Bus Conversions dot Com Bulletin Board
December 21, 2014, 04:04:28 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an Online Subscription:  It will not get lost in the mail.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 [2] 3 4 5 6 7   Go Down
  Print  
Author Topic: Run Fridge off Starter Batts?  (Read 9513 times)
Jerry32
Hero Member
*****
Offline Offline

Posts: 726





Ignore
« Reply #15 on: January 25, 2010, 10:54:54 AM »

In the daylight I shut off all ac and run on solar only. I think the TV draws mor than the fridge and with two sat systems going ( Dish  & datastorm hughes ) the batteries get charged too. Jerry
PS i would put pix in but don't know how to do that.
Logged

1988 MCI 102A3 8V92TA 740
JackConrad
Orange Blossom Special II
Global Moderator
Hero Member
*****
Offline Offline

Posts: 4447


73' MC-8 8V71/HT740 Southwest Florida


WWW
« Reply #16 on: January 25, 2010, 10:56:50 AM »

FYI  Nellie's refrigerator is a gas absorbtion type unit.  Jack
Logged

Growing Older Is Mandatory, Growing Up Is Optional
Arcadia, Florida, When we are home
http://s682.photobucket.com/albums/vv186/OBS-JC/
bevans6
Hero Member
*****
Offline Offline

Posts: 4877


1980 MCI MC-5C




Ignore
« Reply #17 on: January 25, 2010, 11:30:13 AM »

OK, extremely rough back of the envelope calculations on the cost of running an RV fridge vs the cost of running a 120 volt compressor fridge "off the grid" - no hookups, only batteries and a generator.  For the sake of argument I considered an 8 to 10 cubic foot fridge, because that's what I have.  And all from scratch - no nothing to start with, and no other use for any of the equipment.

Propane RV fridge - $1400
Propane tank and rudimentary plumbing (a hose) - $100.
Half tank of propane a month (I get two months from a tank, small fridge I guess) $20/mo.
12 vdc to run the fridge controller - free, it's a tiny draw.

Total $1,500 plus $20/month running costs.

120 volt home style fridge  - $500 (mid-range kinda nice model)
Energy consumption 375 kwh/year, 42 w/hr.
convert to battery power at 12 volt - 3.5 amps/hr
round up to 5 amps/hour inverter draw, call it 120 amps/day
At 50% discharge limit, you'd want 240 amp/hrs of battery for 24 hour cycles - $250
You'd want a 50 amp charger to recharge, call it $500 for a good one
You'd want a 2KW PSW inverter, call it $1,000
You'd want a reasonable generator to power up the charger - $1000 for a little Honda
Run the generator for 2.5 hours per day, half a gallon an hour, $112 per month for gas to run the gennie.

Total for house fridge - $3,250, and $112 per month.

Obviously there are other considerations, like "free" power from a hookup, using the inverter for other things, having the batteries to run lights, etc.  But the stuff to run the fridge "off the grid" is not particularly cheap.  On the other hand, once you have the RV fridge, it is cheap....

Feel free to take shots, I spent all of 10 minutes on this.  It took longer to type than to figure out the numbers...  Grin

Brian
Logged

1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Spicer 8844 4 speed Zen meditation device
Vintage race cars -
1978 Lola T440 Formula Ford
1972 NTM MK-4 B/SR
Just Dallas
Bus Conversion Stuff on a Budget
Hero Member
*****
Offline Offline

Posts: 842



WWW

Ignore
« Reply #18 on: January 25, 2010, 12:27:47 PM »

Removed
« Last Edit: July 15, 2010, 01:25:03 PM by Now Just Dallas » Logged

I'm just an old chunk of coal... but I'm gonna be a diamond someday.
kyle4501
Hero Member
*****
Offline Offline

Posts: 3153


PD4501 South Carolina




Ignore
« Reply #19 on: January 25, 2010, 01:43:01 PM »

I guess the best answer is "it depends”.  What are your future goals?
We used to have a 3 way fridge. It could kill a couple of batteries in only a few hours! Pulled a considerable load on the alternator of the car we were pulling the camper with too. So, based on my experience, I wouldn’t recommend using your start batteries if the engine isn’t running!
If you’re planning on adding propane, start there. We’ve had great success with running our’s on propane while driving or parked overnight.
If you’re worried about a fire, good ole 120V has started more fires . . . . There is a good reason to follow “the code” on either installation.  If properly installed & maintained, both are equally safe.
Concerning compressor fridges, the right house fridge with extra insulation & the condenser coils on the back & cold plates inside will use less electricity than a side by side frost free model. Another electricity saving option is to disconnect the heater around the door (it prevents condensation).

