Yacht electrical system design

[Carbalu]

Hi all, new to this forum but looking forward to everyone’s wisdom. I’m looking at a complete overhaul and redesign of the electrical system I’m planning on putting into my 30ft sailing yacht. This is my initial design and please bear in mind I haven’t finished yet with wire sizes, fuses etc it more getting peoples opinion on the system layout that I would appreciate. Many thanks and look forward to it.

 

[wingcommander]

Personally I wouldn't bother with a solar panel on the starter battery, is normally back to fully charged within minutes. If you already have it and the mppt use it on the house bank. The rest ime still trying to get my head around. ( Not a sparky by trade)

 

[Carbalu]

Personally I wouldn't bother with a solar panel on the starter battery, is normally back to fully charged within minutes. If you already have it and the mppt use it on the house bank. The rest ime still trying to get my head around. ( Not a sparky by trade)

My thoughts with that were that being a vital bit of equipment I wanted the assurance that the starter battery effectively had that redundancy of its own source to charge, but can see your point of view thank you

 

[dunedin]

Personally I wouldn't bother with a solar panel on the starter battery, is normally back to fully charged within minutes. If you already have it and the mppt use it on the house bank. The rest ime still trying to get my head around. ( Not a sparky by trade)

I would agree with that, we don’t have the solar connected to engine start battery. Never had an issue but invested in high amp long jump leads to power from domestic bank in emergency at about £40.

 

[IanCC]

I am really no expert but i wonder about your mains battery charging set up. Anything with 'inverter' written on it tends to be expensive as does dc to dc battery charger. Why not just have two mains battery chargers. They don't need, imo, to be a huge ampage because, unless you have something very fancy, the actual ampage being dumped into them will be quite modest once the engine has been switched off. But then i am not sure which way your dc to dc is working. From starter to leisure when the engine is running or the other way around when on mains. Maybe they do both, no doubt someone will correct me.

 

[Sandy]

Hello and Welcome

Have you considered a VSR between the starter and house battery? Would save considerable number of beer tokens as you don't need a separate solar panel and MTTP. Works for me.

Quietly scratching my head about why you need a big invertor on a boat, but I don't use a hairdryer or curling tongs.

 

[William_H]

I would agree with that, we don’t have the solar connected to engine start battery. Never had an issue but invested in high amp long jump leads to power from domestic bank in emergency at about £40.

Using jump leads can be a viable emergency jump start arrangement however it can be dangerous if any sparking occurs when connecting or disconnecting. Considering that after a time you will have a start battery failure I think it far better to have hard heavy wired negative from house to engine battery and have a hard wired in high current emergency paralleling switch in lieu of jump leads.
I would think most perople on this sized yacht would be happy with a tiny solar PV panel connected to engine start battery with no controller or cheap pulse width controller. No MPPT needed. I think OP perhaps needs to think in terms of what systems like B2B charger he really needs. Yes it can give faster charging of domestic battery from engine alternator but does he really need that fast charge. likewise an inverter. Only experience actually using the boat will determine if these fancy add ons are needed. ol'will

 

[Tranona]

Agree no need for solar to the start battery nor for a charger/inverter (unless you are going to have a very large domestic bank) nor a DC/DC. Much simpler to have a VSR between the start and the domestic bank and a switch to connect the house bank to the starter for the highly unlikely emergency. For mains charging a 2 output 20 amp charger connected to the 2 banks will be fine up to a domestic bank of say 250Ah. Each bank should have its own isolator.

I have much the same size boat and have a BEP switch cluster which has a VSR and a parallel switch with a dedicated start battery and 2*95Ah AGMs for domestic a 15A mains charger to just the domestic (but if I were buying new I would fit a 20A 3 outlet Victron). I have a bow thruster and windlass with a bow battery charged by a DC/DC from the start battery. No solar as I don't do the sort of sailing that justifies it, but if I did it would be to just the domestic bank..

Most important from a power management point of view is to include a battery monitor in your system so that you know what is happening from both usage and charging so good to see you have one..

 

[PaulRainbow]

Funny how so many of you know the OPs needs or plans better than he does and are adamant there is no need for an inverter.

 

[Tranona]

Funny how so many of you know the OPs needs or plans better than he does and are adamant there is no need for an inverter.

Just the perils of not giving full information when asking the original question. Not unreasonable to question the need for a charger inverter on a 30' boat when there is no indication of size of bank or what is the intended use.

Don't see anything that suggests "adamant" is an appropriate observation - just asking the question.

 

[PaulRainbow]

I am really no expert but i wonder about your mains battery charging set up. Anything with 'inverter' written on it tends to be expensive as does dc to dc battery charger. Why not just have two mains battery chargers. They don't need, imo, to be a huge ampage because, unless you have something very fancy, the actual ampage being dumped into them will be quite modest once the engine has been switched off.

A decent 2000w inverter with built in 70a charger is £349.99. Fiting two Victron chargers would cost more than that, but you wouldn't fit two, you just fit one with two outputs (actually three, as a rule).

