BCS Battery Current Saving Device for Fridges

Submitted: Friday, Mar 19, 2004 at 11:56
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Hi all

For general info and comment, there are a few posts around that talk about this current saving device. Some good some not so good. I have been talking to the guy who manufactures these devices and he sent me the following email. Sounds good enough for me to trial one. Any thoughts/Commennts

Cheers Cruisin

The BCS was independently tested at University of WA and, for donating two units for research purposes, I was supplied with a full report on test results. They used one unit in house and the other was used in a 4WD on a desert trip.
The fridges used were identical Engel fridges.
The in house test showed:
Engel without BCS over a one hour period:
9 starts - ran for 18 minutes - Current draw 1.5A - mean temp 4C and ranged between 3C and 5C. (C being Celsius)
Same fridge with BCS:
2 starts - ran for 12 minutes - Current draw 1.0A - mean temp 4C and ranged between 2C and 6C.
The desert trip showed over 1 hour period:
12 starts - ran for 36 minutes - Current draw 3.0A - mean temp 4C and ranged between 3C and 5C.
Same fridge with BCS:
2 starts - ran for 18 minutes - Current draw 1.5A - mean temp 5C and ranged between 2C and 8C.
It concludes that start up of an Engel _Affordable_Storage_Drawers.aspx up to 300% more current than it takes when running, keeping in mind that start up takes less time than running but even so the Engel _Affordable_Storage_Drawers.aspx 100% more current under its own thermostat when compared with one controlled by a BCS.
With your Waeco drawing 3.5A my guess is that start up goes as high as 8.0A and cycles down once the motor runs at full speed.

As for your question having a vehicle locked up with an extremely high temperature inside, you will find that the fridge, under its own thermostat would run almost constantly in any case. If you were to get in that situation, you would (with a BCS) probably set the 'time on' period to 15 minutes or so on and 20 minutes off. The current saving would then most likely be more pronounced because you would have just two starts in an hour where your Waeco would be on/off constantly.
In any case, I do not claim that the BCS is the ultimate answer but I feel that any improvement has to be worthwhile and the BCS certainly does that. I have had feedback from a number of people stating that they save as much as 70% of current use. Again I should stress that each situation differs, depending where you are, what the ambient temperature is and, as you suggest, the high heat build up in a locked vehicle in a hot environment.
I have used my BCS now for more than 10 years on a trailable yacht without it ever failing to do its job and it made life so much easier. It certainly was a major improvement than having to re charge the batteries constantly just to keep up with the fridge.
So far as checking temperature goes, the BCS is like any other electronic instrument. You soon get used to using it, at first you tend to check the temperature constantly but after a while you build up sufficient faith that all seems to be going well and perhaps only glance sometimes at the thermometer. By the way, normally these fridges don't have a thermometer. I only use one to give a visual aid.
And to sum up on your comments, I agree that it is a compromise but a very positive one.
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Reply By: Member - Wim (Bris) - Friday, Mar 19, 2004 at 14:56

Friday, Mar 19, 2004 at 14:56

Not enough info. I would like to see overall results. Watts consumed over a twentyfour hour period.
Same result may be achieveable by widening the throtlling range on the thermostat.
Resent post questioned the temperature control of various fridges. This method widens the range by three times.

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Follow Up By: Cruisin - Friday, Mar 19, 2004 at 15:23

Friday, Mar 19, 2004 at 15:23
Hi Wim

How do you open the throttling range of the Fridge thermostat easily ???
From information I have sourced on the Internet common Houshold Fridge ranges, range from 2 C to 8 C. Obviously the ideal would be to set your fridge to a specific temperature i.e 4C and the Fridge would hold that temp. The trouble with that is that you get alot of Fridge cycling to keep the temperature range as close to 4 C as possible. The
guy who designed this product is saying that food does not spoil if the temperature stays under 8 C, therefore why cycle your fridge as much to maintain that narrow range of temperature variation. If you can preserve food Ok with that range and use less of your Battery resources...is that not a good thing ???

Ohms law will tell you the Watts used over 24 hour period for the test.
i.e For Desert trip with BCS 1.5Ax24hour = 36A Power =V x I
therefore Wattage = 12V x 36A = 432 Watts over a 24 Hour period as opposed to 864 Watts without BCS....

