Embraco compressor Whirlpool fridge

[highdesertranger]

do the math, stern provided you with the formula. 110volts x 1amp = 110watts. 12v x y = 110w so y = 9.16 amps. more then what I said but I just rounded it off the top of my head. btw 9a at 12v is way more then a 12v refer and we are not factoring in the inefficiencies of the invertor. good invertors are usually in the 85% range. cheap ones are in the 60-75 range. highdesertranger

 

[SternWake]

If the question is


Does the higher amp draw mean that the compressor runs for less duration when it does cycle on? the answer is mostly yes.

But, the 9 amp inverter load for 5 minutes per hour is not equal to the 3 amp 12vdc for 15 minutes every hour.


One factor is Peukert. 

A fully charged healthy battery rated at 100AH can support a 5 amp load for 20 hours before voltage falls to 10.5v, but it cannot support a 20 amp load for 5 hours.  The higher the load on the battery the less capacity it has to give.

Also the 5 and 15 minutes examples above are just made up numbers. I have no idea how long your compressor will run each hour, or how it would compare to the same size fridge running on a Danfoss compressor in the same exact conditions.

My danfoss compresor, if I return the resistor to speed up the compressor to 2500 rpm from 2000rpm, amp draw goes up by ~0.6 amps, but the time the compressor runs will be less.

But the lesser amp draw for longer, is more efficient and keeps the load below the 4.5 amp load at which my battery earned its 20 hour capacity rating. 

YOu should ge the kill a watt meter, because actual data lies within, and then one can determine how much battery capacity is required, and how much recharging capacity is required to keep the fridge powered anf get a respectable lifespan from the batteries powering it.

Everything else is a guess, edg u muncated or not.

The Kill a watt is ~25$.  A great tool for living on battery power is the DC  Clamp on Ammeter.  These can be had for as little as ~35$.  With it, on One of your inverter cables while it is powering the proposed refrigerator over a period of time, One can also get a good idea of how much the fridge will consume, and be able to use the tool later for other things/loads/ charging sources to see how many amps are flowing.

The following product is an example, not a personal recommendation as I do not own this exact product:

https://www.amazon.com/Uni-T-UT210E..._UL160_SR160,160_&refRID=17NS2HT4J7CBCEWYAAKF

 

[jonsun]

Im sure you know that the battery cannot deliver a high load for a short duration because of it's internal resistance. That changes significantly for AGM or multiple batteries.

 

[jonsun]

do the math,  stern provided you with the formula.  110volts x 1amp = 110watts.  12v x y = 110w so y = 9.16 amps.  more then what I said but I just rounded it off the top of my head.  btw 9a at 12v is way more then a 12v refer  and we are not factoring in the inefficiencies of the invertor.  good invertors are usually in the 85% range.   cheap ones are in the 60-75 range.  highdesertranger

 

[Oneleggedcowboy]

Ok I understand the math sorta.....Thanks to yall for trying to educate me.

 

[Oneleggedcowboy]

So yesterday I put the Embraco compressor 1 amp Fridge into the slide in camper with a 245 watt 24 volt panel and a 20 watt Eco Worthy MPPT controller. I hooked up a so so 12 volt marine group 27 battery. I took the 6 volt Trojan out and put them back into the travel trailer last fall.  I hooked up a old 700 watt Hsrbor Freight inverter, the fan runs anytime it is turned on so I don't like it. It's 700 watt running and no idea what peak. It started and ran the fridge great for about 10 minutes and the freezer plate got cols so hopefully it's working good. I filled it up with water bottles. The battery came to full charge fairly quick. So I left it not running. This way I can start it in bright sun this moring to do the bring temps down and start cycling. It's almost 9 am and I am headed to the barn to turn it on!!!   Wow I love experiments!

 

[Oneleggedcowboy]

Possibly not doing well. Fridge ran off and on all day and battery stayed full. One hour b4 dark battery went to 12.7 with 1.5 amps still going in. My theory solar panel was doing all the work and battery not losing any charge so to speak. Cut it off and was full charge at dark. I need s Kill a watt meter and 2 golf cart batterys to continue this.

 

[SternWake]

Possibly not doing well. Fridge ran off and on all day and battery stayed full. One hour b4 dark battery went to 12.7 with 1.5 amps still going in. My theory solar panel was doing all the work and battery not losing any charge so to speak. Cut it off and was full charge at dark. I need s Kill a watt meter and 2 golf cart batterys to continue this.

