Stock refrigerator for 1997 400 Diesel Sundancer

[Wild Rover]

Hello, I am considering getting a solar panel to keep my batteries charged when on the hook. The main draw of course is my fridge, which I prefer to keep running. I need to know the power consumption of the fridge, which is the original and still works well. The battery arrangement on the boat is "port" and "starboard", and it looks like the fridge runs off the starboard battery. I then have trouble starting the starboard engine the next morning due, I assume, to the constant drain by the refrigerator. Does anyone else have this problem? I am not mechanically inclined, but I would think rearranging the batteries so that one pair are "house " batteries and the other pair are "starting" batteries would at least take care of the engine starting problem , as only the "house" batteries would be drained? That being said, I would think a solar panel would keep the battery charged as the fridge consumes power. I need to know what wattage solar panels to purchase (along with the appropriate charge controller). Any recommendations from the group? Thanks Mike K--Wild Rover

 

[techmitch]

Hello, I am considering getting a solar panel to keep my batteries charged when on the hook. The main draw of course is my fridge, which I prefer to keep running. I need to know the power consumption of the fridge, which is the original and still works well. The battery arrangement on the boat is "port" and "starboard", and it looks like the fridge runs off the starboard battery. I then have trouble starting the starboard engine the next morning due, I assume, to the constant drain by the refrigerator. Does anyone else have this problem? I am not mechanically inclined, but I would think rearranging the batteries so that one pair are "house " batteries and the other pair are "starting" batteries would at least take care of the engine starting problem , as only the "house" batteries would be drained? That being said, I would think a solar panel would keep the battery charged as the fridge consumes power. I need to know what wattage solar panels to purchase (along with the appropriate charge controller). Any recommendations from the group? Thanks Mike K--Wild Rover

Your info. says "boatless" please update.

 

[Wild Rover]

Thanks Mitch, fixed it

 

[dtfeld]

The Starboard batteries are (likely) your house batteries. If your having trouble starting the the next morning, those batteries need to be pulled, tested, and probably replaced. As far as the addition of a solar panel, it's not that simple. The amount of energy produced, is very limited on a boat as it hard to get the panels oriented to produce max power. It might help, but your bigger bang for the $$ is new batteries (you dont indicate how old the batteries are).

The way these boats work is, if you drain the house/starboard bank, you use the emergency start switch to connect the port batteries and that is supposed to get you enough power to start the starboard engine. Or you could start the generator in the morning (a lot of us do this) to get the batteries topped up via the main battery charger (or converter in Sea Ray speak). The generator is the power source of last resort, so you want to be very sure the generator battery is in good shape.

 

[dtfeld]

To answer the question of adding solar, it will help, but you have to do some math to see if its worthwhile, because there are so many variables with a fixed flat mounted solar array mounted on a boat swinging on the hook in the wind and tides.
Here's my (very rough, back of a napkin) math...

Lets assume you have the original Norcold. The compressor draws about 5.3 amps running on 12V DC, runs 50%-60% of the time (duty cycle). Mine before it died ran 100% of the time. Calculating watts of power consumed (50% duty cycle) 5.3A X 12V x .5 x 24hrs = 763 Watts and (60% duty cycle) 5.3A X 12V x .6 x 24Hrs = 915 Watts, so lets call it about 800W per day. This is pretty typical for a dual door marine fridge. Add another 400-500 watts if your also running a cockpit fridge (a MUST for keeping beer cold). So your refrigeration power consumption is about 1100 to 1400 watts a day. Lets use 1500 Watts.

So then the question is how many solar panels do I need to produce that amount of power? Lets assume you get 4 hours of useful sun a day in CT, your DC system is 85% efficient, and you get 50% of the rated power out of the panel over those 4 hours (because you cant position the panels at the optimum angle easily on a moving boat). Roughly speaking you would get 150W out of each 100W panel over those 4 hours, so you would need about 10 100W panels.

That's a lot of real estate.

 

[Maybe A Dancer]

Over the last 20+ years we have done a lot of overnights on the hook The 6.5 kW Northern Lights in my 10 meter burned about 0.25 - 0.5 gallons per hour

I expect the 9 kW in the Sea Ray to burn a bit more - likely less at night with no fridge/ice maker doors being opened.

So 24 hours at .25 gph = 6 gallons per day

6 gallons at $5/gallon = $30 for the all that HVAC, comfort, convenience and reliability.

Running that stereo with an amp, maybe two amps one in the cockpit and one in the salon? Well that's a big draw too.

If something, ANYTHING happens and I have to GO, LEAVE or just MOVE THE BOAT I don't want to have to wait for a bank of batteries to charge.

these 1800 RPM gennys are designed and engineered to run 24/7

Anyhow - that's my .02

and yes, STINKPOTS are very different than RAGBAGS !

BEST !

RWS

 

[Wild Rover]

Thanks, no question running gen more is easiest solution

 

[RollerCoastr]

For the most part, your port bank powers external/cockpit circuits and the starboard bank handles cabin/“house” loads.

I like it that way and have found it to be highly functional. If you do happen to exhaust the house bank, safety items such as GPS, VHF and nav lights are still operational from the port bank.

I’ve spent many days on end at anchor without depleting either bank with minimal genny usage and without compromising comfort.

I fire it up in the morning and it works its butt off heating water, running the toaster, coffee maker, micro, maybe the stove, charging all the batteries and moving/freshening air and chilling the fridge set to the max cold temp.

When all that is done - we’re fed, showered and batteries are topped off and the fridge is cold, I shut it down and enjoy the day. We repeat around dinner time, but this is usually a shorter stint.

The fridge gets dialed-up to the warmest safe temp and its doors stay shut. (I put frequently-accessed items in a cooler and use frozen water bottles to help the ice)

This routine works with <4 hours of genny time per day and both engines will crank at any time w/o being paralleled. (Yes, I have easier-to-spin gas engines, but also smaller batteries)