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Bob and Susan
Elite Nomad
Posts: 8813
Registered: 8-20-2003
Location: Mulege BCS on the BAY
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for vacation camping i'd too go with a generator...but not a noisy "harbor freight" unit
a honda eu2000 or a eu1000 these things are really quiet...i would get the service warranty...they can break
way lighter too...batterys are HEAVY
....
on the other note...capt needs to pay up...
i said resistor...they look like a transformer...any real electrical store sells them
you "hook" one side to the positive cable and one to the negative cable
then remove the battery
works EVERY time...if the alternator is good the engine continues to run...if not it dies
[Edited on 12-28-2012 by Bob and Susan]
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captkw
Ultra Nomad
Posts: 3850
Registered: 10-19-2010
Location: el charro b.c.s.
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Mood: new dog/missing the old 1
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are you out of your mind ???
I'm a electrical GURU aka engineer with about 40yrs hands on and study...you are likely referring to a ballest resister that might look like a
transformer to you !! be aware tranformers can also be torridal.....BOB..you are in over your head here........,no cookie for you !!! Lets start with
OHMs law,,,guass,,joule...coulomb and thats of the top of my head...till you come up with signs of electrical knowadge I wil not respond to your
foolish jabs at something you dont have aclue about......enjoy the weather and I'm buying the drinks...K&T
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Bob and Susan
Elite Nomad
Posts: 8813
Registered: 8-20-2003
Location: Mulege BCS on the BAY
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see you can't say why it doesnt work because it does...
the alternator "sometimes" will spike current
the battery buffers the car electronics like a battery in a laptop does for a computer using "un-clean" energy
if you put a resistor as a replacement "battery" you buffer the car electronics
it is really simple for a car electrician to understand...we simpletons need to understand it in our language not in
"OHMs law,,,guass,,joule...coulomb" who talks like that?
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Alm
Ultra Nomad
Posts: 2753
Registered: 5-10-2011
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| Quote: | Originally posted by captkw
They dont need any voltage unless for the peizo starter and thats easy to deal with...Aborption fridge runs on propane !! |
Sorry Cap, but no, only very old LP fridges with mechanical thermostat don't need 12V voltage. Majority of units made in the last 5 or 7 years - if
not all - need 12V for thermostat and to open-close the gas flow. Count on 10-15 Ah draw per 24 hours.
And No, they are not very reliable. Less reliable than 120V or 12V compressors, and more maintenance. Some 12V compressor fridges are junk too, not
made for salty air close to the sea.
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captkw
Ultra Nomad
Posts: 3850
Registered: 10-19-2010
Location: el charro b.c.s.
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Mood: new dog/missing the old 1
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learnig every day
I have not worked on any of the new ones,,and I'm not surprizzed..But they dont need much current,,no?? I have repaired a lot of dometics that I guess
your right about 6/7 years old and they did not Have to have ac/dc for the safety valve...last year I worked on a norcold (bad element) on the 120 v
side and was greeted with a few controlboards with Ics,,fet,zenors and alot of stuff I felt was bad designed IMHO..fridge,,stove,toilet,,toilet paper
should be kept simple!! PS just reraead Alm post...thats a lot of wasteful draw...is that a solinoid gas shut off valve draw !!! if so...bypass the
damn thing..LOL
[Edited on 12-28-2012 by captkw]
[Edited on 12-28-2012 by captkw]
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landyacht318
Nomad
Posts: 247
Registered: 7-28-2007
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I hope no one here decides to test their automotive charging system by disconnecting the battery with the engine running.
File this one under old wive's tales which should have been buried with the mentally unstable and malicious wife, back in the '70's.
Engine computers are not cheap.
And confusing a resistor with a capacitor and the capabilities of either is most amusing and leads me to believe someone is being humorously engaged
in the holiday happy sauce.
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captkw
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Posts: 3850
Registered: 10-19-2010
Location: el charro b.c.s.
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Mood: new dog/missing the old 1
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landyacht318
Hola,well said and is your "name" have anything to do with chrysler ?????
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landyacht318
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One guy over on RV net posted the 24 hour amp draw of his modern absorption fridge, and it was, IIRC, almost an amp hour per hour.
That is more than my Danfoss powered Compressor fridge uses 75% of the time, and I save the propane for cooking.
