Refigeration Amp Hour usage survey

[SV THIRD DAY]

Originally Posted by typhoon

The last two dayshave been very hot up here . With the inside of the boat at 35 Celsius . These turned out to be my worst amp hour days . 38 Ah . No alchemy here . Just counting . I have yet to insulate my two top doors which I will do this week with aerogell . The doors actually feel cold to the touch so there is a lot of btu's going up up and away from there .

Where is what I love about Typhoon's real live data and numbers.

There are "experts" out there that will tell you and argue with you forever that his numbers are impossible to get at the ambient temp and box size he has. It can't be done they will scream from the rooftops while banging their chests. It's the same folks that say our published data of 24AH for a 7CF box 1/3 freezer and 2/3 refrigerator with R30 insulation at 70-degs ambient are faked or bogus or a lie. Of course our test box is running right now at the office showing these results, but I'm somehow an evil villain spreading lies, heck...I'm akin to an ISIS fanatic for even suggesting such craziness...(you should see some of the crazy PMs I get)

Carry on Amigo...
I love seeing real life test data trump the naysayers!

Not back to my deck project after tossing in a few Flash-Bangs, but it's natures release...

[a64pilot]

Originally Posted by Mike OReilly

Thanks again Chala, I really think there must be a fault with the thermostat. I did have the compressor cycling about a week ago. We then went into some really hot weather (low/mid 30C, and high humidity). Since then it's refused to cycle off. Our whole setup is old, and I'm sure we're not as well insulated as we could/should be. The radiator is also caked in some plastered dust. It's in an inaccessible area, so hard to get at and clean ... but I'll try that next.



Anyway, we're on board all the time now. And with sun in the sky we can keep up with the draw, so we're basically running all day and shutting off overnight. Things stay cool enough. Once we're done for the season I'll take a stab at some real testing/maintenance/surgery. Hard to do when the box is full of beer .

What your calling the radiator is I believe the condenser, if it choked in dust that could very well cause your problem, it's job as you know is to get rid of the heat, and allow the gas to phase change into a liquid, and the of course the liquid evaporates in the evaporator, and that phase change absorbs heat, heat that is supposed to be dissipated in your clogged condenser.
As it is, your system is working hard now and likely at higher than desired pressures, you would do it a great favor by cleaning the condenser, a good kitchen spray and water and maybe a soft brush should do it.
They are always in a nearly inaccessible spot, mine is too.



Sent from my iPad Pro using Cruisers Sailing Forum

[zboss]

My values are definitely not guessed... We have a stainless lobster that shows how much power was used the last 24 hours in both graph form and digital readout. It also shows a graph of the last 24 hour temp, the cycle %, and so on. We can even have it boost the output to cool down further when the batteries reach a certain voltage. It also automatically defrosts the fridge when not used in a spillover situation. Includes a circulation fan and led lights as well!

The catch is... It only is certified to work with certain model compressors.

http://stainlesslobster.com/


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[SV THIRD DAY]

Originally Posted by zboss

My values are definitely not guessed... We have a stainless lobster that shows how much power was used

The Stainless Lobster device is Great.
We tested one for several months in our test box and worked with Arvid the cruiser/owner/developer to develop a unit for Holding plate systems like ours vs just the thin rolled Aluminum evaporation plates. The defrost cycle doesn't really work on holding plate systems because of the holdover capacity nature of how they work (you don't defrost them), but it worked great on alum evaporators and the other features are very useful.

What I really like about the system for use on holding plates is the ability to "store" more energy in the holding plate when it is available either from Solar or while running the engine. That way you will use less energy when the charge source goes away. The amount of energy you can save will really vary based on how often you are in the charge battery voltage range on your boat. A boat for example that never has his batteries above the user-settable "charge voltage" won't really have any energy savings. While a boat that goes into float mode often from solar and does lots of short motor trips or generator charging runs, that use profile can save on power.

The Big bonus of the Stainless Lobster approach is DATA...if finally gives the cruiser the ability to know and start to understand just what is going on with that remotely mounted compressor. Graphs, Data logger, it's a techys wet dream and I have had one running on my fridge and freezer on my boat now for a while and love it. It doesn't have an Amp meter actually measuring the Amps inside of it, but rather the brain has the Amp draw vs Compressor speed programed into it. So by knowing the speed of the compressor it knows the Amps usage and can totalize it for you.

[skipmac]

Originally Posted by SV THIRD DAY

Where is what I love about Typhoon's real live data and numbers.

There are "experts" out there that will tell you and argue with you forever that his numbers are impossible to get at the ambient temp and box size he has. It can't be done they will scream from the rooftops while banging their chests. It's the same folks that say our published data of 24AH for a 7CF box 1/3 freezer and 2/3 refrigerator with R30 insulation at 70-degs ambient are faked or bogus or a lie. Of course our test box is running right now at the office showing these results, but I'm somehow an evil villain spreading lies, heck...I'm akin to an ISIS fanatic for even suggesting such craziness...(you should see some of the crazy PMs I get)

Carry on Amigo...
I love seeing real life test data trump the naysayers!

Not back to my deck project after tossing in a few Flash-Bangs, but it's natures release...

Hey Rich,

Here's another real world, measured usage that's pretty darn close to those numbers. My box it a little bigger, about 9 cu ft but about 1/5 freezer. In Florida winter with 70s day, 50-60 night temps I'm using about 25-30 amp hours/day. That's measured draw with no charging source connected. Summer with ambient in the mid 90s and the boat closed up so 10-20 hotter inside I'm using closer to 50.

