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My Tangaroa MKIV is without any sort of functional electrical system and, now that we are in the depths of winter and there is no sailing to be done, I've decided to remedy the situation.  I know that we need solar panels, batteries, a charge controller and an inverter but I don't know what makes or models are best or where to buy them.

I also need some help with the size of the system.  It will have to supply enough electricity to run: cabin lighting, running lights, autopilot, chartplotter, laptop, VHF, a small refrigerator(open to suggestions), stereo, and several other things I'm probably not thinking of right now.  There will be two adults and two children aboard full time in the Bahamas.  I would prefer to do without a wind generator because they are loud and seem dangerous.  Thanks for your help.


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Two 185 watt panels and four 90 amp hr batteries would  probably handle these needs. More batteries would be better. Minimizing your consumption is the cheapest. Led running and interior lights really helps. I get solar panels and controls from Sun Electronics in Miami. They have the best prices I have found and  a large variety of sizes. They ship a lot. The reefer is the largest load you have mentioned. Inverters use energy. If you can avoid them. It is not efficient to turn 12 v into 120 v and then back to low voltage to charge things. Just some thoughts, I am sure others will have some more input.  I also am not a fan of wind chargers on a boat. David

Hello Brian,

     We are doing the same thing here, my Narai MKIV never had a complete interior and the electrics were jury rigged until now.  Winter is a good time to plan a system and a good time to do interior electric work.  I find it hard to plan on 2 dimensional paper.  It's better to mock up a system with cardboard patterns and plan the layout.  I've just retired from broadcast engineering and the main business of the company was planning and installing large tv facilities.  Documentation was a large part of any project.  The detail work took up most of the time.  I got my solar panels from Harbor Freight when they were on sale.  Panel location has the problem of being shaded by the sails or deck tents.  You should reconsider wind generator because they put out a lot of power.  I have my system divided into port and starboard, plus a separate system for engine, nav lights, and windlass.  The port and starboard circuits have two size 27 wet cells apiece and two 75 watt panels.  The engine circuit has a single dual use battery with heavy cabling forward to the windlass.  The port circuit has a reconditioned UPS 1500 watts that has its own AGM cell batteries and is modified to add two size 27 wet cells.  Both circuits go through a battery switch to a distribution panel in the pilothouse which has 12 breakers to feed power, plus one breaker to bring power in from the wind generator.  This way, when a circuit needs more juice, I can select it with the battery switch and add wind generator power to it.  There are 4 compartments in the starboard circuit and each has 2 separate breakers.  They share in pairs, so the forward bunk and galley have 2 circuits, dinette and pilothouse have 2 circuits.  This way if a breaker trips, there will still be power in the compartment.  The solar panels feed a charge controller that feeds the batteries.  The starboard inverter is 2000 watt and directly connected to the batteries.  I still have a lot to do, such as AC wiring, which gets tricky to make sure ground fault circuit is properly set up, but AC is very convenient for so many devices and it doesn't have a huge voltage drop which reduces weight of wiring.  GFI is essential on a boat and my problem now is finding a ground in the port hull.  It has no metal through hulls.  I might put in a dynaplate there and install the SSB radio on that side.  It's a dual head radio, so we can have a control in the pilothouse on starboard and one in the chartroom on port.  I've been using flexible plastic conduit and U shaped plastic plumbing brackets to mount it.  Unfortunately it's too easy to fill the conduit with wire, so I'll be running more conduit when I do the AC wiring.  Hot melt glue works well to stick things in place quickly.  Hiding away loose wires not only looks better, but protects the wiring from the elements, and secures it to prevent breaking due to fatigue. 

When you size your system, I think the rule is to have battery capacity about 3X the expected load.  That's why it's hard to charge with solar panels only.  I have about 450 amp hours which equals about 1500 watt hours.  The watermaker and fridge use a lot of power.  Use LED lighting whenever possible.  I've been reading a blog of a production cat that has 800 watts of panel, a wind generator, and runs a 11 KW diesel generator for an hour or two every day!  They have 2 freezers and a washer/dryer.  My temporary jury rig system used one battery, ran only nav lights and intermittent laptop and GPS for navigation.  Charging was by running the engine. 

Thanks guys.

The 12 Volt Bible for Boats, by Miner Brotherton, from Adlard Coles Nautical, gives   very easy to understand, non nonsense, straight forward information about batteries and charging. I am an electrical engineer, so I can afford to state this comment. Unfortunately Adlard the old fox doesn't allow any website to appear other than his own, so ... you will have to dig deeper on your own ...

It's also about all loads and wiring. Advise ant tips are good, but not all the details can be given on a page or two.