Also have to take into account that many absorption fridges can't maintain sub 40 degree interior temps in 90+ degree ambients, and many require extra
fans to do so in 80+ ambients.
Don't get started on the unlevel operation aspect of Absorption fridges, nor the modern cost cutting techniques employed by most manufacturers.
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landyacht318
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Posts: 247
Registered: 7-28-2007
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The 318 is a good engine, though I do wish I picked a different handle back in '07
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captkw
Ultra Nomad
Posts: 3850
Registered: 10-19-2010
Location: el charro b.c.s.
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Mood: new dog/missing the old 1
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318...
my boat tower 77 360 with around 400K miles and the heads have never been off...and the only electrical is headlight,brakelight,horn,wiper,heater fan
and running lights..talk about Kiss..but after parking and waking away from her,, you will hear a load burp !!! she has a bit of a drinking
problem......
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landyacht318
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Posts: 247
Registered: 7-28-2007
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Yeah, LA era SB mopars are not the most efficient or powerful but KISS definitely applies to them.
And My hot alternator output at idle speeds is truly pathetic, so I no longer Idle to recharge, but this was not always true, and ignorance was bliss,
at least until the batteries and alternators kept needing early replacement.
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Alm
Ultra Nomad
Posts: 2753
Registered: 5-10-2011
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| Quote: | Originally posted by landyacht318
One guy over on RV net posted the 24 hour amp draw of his modern absorption fridge, and it was, IIRC, almost an amp hour per hour.
That is more than my Danfoss powered Compressor fridge uses 75% of the time, and I save the propane for cooking. |
Every one situation is different - what model, climate, how often to open the door, and so on. Some absorption (propane) models have features like
door defroster, and then it draws more amps. But all of them draw some. Most RV report 12-15 Ah a day for a typical 6 cu.ft propane fridge. 24 Ah a
day seems too high, but possible with fridges larger than 8 cu.ft and a lot of bells and whistles.
Note that 12-15 Ah a day is for a 6 cu.ft propane model. A comparable size 12V compressor fridge, even with added insulation, would draw at least 40
Ah a day, depending on the ambient temperature. You see, LP fridge in hot weather needs more gas, but its 12V draw doesn't increase much. Compressor
fridge in hot weather needs more Ah because this is its "fuel". When ambient rises from 70 to 90, the compressor fridge daily draw rises from, say, 40
t0 70 Ah.
[Edited on 12-28-2012 by Alm]
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mtgoat666
Platinum Nomad
Posts: 20376
Registered: 9-16-2006
Location: San Diego
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Mood: Hot n spicy
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| Quote: | Originally posted by Bob and Susan
"OHMs law,,,guass,,joule...coulomb" who talks like that? |
answer: millions of scientists, engineers and electricians -- including the guys/gals that designed the computer and internet you used to post that
silly question! 
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Hook
Elite Nomad
Posts: 9011
Registered: 3-13-2004
Location: Sonora
Member Is Offline
Mood: Inquisitive
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| Quote: | Originally posted by landyacht318
Danfoss makes many different compressors. the BD 35 compressor is good upto 6 cubic feet with a third of that being the freezer compartment.
At 2000 RPM the Danfoss bd35 pulls about 2.4 amps after a minute or 2. At 3500 RPM it pulls close to 6 amps. A simple resistor placed in the
thermostat circuit allows one to decide on compressor rpm
The BD-50 is the exact same size as the 35, the 50's compressor has a bigger stroke and pulls more electricity.
The compressors themselves have no serviceable parts. The electronic controllers are easily available anywhere, but not cheap(200+$), and the
condenser fans are standard computer fans, also easily replaced.
My old 1.7 cubic foot Norcold pulled 2.7 amps when the compressor was running, and had about a 30% duty cycle at 75f
My new 1.8 cubic foot Danfoss powered Vitrifrigo pulls about 2.4 amps and is down around 25% duty cycle at the same ambient temperatures.
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My Norcold is still running after 8 years. Usually it is not very quiet but for some reason, it cycles very quietly about 30% of start ups.
Are you worried about the controller board on yours? Many stories of them going bad controlling the BD-35.
My information about the Danfoss draw was with the Waeco units. How does the Vitrifrigo achieve so much less draw? Simply the resistor? Better
insulation reduces the duty cycle, as compared to the Waecos?
