Mast preparation continued

With a beautiful day we had a nice slow morning with family and then got back to preparing our main and mizzen masts for painting (well we also washed the dinghy and equipment).

We now have all the wiring out of the main mast.

We have put messenger lines in for them all.

We have removed both winches (a single speed Lewmar 8 and a double speed Lewmar 16, neither self tailing) and all other fittings showing any corrosion.

I was a bit annoyed by the winch mounts. The winches has been fitted with bolts that were too long and so instead of beinfg simply bolted to the winch mount some of them has gone into the mast itself. That has caused more corrosion and extra holes.

So everything is off and the masts have had a wash including a wash of the inside with a hose.

We have decided we don’t have to do a perfect job immediately, so we have not removed anything that we still need and that isn’t showing any corrosion eg spreader roots, spinnaker pole track. Similarly we have decided not to remove winches and cleats from the mizzen (upgrades can come later).

Tomorrow, is clean with acetone, sand, clean and get a coat of primer on. Then we can fill holes we don’t need to reuse with thickened epoxy, then we can sand and clean before a 2nd coat of primer. That then buys us some time for the rest of the work as the aluminium won’t be able to oxidise.

Another task has been looking at all the hardware we need to fit to the masts.

We are now looking at re-purposing the existing Lewmar 16ST for our mainsail reefing. Then 2 Harken 20ST for the halyards. If we can find something suitable secondhand then we will go for that instead.

We are only going to fit 3 actual halyards and supporting hardware at the moment (Yankee or Genoa, Staysail, Main) but with messenger lines for 2nd headsail, trysail and spinnaker.

We are also going to upgrade from cleats to Rope Constrictors for these halyards, skipping all the generations of clutches. Rope Constrictors are about twice the price of a standard clutch but they don’t damage the Halyard at all. But a replacement Halyard is about three times the extra cost. We have found 2 sources Ronstan and Cousin Trestec.

We are going to replace the tired halyard exit sheeves with the newer, simpler plates (and go from 2 to 5 of them so we have support for all the halyards we will ever need.

We have decided to simplify the lighting. We don’t have a simple way to fit lights to the spreaders and get the cables into the conduit at the front of the mast. That means keeping the deck light and the steaming light on the mast Deck light is lower than the spreaders, steaming light is above. However, it looks even simpler to get a combination LED steaming and deck light. One less cable to run up the mast.

Anyway, painting and filling is the first priority. All the fittings can wait for a while.

Battery bank installation progress

Today has included a huge amount of lifting and moving. A large part of that was lifting all 8 batteries on board. You can see the preparation for this in Low down progress

First battery bank has a nearly finished box (needs final epoxy coating and painting plus a lid).

The second battery bank will sit on top.

We need to make some changes to the floor supports. We will fit a new central floor board that will be the watertight lid of the top battery bank.

The top bank will also be 4 batteries and is both longer and wider than the lower bank. The hull shape means the batteries take up a lot less space this way round. Fortunately we have bluetooth access to the BMS of the lower batteries (and the top one that will be under the steps).

We are going to make sure that even if the bilge filled with water our batteries would not get wet (and there will be no exposed battery connections under the water at that point).

Anyway the bilge that water flows into is nearly a metre deeper that where the batteries are, that bilge will have an automatic electric bilge pump, a high water alarm and a manual bilge pump.

Building a “sofa”

The other day we made Lee Boards for our starboard saloon berth. Today we’ve started the process of making them adapt to their other role which is to be a backrest.

It isn’t finished yet. I need to find a way to retain the back rests so they can’t fall forward. Also add a brace to the middle of the length. We might also reduce the gaps between them as it is higher than needed.

Once we are happy then Jane will add padding to them.

It might not be obvious from the photos but I have lowered the bottom Lee Board so that your legs don’t touch it.

It was a bit of a damp day today but we made a bit of progress outside. We worked with Steve to move an unclaimed mast out of the way. It has been alongside us for ages but had recently been moved a bit and was blocking a often used route to the clubhouse. Now it is completely out of the way. The boatyard also cut down all the grass and weeds growing up around our main mast so we were able to a small amount of work on it.