As for me, the price consideration is going to include the total picture - I want an inverter & battery bank large enough to run an AC unit while driving down the road & for several hours while parked. Often, the larger inverters come with an excellent charger built into them along with battery management software. So the inverter, charger & batteries will be there regardless of the fridge we use.
I’ll also have propane to cook with. It is also a clean & quiet way to heat water. . . . Very convenient for boondocking too.



I just don't get the aversion to RV type fridges. Ours runs quietly and cold on propane whenever we are unplugged.  I don't know how much propane it uses but we sure don't notice the consumption and we have to keep it turned to the 2ND from warmest setting or it will freeze things in the fridge compartment. 
If you experience an ammonia leak first hand in the confines of an RV, you will have a much better understanding of some of the aversion. Rare, but it only takes one time to shorten your life.  Sad  I'm thinking the extra venting isn't required for the thing to work, but rather a path for the ammonia vapors to leave without filling the RV. The original owner of my Airstream lost a large part of his lung capacity when the fridge leaked ammonia when he was inside the camper & it was a factory correct installation. Permanent disability.  Sad

Our absorption fridge is set to the 2nd to coldest setting & ice cream is soft enough that you can serve it with cheap plastic spoons & never a fear of things in the fridge getting too cold or freezing.  Grin
Logged

I know you believe you understand what you think I said, but I am not sure you realize that what you heard is not what I meant. (R.M. Nixon)
Sean
Geek.
Hero Member
*****
Offline Offline

Posts: 2553


'85 Neoplan Spaceliner "Odyssey"


WWW

Ignore
« Reply #20 on: January 25, 2010, 02:16:47 PM »

We seem pretty far afield from the OP question.

That said, I need to chime in.

First off, ammonia absorption refrigerators NEED TO BE VENTED TO THE OUTSIDE OF THE COACH.  This is irrespective of whether or not they are being run on (or will ever be run on) propane.  Ammonia gas is deadly; should the unit develop a leak in the absorption system, the gas needs to be able to vent outside immediately.

I would sincerely hope, therefore, that Viviane's fridge is properly installed and vented, and the reason she can not run it on propane is merely that the rest of the LPG system is not installed.  Nellie:  if this is not the case, I strongly urge you to install proper vents, or else remove the fridge.  Again, I think you would be money ahead to sell it and buy a small compressor unit.  (There, now its an on-topic post.)

We all have our biases when it comes to "the right way" to boondock or use a bus, and Brian, your very skewed math clearly tells us yours.  I'm probably slightly biased the other way, but I would be the first person to say that an LP fridge is the right solution for desert rats who already need a large LP system for other reasons.

Among other things, a proper and safe LP system does not consist of merely "a hose," a compressor fridge of similar size and capability to the average absorption fridge is $150 not $500, and uses far less than 375 kWh per year, not even half that.  Dallas's comments regarding maintenance costs are also germane; the last absorption fridge I had went through two control boards before I finally put a Dinosaur in it (highly recommended).  Even one control board costs more than a whole new fridge from Wal-Mart.

If you want to get fancy, for the same money that buys you a decent RV absorption fridge, you can get an ultra-efficient compressor unit running on the 12/24v Danfoss compressor, such as the one I have, and reduce the energy consumption to a tiny fraction of that.  I spend nothing per year to run my fridge, because my 330 watts of solar panels power it indefinitely, with power to spare.  (More expensive, however, than an LP tank.)