What did your cost?
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landyacht318
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Most of the Danfoss controller failures I've read about are due to heat and usually these are on older marine installations units that use watercooled
condensers and have inadquate airflow over the compressor due to a lack of a fan nearby and inadequate natural ventilation in the area in which the
compressor and controller is installed.
The latest models of Danfoss controllers have a rather large heat sink on the back of them. Also they stress hooking the power leads right to the
battery rather than a shared buss to relays or other power surge sources that might screw with the controller. My Controller is a DC only Model.
AC/DC models are available, and even a controller which automatically changes compressor speeds according to load placed in the fridge. The AC/DC
version of my Fridge was another 100$. I decided to put that 100$ toward a real converter/charger which would both power the fridge, every other 12
volt device, and charge the batteries at a high rate whenever 120Vac grid power is available.
As Alm stated, my Fridge is in a camper Van, and the compressor is minimum of about 2 feet from my head when sleeping. I now have 200 watts on my
roof, and Can run my fridge pretty much indefinitely, except perhaps in the PacNW in winter.
I spent dozens of hours Isolating the Norcold fridge from the cabinet to minimize both vibration and sound and achieved good reductions in both. It
was literally floating in a soft foam cushion with no hard attachment points, and still too loud, and would vibrate the whole dang van.
My VitriFrigo is surrounded by an additional 3/4" foam board insulation, and this is then shoehorned into a insulated cabinet, because no real
vibration isolation is needed. The Danfoss makes almost no vibrations and about 1/3 the noise though the initial compressor startup is more abrupt
than the SawaFuji compressor employed by Norcold and Engel.
My IR thermometer at various stages of installation and insulation addition has shown the extra insulation to be very effective. The Door itself is
now the weak spot in terms of insulation as in humid weather, the Stainless steel door face I added sweats.
Part of the reason, besides the small size of the fridge, for the low consumption numbers is how I have the condenser ventilated. I purchased a
different 120mm computer fan and installed it so it pushes air through the condenser rather than pull it through. Cooler air is drawn from the floor
below the fridge, is pushed through the condenser, across the compressor and controller, and out a vent. It has no chance whatsoever of recycling any
preheated air. The Fan I substituted is quieter than the original and draws 1/2 the current. The Van itself rarely exceeds ambient temperatures with
the use of window shades and more computer fans.
I do have an amp hour counter I monitor frequently so my consumption numbers are not just a guess, or like many MPG claims you see on the internet,
vastly exaggerated. My claims are based on minimal door openings of short duration. Obviously adding warm food/beer and multiple door openings
increase the consumption.
I also have added a 40 mm 5.6 cubic foot per minute, 0.03 amp computer fan inside the freezer compartment. It runs 24/7. This keeps the internal
temps much more even, and allows a lesser setting on the t stat. A setting 2 out of 7 keeps the interior about 36.5 degrees F. Without the interior
fan a setting nearly 4 out of 7 would be needed for and average 36.5 degrees, but parts of the floor would be 31 and other parts would be in the mid
40's.
I am not claiming the interior fan itself reduces overall battery consumption. It adds a small amount of heat which must then be removed. However It
allows food within to be cooled down faster, and when I have solar excess available( most days), or alternator power available, I can more easily and
more quickly, lower the temperature of the contents with the thermostat. Then at sundown or engine shutdown, return the setting to normal and the duty
cycle is then significantly lower as the interior contents slowly rise from ~32f back up to 36.5f or higher overnight.
All the different manufacturers of compressor fridges which use the Danfoss BD 35f compressors choose the compressor speeds according to the size of
the condenser, its fan and evaporator plate and intended function for the size of the fridge. Some want faster cool down times and select higher
compressor speeds. Mine came with a 270 ohm resistor to increase compressor speed to 2500rpm. Since mine basically runs 24/7/ 11 months a year,
quick cool down times are not important, compared to overall efficiency, and the slowest compressor speed which allows sub 40 box temps and less than
a 50% duty cycle is most efficient, so I removed the resistor for the slowest compressor speed of 2000rpm.
Your Figures for the Waeco/Dometic/Adler barbor/Tundra(all are now the same company/ subsidiary now) are not incorrect. Danfoss compressors comes in
different flavors and the manufacturers select how fast they want to run the compressor, and they can indeed draw 6+ amps at 3500 rpm though this
would be extremely overkill for my size Fridge.