The parts we need to refurbish the masts have started to arrive. More in the next few days. We are currently thinking about the wiring we need to install and how we can ensure they don’t rattle or chafe inside the mast. The mizzen mast doesn’t have any conduit or any means of protecting/controlling the wires. We don’t yet know what the main mast has.

A lot the work on the masts is going to be weather dependent so we will progress it when we can. Meanwhile there are plenty more things we can do inside 😊

Confusing earth wiring

When buying Vida, our surveyor included concerns about the earth.

We knew that the engine was “earthed” by a jump lead to the stern tube (and the jump lead was very rusty).

I’ve just found these wires connected to the anode that is bolted through the hull.

Quite a collection! We have green/yellow, back, blue and red!

Hardly surprising that the earth wasn’t working!

#Oops

Now we are definitely going to 48volt house battery bank

This answers our pondering House Battery Bank: Should we go 48 volt

So we managed to get these two items from the clearance section at Energy Solutions.

The new MultiPlus II (looks like a decent upgrade from the original MultiPlus). Sized with a 48 volt, 5000 Watt inverter and a 70 amp charger. For the price of a much less powerful 48 volt charger on it’s own.

We had planned to have two smaller MultiPlus units to give some redundancy. We don’t really need that before we set off world cruising so we can wait and add a second smaller one in a few years. The feature set is amazing. For example we can have two power circuits on the boat and one of them will only be supplied if we have shorepower or a generator running. Also we can tell it the shorepower capacity and it will make sure it doesn’t overload it. It can do all kinds of clever stuff mixing shorepower, battery and solar in clever ways (that will mean that we can minimise our shorepower usage as the solar is prioritised).

The Isolation Transformer was an even bigger bargain, the case has some damage (looks like it was dropped onto one corner hard enough to bend the side and bottom panels). It can support a 32 amp 7.0kvA mains supply. It handles 230v and 120v, sorts reversed polarity and protects us from electrical currents that can cause metal fittings on the boat to corrode.

We are very much looking forward to getting these installed (might need to do some weight training to get the MultiPlus II up the ladder and it will need a very strong bulkhead to be fastened to).

Late evening progress

Well we arrived at Vida at 11.20pm and decided it was worth connecting our new mains consumer unit before bed.

We can now use the full 16amp boatyard supply. At the moment I’ve wired in a couple of extension leads. Already a nice tidy up possible from the way we have managed with a “consumer” unit designed for tents.

We are using a cheap domestic consumer unit at the moment. Obviously not a long term solution, but our plans are not stable enough yet to get a marine one which we will probably need to make a custom cabinet for.

House Battery Bank: Should we go 48 Volt?

While we wrote Going 100% electric: the “house” after Going 100% electric: the Motor we had in fact made most of the decisions around the house electrical system before we made the decision that we would go straight to an electric motor instead of the diesel.

Now we are thinking about making a change. The things prompting us to consider a change include:

  • The high cost of 48 volt battery chargers. We do need the option of charging our battery bank when in a marina or harbour (or even ashore in the boatyard). We can imagine spending sometime alongside in winter or even popping every so often just to get the batteries fully charged (the expectation of needing to live in colder climates in Winter is influenced by both Covid and Brexit which might limit our options for where we spend our time).
  • We think our house battery bank has ended up a bit small (4 x 120AH) and so are going to be needing to charge it from the Motor bank (4 x 300AH) quite often.
  • Having two battery banks at different voltages ends up creating quite a lot of extra complication.
  • With one exception (the anchor windlass) we have realised that our 12 volt usage is relatively low (LED lighting, boat instruments, water pumps).
  • While we have specified really thick cabling with big busbars and fuses, it is challenging to power 2 x 2,000 watt inverters from a 12 volt battery bank. The current that we need to safely pass is huge and this is where the vast majority of our house consumption will be (induction hobs, microwave, multi-cooker, watermaker, water heater).
  • We didn’t understand enough about how you can power 12 volt systems from a 48 volt battery bank. We thought they were too inefficient but have now realised that we either incur that inefficiency when charging a 12 volt battery bank from the 48 volt bank for all house uses OR when using a 12 volt house appliance (but not a mains powered item from a 48 volt inverter). The total losses are much smaller if we incur them only as we need the 12 volt power rather than to keep a whole batery bank charged.
  • We deliberately chose 4 batteries for the house bank that had enough output so they could be re-wired to be a 48 volt battery bank for the motor if the main bank failed. However, it would take ages to do. So a bigger 48 volt bank with two sets of 4 batteries wired in series and then the sets connected in parallel gives immediate access.

