Solar Panel What Size for Sailboat Nauticat

[graham460]

Hello Fellow Sailors.
I am from UK - I own a Nauticat 44 based in sardinia Alghero Fertilla .
Marina keeps disconnecting my shore power each time I go away. I returned in June to find all5 batteries DEAD.
So I have to replace them approx 2600 Euros

So I have been trying to find out what size Solar panel I would require to Charge the 4 Engine batteries (Mainly when I am not in a marina)

ALSO I would appreciat a diagram of how the solar panel system works With MPPT have been emailing Victron They just say " Speak to your local shop" NO help there - Dissapointing - No Info from them about a diagram.
I have email some shops in Italy They can seel the products but No Diagram From the Solar panel down to the batteries.

2. a 12v Medium size Fridge
3, Electric light (Incandescent Yes I must try to swap for LED. But unusual Baynot fitting - Staggered)
4. Raymarine Sensor touch Plotter. Plus Raymarine Controls Wind Engine oil pressure etc.
5. Elctric toilet But not used a great deal

6. It would be great to run the Autopilot But I think that would be too much of a drain)

7. I don't really have an Inverter. the Switch burnt out.


So Fellow Sailors

Any help would be appreciated


OH I believe Victron Batteries are good BUT the Battery attachment Is Different it seems to be a spade connection instead of the Normal POST. My Friend said " One of his friends hav a Victron Battery Connector post Snap Off

I could swap for EXIDE EP1200 Which are the ones now installed but Dead.

I WAS THINKING OF A SOLAR PANEL MAYBE 1.2M X 900mm or maybe 2 1000mm x 1000mm Any Advice. Either side of the Boom.

Do they Need to be attached on a wooden frame. ?
There are some you can walk on But are they powerful enough ?


Best regards
Graham

 

[graham460]

Caio

 

[Tranona]

You have asked some very big questions to which there is no simple answer. First, why do you think you have 4 engine batteries? The norm is one battery to start the engine and then a service bank sufficient to support your power consumption when the boat is in use.

If you just want to keep the service bank topped up when you are not here you do not need a lot of solar. However if you want to reduce your dependency on shorepower and engine charging by harvesting energy from the sun (which is sensible where you are located) then you need as much solar as you can reasonably add on the boat. Power generation is only part of the system so you need to think through your typical consumption and what you need to support this (energy generation and storage).

If you just want to connect solar panels to your existing house bank then it is very simple. Direct from the MPPT to the terminals on the house bank and programme the controller to math the type of batteries you have. There is nothing magic about it that requires a wiring diagram - the challenge is often finding a way of routing the cables from the panels to the batteries. You may have bus bars for the service circuits rather than everything coming direct off the terminals so if you don't understand how your boat is wired best to get a professional in.

 

[graham460]

Thank you.. Yes I will get a friend that used to be an electrical engineer years ago inItaly.. I just wanted to Know MYSELF as I generally do everything myself.. I like to Check it has been done correctly.

BATTERIES - you need powerfull batteries to Start the Engine as it is a 130Bhp 6 Cylinder Ford Dover engine so It need some OOmph to start it. that why it needs topping up. Thank you for your support Ye si would like to also run the fridge when Cruising

 

[Tranona]

Thank you.. Yes I will get a friend that used to be an electrical engineer years ago inItaly.. I just wanted to Know MYSELF as I generally do everything myself.. I like to Check it has been done correctly.

BATTERIES - you need powerfull batteries to Start the Engine as it is a 130Bhp 6 Cylinder Ford Dover engine so It need some OOmph to start it. that why it needs topping up. Thank you for your support Ye si would like to also run the fridge when Cruising

It is rare that engine batteries need topping up as they are charged quickly as soon as the engine starts and the alternator runs. If they are losing capacity after a period of non use then they are probably on their way out. Typically you will have a split charge system that ensures the start batteries are charged. It is also sensible to have a means of using the house bank to start the engine in an emergency. "Powerful" for engine start is measured in CCA not capacity, so you need different types of batteries from the service bank, I use a high capacity AGM of only 32Ah capacity to start my 30hp compared with a "normal" car type start battery that would be double the capacity and size to get the same CCA. If you really think you need solar for the start battery then you can always split the charge, but really it should not be necessary. Solar is best for feeding domestic consumption.

