Energy usage - 2003 Bavaria 38 - Isotherm mod43701ee100000

[mjt2]

Hi,

I recently acquired a 2003 Bavaria 38 and want to add solar. I'm researching the power draw of all of the boat's equipment.
I found the boat has an Isotherm mod43701ee100000. The specifications from Fischer Marine says it draws 1amp but up to 6.5amps.

What I cannot find is how often one should expect the compressor to cycle. I certainly wouldn't expect (once it is cooled to the expected temperature) that it would run 24hrs/day at 6.5a, nor would I expect even 24hrs/day at 1a.

Can anyone please share either or both of these things?
1. Specs from Isotherm for this model that says how often to expect the refrigerator to run
2. Your experience on how much energy your own fridge is using

Thanks!

[Yngmar]

The fridge will run as long as the thermostat commands it. So it depends on many factors, insulation, ambient temperature, how much warm beer you just packed in there, how often someone opens it to remove cold beer, etc. - you'll not find those things in the spec

Ours varied between perhaps 25% duty cycle in winter and over 90% in a hot summer.

[mjt2]

Thank you! 

Living in FL, it is "hot" most of the time (hot/cold always being relative). So, I guess worst case, I should plan 6.5a * 24 hours *.9 = 140 ah for the fridge for 1 day. Much appreciated!

Matthew

[symphony2]

Suggest you install a battery monitor so that you can more accurately measure your energy consumption. The fridge is of course the biggest draw But you are fortunate that you are in a location where you can meet a lot of the demand from solar.

[Lazy Pelican]

We have a B39 2006 with a fairly standard cruising set up. We’re in Greece and find 350w solar on a stern arch is adequate. Actually it’s more than we need this time of year but sufficient in October.
We previously had 180w which wasn’t really enough.

[mjt2]

Thank you. I'm considering 600-800 watts. Hopefully, that will be enough to run the fridge, GPS, AIS, radio, radar, autopilot, and night nav lights plus some cabin lights if needed.  I suspect radar won't run all the time if I have AIS on, just during bad weather and night when non-AIS boats can't be easily seen. Right now my power budget is just under 300 AH / day for cruising, less whatever the boat can produce.

[mjt2]

Suggest you install a battery monitor so that you can more accurately measure your energy consumption. The fridge is of course the biggest draw But you are fortunate that you are in a location where you can meet a lot of the demand from solar.

Thanks, it's on my list. :-)

[Yngmar]

I calculated 400W and ended up fitting 600W as that was cheaper (house roof panels). The 600W were enough to run everything you mention plus have spare power for a 12V energy recover watermaker, which we fitted later. These days the same space will yield you about 700-800W.

The old Pathfinder Radomes can run in interval mode to save power - it wakes up every 2 minutes, does 3 scans (triggering any guard zone alarms you may have set) and goes back to standby.

You'll also have to work out the battery capacity for night sails