Power Management

[Neil McDonald]

This is a good time of year to contemplate future boat projects. I have been thinking about how best to reduce battery load when at anchor and would appreciate some feedback on some ideas: 1. Change out some or all of my MR16 halogen reading lamps with Dr LED Magnum Ring LED bulbs. I know that they will fit electrically, but does anyone know if the diameter of the bulb is the same? If larger, they will not go into my existing light fittings. 2. I have been looking at a 9W dual power Alpenglow overhead fluorescent unit for the interior of my H35. Has anyone any experience on whether one of these units alone will provide reasonable light level for the interior of my H35. Or should I be thinking about two units?3. The cooling unit for my fridge is hidden in a tiny cupboard under the stove - and it heats up this space very effectively. Obviously it is not going to work very efficiently sitting inside a hot cupboard, so I am looking at ventilation options. Adler/Barbour sell a ventilation fan unit for this purpose but this will never fit into the available space, so I am considering installing one or more computer fans for this purpose but have no idea what SCFM size to use. I know that HVAC designers use air changes per hour as design parameter. If I had any idea on an appropriate "air changes per hour" figure I could probably measure the cupboard and calculate my needs. Any advise on this topic?Neil

 

[shorty]

LED's etc

I have replaced all bulbs w/LED's. 2 ea.Dr. LED 15LED 18W bayonet, some generic ones from superbrightleds.com, and a couple sensibulbs from sailorssolutions retro-fitted in overhead fixtures. Have a standard florescent tube in the head. Dr. LED's better than generics, sensibulbs work well in the overheads.A recent thread was speaking favorably about Alpenglow.When conferring with a HVAC contractor about cooling off my woodworking plant with chicken house fans on summer nights, he said 3 changes per hour. I had one fan that was ~1 change per hour which was spitting into the wind. Added two more for 3/hour & it works great. A computer fan would likely change the cupboard a lot more than 3 times/hour. Don't forget an inlet vent.

 

[shorty]

But then again

you probably have a proportionately much higher heat load in the cupboard then I have in my plant.

 

[Steve Dion]

Neil, what type of lighting do you have now?

Neil:Our Hunter Vision 36 has recessed lights. I sent one of them to AlpenGlow and Bob made a replacement unit for about $60 or so. I had several of them made with Red LED's so we can use them at night.Bob tested our old units and determined that his dual power florecents put out about 40-60% more light. It has made all the difference in the world with these units.I would try a single unit and see if it is worth adding additional units. I assume that your units are surface mounted. We had a similar situation on our Hunter 31. We added a single unit over the table in the main salon and it provided very good lighting. We later added one of the AlpenGlow units over the galley too.I am sold on his products. I would contact him and ask about using LED's for the different areas. Bob knows lighting and can give you some very good guidance. For the compressor cooling I would suggest that you cut a vent as high as possible and put a grill over the hole. Then you can use a computer fan (they come in either AC or DC (obviously you would want DC units). You also want to cut a hole either in the bottom of the cabin that can suck cool air either off the cabin floor or better yet from the bilge area. This should help even if the fan is not being run while the refrigeration unit is on.

 

[Neil McDonald]

Project Planing

All my existing lights are MR16 halogens - they were a retro-fit by a previous owner. Some are recessed and some are on adjustable stalks. They provide excellent, but power hungry lighting, so I will keep some of them as-is (probably the recessed ones)for the times that I am hooked up to shore power. I plan a low level vent inlet and high level exhaust - but have not decided whether to push air in or pull it out with the fan(s)!

 

[Steve Dion]

I would exhaust the hot air.

Neil:I would exhaust the hot air and the cooler air with replace it. It will also prevent a fan from being in a lower "moist" position.

 

[Dan]

If you could cut vent holes

If you could find a way to cut vent holes, natural circulation will work. They probably don't have to be very large. Start with a small hole and you can always cut it a litttle larger as needed.Puting in a fan is increasing the electrical load.

 

[Landsend]

LEDs, Insulate the ICE BOX better, Cut air holes...

You can use a 12volt computer fan to move the air. And Hella low draw cabin fans.

 

[Ross]

A 3 inch computer fan will move 24 cubic feet

of air per minute. If the space with the reefer' is 2x2x3 then you have 12 cubic feet much of which is taken up by the reefer'. So one 3 inch fan should give you at least 3 air changes per minute or 180 changes per hour. You will need also a 3 inch inlet. Put a screen over both openings that you can easily remove for cleaning.

 

[Ross]

For you lighting needs you should determine how much light you need and where y

All of my interior lights are on separate switches. I am fanatical about turning out lights where they aren't needed. For just moving around light after dark I light a 6 candle power lantern. I don't much like LED lights because they have a narrow sprectrum of color.

 

[Patrick S/V Shangra-La]

I use an oil lamp

in the cabin at night it gives a very rustuc feel to the boat. I have my refer unit in the lazarette with a much larger volume of air, though down here I really should have a water cooled system, I am also replacing my anchor light with a LED combo tri light / anchor light. The idea Dan had of vent holes for passive circulation sound like a good one. I have a fluorscent lamp in the head does a great job but the wife hates them, none added in the cabin to keep a happy boat.

 

[newly anonymous]

one fan, two vents

I used a three-inch computer fan to vent the appropriate locker on a system with water cooling, but didn't get great results until I cut a second vent that served as an air inlet to match the air exhaust created by the fan. I had initially hoped that the fan would pull air up through the bilge, but it worked significantly better once the additional vent was added.

 

[Eufrades]

Don't use a fan

If it were me my first try would be the natural convection. For three changes per hour I would think that would be more than sufficuent. I would take temperature measurements before and after I made any changes so you know that you're getting the best bang for your watt. If you find a substiantial temperature drop by just ventilating, then I wouldn't bother putting in a fan. Those solar fans that are available to ventilate a whole cabin won't move nearly as much air as a computer fan and look at the space they take care of. I think a fan would be wasted wattage.Also i'm a big fan of Led lighting. I'm rebuilding right now, and plan on making all of my cabin and marker lighting Led.

 

[Ross]

Eufrades, The computer fans draw.08 watts

I run four on my boat with a dedicated 5 watt solar panel. The compartment under the Vee berth has one there are two running as exhaust fans in the cabin and one in the lazerette. There are also an equal number of vents for air intake. They can be had for free if you are willing to dismantle junked computers and you can get a solar panel on Ebay for 25 dollars delivered. Tie the panel to a small dedicated 12 volt battery and the fans will run constantly.Edit to correct a mis-statement : the fans draw 0.8 watts

 

[Brian M H23]

What about

what if you hooked the fan up to the compressors power source? then it'd run at the same time, and I bet you'll never notice the increased draw.