 

[William_H]

Choice of solar panels is almost entirely dictated by available space and mounting arrangements. The more power the better of course. The panel is simply connected by robust wiring to the appropriate terminals on the controller. Other terminals will show output battery connection. This should be made close to the battery ie battery side of isolation switch. You want to be able to switch off batteries when you leave the boat but have solar charging them. Fit a fuse in the positive wire from controller to battery near the battery. This to protect wiring from current flowing from battery to a possible short.
As suggested batteries may have been near end of life anyway. They don't last for ever.
Comments re needing 4 batteries to start large diesel engine do seem a little strange. usually with larger diesel engines a 24v battery system is used.
if a 12v system then yes start current may be very large. Yes conceivable that boat has a very simple system of one battery (4in parallel) for engine start and services. This may work out OK if you are diligent in not discharging batteries too much when sailing or over night. Save some charge for starting engine to recharge.
If you over do it especially if batteries are old you are really stuck with no engine start.
The better way to do it is to have optimised battery type for engine start isolated from, all other loads. Then you have optimised deep cycle batteries for domestic loads that are isolated from engine start batteries. There are then various ways to charge both battery systems when the engine is running.
OP may have this and be unaware or perhaps not. Dual batteries not only reduces worry about deep discharge with fridge etc but also gives an additional battery system for jump start when and if engine battery dies.
It does seem OP needs to research his system he has, then ask more questions here on way forward.
Certainly almost any small PV panel will aid in keeping batteries alive in long period of inactivity. ol'will

 

[andsarkit]

I sailed with a friend who had a Nauticat 44 and was very impressed by the ring binders containing all the vessel details and circuit diagrams. It might help if the OP can post any relevant pages assuming the previous owners have not changed too much of the electrical systems. From memory the factory electrical installation was very good with busbars and circuit breakers in a large accessible cabinet.

 

[Sandy]

The wiring is really simple from solar panel to battery

Solar Panel → MTTP → House Battery Bank. (You will have to size the MTTP for the amount of amps the solar will throw at it)

Optionally, if you want to charge your engine from the solar panels.

House Battery Bank → VSR → Engine Bank. Once the house batteries hit 13.8v the VSR makes a circuit with the engine batteries and a current flows.

Victron's service model is also really simple - you deal with their dealers. My SmartShunt died after 24 months, I contacted the dealer and within 24 hours they replaced the shunt.

As a manufacturer the last think I'd want to be doing is speaking to end users - as an end user the first place I want to be speaking to is the manufacturers, but I am an engineer.

 

[graham460]

Thanks

 

[graham460]

The wiring is really simple from solar panel to battery

Solar Panel → MTTP → House Battery Bank. (You will have to size the MTTP for the amount of amps the solar will throw at it)

Optionally, if you want to charge your engine from the solar panels.

House Battery Bank → VSR → Engine Bank. Once the house batteries hit 13.8v the VSR makes a circuit with the engine batteries and a current flows.

Victron's service model is also really simple - you deal with their dealers. My SmartShunt died after 24 months, I contacted the dealer and within 24 hours they replaced the shunt.

As a manufacturer the last think I'd want to be doing is speaking to end users - as an end user the first place I want to be speaking to is the manufacturers, but I am an engineer.

Thank Sandy I was just wondering what APPROX size of Solar panel or panels Would charge my batteries and Run my frisdge when Sailing and perhaps the Rayarine plotter.. I suppose i could run my batteries for an hour Hopefully the Victron Display will show me how much power is remaining in my batteries..

 

[Tranona]

Thank Sandy I was just wondering what APPROX size of Solar panel or panels Would charge my batteries and Run my frisdge when Sailing and perhaps the Rayarine plotter.. I suppose i could run my batteries for an hour Hopefully the Victron Display will show me how much power is remaining in my batteries..

Fairly simple to estimate consumption of a fridge by looking at the spec and then monitoring how long the compressor runs in an hour. Of course it depends on the size of fridge, the level of insulation and the ambient temperature. 4-6 amps and in the Med a nominal 200w panel would be enough for that. The sizes you talk about are roughly 200w+. The chart plotter is low consumption. big consumers are radar, autropilot, nav lights at night and domestics.

As I said in post#3 you can either go the simple route of installing a panel that fits easily and connect it to your domestic bank then see how it goes. How much solar you fit depends on how much you want to be independent of other sources of power generation such as running the engine or shorepower. Only you can determine that by monitoring your consumption using your battery monitor and finding the deficit between that and what you generate from running the engine when away from shorepower. Then see how much solar you need to plug the gap.

 

[Sandy]

To add to what @Tranona said it is worth sitting down and totting up the usage in watts or amps of all your kit then multiplying by expected hours usage to get your daily consumption.

I have a wee spreadsheet to do this.

I have 200 watts of solar going to a Victron 75/15 MPPT that keeps up with my needs in summer, but I don't run a fridge as I prefer my beer warm and just a drop of water in my Highland Park.

