Date: Tue, 7 Aug 2007 08:37:52 -0700
Reply-To: Michael Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Michael Elliott <camping.elliott@GMAIL.COM>
Subject: Re: Comments wanted on this portable fridge
In-Reply-To: <vanagon%2007080709342388@GERRY.VANAGON.COM>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Warren, from what I've read a good deep cycle battery will give you
hundreds of cycles to 80% depth of discharge. You'll want to make sure
you're watching it closely. You might think of one cycle to 80% DOD as
one camping trip. So that's hundreds of camping trips.
You can Google around and look for "cycle life" for lead-acid batteries.
The good manufacturers publish this information. A sort of generic curve
of DOD vs number of cycles is at
http://www.windsun.com/Batteries/Battery_FAQ.htm#Cycles%20vs%20Life
For amp-hour ratings, look at the 100 hour, not the 20 hour rating. 100
hour ratings more closely approximate your intended usage.
We use a Norcold DC0040, similar to the Isotherm, and I reckon that it
uses about 20Ah per day, so it's possible that we could get four days
from our 100Ah group 27 battery w/o going below 80% DOD as long as we
didn't run anything else, and it wasn't, like, 80F at night.
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR
Warren Chapman typed:
> Also desperately trying to solve this fridge problem....I need to carry
> more fresh produce than most due to my particular diet preference....so
> volume is important to me. I hate ice chests and wet food.
>
> I've been pretty much convinced on the Engel type solution, but haven't
> pulled the trigger yet mostly due to the high cost.....then recently, on
> an impulse...(motivated by a great price) I recently purchased an Isotherm
> CR65 off eBay ....similar to the Norcold DC0040....slightly larger (2.3 vs
> 1.7 cu.ft.) interior capacity and uses the Danfoss BD35F compressor.
>
> It will install right into Vanagon fridge opening (width perfect, with a
> space left over at the top., sticks out slightly farther than the face of
> the Westy cabinets...easily solved with a bit of frame backing between the
> fridge and cabinets.
>
> Electrial specs are: "average" useage is .7amps/hr, max draw 2.5 amps
>
> http://www.emarineinc.com/products/refrigeration/icr65.html
>
> It cools down quickly and keeps food very cold in my "bench tests" so far
>
> But, I'm still trying to get a grip on all these battery types and
> construction and their various charging/discharging qualites and
> requirements.
>
> It seems that going 12V only and giving up propane comes with some serious
> expense...and space compromises....for the required extra battery capacity
> and (solar ??) charging apparatus.....not to mention the extra weight.
>
>>From what I've read here... for a weekend outing....if you start on
> Friday, a 100AH battery capacity is the minimum....and possibly you're
> risking battery damage on the third day (more than 50% discharge).
>
> Depending on your choices, the fridge will cost $400-$900 and the solar
> panel, controller, battery, etc....another $600-$1000.
>
> Yikes.!!...maybe wet food in an ice chest isn't all that bad.
>
> There is no 100AH battery that will fit under the driver's seat....so
> there goes my precious under the rear seat storage. My goal is to keep
> that darn battery either under the driver's seat or under the van
> somewhere else. One idea I'm looking into is increasing the area under
> the drivers seat.
>
> Would it be possible to cut out the bottom of the battery box under the
> seat and weld in a 3" deeper box section?? Not sure yet what's directly
> under the battery box, but there's almost 12" of length and 7" of useful
> width there already....the limiting factor is the shallow depth. With an
> extra 3" of depth....there might be a 100AH battery that will fit in
> there ...?????
>
> Comments on this?
>
> Also, I keep reading that there are SOME deep cyle batteries that can be
> discharged safely to 80% DOD...that's a BIG 30% increase in useful AHs per
> charge....and would safely get you that third day without (expensive)solar
> help . Which ones ?? and how does their size compares to the 50% DOD
> types. I read a post on another forum that said the 6 volt golf cart
> batteries allow this...but two 6 volts in series must be even larger than
> a single 12V with same AHs.
>
> There's a lot to learn and understand here.
>
> Warren C
>
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