Well, you could try running it overnight, and see if the battery can handle the overnight load, check morning voltage, and make some estimations as to how much juice the inverter fridge combo uses.

BUt the battery might not like being drawn very low, if down to the point the inverter low voltage alarm starts screaming, and should then be fully charged ASAP.

I am not sure how well a Kill a watt works when plugged into a MSW inverter.  the stepped sine wave might confuse it.  I would use the kill a watt plugged into the grid to estimate overall fridge consumption for a period of time, then translate that KWH figure to Amp hours, which then determines how much battery and Solar one requires, just for that one DC load, when one adds 20% more for inverter inefficiency.

 

[Oneleggedcowboy]

Gmorning all!    Got a couple new ideas. Fridge ran great all day without affecting the battery charge. Could not run all nite on my wimpy group 24 marine battery and Harbor Freight 700 watt inverter. 

Therefore how about this... some of yall turn your 12 volt fridge off at nite. So I found a 10 setting per day electric timer. Say I set the fridge to start running at 6 am and it stays powered until 6 pm. Then I set it to get power for 5-10 minutes per hour all nite. I think even the wimpy battery and sorry HF inverter would work. Yes I would have 24 hours loss of .5 amp per hour on my Krieger inverter for a 12 amp daily total. This is not a true loss because remember from 6 am to 6 pm on the average the panel has enough sunlight to do this. So the other 12 hours I lose only 6 amp hours parasitic loss. Now for the fridge it's 1 amp equals 8 amps 110 volt. Let me try this and yall correct my math please? It would be 12 hours at 5-10 minutes run time per hour so let's go with the bigger 10 minutes per hour. That's 120 minutes of run time. That's 2 hours of 1 amp hour equals 8 amps 110. So that's 16 amp hours so 16 amp hours run time plus 6 amps parasitic equals 22 amp hours plus whatever the timer used. It's a digital with battery backup so I imagine very little.

Where to get 22 amp hours?  100 watt panel in peak sunshine gives about 5.5 amps so it would take all of the 4 hours peak sunshine to recharge the fridge usage. My 245 watt 24 volt panel here in the eastern NC at 15 foot sea level got 12.5 plus amps the other day with the MPPT Eco Worthy charger. That's two hours to take care of the battery.

So with my Trojan T105 pair I think this would work!!!   I know my little battery can run the inverter and fridge all day and it can go to 9 pm and only be down to 12.5 volts when I turned the experiment off to avoid endangering the little 24 group battery. I have ordered the $15 timer from ebay.

Wit the 215 amp Trojans the loss of 22 amps at nite would be 10 % of my battery bank. I think I should have about 80 amps available so with a little juggling on cloudy days I should be ok. I imagine if it's cloudy and I don't use the batteries for anything but Led lights I will make it. 

Iwill try this as soon as the timer gets here. Hey its a great experiment and fun even if it fails right? LOL.  I love this forum!!!

 

[highdesertranger]

let me say this, the more doodads you add to a system, the more potential failure points you introduce. also the more money you are spending, getting closer to a 12 volt refer with every experiment. just a thought. highdesertranger

 

[SternWake]

Those who turn their fridge on overnight, then ask it to recool everything back down to under 40F, are using more energy than the person who let it simply maintain sub 40F temperatures.

The difference is WHEN the energy is consumed.  People who drive to recharge or have solar that can cover the load and also recharge might have batteries that benefit from such a strategy.

 but THe turning the fridge off or limiting its run time to save battery, actually uses more overall electricity when the fridge has to recool everything back down. The duty cycle will increase significanlty for many hours.

And there is no guarantee the foodstuffs inside will remain below 40F, which is the whole point of refrigeration.

Last time I turned off my fridge, as I was wanting to recharge at the limits of my plug in chargers, 65 amps instead of 62 with fridge on, I forgot to turn it back on, and mid morning some 10 hours later, my cold plate had defrosted and a big puddle of water spilled out my door.

 

[Oneleggedcowboy]

I agree High desert Ranger completely. That's why I am looking at a Truck Fridge unit also. It has a freezer. It is also a upright and not a chest type so all the cold air will run out when you open the door. They ar about $500 for a 1.7 cu. Ft.

