Wanderlodge Owners Group  
BuyByeBlueBird.com
Donate

Go Back   Wanderlodge Owners Group > Mechanic's Corner > 'Bird Projects & Modifications

'Bird Projects & Modifications Share with us that latest project or modification that you have done to your 'Bird right here.

Site Search:
Reply
 
Thread Tools
  #181  
Old 04-14-2019
DW SD DW SD is offline
Senior Member
 
Join Date: Jul 2010
Location: Encinitas
Posts: 1,523
Default

Quote:
Originally Posted by NoGas View Post
As to power use... Long before I installed my Samsung RF18 I found a spreadsheet on the jackdanmayer.com website (lots of good stuff there, still). If you can navigate around one, it will allow you to determine your power use vs available supply, including solar. You will see that the RF197 (predecessor to the RF18) had a per day use of 1,219 watt-hours. That’s very close to Peter’s number. Enter your coach’s specifics into that spreadsheet to see how your battery bank and solar (if you have it) will fare. Google sheets copy is tailored to my solar/battery configuration.

Direct link to Spreadsheet on his site: http://www.jackdanmayer.com/Files/So...frigerator.xls

Link to my copy on Google Sheets: https://docs.google.com/spreadsheets...jJ9hqUnLlYutvM
Interesting information. Even very efficient compressor fridges draw a lot of power if you only have 300 to 400 amp hours of useable 12V DC available. (6 golf carts or stock M380 batteries)

I’m happy for those satisfied with their compressor fridge conversions.

I will offer an alternative perspective.

I still run the ammonia fridge. At most it draws about 1.5 amps x 12 x 13V = 244W / day. 12 represents hours of running. So 50% duty cycle. That’s actually a high estimate as I believe it ran about 15% to 20% duty cycle.

9 months ago I installed 3 X 290W panels with Magnums PT100 mppt charge controller. Squeezing 2 panels between Front AC and fridge rain lid required moving the rain lid back by about 2”. I made an aluminum offset plate 2” larger than the original opening for this duty. And drilled a few hundred 1/2” holes in the plate to allow ventilation.

Wanting to make sure my fridge still transfers heat well, which is the key to any cooling, I added a 10” brushless puller computer fan with a thermostatic controller. This setup cost about $30 from amazon. The fan is mounted to the fridge access panel so it side draws in fresh air.

My fridge has never run more consistently or cooled down so quickly - and I credit the fan I installed. It cools in 3 or 4 hours from hot start. The freezer quick freeze pad is cooled in about 2. For example if I wanted to put beer or milk in there before the fridge is ready.

My freezer will freeze ice cream too.

Point here is that fridge is power efficient for those who don’t like running generators for lengthy periods of time.

I dry camped for 9 days near Santa Barbara a week ago including with several days of clouds and didn’t run my generator once. We used microwave for reheats but no long (30min) cooking. Also use espresso maker, hair dryer etc. and a few hours of tv for a kids movie every few days.

Batteries were in float every afternoon except one when the clouds were thick but the system caught up the next day. Even that day, the batteries were only missing 20 amp hours. So 97% charge state.

I love not running the generator!!! Or even thinking about the batteries.

Admittedly I haven’t tested my setup In high (110F) ambient temps. We might one day. But generally we camp in temperate climates. I think the fridge would keep up since it doesn’t run much now.

In the end it is obvious there is no one-size-fits-all solution.

I’d suggest installing a auxiliary to aid cooling fan before giving up on the ammonia fridge.

Do please take my comments in their intended light. Not trying to start a debate or argument.
__________________
Doug W.
Encinitas CA
2004 M380
Ex-PT36
Reply With Quote
  #182  
Old 04-14-2019
susanmarycamilleri's Avatar
susanmarycamilleri susanmarycamilleri is offline
Senior Member
 
Join Date: Jan 2008
Location: vancouver Is.
Posts: 1,685
Default

Doug

Most RV fridges use 12v all the time to run the control board. Even on 120V, the 120V powers the heating element, and 12v powers the control board. So your fridge is using about 18watts of power (from your figures) for the control board, I suspect, and the majority of the energy is supplied by the propane. Unless you shut the fridge off at night, I suspect it is always using 12v power, 24/7.
Reading other articles the fridge will use 12V all the time, but when the burner turns on the 12v increases to hold the propane valve open. From reading it sounds like you can count on about .5 amps when the fridge is not burning propane, and from your numbers, 1.5 amps when the propane is burning.
Still, if you are happy with the absorption fridge, they are a good way to go, but they do have limitations as you stated. They can only lower the temperature bur 40-50 degrees F from ambient, according to what I have read. So once you are above 85-90 degrees ambient milk doesn't last long in the fridge. That is my experience as well. One of the major reasons I switched to a house fridge was that the propane fridge doesn't cool well in warmer/ hot conditions.
The only other consideration I think worth mentioning is more RV generators die from lack of use, than from over use. I have looked at solar, but where I live and the way I use my bus, I think it is much cheaper to use the generator, rather than buy solar. I don't use the generator that much as it is, barely enough to exercise it as it should be. If I was full timing solar might be a consideration.
Absorption fridges are good in the correct application. Sound like it is the correct match for your lifestyle.
__________________
Peter Haggins
Courtenay, BC
Canada
96wb42
Mid Door
Reply With Quote
  #183  
Old 04-14-2019
DW SD DW SD is offline
Senior Member
 
Join Date: Jul 2010
Location: Encinitas
Posts: 1,523
Default

Thanks Peter for the alternate perspective.
I know the control circuitry consumes 12V DC - .5 Amp might be a good estimate. I lump that in with my static draws, which are 3.5 Amps without the inverter on search, though not fair in apples to apples comparison.

The propane safety sniffer and solenoid is probably 1 to 1.5 amps of that. I guess an all-electric coach can count that as another benefit to electricity accounting.

I know when I traveled back from Georgia last summer in very high temps (many days @ or over 100F), my milk and beer was always cold (am guessing 45F or below). I didn't have a thermometer inside the fridge to collect any data. Nor did I have a fan in the external cabinet.

All that said... 100% I know I can't beat the laws of physics and this fridge has real limitations.
This summer I hope to go to Lake Havasu for a week or so. That will test my refrigerator and I'll report back.

Maybe I'll be doing the Samsung swap, too! Or a compressor install on the dometic.

Thanks much!
__________________
Doug W.
Encinitas CA
2004 M380
Ex-PT36
Reply With Quote
Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Samsung fridge install BigR317 'Bird Projects & Modifications 34 11-28-2017 11:20 PM
Hooking up Samsung LED TV to Bose 321 in M380 Scott White M380 (Unique Issues) 2 04-09-2015 08:28 PM
Samsung Home Style Refrigerator rrueckwald General 7 12-08-2014 02:22 AM
Samsung fridge install Randy Dupree 'Bird Projects & Modifications 18 12-07-2014 09:53 AM
Samsung Refrigerator waharbird General 23 07-13-2013 02:53 AM

Web Search:

All times are GMT -4. The time now is 04:17 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.