Cheers Cruisin
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Follow Up By: Member - Wim (Bris) - Friday, Mar 19, 2004 at 15:52

Friday, Mar 19, 2004 at 15:52
Interesting subject this.
Can you tell me why the current draw is different?
On larger systems it is considered poor energy management to run comp temps lower than needed due to higher energy needed for the lower temperature. Lower suction temp/press means higher DP = higher current draw.
A previous post related to the subject of varying temperatures in fridges and whether this is a good thing. Hence why a lot of people monitor fridge temps.

regards Wim
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Follow Up By: Cruisin - Friday, Mar 19, 2004 at 16:18

Friday, Mar 19, 2004 at 16:18

The current draw is different because the BCS device works on the principle of fewer Fridge "starts". A fridge running from the thermostat will start and stop about 10 times in an hour to maintain say 4 degrees.
The BCS device is basically a timer that you set. So you set the device to run for e.g 10mins then it takes power away from the fridge for 20 minutes...run for 10 then off for 20. As you can see from this example you have only started the compressor 2 times in the one hour as compared to 10 times when not using the BCS. It is the starting of compressors that uses the most current. When you multiply this by say 36-48 hours the amount of starts saved is substantial.
This of course is a compromise and that is why you get a larger temperature deviation as the fridge is off for a longer period. But it all comes down to what is an acceptable temperature where food will not spoil and battery life.
Starting to sound like a salesman...havent even bought one yet.
But I will to trial it out. I have a thermometer that can record Max and Min values so I will try this at home prior to going bush and will see how it performs in a hot car and in a normal environment. This device certainly requires more user intervention than relying on the thermostat but hopefully should not take too long to master.
Anything to get more out of the battery and for a small price unlike Solar

Cheers Cruisin
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Reply By: Member - Paul T- Friday, Mar 19, 2004 at 16:28

Friday, Mar 19, 2004 at 16:28

Very interesting topic.

How about posting your results when you have them? I for one would be grateful for any info re this subject

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Follow Up By: Cruisin - Friday, Mar 19, 2004 at 16:36

Friday, Mar 19, 2004 at 16:36
Will do
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Reply By: Member - Wim (Bris) - Friday, Mar 19, 2004 at 16:31

Friday, Mar 19, 2004 at 16:31
Like I said interest subject this.
It is not my intention to knock this product, just have lots of questions.
Can I achieve a similar result by changing the setpoint from 4deg C to 7deg C? Same resulting max temp but min 6deg C. Therfore 4deg C difference at min between fridge and ambient space. Saving?
I am not trying to be smart but this is an area I have worked in every day for over thirty years, therfore many questions.

Regards Wim
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Follow Up By: Cruisin - Friday, Mar 19, 2004 at 16:50

Friday, Mar 19, 2004 at 16:50

No I understand entirely. I still have lotsa questions also. I dont represent this product in anyway so no offence taken if you want to knock it. I'm just looking for a decent sollution to extend battery life with out the massive Solar cost.
If you could set a max and min temperature in your Fridge this would have the same effect in current saving but take away the need for user intervention based on varying ambient temperatures as the thermostats will decide when to turn on or off the fridge. This would be excellent.
The BCS device has no reference to temperature, and the fridge will only will only turn on when the timers are up based on your input.

Cheers Cruisin
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Reply By: Member - Wim (Bris) - Friday, Mar 19, 2004 at 16:49

Friday, Mar 19, 2004 at 16:49
Thought about this some more and I guess the only way I am going to accept the product claims is to see data similar too:
Two identical camping fridges in the same room with the same setpoint (note this may not be based on dial setting) and the same product in side. Vary the room temp over 24hrs to mimic actual outdoor conditions. Have one fridge installed with savings device. Monitor the total watts consumed of each fridge for the entire 24hr period
After 24hrs change the savings device onto the other fridge. Without changing anything else re run the test.
The results should then prove without doubt the savings gained.
Seriously Cruisin this is a worthwhile subject and I for one would buy this device if it saves my batteries.

