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post #7 of Old 01-07-2003
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Electrical Upgrade

Ok Keith -

Here is the good news - I was COMPLETELY clueless about electrical stuff when I got my boat three years ago. In fact - I needed a friend who had some electrical background to do some very basic wiring! I have since learned and done a lot of electrical work on the boat including replacement of shore power plug, complete rewiring of the battery banks to the charger and alternator etc. It seems daunting - but it is NOT that hard!

Some general considerations:

Batteries: these are the heart of your electrical system and you want to size accordingly. So - you do need to estimate what your usage will be. Many books (I''m thinking particularly about Nigel Calder''s Boat and Electrical Systems) have tables that estimate what everything draws (lights, autopilots, etc.) You want to have capacity about 4 times your usage.

There are several different kinds of batteries. "Wet" batteries require you to check/top off the cells with distilled water on a fairly regular basis. Gel cell batteries are virtually maintenance free. If you can stand checking the fluid levels on the batteries - golf cart "wet" cells are your best bang for your buck.

Alternator: Think of installing a high output alternator with a charge regulator. When off the dock, this will be your main (only?) means of recharging.

Amp Meter: For about $200 bucks you can get a Heart Link ammeter/battery charge monitor. I highly recommend this. With this system you can tell EXACTLY what each electrical item on your boat draws (by turning off everything but the item you are measuring). You''ll know exactly what you are consuming and exactly the charge state of your batteries - indispensible!

Shore power: It''s easy enough to install a shore power plug. You then need to run it to your electrical pannel and from the pannel to a 3 step battery charger. It is fine to run your 12V stuff off the batteries when they charge.

It is also important to make sure you are using the appropriate wire/cable for the various run lengths from the alternator to the batteries to the switches and back to the engine block. Otherwise, you won''t get the most from your system.

If you want more information there is a book called "The 12 Volt Bible" that is pretty good and available on line or in most marine stores.

I HIGHLY recommend you contact Jack Rabbit Marine in Stamford CT to discuss your system. They are GREAT people and marine electrical systems is their specialty. They will know precisely the best equipment for your particular needs once they (and you) know what your needs are. If you provide the length of the various runs, they will prepare you wire lengths to order and finish the ends to marine standards.

By the way, don''t get all worried about the ABYC standards: it boils down to this: Various colored wire is used for various purposes to make sure you can identify the right wire when digging through your boat. Beyond that - use marine grade wire! You can use the cheaper THHN stuff from Home Depot (oil and water resistant) but the true marine grade stuff has the best coating and will stand up to the elements far better (You DO get what you pay for!). And when attaching ends (forks, but connectors etc.) to the end of the wire, make sure you use appropriate heat shrink tubing to prevent moisture from getting into the the connection and causing corrosion/shorting. Again - get the good heat shrink tubing from a marine store - it''s better than the cheap stuff from Home Depot. Do it right the first time and you will enjoy many, many more hours of a trouble free electrical system.

Good luck!

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