Date:         Thu, 13 Sep 2012 09:11:23 -0700
Reply-To:     Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Subject:      Re: Danfoss VS Sawafuji Compressor. Which is Electrically More
              Efficient?
Comments: To: neil n <musomuso@GMAIL.COM>
In-Reply-To:  <CAB2Rwfgi_HJvVb6By8YPT5z42Ld4s43Bfzg8LncWNWFqtCbq7w@mail.gmail.com>
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________________________________
 From: neil n <musomuso@GMAIL.COM>
To: vanagon@GERRY.VANAGON.COM 
Sent: Wednesday, September 12, 2012 10:01:22 PM
Subject: Danfoss VS Sawafuji Compressor. Which is Electrically More              Efficient?
 
> Hi all.

> On the internet, there appears to be lots of hype, opinion and
> conjecture about the Sawafuji or Danfoss compressor fridges, and the
> amount of amps each consumes.  i.e. Engel VS Waeco. I know fridge
> power consumption has been discussed here before but it seems to me
> that there's too many variables. Looking at this from another POV....

> If a Sawafuji and Danfoss powered fridge were wired to be manually
> switched on/off at 15 minute intervals, (bypass thermostat) and each
> had the same test conditions, which fridge would consume less amps in
> an hour?

MJ: I think you forget that the temp in each fridge will not be the same just because the compressor is run the same amount. 

The relevant comparison would be to put similar size chest models next to each other. Set thermostat and verify that they keep a particular inside temp (e.g. 4C). Then measure AH consumed by each over a typical day (or week for better accuracy). Put some jugs of water inside each for a realistic thermal mass.

> It seems that in terms of current draw to "power up" either of these
> compressors, the Sawafuji may have the advantage. Is that advantage
> significant enough to make it the winner?

I think not. Startup current spike is so brief that it does not affect average Ah consumed. There's also no compelling scientific reason one compressor type would be inherently more efficient than the other.

Martin