So a little maths about the issue with power over 12v cables.

P = power in watts (W)
V = voltage in volts (V)
I = current in amps (A)

Power = Current x Voltage or P = I x V

Switching it around we have I = P / V
So 4,000 watts from 12 volts = 4,000 / 12 = 333 Amps
Whereas on a 48 volt system we have 83 Amps

More amps = thicker cables and lots of care to avoid melting connections or high losses.

The disadvantages of changing from a 12 volt hour battery bank

Our current thinking

  • As we install them, we will configure all 8 batteries as a single 48 volt battery bank. This is pretty straightforward.
  • We will sell our unused 2 x 2,000 watt Victron Phoenix inverters (get in touch if you are interested).
  • We will use our Victron Orion 48 volt DC to 12 volt DC converter to power all our 12 volt appliances. We can always add extra Orion’s to run together if we need more power (eg for the electric auto-pilot)
  • It would be very expensive to add enough Orion’s to provide all the 1,500 watts at 12 volts for the windlass. So we will add a 12 volt battery close to the windlass. When the windlass isn’t being used we can charge the battery through the standard 12 volt system.
  • We will add 2 x 48 volt 3,000 watt Victon Multi-plus charger/inverters (2 of them to provide redundancy, we can run appliances with some limitations off one of them).

The Multi-plus inverters are smart. They provide mains power to the boat circuit and they automatically take that power from a shore power connection or if that isn’t available from the battery bank. When connected to shore power they automatically charge the battery bank. Two of them can put a total 70 amps into the battery bank.

We will have a 48 Volt battery bank with a total capacity of 1,680 AH (4 x 300 plus 4 x 120). Suppose we arrive at a marina with it fully depleted (ie down to 10% charge). That means we need to put in 90% of 1,680Ah which is 1,512 AH. At 70 Amps charging we are talking about 21 hours to fully recharge the battery bank (realistically we would expect many marinas to be limited to either 16A or 32A supplies so this will be a lot slower). Gradually we would expect marinas to upgrade their electric supply as the number of electric boats increases.

While there are costs to this change it does simplify a number of things, particularly with cabling and charging. All our charging goes into the one battery bank without having to switch solar panels between banks or do inefficient bank to bank charging.

It gives us much simpler use of the battery capacity as we can choose how we allocate the available power between house and motor. For example if we are not going anywhere and expect some sunny days in a while we can use all the capacity for the house. Or if we are motoring up a river to a marina all the house capacity is available for the motor.

In the long term we would expect more boat appliances to be available in 48 volt versions which will gradually reduce the need for DC to DC converters.

We haven’t made a final decision on this yet, but it does look like we are heading this way at the moment.

Into 2nd wave lockdowns

So a quick update on where we are at. The situation for Manchester is still chaos without agreement between the national and local governments regarding the level of lockdown we should be in. However, we are expecting to be more restricted soon (bearing in mind that Manchester has had it’d own lockdown for months anyway). As for travelling to Wales it is hard to find clear guidance as to whether the Welsh government have now made it illegal to travel from either tier 2 (High) or 3 (Very High). We took the view that it would have been wrong to go on Thursday when a ban was expected from 6pm on Friday (still unclear if that has happened). There now seems to be an expectation that a Welsh “Circuit Break” ban for a few weeks will be announced in the morning. We are working on the assumption that we might not be able to get to the boat again this year.

Fortunately we left her in good shape, the most watertight yet. So we are not worried about any problems on board.

