Wednesday, 30 May 2012
After re doing the gas main I wanted to get a gas check done. As this forms a significant part of the UK BSS certificate I thought I might as well have the hole thing done. I I have built the boat to the RCD I didn't need to have this done for for years but I thought why not, it wasn't much more in cost. I am pleased to say that the whole boat and it's systems passed first time and the certificate was issued. So the boat now has belt and braces paperwork.
Thursday, 24 May 2012
The last couple of days on the boat has really been themed with electrical things.
I was most excited to find this GSM gadget. I wanted the ability to get the boat ready for our arrival by switching on the inverter which would then power the heating and fridge. Initially I was thinking just one switch but as I looked I found I could get this 7 channel unit for the same sort of price. I added a fuse inside the unit as its easier to get to there, I might also add and LED to show the power status.
The black relay is operated by phoning the unit. The clever bit on this is it will accept numbers form a white list only. Phoning this relay accepts the number then hangs up (no charge call) and switches the relay either ON or OFF depending on where it was left. This relay can also be TXT operated.
The rest of the blue relays are TXT operated only again on a white list. A message can be to turn either =ON or =OFF. As well as a number of other functions a TXT can be sent to get the status of all the relays.
So I have set relay one to switch on the inverter, two to set the heating on and three to control the fridge. The other channel's I'm sure I'll find a use for. I've put the wiring tails in ready.
Next job was to parallel the alternators. The reason is because the 115amp alternator charging the start battery is effectively doing nothing after a few minutes whereas the 115amp alternator is working flat out. Easy to establish as the start one is cool, the domestic one is too hot to touch.
Alternator parallelling is simply joining the output of 2 or more alternators, but it's best not to permanently wire the together.
To best make the connection a contacter, a type of big relay is used.
This one has a 150amp continuous rating
There are different ways of switching the relay from a simple switch on the dash, or via a self energising relay system. What ever way its important that the relay drops when the engine is stopped. I have fitted an LED to display the status of the contactor. I haven't yet installed this on the dash its just on a fly lead.
I have chosen to use a self sensing relay driven by the output or the start battery alternator. The system listens to the voltage of this alternator, once it sees its charging it switches its internal relay which in turn energises the contacter and the parallelling is made.
This is the sensing system and its adjustable
to ensure correct switching
And this is the finished job.
The top alternator is (was) the start battery the lower is (was) the domestic, although once they are joined it is simply one curcuit, each sharing the workload over both battery systems.
The results so far are that both alternators now run at a moderate temperature. I also noted that the battery monitor was showing 14.6v I never saw this as high before. My conclusions so far are that it,s working as it should. Time will tell and if in the unlikely event it proves troublesome it's easy to de-activate.
Tuesday, 15 May 2012
Thursday, 10 May 2012
After discovering I'd installed the gas main wrong by using soldered joints I had to re do it. This involved a bit of cosmetic damage to get at the old one to remove it and replace with the new. This will be fixed in due course.
So now all joints are made with compression fittings and all joints are available for inspection and adjustment if necessary.
Well you get the idea. I have done the soapy water test which it passed and the Mk1 nose test and at the weekend I will be borrowing a manometer to do a drop test. And for full belt and braces I have booked a gas safe inspection as well.
I finally got around to fitting the gas struts to lift the bed.
And finally an Ahh! moment out of the window today.