Have a good weekend.
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Reply By: Member - Raymond - Friday, Mar 19, 2004 at 17:17

Friday, Mar 19, 2004 at 17:17
One point though is if the fridge is getting as high as 8 degrees and the normal temperature to keep food fresh and not spoiling is 4 degrees, what happens to the food. Several years ago made the mistake of putting a plastic container in the Engel to divide the engel in half which was too close to the sides. Over two trips found the cryovac meat bags where expanding, felt that the Butcher was the problem, went to see him. He check the fridge, the temperature in the fridge was 4 degrees, in the plastic container 6-7 degrees. After cutting large holes in the plastic container around the sides the temperature dropped to 4, meat ok on next trip
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Reply By: Member - Brian (Gold Coast) - Friday, Mar 19, 2004 at 19:22

Friday, Mar 19, 2004 at 19:22
Wise to keep an eye on your fridge temps.... you don't want to be outback with a fridge full of spoiled meat! There is a reason why most refrigeration systems run4 degrees C. So while I am interested in the outcome off the tests on this BSC device.... I don't want to get crook either!!!
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Reply By: Cruisin - Friday, Mar 19, 2004 at 19:59

Friday, Mar 19, 2004 at 19:59
Hi all

Have done some more research on refridgeration. Whilst to some this may have seemed obvious but I did not know this. I found the following on the Internet and it talks about safe temperatures for storing meat. At the end of the day this is the only item apart from beer that needs to be protected by cooling at a certain temperature. Please read below. The temperatures quoted are in Farenheit so 40 degree's farenheit = 4.4 degrees Celcius.
So its looks like its back to the drawing board for a sollution to longer battery life.
You could possibly use the device but with a narrower temperature range but then the current saving benefits drop also. Before I disregard this device altogether I will talk to the manufacturer to see what he says.

All these threads may have been for nothing but at least I have learnt something.

Cheers Cruisin

Importance of Refrigeration Refrigeration slows bacterial growth. Bacteria exist everywhere in nature. They are in the soil, air, water, and the foods we eat. When they have nutrients (food), moisture, and favorable temperatures, they grow rapidly, increasing in numbers to the point where some types of bacteria can cause illness. Bacteria grow most rapidly in the range of temperatures between 40 and 140 °F, some doubling in number in as little as 20 minutes. A refrigerator set at 40 °F or below will protect most foods.
Types of Bacteria in Refrigerated Foods There are two completely different families of bacteria: pathogenic bacteria, the kind that cause foodborne illness, and spoilage bacteria, the kind of bacteria that cause foods to deteriorate and develop unpleasant odors, tastes, and textures.
Pathogenic bacteria can grow rapidly in the "Danger Zone," the temperature range between 40 and 140 °F, but they do not generally affect the taste, smell, or appearance of a food. In other words, one cannot tell that a pathogen is present.

On the other hand, spoilage bacteria can grow at low temperatures, such as in the refrigerator. Eventually they cause food to develop off or bad tastes and smells. Most people would not choose to eat spoiled food, but if they did, they probably would not get sick. It comes down to an issue of quality versus safety:

Food that has been left too long on the counter may be dangerous to eat, but could seem fine.
Food that has been stored too long in the refrigerator or freezer may be of lessened quality, but most likely would not make anyone sick. (However, some bacteria such as Listeria monocytogenes thrive at cold temperatures, and if present, will grow in the refrigerator and could cause illness.)

Safe Refrigerator Temperature For safety, it is important to verify the temperature of the refrigerator. Refrigerators should be set to maintain a temperature of 40 ºF or below. An appliance thermometer can be kept in the refrigerator to monitor the temperature. This can be critical in the event of a power outage. When the power goes back on, if the refrigerator is still 40 ºF, the food is safe. Foods held at temperatures above 40 °F for more than 2 hours should not be consumed. Refrigerator thermometers are specifically designed to provide accuracy at cold temperatures. Be sure refrigerator/freezer doors are closed tightly at all times. Don’t open refrigerator/freezer doors more often than necessary and close them as soon as possible.
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Follow Up By: V8troopie - Saturday, Mar 20, 2004 at 02:23

Saturday, Mar 20, 2004 at 02:23
Cruisin, a couple of comments; first, when you multiply Amps by time you get Ah ( amp hours); when you multiply watts by time you get Wh. To write it any other way is very confusing.

