Added a 12v Fridge Fan...

[peislander]

I noticed the tiny fridge in my small but mighty Camplite 11FDB had less than ideal distribution of "cold" in the compartment. I could have food near the back get really cold or even get ice crystals while other food near the door was moderately cold. The way such issues are usually remedied is to add a battery-powered fridge fan accessory of the type sold at places like Campers World. Those battery ones are relatively bulky compared to my tiny fridge & I don't like buying batteries. So what I did was install a 12v fridge fan system purchased on-line from >> [a href="http://rvcoolingunit.com/Dometic-Evaporator-Fan-Greater-inside-Cooling-Deluxe-Model-P2428153.aspx"]RV Cooling Unit Warehouse[/a] <<. They are a company dedicated to helping rv owners have better performance from their rv fridges. If you are having any fridge problems they are a great resource as they sell competitively-priced replacement parts & controllers, as well as various accessories. My understanding is most of their customers install the parts themselves so they provide DIY instructions. Visiting their site you will learn how to make your rv fridge more efficient.
[a href="http://rvcoolingunit.com/Dometic-Evaporator-Fan-Greater-inside-Cooling-Deluxe-Model-P2428153.aspx"]
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[mitch]

That's a nice tip, I have one of the battery ones you mention and I hate buying batteries so I may copy you. Thanks

[charliem]

[font size="3"]PEI,

Any idea how much DC current the fans pull? No specs on the web site. And are both fans necessary? I'm thinking of main battery life in dry camping situations. I currently have the little blue battery cube unit and it really seems to help.
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[drdave]

[font size="3"]PEI,

Any idea how much DC current the fans pull? No specs on the web site. And are both fans necessary? I'm thinking of main battery life in dry camping situations. I currently have the little blue battery cube unit and it really seems to help.
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It looks like they put 2 computer fans in an aluminum housing and a switch.  The computer fan I'm looking at is 0.21A ... found another in my stash of spare parts....  0.56A.   Pretty much a mousefart.   

[peislander]

Tomorrow morning before work I'll turn on the fan. I'll then review the amount of amp-hours used 12 hrs later as monitored by my battery monitor. From that info I should be able to advise how much juice the sexy fans absorb. Keep tuned kids!

[drdave]

PEIslander: Could you post some pictures or a careful description of how you ran the wire out of the interior of the fridge and where you connected to 12V?  

[thudd3r]

the fans arent just like computer fans...they are computer fans.  looks like they are modifying a premade hard drive cooler by adding a switch and the clamps.  pretty good idea.

here is one that uses 50mm fans (but they make then with different sizes...your appears to use 80mm fans).  notice the aluminum housing is identical


[img style="" style="max-width:100%;" src="http://images10.newegg.com/NeweggImage/productimage/A6UM_130679225933696608vxBgeBk0ga.jpg"]

http://www.newegg.com/Product/Product.aspx?Item=9SIA6UM2KD2448&cm_re=hard_drive_cooler-_-9SIA6UM2KD2448-_-Product

[charliem]

It looks like they put 2 computer fans in an aluminum housing and a switch.  The computer fan I'm looking at is 0.21A ... found another in my stash of spare parts....  0.56A.   Pretty much a mousefart.   

[font size="3"]When you're dry camping a 1/2 Amp constant load (12 AH/day) is not insignificant.[/font]

[charliem]

[quote timestamp="1434417196" author="@peislander" source="/post/12353/thread"]Tomorrow morning before work I'll turn on the fan. I'll then review the amount of amp-hours used 12 hrs later as monitored by my battery monitor. From that info I should be able to advise how much juice the sexy fans absorb. Keep tuned kids![/quote][font size="3"]What type of battery monitor and can you isolate the fan load from other loads such as propane alarm, fridge electronics, electric gas valves, etc.? Can you measure the fan current directly?[/font]

[peislander]

It is just anecdotal but I think my daily Ah draw with the trailer sitting idle is about 1/2 Ah per day. That would relate to the draw from the propane alarm, and my battery monitor. I typically have the fridge turned off and I have no tank monitoring system. I say anecdotal because I've never made any effort to get a accurate grasp on that usage.