[SV THIRD DAY]

Bingo...
One doesn't have to spend 100AH/day to have cold beer!

[StuM]

Originally Posted by SV THIRD DAY

Well enough Anecdotal examples and you get somewhere...but that's the hard part...getting an accurate sample of cruisers.

This I can tell you, add more solar until you have no room for more...then squeeze on more. Solar panels are like Garlic...you can't have too much. We went from 260W...to 430W...and now have 1300W...finally enough!

For now

[RaymondR]

Engine fuel consumption and fridge amp hours are the two fish stories of the yachting world. I am sure we have all heard them. "I have a V16 which puts out 1,000hp and only uses 1/2 a gallon of diesel an hour whilst driving my sixty footer at 10 knots." and "I have a walk in freezer which will keep a bulls carcase at minus 60, runs all night and through the summer on a 100 amp hour battery with a 40 watt panel etc, etc"

[skipgundlach]

Originally Posted by SV THIRD DAY

I agree....Skip's Unit's power usage is just crazy a water cooled BD80 with his box size and type of insulation just shouldn't be using those type of numbers. I've spent lots of back and forth time trying to help...but just had to admit that I couldn't figure it out without being on the boat myself. Heck if Skip will have cold beer for me, I will offer to do that the next time I am in Florida!

Hey, Rich!

I hope and pray that we'll actually be cruising during our first Commodore season when the annual SSCA meeting happens.

However, if we're not, we'll be there, and Melbourne's only an hour and change away from where Flying Pig would be moored.

I'll definitely take you up on your offer, give you the Vee to sleep on the Tempur-Pedics, and take you to dinner, let alone a beer.

And, as I type, I've got the freezer asking for zero at the plate, and it can't do it, just after (box frozen for a couple of days, now) a defrost. I'd been sent the wrong thermostat manual; that affected my accuracy in box settings...

Back to capacity, at 'auto', I never saw it shut off. I went to 'high' and never saw it shut off. So, I went to 'medium' and the indicated box temp rose slightly as it still never shut off.

Given that the plates were reading zero when, in fact, the cutoff had been set for +5, I suspect that if I shot the plates, I'd find them well into negative territory despite it not having reached the cycle point. But it's not cold enough that we don't still have the spillover fan run occasionally (the reefer creeps up a couple of degrees over many hours; during other tests, we got it cold enough that the reefer stayed at or just under 32F, not cycling at 34 as designed).

So, I look forward to seeing you again soon, and thanks for the boost into Commodore (a board member has to sign off on the application, for those not familiar with the process; Rich is a board member)!

[MooGroc]

I don't know how many amp hours per day my fridge consumes because I don't have an isolated amp meter on it. I do have a link 10 that tells me total boat amp hours consumed.

I calculate that my fridge was using about 70 amp/hours over night (when there is no solar charging, thus easier to measure). I felt this was high so I worked on my box insulation this spring. After realizing that a complete box rebuild was way too big a project I followed some good advice I found on this forum. I added 2 layers of Aerogel on 3 of the sides, the bottom and in the cover.

There are still spots with poor insulation, but overall I improved things a lot. Now I'm seeing about 25 amp hours drain overnight.

This is with about an 8 cubic foot box and a bd35 Seafrost unit.

[chala]

Originally Posted by Mike OReilly

I really think there must be a fault with the thermostat.

Another thing that you can check is that. The sensor of a thermostat is often attached to the suction pipe near the evaporator or at the evaporator. It is nomally easy to check if the sensor as become detached.

Originally Posted by typhoon

Design your systems properly , make sure they are running right .
No black arts needed. ��

So true, so simple no need of smoke stack theory.
Every motor is built for a nominated power output. The power output of the compressor on my freezer is rated at 240V 0.8A 0.8pf ac, this equal to 153.6W which is a little more than a BD 35, 50 or 80.
To be remembred, at a higher voltage an electrical motor use less amps, at a lower voltage it use more amps. On a dc system as the voltage change, the amps also change, to be more accurate, VA should be used insted of A.
On a 240V 5 kW ac genset used for cooking, charging batteries, etc, 160W is peanuts.
On main engine with a 24V 80A/12V 80A system 160W at 28V is also not a problem.
On the 24V 100A batteries, with an 1200 W inverter, 160W at 28V decreasing, for a running time of an half to one hour, is also not a problem.
To be noted the inverter display accurate dc A, VA and V.

[chala]

Originally Posted by SV THIRD DAY

but rather the brain has the Amp draw vs Compressor speed programed into it. So by knowing the speed of the compressor it knows the Amps usage and can totalize it for you.

Good to know that something got some brain.

[SqPeg]

How does one measure these things?

[SV THIRD DAY]

Wise man say,
It's only too much power if you can't make more.
Solar is cheap and life is too short to drink warm beer.

[skipmac]

Originally Posted by SqPeg

How does one measure these things?

There may be other ways but for me I installed battery monitor that keeps track of amps in/out, battery voltage, etc. Of course I installed it primarily to monitor the batteries but it is useful for measuring usage of different devices on the system and other things as well. The brand and model I have is a Victron 602.

I just turned off all other electrical devices, zeroed the amp counter and checked it again 24 hours later. Did this a few times under different conditions to confirm the data.

If you don't have a battery monitor but have a Volt meter that will measure amps you can guestimate your use by measuring how many amps the fridge is drawing when the compressor is running. The keep track of how often and how long the compressor runs, multiple the average amp reading by the total time the compressor runs in hours and you have the total amp hour usage.