| [GMCnet] Refrigerator Advice [message #311991] |
Tue, 10 January 2017 16:51  |
glwgmc
Messages: 1014
Registered: June 2004
Karma:
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Senior Member |
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It is very hard to get enough battery power into one of our coaches to make household refrigerators work well unless you are nearly always plugged into shore power or willing to run your generator or the engine when not. Note that even the largest 45 foot rolling condos with six or even eight 8D batteries with over 1000 amp hours can only dry camp for a day or at most two before needing to run the generator. To prove this for yourself, get a Watt meter like a Killawatt unit and plug your home refrigerator into it. Use the refer normally for a few days and then read the number of KW consumed. Convert that into average watts per hour at 120vac. Know that even the most expensive inverters are not 100% efficient so when you convert that into amps per hour at 12vdc know that you will need to increase that draw assumption to make up for the less than 100% efficient conversion from 12vdc in the batteries to 120vac needed by the refer. The numbers will scare you when you consider that about the most battery capacity you can cram into a GMC is four 6v golf cart batteries (around 400 to 450 amp hours of capacity with around 200 to 225 amp hours available. If you have to run the furnace while also servicing the inverter power needed to run your home style refer your run time will drop much more quickly as the furnace alone will consume 7 to 9 amps per hour of operation.
A more complete explanation of all this is contained in a presentation I made to GMCMI a couple of years ago that you can download from the GMCMI.org web site: http://www.gmcmi.com/wp-content/uploads/2013/02/GMC_Battery_Presentation_-_Jerry_Work.pdf
Bottom line, at least for me, is you cannot beat propane for space heating, water heating and running the refer while dry camping in a GMC. In another presentation made at the GMCWS rally in Coos Bay, OR, in October of this year I also talked about running our Onan generators on propane, as well: http://www.gmcmi.com/wp-content/uploads/2016/10/Feeding-the-Barbarian-Jerry-Work.pdf Once you make that switch you will never look back at things like home refers and massive battery banks because your Onan will start easily, run quieter and more smoothly, outlast you and the next several owners and have no more ugly exhaust smell so you can run it easily and as often as you need to to keep everything in your GMC running comfortably whether plugged into shore power or not.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
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Message: 12
Date: Tue, 10 Jan 2017 14:33:59 -0700
From: Jon Roche
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Refrigerator Advice
Message-ID:
Content-Type: text/plain; charset="utf-8"
Others may chime in on the actual math, but the batteries charge rate will vary. I think it takes longer then 2 hours to charge up a house bank
drained down 75%. the batteries will not take the full 45 amps.
i can only say my experience. with my original 12v marine battery, the fridge seemed to kill the battery in a 24 hour period or less. I then
upgraded to 2ea 6v golf cart batteries, about 215 amp hour, and it would last 36-48 hours. I added 65 watt solar, and it did not really add any
time, batteries were drained dead by sunday morning when I had rolled into camp friday night. I then stated putting Ice in the fridge, and it
seemed to help getting me through Sunday.
with my 2 golf cart batteies drained all the way down, a 2 hour drive home(alternator charge), they were charged up quite a bit, but never topped
off 100%.
remember when the sun hits the coach, and you are not running A/C, it can get really hot. Also the back of the coach fridge is usually exposed to
outside temps. (obviously not the case if you install a residential unit, you will probably close off the back of the fridge compartment).
there are people who run electric fridges and are plenty happy with them. My experience though, is if you ever want to make it longer then 2-3 days
without a power cord, then a propane fridge is the way to go.
--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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Jerry & Sharon Work
78 Royale
Kerby, OR
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