We have some jobs we can do at home, while many of these are not urgent as far as launching is concerned they will at least allow us to feel we are making some progress while we can’t get to the boat.

Propeller Shaft: I wrote about the pitting issues in my last post. As none of the pitting is where bearings or seals go we decided to try to tackle it. Where there is pitting which is probably caused by electrical currents – either through poor earthing (electrolytic) or by currents between dissimilar metals (galvanic) – we are going to remove it. Pitting encourages more corrosion. The best way to avoid corrosion in stainless steel is a bright mirror polish and to have not used any other metals (eg saws or files) to achieve it.

So I have started removing the pitting using the angle grinder with a flap sanding disk. None of it is deeper than about 1mm. So far I’ve done about half of it (starting with the worst bits).

Once I have used the 80grit flap sanding disk to remove the pitting the shaft is no longer perfectly round and is definitely not smooth or polished. So I have 50m of a 25mm wide strip of 80 grit Emery Cloth. Using a strip of this wrapped around the shaft it should be possible to get it pretty smooth and round. I then have finer grades to remove the scratches before using a paste with a cloth to polish it as smooth as possible.

That should keep me busy for hours. A new propeller shaft would be a simpler solution but this should be perfectly serviceable for a few more years and saves waste.

Motor Mount brackets: I have the 4 angle brackets that will be bolted to the original engine bearers and which the flexible mounts will be bolted to. Just got another 10 or more holes to drill in them (10mm). That will leave only the 4 holes in the motor frame for the flexible mounts (not quite sure what size they are and the position isn’t finalised yet).

Domestic Battery Box: I’ve got to make some cut-outs in the timber for the nuts where the leads bolt to the busbar so that the busbars can be fitted. I can also make a lid (and adjust the design for a new expectation that the batteries will be lowered into it via opening the cockpit floor).

Motor Throttle Our motor throttle has a 6mm square shaft and I need to make or find a control lever for it. Trying to find something that doesn’t cost much, is reliable and doesn’t look clunky.

Motor Controller Heatsink: I want to get a really big and effective (and cheap) heatsink for the controller (because apparently they get really hot). My idea is so mount this through the (to be built) bulkhead between the motor compartment and the cockpit locker. This way the heat gets put into the cockpit locker while the controller is away from it in the motor compartment.

Dinghy: Jane has nearly finished the cover for the dinghy. I need to get and fit removable launching wheels to get it over the mixture of rocks and shingle where we will launch it.

Solar Panel mounts: I should be able to make everything I need to mount the solar panels to to the boat both on the wheelhouse roof and at the guardrails.

Propeller: We have the propeller at home and it still needs a lot of cleaning. One day money permitting we will replace it with a Bruntons Autoprop Ecostar, until then cleaning it is.

Emergency Steering: The two part emergency tiller (if the wheel steering breaks) has probably been in storage under the after cabin bunk for the whole life of the boat. There has been a little corrosion which means the parts no longer fit together. So we will fix this.

Consumer Unit mount: We now have a consumer unit for the mains power. We have a place for it which will allow us to access the trip switches. It is quite large as we have one switch for each of the 13 sockets we will have around the boat, we are running a separate wire to each rather than a ring main. However, it will need to be lowered for full access so I’m making a wooden frame for it to slide up and down in.

Navigation and control systems: I have plenty of fun planned getting Raspberry Pi computers sorted to run the chart plotter and other navigation software. I want them to interface with all our instruments, with the battery management systems, the solar charge controllers etc. We will have an indoor and an outdoor Pi so we can see everything when steering or when below. The indoor one will also be our entertainment centre and office computer.

Holiday progress day 9: Electric Motor reliability

Well not much progress today because we nipped home last night as our old Diesel engine was being collected today. The forecast had also helped make the decision with another storm coming through.

So rain nearly all day for the time we were in Manchester, rain for the journey back to Beaumaris and rain most of the evening.

The key progress is emotional, with the sense of freedom from having an engine sitting in our trailer, waiting to be sold. As we were driving back we were remembering all the expensive work we would have had to do in order to get what was a good engine working.