 

[Oneleggedcowboy]

Ops wrong button.
They are about $500 for a 1.7 cu ft. Plus $50 freight. 
Now I own the 110 volt fridge which is a 2.88 cu ft, I own the inverter, I own the various batteries, I own the solar psnels, wiring MPPT controller etc. So for a $15 timer I could very well solve this corundum once and for all.  Oh by the way I just got back from Lowes with a $16 timer that has 16 settings!!!   Whohooo I feel a experiment coming on 2moro!  And yes it to has a rechargable battery for power outagesto protect the programing.
I also suspect cold air running out when you open the door is not the huge issue either. Somewhere Stern wake mentioned the cold contents restore the cold air as soon as you.close the door. We shall see. Could not find a Kill a Watt meter today in town so might be a Amazon.purchase.

 

[SternWake]

Looking forward to some Data from your experiments and results,
 But I do not know how well the kill a watt will work plugged into a HF MSW inverter.  They are reported to have a very choppy square wave.


YOu should also have a thermometer,  The DC clamp on ammeter will be invaluable later too.

OR

This is a neat voltmeter/ammeter combo meter, just slide an inverter cable through the  round hall effect sensor.

https://www.amazon.com/gp/product/B01DDQM6Z4/ref=s9_dcacsd_bhz_bw_c_x_3_w

Its resolution is only to 0.2 amps though.

I have mine on dashboard reading total alternator current, but soon will move sensor to a battery cable to see amperage into, or out of battery while driving.

As far as cold air spilling out on a front loader, well as long as the door is not left open for a minute each time, so that the skin of the items that are already inside and cold, start absorbing heat, there will be no measureable difference in battery consumption.

Also the very act of opening a Lid, or a door, exchanges a certain amount of air inside anyway.  The air itself does not have much thermal mass anyway, but of course it is better to keep the door open for as short a period as possible, and not open and close it 30 times for each meal made.

Bad habits from the convenience of stick and brick fridges should be unlearned, unless one finds they have a solar surplus. Then one can simply not even give a shit either way.

 

[Oneleggedcowboy]

Hey Sternwake the thermometer is already in there. It's s big clunky plastic think but should work for this project. Just looked at a P3 4400 Kill A Watt meter on Ebay. It measures kilowatts. Is that like a adding up thing or a it takes 900 watts to run it? I have my 16 position digital heavy duty electric timer programed. Starting out with 5 minutes per hour for the dark hours. I will use the kill a watt with house current.

 

[SternWake]

KWHours is like how the electric company bills a residence


Watts is just an instant measurement of current consumed
Watt hours is cumulative energy used over a period of time

Sams as amps
1 amp load is a one amp load
1 amp load for the duration of an entire hour is 1 Amp Hour consumed to power the load

 

[Oneleggedcowboy]

Well that could of worked better!   Fancy digital electric timers do not like modified sine wave El cheapo HF inverters!   LOL. Fried that bsby, it even made a fritzy frying noise when I plugged it in.   So back to the past....  I used to keep the show horses under lights in their stalls for 16 hours a day so they didn't get a long furry hair coat. So I have several mechanical timer. The will only let you do 30 minute stop and start cycles as a minimum so I set it to start powering at 6 am and stop a 6 pm. Then come on for 30 minutes st 9 pm snd 12 am and 3am. It's running now so we will see how it goes tonite. Cross your fingers! LOL

 

[SternWake]

Digital timers are seemingly the one standard item that will always not work properly on MSW inverters.

 

[Oneleggedcowboy]

Yep I would say they don't even remotely get stsred before they deep fry!!! LOL

 

[Oneleggedcowboy]

So new valuable piece of need to know intel.  Do not buy 2 garden thermometers in terrace cotta from Dollar General for a buck each to track temps in your freezer and fridge. My freezer according to them is 20 below zero and my fridge is at zero!!!   LOL 

So the fridge shut down the inverter during the 3 am operation. I checked it a 8.30 am and the inverter was squealing but the ice was still frozen in the freezer.  So it ran from 5 pm to 6 pm with no solar input then had two full 30 minute cycles and died in the 3am cycle. . Therefore at 30 minute duty cycles I changed the shutdown to 5 pm and startup at 9 am with 3 thirty minute on cycles schedule equidistantly during the nite. 

Yes a cloudy day would be bad news. However remember the 12 bolt marine sad shape battery and constant double fan sorry HF inverter!

Still experimenting. Need a fridge and freezer accurate thermometers.