As with so many things, it all comes down to how you use your coach.  Some folks don't want to have to level the coach, even when parking for the day to do something elsewhere, which is another consideration with absorption refrigerators (whether they are running on propane or on electricity).  Others don't want to cut more holes in the coach for the required venting, something compressor units don't need (although there must be airflow for the condensers to shed heat).

The big deal, for a lot of people, is that an electrical system is almost mandatory (you need it for lights, pumps, controls, fans, etc.) whereas an LP system is optional, and adds a great deal of complexity and safety concerns to a coach over one that is all-electric.  If you are not using LP for anything else, such as heating and hot water, than putting it in just for a fridge can be a huge expense that may not be justifiable.  OTOH, if, as I said earlier, you already have an LP system for other reasons, adding the fridge to it may be the best strategy.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com
Logged

Full-timing in a 1985 Neoplan Spaceliner since 2004.
Our blog: http://OurOdyssey.BlogSpot.com
luvrbus
Hero Member
*****
Offline Offline

Posts: 13128




Ignore
« Reply #21 on: January 25, 2010, 02:48:40 PM »

I put a lot of thought into fridges before changing over to the RV type as they are called.
It does take a lot of generator time for a house type fridge without solar.
The way Sean is setup with a large battery bank and on the move all the time that would work well for some but we never stay in over priced RV parks.
The RV gas fridge was my second choice a Sun Frost dc model was my first choice having had one in the past.
Think the RV fridges are expensive price one of those babies.
Kyle I do run my AC off inverters driving and my batteries will last a short period of time running 1 AC while stopped I can get about 3 hrs if it is not real hot the draw back is 1 AC will not keep the bus cool.
The RV fridge has worked for us without any hiccup's so far.



good luck
« Last Edit: January 25, 2010, 02:56:20 PM by luvrbus » Logged

Life is short drink the good wine first
niles500
Niles500
Hero Member
*****
Offline Offline

Posts: 1203


ROSIE




Ignore
« Reply #22 on: January 25, 2010, 02:56:20 PM »

The one thing Sean usually brings up in the Propane vs. Electric discussions is travel ability - If your a traveler and not a parker - The restrictions placed for some tunnels, bridges and ferries can be quite onerous for travelers that have to travel significant miles due to propane restrictions - FWIW
Logged

(\__/)
(='.'=)
(")_(")  

- Niles
Nellie Wilson
Full Member
***
Offline Offline

Posts: 243





Ignore
« Reply #23 on: January 25, 2010, 03:07:27 PM »

Wow! "Food for thought," indeed!

But since I've already got the fridge, sounds like I should stick with it? It works great, and I can follow Sean's advice (pack it with cold stuff) between stops. At least until I hook up propane. I've got a couple full bottles so just need a regulator and some hose (I guess?). Anyway, I need it to run my stove and oven.

I shied from propane (partly) because I didn't want a hole in my wall; I'd considered venting through the floor but didn't know if that would work. But sounds like it does!

I was also concerned about fire and, if it flames out, CO poisoning (and still am). That ammonia thing Kyle mentioned doesn’t sound so swell either.

As for servicing, I’m thinking of pulling it out from the wall and cutting a large re-sealing inspection port’ in the enclosure (thanks for the thought, Bevans).

I also didn’t want any holes in my roof. But since I’m stuck with that, thinking of using the frig vent for my holding tank and A/C vents too … a ‘3 birds with one hole’ kind’a thing.

No decisions yet, still reading and absorbing - but you guys got me thinking (not my longest suit). Huh

Nellie
Logged

Had to change a tire... Angry  got to put it on backward... Undecided  still trying to fix it on photoshop... Huh Roll Eyes Huh
luvrbus
Hero Member
*****
Offline Offline

Posts: 13128




Ignore
« Reply #24 on: January 25, 2010, 03:17:55 PM »

Niles, that maybe true in some parts of the USA but it has never been a problem for me.I grew up in Texas and go back 3 or 4 times a year and I have my first time for anyone to ask about propane on board.
 I have been through the Baytown and Washburn tunnels 1000's of times same with the Bolivar and the Lynchburg ferries in Texas.  


good luck
Logged

Life is short drink the good wine first
Sean
Geek.
Hero Member
*****
Offline Offline

Posts: 2553


'85 Neoplan Spaceliner "Odyssey"


WWW

Ignore
« Reply #25 on: January 25, 2010, 03:28:34 PM »

Niles, that maybe true in some parts of the USA but it has never been a problem for me.I grew up in Texas and go back 3 or 4 times a year and I have my first time for anyone to ask about propane on board.


