Help with battery install melbourne

Hi guys, could anybody recommend a marine electrician that can help to install some batteries and general switch panel stuff in Melbourne, I'm based in RMYS marine St Kilda.

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FabulousPhill said..
At the end of this post with TrailerSailerPlace are 2 downloadable books (PDF files) showing the electrical system and small boat wiring in particular:
trailersailerplace.com.au/phpBB3/viewtopic.php?p=224602#p224602
You can begin yourself. Or someone might have a electrician's contact details.

I did mine myself, but that was during the Melbourne covid lock-down and I had A LOT of spare time to read the 12V bible and get all the right components etc. It is important to do this with DC installations because if you mis-specify anything it can easily cause a fire. Also, i removed the old dual-battery system (two identical batteries that are used for both house battery and starter battery) and instead installed a dedicated starter battery (AGM) and a top-of-the-range lithium house battery. They have different voltages, but the smart dual charger I bought can take solar-panel current OR alternator current and deliver the right voltage and charging patterns to the two batteries. A lot of the details have faded from my memory (I'd probably have to read the 12V book again) and I can't recall the brand of dual-charger off-hand (it's an Australian company) but it all works really well, and the starter battery is always prioritsed over the house battery so hopefully I'll never be caught out. See attached circuit diagram ... but please read up on DC wiring if you go for a DIY install

Imho this one is very well compiled
www.whitsundaydiscountmarine.com.au/assets/files/DIY%20Boating%20Magazine/Electrical/Marine%20Electrical%20Systems.pdf

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neilmac01 said..
Thanks guys, My set up is similar to Bluewater bound without the solar panel (yet, will do later). I have read lots and watched tons of videos but most of these setups were more complicated than what I needed and confusing. I finally got to speak to a guy at Solar4rvs who knew what he was talking about and we worked out what was needed. I have an electrician coming to me soon who will install shore power and I will also get him to check out the rest of the system - batteries, switch panel etc. JonE also sent me the name of a marine electrician in Melbourne. I did have a dual battery system but wanted to seperate the Start and House system. I'm thinking that I will rely on the Alternator to keep the Starter charged and use shore power to top up the house Lithium battery. I can also top up the Start battery from shore power if required.

Here is a diagram for the House Battery.

I've been kept away from my boat for about three weeks, but when I'm next aboard I'll get the name of that clever dual charger - I do recommend it, because the solar is trickle charging both systems (starter first, then house) between visits. I only installed about 60W of panels (can't quite remember) but that's plenty, even for weekends away, because a bit of motor-sailing tops things up when then sun isn't enough. For longer voyages (which I hope to make one day) I'll put in more panels, but for now I'm very pleased with it

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Here is a diagram for the House Battery.

If I was doing it, I would run my fridge via the 12V distribution panel, so there is no confusion about whether the fridge is left on or not to avoid flattening the battery when I leave the boat for a while.

" I can also top up the Start battery from shore power if required"

If you don't have an isolating transformer, then I would hesitant to leave the boat on shore power for extended period, to avoid galvanic corrosion ... or maybe even lightning !

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neilmac01 said..
Hi Andrew.

My fridge is a Kings drawer fridge. They recommend powering the fridge direct from the battery. Don't really know why. Maybe a RV thing. I think sometimes I may want to leave the fridge on while away but I would like to have all other "House Power off, Not too worried about it though.

I will be putting a galvanic isolator on the shore power.

I'm at RMYS, a lot of people here have shore power connected 24/7 running dehumidifiers etc. Have not heard of any issues. On my previous boat I even left the charger on to keep the battery topped up. Good Victron gear. They are strict here about how shore power is connected.

Kings probably recommend direct connection to the battery because their own power cable is specified correctly. If the current flows through other circuits, there is the risk that the owner is unaware of what gauges of wire it's passing through and some small wire could heat up and start a fire.

On a more general point, the most helpful thing I ever read about electrical system design was (on this forum I think) from a guy who said he always thought in terms of 'sources' and 'applications'. If the battery is source 1, then a loop of heavy cable out to a +ve bus bar could be considered source 2 - that is, a place to take positive current from for any number of 'applications'.

Each 'application' is a loop of wire that goes out to, say, a light bulb or radio, and returns to a 'common earth' bus bar somewhere else. Whether you have one 'common earth' bus bar, or several, they will be connected with heavy gauge cable back to the negative terminal of the battery.

Once I read that, I could start to read circuit diagrams. Around the boat you might have, say, five 'sources' and from those sources, loops of wire to 'applications'. On boats, nearly every 'application' circuit needs to return to the 'common earth' via some kind of circuit breaker - usually a switch panel, where each switch can break one circuit, or several circuits (e.g. one switch turning off three lights).

To design a wiring system, then, you are really just adding several parallel circuits to the battery to creats those 'source' bus bars - i.e. you are not linking them in series - and from those bus bars, each 'application' returns to earth via a circuit breaker switch somewhere (many applications have their own on/off switches as well, but should still go back through a circuit breaker somewhere before returning to earth).

I don't know if that is helpful, but that's the bit of knowledge that made the whole thing comprehensible to me. From there, you just need to know what gauge of wire to use for each circuit to prevent wasteful voltage drops (and overheating) along each length of cable, what kind of switches to use, and how to use fuses and automatic circuit breakers to keep it all safe.

After redoing the electrics on my boat, I'm hoping to work out a 48V off-grid system for my shed at home (where I live there are power cuts about once every two months). 48V is the highest voltage it is legal to work with without a sparkie's qualification and when stepping up the voltage to 240V through an inverter, it's less of a jump than from 12V to 240V. From what I've read, a lot of live-aboards are doing this on their yachts too, and there are a growing numbre of 48V appliances being sold to cater for them.

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I'm at RMYS, a lot of people here have shore power connected 24/7 running dehumidifiers etc. Have not heard of any issues. On my previous boat I even left the charger on to keep the battery topped up. Good Victron gear. They are strict here about how shore power is connected.

I used to berth a boat at RMYS. Without an isolating transformer, the engine anodes almost dissolved in front of my eyes.