And here the Adlard website: www.adlardcoles.com

My website: www.phefo.com

Thanks Hans.  I'll pick it up.
thanks for all the good advise. I was just thinking that the "12 Volt Bible for Boats" was written in 1985, and thus may not reflect the development of new technologies over the last 30 years. This also includes the great developments in the "green" energy technologies available to us today.
lots of good advice here, Brian.  If the cost of all you are planning to do here is a problem, just remember that you will not be heating the house up there in the north country while you are comfy in the Bahamas.  We agree to go solar, go LED everywhere, make do with minimal in the gadgets line,  and that will leave you maximal time to enjoy the islands.    We got our new galley LED lights at Home Depot and saved a bundle.  They can be made to go on 12 volt with a little modification that is easy to do yourself.  We will be putting them everywhere as funds come available.
My electrical work over the winter and this spring have changed a bit from my original plans.  I got a bunch of "Capri" track lighting fixtures on ebay at a low price.  I was originally looking for aircraft style eyeball lights.  The capri lights take MR16 halogen bulbs, but LED MR16's were available from Hong Kong for less than $5 a bulb.  The track lighting fixtures had to be modified so that they could be surface mounted individually.  The LED bulbs are 3W.  Also CCF fixtures from a canadian company.  Also festoon fixtures that came with the boat can take festoon LED bulbs.  Ann and Nev's idea to use an efficient freezer to make ice for icebox is a great idea.  The local BJ's wholesale has a 3 1/2 cu ft freezer for about $150.  It runs on AC.  I obtained a used UPS and modified it to add external wet cells, such as 200 ah of deep cycle.  It puts out real sine wave AC.  No need to have a shore power/ship power switch.  The UPS is always the AC source for the boat and accepts shore power to charge its batteries.  Also my harbor freight solar panel kits came with 2 CCF lights per kit.  They run on 12V and the bulbs can be used in any household style incandescent socket which of course would be wired to the 12V system. 

Oh, oh, oh, when I look at my previous posts, they are so full of mistakes.  Sorry.  The UPS ran on 24 V not 12, so that is out of the equation, not a bad idea though.  I ended up not running redundant circuits to every space.  The local electrician who begged to fish at our dock gave me a bunch of 10 ga wire that I've been using to make a circuit to each space.

In the galley I have to make a separate circuit for the water pump.

I've gone with electric faucets with the water pump activated as needed and no water pressure maintained in the system.  In one hull it seemed to work OK, but then I had a problem with the existing SHURflo faucet in the galley.  The cheap Harbor Freight pump I'm using draws 7.5 amps on start up and 5 amps when running.  The switch in the faucet is only rated for 4 amps, maximum.

I like the idea of an on demand system, just think of a pressure system and something comes loose in heavy weather.  All your fresh water in the bilge.  It looks like there are way more ordinary faucets available compared to those with an electric switch.  I've got Whale and SHURflo. 

One solution is to run high amp plus and minus to the pump, and incorporate a relay to switch it to the pump motor.  Bring plus through the faucet switch back to the relay and bridge minus to the low side, so a plus from the switch will activate the relay.  The relay impedance and voltage should be compatable with the system (12VDC) and in my case under 2 amps (10 to 15 ohms). 

Now I got to go back and rethink the port hull where the faucet switches are carrying the full pump amps.  It seems to work well over there, but the smart thing is to put a relay in there too.


The work in the galley pump area is under the forward bunk, so it is logical to run the circuit for the forward bunk when I run the galley pump circuit.  The run will end in a terminal block and I expect to put a Harbor Freight charge controller there, not as a charge controller, but as a 12V distribution point, which they are good at.  They are not so good as solar charge controllers.  I plan to put a 12v cigarette lighter socket in the older controllers.  I have 4 of them.  The 2 newer ones already have the cigarette lighter socket, and they have a digital display of battery voltage. 


I would guess that plumbing and electrical are almost as bad as fairing and sanding, on a larger Wharram.


We like our foot pump water pressure very much.  Ann and Nev

Ahoy Ann and Nev,

     I was concerned about Nev's knee operation.  I had to go through something like that with my shoulder, and I thought my sail lifting days were over.  Now Nev must contemplate giving up his galley chores with the foot pump.  Just drag back to the dining lounge, get some Scottish pain medication,  Let the designated cook pump the dishes.  Gotta hold on from the pain, but good to see the vessel is under good management.


     I think I had from Thankgiving to New Year's, a rough time with the recovery.  I know I was rowing in March, but that was a light winter and spring.  I remember going in for a visit to the surgeon and seeing  an unlucky fellow who tried to move furniture before he was ready.  He had to have it all redone.  A man has to know his limitations. 


     The rehab probably made me stronger than I am now, but boatwork has its own reauirements, so you have to be careful what you do and be glad if you wake up and nothing is hurting too much.  I never worried about my knees so much, other than breaking my leg falling into a hatch and finding out it was broken the next year at the doctor's.


     You are the hull #1, and all who follow are attentive, you set the outward bounds on two people with a large catamran, sailing on a pension.  There seems to be a societal draw away from the sea.  Just stay in your hut and watch the digital TV and buy some of these products.  How different is it to do what you do.  The mirrors of the sea and sky provide a lot of entertainment, don't they, and you have to get out away from the land to see it that way. 

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