  • The survey required the raw water seacock to be changed. That was bonded in so thoroughly it needed cutting out with a hole saw. Possible with the engine in (although the two cockpit drains would have been much more difficult).
  • the survey warned that the cutlass bearing was worn and that the stuffing box needed to be repacked. We found that the propeller side of the coupling to the gearbox needed to be cut off (and so would have needed a replacement). We also found that the propeller shaft is too long to slide out because of the skeg, so we would have had to lift the engine for the propeller shaft to come out under it, that would have meant cutting off the rusty original engine mounts and replacing them.
  • the survey warned of a leaking fuel filter, would we then have found that several of the valves in the various fuel lines were seized and would we have felt we needed to add inspection hatches to the fuel tanks, replaced all the fuel lines and thoroughly cleaned all the system and all the fuel? As we did that we might have noticed and been concerned about the very rusty fuel vent fittings and the condition of the fuel filler hoses.
  • In this process would we have noticed and dealt with the rusty paraffin fuel tank for the boat heater (that failed and spilt paraffin everywhere just as I arrived at the recycling centre).
  • When would we have taken out the hot water calorifier (heated by the engine or by a mains system condemned in the survey) that was buried behind the paraffin tank, under the rusty fridge compressor and under the unreliable water pump? Because when we did take it out, we found it rusty and leaking out of sight.

In short, because everything around the engine wasn’t replaced with the new engine, we would have had large costs to get afloat with this engine and far more over time to get it to a point where it would be reliable with the many problems with the setup diesel supply (particularly water in the fuel and no way to get it out, modern problems diesel bug growing due to the use of bio-diesel and no way to get it out, old sludge in the tanks causing blockages in the pipes before the filters).

We are more and more glad that we took the plunge and decided to go fossil fuel free from the beginning rather than first fixing what we had. So we have not spent any money on fixing the diesel but all on preparing for where we believe all yachts need to be going – fossil fuel free.

Again we have been watching more YouTube videos and seeing more people having problems with diesel fuel, the old idea that diesel engines are this magical safety device because they are always reliable just isn’t the case for lots of people. Also the amount of nasty, cramped, smelly maintenance and the impact that has on sea sickness and morale needs to be acknowledged more openly in the sailing community.

Obviously, at the moment we have very little to be sure of in terms of the reliability of our electric motor system, how dependable will it be. However, from all we have studied so far we are quite confident. We will have a good installation of a brushless motor, that will be in as dry a place as possible, with potential backup batteries and tools/spares for making cables.

We have come to realise that the Rival 38 centre cockpit has a number of really good features for a reliable electric motor installation.

  • the bilge is really deep and large. So even if we get a lot of water on board it is going to be a long way from the motor or the batteries, we have made this so it is visible for checking as well as making it possible to access the pumps and hoses (initially we are fitting both an automatic large capacity electric pump and updating the original manual pump)
  • the motor compartment is not accessible from the companionway steps (but instead from the corridor to the aft cabin). Very often these steps lift up for access but that also means there is potential for water to get into the motor compartment whether it be from spray or people climbing in with wet clothing etc
  • the motor compartment is large enough so that our batteries, motor and controller can be right next to each other, so short cables that we cann easily inspect that don’t go through bulkheads where they can get damaged or through bilges where they can get wet.

We are also implementing a few things they we hope are best practice to help with the reliability