LP tunnel restrictions are a real problem in the northeast and on the west coast.

No LP at all is allowed in any tunnels in or connecting to New York City, as well as Boston.  All of Maryland and Virginia tunnels allow only limited amounts (there are very specific rules) but the valves must be hand-closed at the tanks.  Tunnels in California generally allow no LP or severely limit the amount.

As with many things, Texas has among the most relaxed DOT rules.

All of these issues are a matter of state or local law and vary widely.

-Sean
http://OurOdyssey.BlogSpot.com
Logged

Full-timing in a 1985 Neoplan Spaceliner since 2004.
Our blog: http://OurOdyssey.BlogSpot.com
philiptompkjns
Full Member
***
Offline Offline

Posts: 193




Ignore
« Reply #26 on: January 25, 2010, 04:31:58 PM »

Niles, that maybe true in some parts of the USA but it has never been a problem for me.I grew up in Texas and go back 3 or 4 times a year and I have my first time for anyone to ask about propane on board.
 I have been through the Baytown and Washburn tunnels 1000's of times same with the Bolivar and the Lynchburg ferries in Texas.  


good luck
I took the class C across the bolivar ferry a  few  times. they always pull me aside and check that  the propane is off and sometimes check for drugs illegals, ect. but  aside from that no problemo.
Logged

1990 102a3... Just got started, don't  know  what I'm doing.
luvrbus
Hero Member
*****
Offline Offline

Posts: 13128




Ignore
« Reply #27 on: January 25, 2010, 04:52:24 PM »

That has never happen to me at Bolivar and I cross with my Eagle and toad a least 4 times a year last spring there were 4 of us from the Eagles group and they didn't pull us to side you must look suspect to them driving a class C LOL just kidding  



good luck
Logged

Life is short drink the good wine first
niles500
Niles500
Hero Member
*****
Offline Offline

Posts: 1203


ROSIE




Ignore
« Reply #28 on: January 25, 2010, 05:35:20 PM »

Luvr - If only all the US was like Texas  Wink  With crazies packing their underwear with explosives, the next incidence involving ANY type fuel on any of those conveyances, accidently or on purpose, will probably bring on a whole new set of restrictions - These days not a matter of if but when - Your right that it probably won't affect many travelers, but for those who travel the Seaboards it can definetely put a cramp in our style - I carry a 20 lb'er for the belly grill (always off) If they ever try to restrict me I'd simply give it away as it's a whole lot cheaper than fuel for the detour and some of the best scenic views are before, during and after bridges, tunnels and ferries - FWIW
Logged

(\__/)
(='.'=)
(")_(")  

- Niles
buswarrior
Hero Member
*****
Offline Offline

Posts: 3571


'75 MC8 8V71 HT740




Ignore
« Reply #29 on: January 25, 2010, 07:26:45 PM »

Yup, no matter if you are a conspiracy theorist or go with the flow...

How about this?  Bin Laden's next best move is to use an RV or converted coach for the next bombing attempt, with an aging couple at the controls...

No amount of lobbying or other political pull will stop the wave of compliance that will rain down on our heads.

Anyone familiar with the treatment of the trucking community in the hands of the authorities knows what it might turn into.

The day after that, you'll find me walking, slowly, wearing only a thong, hands in the air...

oh, on topic, I'm supportive of all-electric, Nellie, install that fridge properly and stop screwing around, folks with long generator run times need to get a good charger, or more batteries, or better understand how to use their rigs.

happy coaching!
buswarrior
Logged

Frozen North, Greater Toronto Area
Pages: 1 [2] 3 4 5 6 7   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!