Not even close.

I have tested it with my Fluke DMM and an Amp Meter and a Clamp Meter plus a 240v socket analyser which also give the full data, Dometic also quote that it does use as little as 8.8 watts, And it does because I have measured it So the 46 and 64w figures are it's Surge Measurements which it only does when it is first switched On.

thanks again.

John.
 
You're in England, you don't even need a fridge. :rolleyes:
That thing won't be working hard in that environment, take it to Darwin and it'll bloody use full watts there.
 
Occasional_panner said:
You're in England, you don't even need a fridge. :rolleyes:
That thing won't be working hard in that environment, take it to Darwin and it'll bloody use full watts there.

LOL, I've got it set to reverse cycle so it warms me Beer,

I have seen it hit around the 39* mark once or twice, It hasn't rained here in nearly 2 months and it's getting warmer.

The winters are getting warmer at around -27*c was the worst and the summers are getting cooler.

They said on the News that Over 12,000 or 20,000 people died here last winter because of the cold ?.
 
I left England over 50 years ago, I have no wish to return :) But I do remember asking for a plastic cup of ice to drink the Fosters I bought on a north bound train out of London when I returned for my father's funeral. The beer was just on a rack behind the counter (it was "summer").

Rarely do appliances match the rating exactly. Fridges in particular as so many variables need to be considered, notwithstanding, ambient temp. cable lengths, and actual battery volts.

However, the logic of the calculations I penned in my previous post, related to ratings will in context apply similarly to actual readings.

Here's an example from my equipment; I have a Toshiba Satellite Laptop, it has a power pack that transforms 240VAC to 19VDC. The 240VAC rating is 2 amps which = 480 W. The output is 19VDC rated at 6.32 amps which = 120 W. A huge efficiency loss of 400%.

So to run the power pack from an inverter (next size up would be a 600W) will probably use 480/12 = 40 amps of battery + efficiency loss. No way !

But, I have a 12 VDC to 19 VDC (variable voltages) laptop power supply rated to a max of 150 W which powers and charges from my caravan/car aux batteries and it's max amps would be 12.5 A.

However I've noted that when the laptop is being used and charged at the same time it only uses about 4 amps and when the laptop is off, but charging it reduces to <3.0 amps. So more often than not I use the laptop internal battery, turn it off then charge. Unless it's already full, in which case it's only running the laptop and keeping the internal battery topped up.

Conclusions - the 12 VDC adaptor is much more efficient than inverting 240VAC and the actual figures don't match the rated loads :)
 
I think your right, They list a load of figures and they over rated them, If I had not bought all these gizmo's and measured them I would never of known how low they are, Yet on domestic appliances they under estimate them so they always chew mor power than they quote.
 
I bought some plug In meters because I needed to trace where I was using too much power at home last week because my power bill shot up by about 3X it's normal rate, Found the culprit some how I had knocked the House fridge setting/Dial and it added a couple of KWh to the bill Per Day,

Since then I have been testing this cooler hooked up to one of the meters and it is using 215 watts per 24hr period, It Logs the Run time only and gives you the Hi and Lo watts/Peaks as well as the voltage and Amps and Watts as well as KWh and the Power Factor as well as the cost of the Electricity, Only took me half a day to find out where the power was going, Lol.

https://www.ebay.co.uk/itm/Power-Co...263696216420?_trksid=p2349526.m4383.l4275.c10
 
RR - I suppose your Thermo Electric cooler is getting a hammering, with the unusual "heatwave" in the U.K. :) ]:D
 
condor22 said:
RR - I suppose your Thermo Electric cooler is getting a hammering, with the unusual "heatwave" in the U.K. :) ]:D

Yeah not arf, Lol. 33.2*c in Scotland on sunday and it was around 31*/32* here down south,

Now the house fridge has gone on the fritz, I raised the temp a couple of times but because I wanted to balance out my power bill and just as I got it all set right the weather gets is warmer the fridge is now using more power than ever, :mad: :mad: :mad:

Oh well at leased I got the facts and figures to work from in the future when the weather cools down again :Y:

the little cooler works well as far as coolers go, I think a smaller one would of been a bit more flexible.
 

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