If I account for that 1/2 Ah it appears the fridge fan system uses 6.9 Ah per day. I'd say that is not an insignificant amount if you were boondocking for more than a couple of days. Of course you can still use the fan when on shore power. My battery monitor is a Victron Energy BMV-600S. Earlier I had a posting that included info on that monitor. You can find it >> [a href="http://livinlite.proboards.com/thread/1077/added-dc-inverter-battery-monitor"]here[/a] <<.

tlbones --- I will try and take some pics showing how I powered up the fans. In the pic above you can see the wire leaving the compartment. Just above the fins there was an existing hole associated with what I think is the fridge's thermostat sensor  --- you can just see the edge of a metallic tube just below where the wire goes out.

[mitch]

[quote source="/post/12403/thread" timestamp="1434496473" author="@peislander"]It is just anecdotal but I think my daily Ah draw with the trailer sitting idle is about 1/2 Ah per day. That would relate to the draw from the propane alarm, and my battery monitor. I typically have the fridge turned off and I have no tank monitoring system. I say anecdotal because I've never made any effort to get a accurate grasp on that usage.

If I account for that 1/2 Ah it appears the fridge fan system uses 6.9 Ah per day. I'd say that is not an insignificant amount if you were boondocking for more than a couple of days. Of course you can still use the fan when on shore power. My battery monitor is a Victron Energy BMV-600S. Earlier I had a posting that included info on that monitor. You can find it >> [a href="http://livinlite.proboards.com/thread/1077/added-dc-inverter-battery-monitor"]here[/a] <<.

tlbones --- I will try and take some pics showing how I powered up the fans. In the pic above you can see the wire leaving the compartment. Just above the fins there was an existing hole associated with what I think is the fridge's thermostat sensor  --- you can just see the edge of a metallic tube just below where the wire goes out.[/quote]6.9 Ah per day is a fair chunk,  when I'm boondocking I use no more than 20 Ah per day and that includes the fridge on propane, Water heater, and lights as needed. 

[charliem]

[quote timestamp="1434496473" author="@peislander" source="/post/12403/thread"]It is just anecdotal but I think my daily Ah draw with the trailer sitting idle is about 1/2 Ah per day.
[/quote][font size="3"]The 1/2 AH/day seem light. When I measured my 21RBS with only the propane detector and fridge keep alive electronics (fridge off) I read 90mA. Admittedly this was with a clamp on Ammeter so not perfectly accurate, but that multiplies out to 2+ AH/day. I'm also assuming LL used the same propane detector.
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[peislander]

Charliem -- what do you mean by "fridge keep alive"? I just checked and my 24-hour usage was 0.4 Ah. From what I can tell that usage is only the propane detector & the Victron Energy Monitor. Are you saying the 3-way fridge would use 12v dc even if turned completely off --- mine is off. I do have a SureSine Inverter but it is switched so my understanding is when off it uses no power.

I agree that in all likelihood we have the same detector. We may not have the same fridge. In the small but mighty Camplite 11FDB they use a small but not so mighty fridge -- just 2.5 cu.ft. with no freezer compartment.

[charliem]

[font size="3"]OK PEI,

You asked for it so here comes some Geek speak (engineer talk). Most electronic devices that have a momentary push button (push and release) switch to turn it on/off have a small amount of circuitry that is powered all the time. It's function is to monitor for that button push and power up the device. A good example is a modern television controlled by a remote control. There is a small circuit in the TV, consuming some power, which constantly awaits the push button signal from the remote. When the signal is detected the monitoring circuit turns on the rest of the TV. Sometimes, to prevent accidental operation, the button has to be held for a few seconds, but the principle is the same. [/font][font size="3"]If your fridge is like mine, although not so mighty, it has a touch button to turn it on or off. [/font][font size="3"]The alternative control, those that are totally off when they're off, are toggle switches like light switches, pull chain lamp switches, and rotary knob switches that click on and off. There are such things as toggle push button switches, but they also click on and off. The amount of power drawn by these monitoring circuits is small, but it adds up when you're dry camping or running off grid on solar. To further muddy the water there are "instant on" devices that come to life very quickly after pushing the button, and they consume considerable power when in standby, but most of those went away with the demise of the vacuum tube.

So all of that said, if your measurement of 0.4 AH/day is accurate the current draw would have to be 16.67 mA (0.4/24 = 0.0167A). This seems very low from what I've read about the propane detectors. As I said I'm a bit skeptical about my clamp on ammeter at very low currents so I'll go out and measure it with a true digital multimeter and report back shortly. Something I've been meaning to do anyway for my own curiosity.
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[whoofit]

My LP detector draws much than yours. Right around .3A IIRC.