  • The motor is brushless for no maintenance and high efficiency. It is air cooled to keep our moisture (we will need to monitor temperature and might need exhaust fans)
  • All our battery banks are going to be in boxes that are watertight from below with a top that means any drips from above will not make it in. Build from epoxy coated plywood with a strong timber frame that does not allow battery movement but does allow air circulation for cooling.
  • The motor frame will have a watertight undertray and a lid that directs any drips clear of the motor.
  • Our batteries that are connected in series will have automatic battery balancers to ensure they are evenly charged. Those in parallel will have huge busbars and identical cables for equal loading.
  • We are over specifying all our battery cables and have a full size professional crimping tool to make the best possible connections.
  • Most of the batteries (5 out out of 8) have a bluetooth BMS and I will be monitoring this automatically from our Raspberry Pi system
  • All our solar chargers, battery balancers, battery monitors are from Victron with bluetooth capability so we can monitor them from their app and from the Raspberry Pi system
  • The SignalK system on the RaspberryPi will allow us to add a number of sensors to monitor temperature, humidity etc of everything, so we should know if there is a problem in any battery, bearing, motor, motor controller etc
  • We are installing a dripless seal for the sterntube. This should minimise maintenance and the chance of any salt water coming into the engine compartment.
  • We are installing an Aquadrive. This absorbs all the thrust from the propeller which means the engine and the bearings are free from these loads. It also means that the alignment of the motor is not critical. Both these mean that the motor will be on very flexible mountings so there should be much less vibration in the motor frame as well as in the boat. That should help avoid things shaking loose.
  • We plan to install an automatic dehumidifier for the motor compartment so keep the air in and around the motor plus electronics as dry as possible.
  • The cockpit floor is removable for lifting diesel engines in and out. All our electric stuff is small and light (heaviest individual items under 40kg). Even the motor in it’s frame is under 70kg and we can put it in the frame in the corridor next to where it will go. So we will use a more secure sealant on the cockpit floor, it would be possible to get it up but not as easy as it has been.
  • We will have a much more sealed bulkhead between the motor compartment and cockpit locker. So when you put wet ropes, fenders, sails in there it will drain into the bilge directly and not splash through lots of holes.
  • We are re-routing the vent for the main water tank so it doesn’t go through the motor compartment (reduce chances of water ingress)
  • The boat does not have a working electrical earth at present, we will make sure it is implemented and tested to protect the systems from galvanic corrosion.
  • All new composite cockpit drains and seacocks should reduce condensation and with much higher quality hoses should be more watertight.
  • We are not in a rush and so we can take the time to build it up slowly, carefully and with clear layouts and documentation
  • As we are doing all the work ourselves we know how it is installed and how to maintain it

Despite all that there are still some risks:

  • The biggest is the motor controller, the wiring is complex (for us, fortunately we can bring in our son who is an electrician). Also they are programmable and we don’t have the tools to reprogram it (particularly for regen but potentially also for things like throttle response and max revs)
  • We don’t manage to generate enough electricity to charge the batteries enough (separate updated blog post on generation to come)
  • We do something stupid with one of the expensive components so we need to spend a lot of money replacing it (eg shorting a battery, wiring something wrong).
  • Something we have not thought of

Compared to our lack of understanding of diesel engines this feels like a comfortable place to be 🙂 We think that overall we should be more reliable than diesel, better to live with and because of these be both more convenient and safer than a diesel engine while obviously being incredibly better for the planet.

Going 100% electric: the “house”

I recently detailed where we are at with the Electric Motor, now for the domestic “House” side.

The House power supply

I have started building the battery box which will sit above the motor and motor batteries in the motor compartment.

We have 4 x 120AH Lithium (LiFePo4) batteries from KS Energy KS-LT120B. These have Bluetooth BMS’ which I have been able to connect to from a Raspberry Pi (so one day will be able to monitor and control from the integrated navigation system). Their high continuous current rating of 160 Amp and 30 seconds surge at 250 Amp means they are easily able to power our inverters. It also means that we could rewire them in series to replace the motor batteries if we needed to.

These batteries are going to be connected in parallel so they act as a 12 volt, 480AH bank. This is one decision we agonised over. An alternative would be to have a 48volt house battery bank (and even have a common battery bank for the motor and house – such as Sailing Uma have). The biggest advantage of a 48 volt system would have been for the inverters. However, there are also disadvantages, particularly if you want to add additional battery capacity (you need to add four 12 volt batteries at a time).

Powerful 12 volt inverters require a lot of current, they therefore need very thick cables and short cable runs. Ours are going to be very short and so on balance we have gone for the simplicity of running everything on the house side at 12 volts.

