12V Refigerator Questions

[highdesertranger]

well I run 2 engel 40qt(2.5 amps each) off 175 watts of solar and 2 Costco marine batts. works for me. highdesertranger

 

[Spaceman Spiff]

Highdesertranger, if you don't mind my asking:
1. what else do you typically run with 175W solar?
2. how many amps per day do you get in the winter?
Thanks -- Spiff

 

[highdesertranger]

I recharge my lap top occasionally, and charge a dewalt 18v battery when needed. where I go the is usually no internet access so I only use the lap top for my mapping programs, not much power needed, it's mainly for my 2 engel refrigerators. I really don't have a figure on how many amps I make in the winter, but I do add another 65 watts that I can point right the sun. also remember I do most of my exploring/prospecting in the high desert where you have very few cloudy days. highdesertranger

 

[Spaceman Spiff]

Thanks, Highdesertranger!

A five day test of my 30 year old frig in 90° ambient is averaging 40 amp/hours a day. Doesn't leave much capacity for anything else.
-- Spiff

 

[Ballenxj]

A five day test of my 30 year old frig in 90° ambient is averaging 40 amp/hours a day.

That works out to be 1.6666 watts per hour based on a 24 hour day. Not too bad for a 30 year old fridge.

 

[highdesertranger]

ballen I think you are confusing amp/hrs and watts. highdesertranger

 

[Ballenxj]

ballen I think you are confusing amp/hrs and watts. highdesertranger

OOPS! You're right. I should have said 1.6666 amps per hour.
Still not bad fo a 30 YO fridge.

 

[Zil]

But S.Spiff said "40amps/hour a day" that translates 40 amps per hour each day.
That ain't good.

 

[Ballenxj]

But S.Spiff said "40amps/hour a day" that translates 40 amps per hour each day.
That ain't good.

I'm pretty sure he meant 40 amps used per 24 hour day. That is what I based my math on anyway.

 

[SternWake]

It is Quite rare that my modern 12v compressor fridge will use more than 24 A/h in 24 hours, and that is to hold sub 35f temps everywhere within.

 

[Spaceman Spiff]

My apologies Zil. I was tired and apparently had a brain fart :s
Should have been clearer: refrigerator used 40 amps in 24 hours, (should have read 40 amp-hrs per day). I am estimating that in the winter, in Arizona, I should get about 50 amps out of two 100 watt solar panels per day
(2 x 100W / 12volts x 4 hours a day x 75% efficiency).
Going to have to find some more shekels for a new frig
-- Spiff

 

[Spaceman Spiff]

Update and a couple more questions.

I talked with a refrigeration tech and he suggested to invert the refrigerator for a while (apparently things can settle and clog the small heat exchanger tubes). Tipped the refrig upside down for a week and then uprighted and restarted it. With the refrig and freezer full of water bottles, the refrig is using about 27 ah in 24 hours (vs about 40 ah/day before). The end result is that it works well enough and my finances dictate using the old frig for now. I will be installing it, with 2" of Formular around sides, this coming week.

A couple of questions:

I am installing a 120mm Noctua exhaust fan (to outside) in the refrig cabinet, controlled by a thermal switch. At what temperature should the fan come on at? I currently have 80° switch.

I want to be able to track inside temperature without opening the door. What do you use? I prefer a wired remote sensor (1/5 the price of wireless) but do not like the wire coming out the door. Any ideas?

And thanks ahead of time for your willingness to share your expertise:exclamation:

-- Spiff

 

[Zil]

http://www.baylinerownersclub.org/~...opics/23048-norcold-de-251d-power-consumption

 

[SternWake]

The Noctua fan draws so little I would not blink about letting it run 24/7.

If it is a danfoss compressor powered fridge, just have it come on with the compressor.

http://www.ra.danfoss.com/Technical...nit_101n0600_12-24vdc_08-2011_dehc100m602.pdf

Not sure the best temp for a snap switch to activate an additional fan:

This guy is the Danfoss compressor fridge king, but he is not aware of, or just ignorant of, the Newer muffin fans which move more air for less noise made and current consumed. The Noctua Nf-f12 is just downright impressive. 0.05 amps for 53cfm.
http://www.kollmann-marine.com/Fans.aspx

 

[highdesertranger]

I also would like to keep track of my refer temps. I have seen the wired ones but not sure if I want having a wire going past my door seal and the remote ones made for refers are quite pricey. has anybody used a regular wireless indoor outdoor thermometer? my idea is you could place the outdoor wireless sensor in the frig any thoughts? some will even keep track of the high and lows in a 24hr period. highdesertranger

 

[SoulRaven]

I want to be able to track inside temperature without opening the door. What do you use? I prefer a wired remote sensor (1/5 the price of wireless) but do not like the wire coming out the door. Any ideas?

And thanks ahead of time for your willingness to share your expertise:exclamation:

-- Spiff

I have a little indoor/outdoor thermometer with a wireless remote sensor <$10 and if I want to test the temp in the icebox, or anywhere else, I just put the remote sensor in.

 

[Spaceman Spiff]

I have a little indoor/outdoor thermometer with a wireless remote sensor <$10 and if I want to test the temp in the icebox, or anywhere else, I just put the remote sensor in.

Would you mind sharing the source for this thermomoter? -- Spiff

 

[akrvbob]

Walmart sells them cheap or you can get them at Amazon.

When I bought my Dometic fridge I wanted to know more so I put mine inside it and it worked fine. It's much more accurate than the thermometer on the read out.

However, it broke about 5 months later so I replaced it. It broke also 5-6 months later. I think it's the moisture in the air inside the fridge. My second one I put inside a ziploc baggie but it didn't help.

They are so cheap it's not that big a deal and you can buy extra remote sending units, that's what breaks.

My complaint with my Dometic is it tends to let the inside get too warm, then come on and get too cold. But by watching the thermometer I could take control of it by turning it on and off as it needed. I think that will save you some electricity too.

They really help you understand what is actually going on in your fridge so I think they are worth getting.
Bob

 

[highdesertranger]

thanks off grid and bob. I wonder if you vacuum sealed the sensor. highdesertranger

 

[Spaceman Spiff]

thanks off grid and bob. I wonder if you vacuum sealed the sensor. highdesertranger

hey highdesertranger, great minds think alike!

I was thinking the same thing: vacuum seal bag, an appropriately sized jar, or even a zip loc bag. Anything to keep the moisture out of the electronics.

I have to admit though that the remote sensor for an Acu-rite weather radio/night stand combo that I got at Christmas is already dead. Spent its whole life just sitting on my desk. Mortality might have more to do with cheap electronics. Which is why I am still thinking about finding a way to get a wired sensor in the refrig.

-- Spiff