Also the consumption figures listed by different manufacturers are unclear as to whether that is compressor consumption while running, or average
amount consumed over an hour, and perhaps intentionally so
VitriFrigo is assembled in Italy. I spent 600$ on the c51is with free shipping, though that price has increased to $630 last I saw.
I could have bought a very similar Chinese assembled TruckFridge with the Danfoss for 100$ less. These seem to use a different thermostat dial,
slightly different condenser with a smaller fan placed on it. I think Vinny cares a little more than Chin Ho about the workmanship/ fit and finish,
and I do not think my condenser fan relocation would have been possible with the Chinese version.
There are now some chest style compressor fridges out there now which are using a Knockoff of a Danfoss compressor. Edgestar is one brand. They also
have variable compressor speeds and you can get these chest style fridges for under 300$. Reviews of these range widely.
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captkw
Ultra Nomad
Posts: 3850
Registered: 10-19-2010
Location: el charro b.c.s.
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Mood: new dog/missing the old 1
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Couldit have said it better myself.. LOL
Nice post !! 
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Hook
Elite Nomad
Posts: 9011
Registered: 3-13-2004
Location: Sonora
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Thank you for taking the time to write such a detailed reply. Very edifying for me.
Yes, the Edgestars have gotten a number of bad reviews. Same ol story from China. Little or no QC. Brand new units arrive non-op.
Having the Norcold has really extended the range of my Dometic absorp fridge. It is a 2002 model that had some issues when I got the camper used. The
Dometic main board was replaced with a Dinosaur and the T-coupler went. But I can still get 50 or > degrees below ambient temps that are 90 or
below. Having all drinks in the Norcold really helps.
There is no way I could ever go all-compressor fridge. I just dont have the battery capacity or space for more, nor the area for the needed solar
panels. And traveling in the mountains of the US and Canada in August and Sept, you get your share of overcast days.
As I live in the low desert of Sonora for 10 months, I really have no desire to spend much time in hot deserts when I travel the US. We want to be in
the mountains.
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willardguy
Elite Nomad
Posts: 6451
Registered: 9-19-2009
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| Quote: | Originally posted by landyacht318
Most of the Danfoss controller failures I've read about are due to heat and usually these are on older marine installations units that use watercooled
condensers and have inadquate airflow over the compressor due to a lack of a fan nearby and inadequate natural ventilation in the area in which the
compressor and controller is installed.
The latest models of Danfoss controllers have a rather large heat sink on the back of them. Also they stress hooking the power leads right to the
battery rather than a shared buss to relays or other power surge sources that might screw with the controller. My Controller is a DC only Model.
AC/DC models are available, and even a controller which automatically changes compressor speeds according to load placed in the fridge. The AC/DC
version of my Fridge was another 100$. I decided to put that 100$ toward a real converter/charger which would both power the fridge, every other 12
volt device, and charge the batteries at a high rate whenever 120Vac grid power is available.
As Alm stated, my Fridge is in a camper Van, and the compressor is minimum of about 2 feet from my head when sleeping. I now have 200 watts on my
roof, and Can run my fridge pretty much indefinitely, except perhaps in the PacNW in winter.
I spent dozens of hours Isolating the Norcold fridge from the cabinet to minimize both vibration and sound and achieved good reductions in both. It
was literally floating in a soft foam cushion with no hard attachment points, and still too loud, and would vibrate the whole dang van.
My VitriFrigo is surrounded by an additional 3/4" foam board insulation, and this is then shoehorned into a insulated cabinet, because no real
vibration isolation is needed. The Danfoss makes almost no vibrations and about 1/3 the noise though the initial compressor startup is more abrupt
than the SawaFuji compressor employed by Norcold and Engel.
My IR thermometer at various stages of installation and insulation addition has shown the extra insulation to be very effective. The Door itself is
now the weak spot in terms of insulation as in humid weather, the Stainless steel door face I added sweats.
Part of the reason, besides the small size of the fridge, for the low consumption numbers is how I have the condenser ventilated. I purchased a
different 120mm computer fan and installed it so it pushes air through the condenser rather than pull it through. Cooler air is drawn from the floor
below the fridge, is pushed through the condenser, across the compressor and controller, and out a vent. It has no chance whatsoever of recycling any
preheated air. The Fan I substituted is quieter than the original and draws 1/2 the current. The Van itself rarely exceeds ambient temperatures with
the use of window shades and more computer fans.