But then i am not sure which way your dc to dc is working. From starter to leisure when the engine is running or the other way around when on mains. Maybe they do both, no doubt someone will correct me.

The DC-DC charger will only charge in one direction.

 

[BabaYaga]

#5 in the schematic should not be a bus bar, but could be a terminal block such as this:
Terminal Block - Blue Sea Systems

 

[Andrew_Trayfoot]

A decent 2000w inverter with built in 70a charger is £349.99.

@PaulRainbow
Can you post a link to that inverter/charger

 

[Andrew_Trayfoot]

https://www.dex.siemens.com/plm/capital-electra-x?cclcl=en_GB

This free cad software may help you.
Saves redrawing the whole thing 10 times!

 

[PaulRainbow]

Hi all, new to this forum but looking forward to everyone’s wisdom. I’m looking at a complete overhaul and redesign of the electrical system I’m planning on putting into my 30ft sailing yacht. This is my initial design and please bear in mind I haven’t finished yet with wire sizes, fuses etc it more getting peoples opinion on the system layout that I would appreciate. Many thanks and look forward to it.

I would forget the DC-DC charger and the engine solar panel and controller. The DC-DC charger will allow the mains charger to charge the engine battery or the alternator to charge the domestic bank, but not both. Fit a Victron Cyrix VSR. This will allow the alternator to charge the domestic bank, the mains charger to charge the engine battery and the domestic solar panel to charge the engine battery.

You need to fit a isolator to the engine battery.

Fit an emergency parallel switch (use another isolator switch) between the load terminals of the engine and domestic isolators.

The panel marked "dc dist" is isolated by the main isolator, this means that none of your charging systems can work with the isolator turned off. Connect the isolator load directly to the DC distribution panel. Replace "DC dist" with a busbar for all negative loads and charging sources, connected to the shunt for the battery monitor, the engine battery negative and engine negative go here too.

The solar positive and the domestic VSR connections need to be made battery side of the domestic isolator. Fit another busbar close to the domestic bank and connect the fused cable to the main isolator to it. Also connect the VSR and solar controller positives to it (both fused). Connect the inverter/charge positive to this busbar to, via a fuse and an isolator.

 

[PaulRainbow]

@PaulRainbow
Can you post a link to that inverter/charger

No problem: 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

 

[Carbalu]

#5 in the schematic should not be a bus bar, but could be a terminal block such as this:
Terminal Block - Blue Sea Systems

Yes that’s what I meant to write terminal block, is that the same for #4 as well?

 

[Carbalu]

I would forget the DC-DC charger and the engine solar panel and controller. The DC-DC charger will allow the mains charger to charge the engine battery or the alternator to charge the domestic bank, but not both. Fit a Victron Cyrix VSR. This will allow the alternator to charge the domestic bank, the mains charger to charge the engine battery and the domestic solar panel to charge the engine battery.

You need to fit a isolator to the engine battery.

Fit an emergency parallel switch (use another isolator switch) between the load terminals of the engine and domestic isolators.

The panel marked "dc dist" is isolated by the main isolator, this means that none of your charging systems can work with the isolator turned off. Connect the isolator load directly to the DC distribution panel. Replace "DC dist" with a busbar for all negative loads and charging sources, connected to the shunt for the battery monitor, the engine battery negative and engine negative go here too.

The solar positive and the domestic VSR connections need to be made battery side of the domestic isolator. Fit another busbar close to the domestic bank and connect the fused cable to the main isolator to it. Also connect the VSR and solar controller positives to it (both fused). Connect the inverter/charge positive to this busbar to, via a fuse and an isolator.

A lot to process here lol from my understanding having the dc-dc charger all connected via the lynx distributor will allow the engine batter to be charged first before it redirects the charge to the house bank when using the engine/alternator?
Fair point about the engine battery isolator. From my thoughts the isolator that is connected to the house bank isolates the house bank from the lynx distributor. Maybe I labelled the diagram incorrectly confusing the situation sorry.

 

[dunedin]

Using jump leads can be a viable emergency jump start arrangement however it can be dangerous if any sparking occurs when connecting or disconnecting. ......

As an emergency last resort, jump leads have the huge benefits of cheap and simple. No electronics or switches to fail. Never needed in 2 decades, but good to know available.

By contrast have jump started lots of cars over the years - almost all other people's. Not dangerous if used carefully.

 

[Carbalu]

Just the perils of not giving full information when asking the original question. Not unreasonable to question the need for a charger inverter on a 30' boat when there is no indication of size of bank or what is the intended use.

Don't see anything that suggests "adamant" is an appropriate observation - just asking the question.

My apologies, perils of being a newbie here and not explaining everything fully, I wanted the inverter charger in there as we will be doing quite a bit of extended cruising and wanting the facility for a. The mrs to use hair dryer, being able to charge laptop, use of a few small electrical items when at anchor like TV or kettle etc, not massive amounts but wanting to have the ability to use 240v if we need it