Now, your fridge gadget; it very much sounds like another type of snake oil, never mind the university test.
Lets do some figures. You say the start up current is as high as 300%. 300% of what?? I'll assume you mean the running current is 100% and the start up current is 3 times larger.
I'll venture to say it is more like 10 times higher, but very brief in duration. Say, it'll average at 10 times higher over one second ( a very poor fridge motor - propably an Engel :-).

So, if the fridge _Affordable_Storage_Drawers.aspx 1.5 A when running it'll draw 15 A for one second during start up.
Now, lets say the fridge runs for one hour and cycles 4 times - a reasonable assumption.
Running consumption = 1.5A x 12V = 18W x 1 hour = 18Wh
Starting consumption= 15A x 12V = 180W x 1 sec x 4(cycles) =180/3600x4=0.2Wh.
That's a tiny bit over ONE percent more power used from the motor starting during the one hour test period.

Is it *really* worthwhile to buy a gadget that improves something by a fraction of one percent?

You decide

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Follow Up By: Cruisin - Saturday, Mar 20, 2004 at 08:56

Saturday, Mar 20, 2004 at 08:56
Hi V8troopie

I think your onto something here. Even if you make your figures worse hyperthetically....really worse....if you had a fridge like this you would throw it !!

i.e 20 starts per hour, 20A startup current and 3 Seconds for a start duration, the power savings still only come to

Running consumption = 1.5A x 12V = 18W x 1 hour = 18Wh

Starting consumption= 20A x 12V = 240W x 3 sec x 20(cycles) =240/1200 x20cycles = 4Wh. minus the 2 starts you would have with the BCS device anyway = 0.4Wh equals 3.6Wh savings.....

This equates to a 20% savings. Now I know a Fridge will not be this bad but just to demonstrate a point. Even 20% saving with the device is not really worth all the user input and thought you have to give, regarding ambient temperature and where you have this device set to.

Some people on this post think I'm trying to flog these devices, does this sound like I'm selling them.

Cheers Cruisin
P.S I think the penny has dropped v8troopie
But thats what these forums are all about arn't they ?
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Reply By: rolande- Friday, Mar 19, 2004 at 20:18

Friday, Mar 19, 2004 at 20:18
Nice ad cruisin', how much do you sell them for???
P.S. Did you get any replies on the campertrailer forum at Yahoo! groups before they deleted the ad?
AnswerID: 51092

Follow Up By: Cruisin - Friday, Mar 19, 2004 at 22:22

Friday, Mar 19, 2004 at 22:22
Nothin to do with me mate

What was written under the line above is an extract from the guy who sells them. If you notice I'd already signed off. I'm just currently researching the idea.
The device has merits but is not perfect.

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Reply By: Member - Paul- Saturday, Mar 20, 2004 at 09:00

Saturday, Mar 20, 2004 at 09:00
Why would the run time be any different. You are still asking the fridge to do the same job. To maintain 4 deg with a differential of 1 deg will consume the same amount of power as 4 deg with 3 deg differential. The time between cycles will be longer and the run time will be longer with the greater differential. Minimal differential will cause the time between cycles to decrease but the run time will also decrease due to the lesser temp it has to drop. Start up current will be negligable as far as overall current consumption is concerned because it is only inrush current. We use an Engel 40l for day/overnight trips and a Chescold(running on gas) for extended stays. This setup ensures plenty of capacity without the need to maintain charge in the secondary battery.

AnswerID: 51130

Reply By: Member - Steve - Sunday, Mar 21, 2004 at 05:08

Sunday, Mar 21, 2004 at 05:08
So it all comes back to the sensible things we learn like Have enough of a power cord to be able to store the fridge out side the Fourby when Camping. Have a good insulated cover. They really work. Actually I reakon I use the most power keeping the beer cold. Well on the way to the camp the cars running and it's full O beer. The the next day you fill it up and then you may add some more during the day cause it's tasting realy good. (It does that) So to stop all this cycling that happens I turn the car on and set the temp as low as it goes for about an hour. Even though the temp will show -6 or so the food wont be in an hour and if you have some meat at the bottom it will not hert to be real close to freezing. Then turn it back to your 4c setting and the start ups are a lot less. The battery cops 40 amps or so as well and I don't mind running the car at idle. You can go for a drive a s well ?
AnswerID: 51227

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