Reply
 
Thread Tools Display Modes
 
Old 03-25-2015, 03:21 PM   #71
Bus Nut
 
Join Date: Feb 2015
Posts: 258
Quote:
Originally Posted by family wagon View Post
While that IS true... the effect can be mitigated to a degree by keeping the fridge (or freezer) as full as possible, even if only with old milk jugs filled with water. Warm room air can quickly trade places with the cold refrigerated air when the door is opened but room heat won't transfer so quickly into actual "stuff" like water. Depending on a person's energy budget it might be "good enough" to have a front-opening fridge/freezer, mostly filled to limit the amount of air contained inside, and accept the remaining inefficiency penalty vs the top-load in order to have the front-load convenience.
Also... if you don't want to go with a top-loader (see my link above) you can hang plastic strips inside (about 4" wide overlapping strips cut from 10mil or thicker plastic - relatively cheap) or set up an "air dam" out of a piece of plexiglas. You'll see things like this in delis that can't do a full chest fridge/freezer but still don't want to lose their air.

Opening your fridge as little as possible when you're off-grid helps a lot, too. We carry a large cooler with us on every trip and keep our water and such in there. A bag of ice in it will last a couple of days, and keeps the kids out of the fridge. When we do go into the fridge, it's to load the cooler...
taskswap is offline   Reply With Quote
Old 03-25-2015, 04:43 PM   #72
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,139
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
Quote:
Originally Posted by taskswap View Post
We carry a large cooler with us on every trip and keep our water and such in there. A bag of ice in it will last a couple of days, and keeps the kids out of the fridge. When we do go into the fridge, it's to load the cooler...
Children are a big factor in my decisions as it sounds like they are in yours. I had been thinking "kids can't easily get into it" is on the cons side of the balance sheet for the chest fridge/freezer... but now I'm wondering whether really it goes on the pros side. Your cooler idea for minimizing trips to the fridge is pretty good.

Related to that, I've been reflecting on my experience two years ago. We did a 10 day trip with a large conventional fridge+freezer; it was powered through an inverter from a pair of used (probably tired) T-105 batteries. I think I had to run a generator about 2 hours each day to keep the batteries up with a 40 amp charger. That was too much. Long-term I think I'll use a small-ish residential fridge+freezer, and for the occasions when we need extra cold space (a long trip where grocery shopping would be inconvenient, and/or have extended family along like we did on that trip) I may fill the freezer section with ice blocks and the fridge with the most delicate perishables, and put the more forgiving refrigerated things into coolers. Ice blocks could be moved from the freezer to the coolers as needed to maintain them.
family wagon is offline   Reply With Quote
Old 03-31-2015, 04:24 PM   #73
Bus Crazy
 
Stu & Filo. T's Avatar
 
Join Date: Sep 2013
Location: Vacaville, Ca
Posts: 1,386
Year: 1988
Coachwork: Crown / Pusher
Engine: 8.3 Cummins
I have a question, Everything household is engineered for the most part at 120/220 volts at 60hertz, what if you hooked up electrical generator that ran at 400hz , what happens to the appliances or chargers?
Stu & Filo. T is offline   Reply With Quote
Old 03-31-2015, 04:37 PM   #74
Skoolie
 
Join Date: Mar 2010
Location: Texas
Posts: 199
Year: 1997
Coachwork: AmTran
Chassis: Genesis
Engine: DT466
Rated Cap: 84
Quote:
Originally Posted by allwthrrider View Post
I have a question, Everything household is engineered for the most part at 120/220 volts at 60hertz, what if you hooked up electrical generator that ran at 400hz , what happens to the appliances or chargers?
The short answer is: "Nothing good."
Timelord is offline   Reply With Quote
Old 03-31-2015, 04:48 PM   #75
Bus Crazy
 
Stu & Filo. T's Avatar
 
Join Date: Sep 2013
Location: Vacaville, Ca
Posts: 1,386
Year: 1988
Coachwork: Crown / Pusher
Engine: 8.3 Cummins
Quote:
Originally Posted by Timelord View Post
The short answer is: "Nothing good."
Your still putting out 120/220 volts just a more pure power
Stu & Filo. T is offline   Reply With Quote
Old 03-31-2015, 05:15 PM   #76
Bus Crazy
 
