Monday, 2 May 2011

Radio room

I managed to dispatch the battery cupboard by the bilge pump in under an hour and get it packed away.  Another mahogany masterpiece which could be used for later.

Dealing with cables is like picking at a thread on your jumper.  It all starts to unwind rather quickly.  I had 5 cables going though the wall of the battery room into the radio room.  The main one being the 24v feed to the 24v fuse boards.  But to get these cables out I had to remove the ceiling of the radio room.  Another 3 hours job defying death and gravity to get yet more marine ply from the ceiling.  This time I was prepared and it all came down relatively easily.  No injuries.

When the ceilings came down the amount of cabling up there was staggering.  For the rest of the day I just kept on pulling cables trying to thin them out.  The downside was that there was a lot more equipment fed from the 24v than I thought.  The problem being that it all seems to flow through the control panels which are an absolute birds nest of control wires.  There was no way that I would ever get to the bottom of that lot.

The only approach is to cut out all these control cables and feeds and run everything manually.  I will not doubt need a new 24v feed but that is simple and can be fed from a standard inverter and avoid the whole battery issues.  Probably a good 2 more days solid work to get the radio room stripped back to the basics.

Yesterday I spent most of the day doing the designs for the new electrical systems.  I have just about finalised the approach.  The basic challenge is whether to put the new systems in from of or behind the existing generator control panels and switch gear.  There are pros and cons to both.  The existing system allows you to choose between generator power or shore power.  If I put the new systems on the inputs then it will act like shore power but with battery back up.  This will enable me to draw a lot more power than is available from shore and the generator switch gear will distribute.  I then just need to upgrade the fuse boxes to modern ones and move them to the battery room.  More on that later.  I can also add in the wind and solar grid ties into the output of the gen switch gear as it will then always be connected and will help power things like the fridges etc.

A careful bit of studying of the existing power loads on the drawings I have show that if you switched everything on in the ship then it will draw about 178 amps.    Two generators would produce that no problem.  Shore power will not.  So some careful designing is required.

I have zoned the power into 3 categories.  The main living power (always on) worst case all on would be 64 amps.  Then engine room services (not needed often) would need about 64 amps and if I want to run the main light and fog horns I would need another 51 amps.  Thats a heck of a lot of amps.

So what will be needed is to get the shore power through the new gear and batteries. If I then want to run the light and signals and engine room services I would run the generators.  This is why the new gear would need to sit in front of the gen gear.  Switch over would create a blip that would reset everything but this is a small issue given the few times I would ever need this.

So a feed of peak 64 amps will be needed.  16 amps from the shore and then peak would come from the batteries.  The system will need to be designed to supply up to 64 via shore power.  Now I can get on and do more detailed product selection.

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