I do have an amp hour counter I monitor frequently so my consumption numbers are not just a guess, or like many MPG claims you see on the internet,
vastly exaggerated. My claims are based on minimal door openings of short duration. Obviously adding warm food/beer and multiple door openings
increase the consumption.
I also have added a 40 mm 5.6 cubic foot per minute, 0.03 amp computer fan inside the freezer compartment. It runs 24/7. This keeps the internal
temps much more even, and allows a lesser setting on the t stat. A setting 2 out of 7 keeps the interior about 36.5 degrees F. Without the interior
fan a setting nearly 4 out of 7 would be needed for and average 36.5 degrees, but parts of the floor would be 31 and other parts would be in the mid
40's.
I am not claiming the interior fan itself reduces overall battery consumption. It adds a small amount of heat which must then be removed. However It
allows food within to be cooled down faster, and when I have solar excess available( most days), or alternator power available, I can more easily and
more quickly, lower the temperature of the contents with the thermostat. Then at sundown or engine shutdown, return the setting to normal and the duty
cycle is then significantly lower as the interior contents slowly rise from ~32f back up to 36.5f or higher overnight.
All the different manufacturers of compressor fridges which use the Danfoss BD 35f compressors choose the compressor speeds according to the size of
the condenser, its fan and evaporator plate and intended function for the size of the fridge. Some want faster cool down times and select higher
compressor speeds. Mine came with a 270 ohm resistor to increase compressor speed to 2500rpm. Since mine basically runs 24/7/ 11 months a year,
quick cool down times are not important, compared to overall efficiency, and the slowest compressor speed which allows sub 40 box temps and less than
a 50% duty cycle is most efficient, so I removed the resistor for the slowest compressor speed of 2000rpm.
Your Figures for the Waeco/Dometic/Adler barbor/Tundra(all are now the same company/ subsidiary now) are not incorrect. Danfoss compressors comes in
different flavors and the manufacturers select how fast they want to run the compressor, and they can indeed draw 6+ amps at 3500 rpm though this
would be extremely overkill for my size Fridge.
Also the consumption figures listed by different manufacturers are unclear as to whether that is compressor consumption while running, or average
amount consumed over an hour, and perhaps intentionally so
VitriFrigo is assembled in Italy. I spent 600$ on the c51is with free shipping, though that price has increased to $630 last I saw.
I could have bought a very similar Chinese assembled TruckFridge with the Danfoss for 100$ less. These seem to use a different thermostat dial,
slightly different condenser with a smaller fan placed on it. I think Vinny cares a little more than Chin Ho about the workmanship/ fit and finish,
and I do not think my condenser fan relocation would have been possible with the Chinese version.
There are now some chest style compressor fridges out there now which are using a Knockoff of a Danfoss compressor. Edgestar is one brand. They also
have variable compressor speeds and you can get these chest style fridges for under 300$. Reviews of these range widely. |
wrap it in some glacier bay VIP's and you'd really have a hot rod! nice job!
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Packoderm
Super Nomad
Posts: 2116
Registered: 11-7-2002
Member Is Offline
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I have the 3 panel setup from Harbor Freight. I usually carry one of the panels and charge up my truck battery and a Diehard jumper battery pack when
they run low.
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Alm
Ultra Nomad
Posts: 2753
Registered: 5-10-2011
Member Is Offline
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Landyacht has done a lot of tune-up to his (already good) Vitrifrigo. Though not obvious from his post, added Styrofoam insulation around the fridge
body was one of those things. Vinny is sure a better brand than unknown boxes from China, but it still comes with same thin walls as all other
built-in 12V fridges.
There are also other boxes to consider with same Danfoss compressor that are cheaper than Vinny and better than knock-offs. Dometic (they purchased
and re-branded former Tundra brand), Novakool (don't confuse it with Norcold), and Isotherm. They come in different sizes, from 1.8 cu.ft like
Landyacht has, to 7 cu.ft. People with truck campers love those small boxes. Engel is better known for their top-loading portable models, but they
make upright built-in models as well, with their own brand compressor.
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