Join Date: Nov 2011
Location: Sault Ste. Marie, Ontario
Posts: 1,328
Year: 1997
Coachwork: Thomas
Chassis: B3800 Short bus
Engine: T444E
Rated Cap: 36
Quote:
Originally Posted by allwthrrider View Post
Your still putting out 120/220 volts just a more pure power
I would guess that all transformers would operate correctly. So your laptop, LCD tv, stereo, etc would probably work (though they may "buzz"). Motor-driven appliances, however, probably wouldn't work and might actually fry.. AC motors rely on the sine wave to operate and, in North America, are configured for 60Hz.
__________________
My build page: Armageddon - The Smell of Airborne Rust
jazty is offline   Reply With Quote
Old 03-31-2015, 05:18 PM   #77
Bus Crazy
 
Join Date: Nov 2011
Location: Sault Ste. Marie, Ontario
Posts: 1,328
Year: 1997
Coachwork: Thomas
Chassis: B3800 Short bus
Engine: T444E
Rated Cap: 36
Quote:
Originally Posted by jazty View Post
I would guess that all transformers would operate correctly. So your laptop, LCD tv, stereo, etc would probably work (though they may "buzz").

Actually, even transformer driven appliances will probably suffer. AC is Alternating Current, after all, so if you continue to increase the AC frequency towards infinity you will eventually approach zero volts.
__________________
My build page: Armageddon - The Smell of Airborne Rust
jazty is offline   Reply With Quote
Old 03-31-2015, 06:08 PM   #78
Bus Nut
 
Join Date: Feb 2015
Posts: 258
A lot of devices will work. (The Macbook Air charger is known to work at 400Hz, for example.) The ones that work will be inefficient. The ones that don't work will fry. You won't know for sure which those are until you let the "magic smoke" out, and once you let the magic smoke out you can't put it back in, and the device is dead forever.

So...
taskswap is offline   Reply With Quote
Old 03-31-2015, 06:26 PM   #79
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,139
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
Did you want the electrical engineering version, or the layman version? "It depends."

The first thing most switch-mode power supplies do is rectify and filter the mains ac into dc. A mains voltage of 120 Vrms ac rectifies to 170 V dc but it's not smooth at all. Big capacitors (relative to the load) smooth it somewhat, then an electronic circuit creates from that a high frequency switching signal into a transformer. This is the main feature that allows switch-mode supplies to be so small and light weight: they still have a transformer (or sometimes an inductor) but it can be much smaller because it's more efficient at higher frequencies.

So anyway.. a switch-mode type supply might get along (probably would?) with 400 Hz input but if it isn't marked for that then all you're left with is to test with the possibility that it'll fail, and perhaps spectacularly. There are still a few electronic items that don't use a swich-mode supply, but chargers, computers, monitors, etc almost universally do use this topology.

Heavier devices -- things with mains-driven motors or line-frequency transformers -- are almost certain to misbehave. Motors might refuse to start, they might overspeed... I don't know exactly; motors aren't my specialty but I do know that for some types the starting arrangements and the running speed are related to the line frequency.

One other curious little thing: if you still have a line-powered clock radio, it might keep time wrong. Some of them were built so cheaply that they didn't have any built-in timekeeping; instead they simply counted the 60 Hz cycles on the mains. If you fed it 400 Hz instead, and if it powered and ran, it might run 6.7x fast. That'll make time really fly!
family wagon is offline   Reply With Quote
Old 03-31-2015, 06:42 PM   #80
Bus Crazy
 
Stu & Filo. T's Avatar
 
Join Date: Sep 2013
Location: Vacaville, Ca
Posts: 1,386
Year: 1988
Coachwork: Crown / Pusher
Engine: 8.3 Cummins
Would there be a way of stepping it down to 60 hertz?
Stu & Filo. T is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Starting my Research.. finding more questions than answers admiller Conversion General Discussions 0 09-15-2014 11:36 AM
electrical questions proconsul100 Electrical, Charging and Solar 5 03-31-2014 01:28 PM
Electrical Questions iowacamper Conversion Tutorials and How-to's 32 11-15-2013 04:09 PM
Electrical questions BUSBOZO Electrical, Charging and Solar 10 02-09-2010 10:20 PM
So many electrical questions Dolores Conversion Tutorials and How-to's 4 07-25-2008 08:48 AM

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 05:57 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.