So our batteries are connected in parallel using a massive 60mm x 6mm tinned copper busbar. We will be using very short 95mm2 cables to connect the batteries to the busbar. All 8 cables will be the same length. This form of connection is one of recommended ways (simplest of them in our opinion) of making sure that the battery use is balanced equally across the batteries.

From the battery box +ve busbar we will have doubled 95mm2 cables to a fuse. Then doubled 95mm2 cables to a shunt (used so that the Victron battery monitor sees everything). Then again doubled 95mm2 cables to the main battery switch. Finally the doubled 95mm2 cables go to a +ve secondary busbar at the forward end of the battery box.

From the battery box -ve busbar we will have doubled 95mm2 cables direct to the -ve secondary busbar at the forward end of the battery box.

The reason for doubling the 95mm2 cables is twofold. First, our inverters could potentially draw more current than one 95mm2 cable can carry. Second, the inverters are very sensitive to any voltage drop over the cable (it can cause fluctuations which can damage the batteries). By doubling the cables and keeping the lengths very short we should avoid both problems.

We will have 4 connections from each secondary busbar. All of them will have circuit breakers or fuses on the positive and all of them will have 95mm2 cables to the circuit breakers/fuses.

  • Inverter 1: a Victron 12V inverter giving up to 2000 watts (95mm2 cable)
  • Inverter 2: a Victron 12V inverter giving up to 2000 watts (95mm2 cable)
  • Lofrans Tigres Horizontal Anchor Windlass windlass 12v connected via 70mm2 cables (thicker than the 50mm2 specified by the manufacturer)
  • Distribution busbar for Main 12volt switch panel (busbars situated above the corridor to the aft cabin, switch panels on the bulkhead above the entrance to the corridor)

The 230volt AC systems

The Victron inverters get connected together into a single mains supply. So we have a 230V 4000watt mains supply via a standard circuit breaker box. The main purpose of having so much 230 volt power is the galley. In the galley we have

  • 2 x single induction hobs (max 2000watts each)
  • Microwave/combination oven/grill (max approx 1000watts)
  • Multi-cooker (max 900watts)

And no doubt we will be adding coffee machine and a few other gadgets.

So we will be able to run any 2 of these devices at full power at the same time (and to be safe we won’t run both hobs on full power at the same time).

Beyond the galley we have

  • 230volt water heater to supply sinks and shower
  • Device like our current laptops which only have 230 volt power connectors.
  • Two wall infrared panel heaters.
  • Power tools (most of them are now cordless but the batteries are charged from 230volts)
  • One day in the future a 230volt watermaker

Our electric outboard motor for the dinghy has a 12volt charger as well as a 230volt one.

4000 watts should be plenty with some simple house rules

  • only one cooking device while using the windlass (why would anyone be cooking when you are either raising or lowering the anchor?)
  • if using two cooking devices then turn off most other mains devices (possibly via the circuit breaker?)

The 12volt DC systems

These are mostly very normal for boats with lights, instruments, electric autopilot (we mainly want to use a windvane anyway), fridge (not planning a freezer), windlass (a lot of current but not for very long).

However, we are also going to be building our navigation, entertainment and office systems around 12volt Raspberry Pi computers and 12 volt screens. This will include WiFi to our phones etc. We will be fitting a hi power/long range 3G/4G antenna that will make it’s connection available via WiFi to everything else.

The Raspberry Pi’s will be used for navigation (we have a touch screen for the cockpit) with OpenCPN as well as for general use (everything from NetFlix to general office to video editing) on a TV screen in the saloon.

We will be using a SignalK server to connect the Raspberry Pi systems to marine instruments (AIS, Radar, WindSpeed/Direction etc). Anyway that is a whole lot of other posts.

Capacity

While it is perfectly ok for us to plan the system so that we can deliver 4000watts for cooking at full power on two hobs or run all these other devices the fact is that we still have a battery bank with limited capacity.

Here we admit there are a lot of unknowns and variables. However, we think that being able to monitor our battery use very accurately will allow us to modify our behaviour to suit the available battery charge (eg no hot showers or minimise cooking power use).

The next key part of the picture is how we recharge our batteries, both house and motor banks). That will have to be a separate blog post.