Size in mm is irrelevant, it is watts rating that you need to look at. I have two panels 1150x460x30mm bought specifically for the 460mm width as they sit on the guard rails and don't clash with the hull. Most standard panels are 667mm. The panels are rated at 5.32 amps, 10.64 amps total, but I've seen 12.50 amps on that rare Cornish sunny day. My next trip towards 60° N should be interesting.

I've gone down the Victron route as I like the amount of data the power management interface gives me and the fact I can export the data to a CSV file and play with it in a spreadsheet.

When setting up your Victron will need a bit of time as you need to know when your batteries are at 100% charge. Then start monitoring. I've switched one electronic device on at a time and ran it for a few hours to see if the power usage in the manual is the same that I am seeing.

I've set my low battery alarm to go off at 60% of power used, just to be on the safe side.

 

[graham460]

You have asked some very big questions to which there is no simple answer. First, why do you think you have 4 engine batteries? The norm is one battery to start the engine and then a service bank sufficient to support your power consumption when the boat is in use.

If you just want to keep the service bank topped up when you are not here you do not need a lot of solar. However if you want to reduce your dependency on shorepower and engine charging by harvesting energy from the sun (which is sensible where you are located) then you need as much solar as you can reasonably add on the boat. Power generation is only part of the system so you need to think through your typical consumption and what you need to support this (energy generation and storage).

If you just want to connect solar panels to your existing house bank then it is very simple. Direct from the MPPT to the terminals on the house bank and programme the controller to math the type of batteries you have. There is nothing magic about it that requires a wiring diagram - the challenge is often finding a way of routing the cables from the panels to the batteries. You may have bus bars for the service circuits rather than everything coming direct off the terminals so if you don't understand how your boat is wired best to get a professional in.

Thanks for the information appreciated I would like to run the fridge and Nav display also plus lights So would a 3oowatt panel be ok.. APPROX.. What about Flexible panels you can walk on

 

[graham460]

Fairly simple to estimate consumption of a fridge by looking at the spec and then monitoring how long the compressor runs in an hour. Of course it depends on the size of fridge, the level of insulation and the ambient temperature. 4-6 amps and in the Med a nominal 200w panel would be enough for that. The sizes you talk about are roughly 200w+. The chart plotter is low consumption. big consumers are radar, autropilot, nav lights at night and domestics.

As I said in post#3 you can either go the simple route of installing a panel that fits easily and connect it to your domestic bank then see how it goes. How much solar you fit depends on how much you want to be independent of other sources of power generation such as running the engine or shorepower. Only you can determine that by monitoring your consumption using your battery monitor and finding the deficit between that and what you generate from running the engine when away from shorepower. Then see how much solar you need to plug the gap.

HellO Sandy (Friday)

Thanks for the information I will copy and paste into a word document and Digest it at Leisure WELL Rapidly as going away Sunday Morning to Boat in Sardinia.

VICTRON Batteries - They have an unusual Connection at the top Different from Car Batteries.. I friend of Mine said He had heard from a friend that they had one SNAP - Plus I would have to change all the Cable End fittings..

I do Agree I do like the Victron

Victron GX Touch 50 (BPP900455050)​

£264.00 Original price was: £264.00.£176.00Current price is: £176.00. Inc VAT.

VICTRON ENERGY MPPT CONTROL​

SCC900500000 - The MPPT Control lets you see the status as well as setup all BlueSolar MPPT Charge Controllers that have a VE.Direct communications port.
Item Number:
SCC900500000
Your Price:
£45.89
Points:
6 Worth £0.30
Your Total:








BUT that Maybe over the Top





I did hear from " Sunshine Solar" Will of a device GLOBAL LINK 520

 

[graham460]

Choice of solar panels is almost entirely dictated by available space and mounting arrangements. The more power the better of course. The panel is simply connected by robust wiring to the appropriate terminals on the controller. Other terminals will show output battery connection. This should be made close to the battery ie battery side of isolation switch. You want to be able to switch off batteries when you leave the boat but have solar charging them. Fit a fuse in the positive wire from controller to battery near the battery. This to protect wiring from current flowing from battery to a possible short.
As suggested batteries may have been near end of life anyway. They don't last for ever.
Comments re needing 4 batteries to start large diesel engine do seem a little strange. usually with larger diesel engines a 24v battery system is used.

Hi William.. Just to give you more info - The batteries were new 2021 Nov 4 of them ( Dual purpose) Exide EP 1200 I think 140ah

I have 2 Separate banks Bank 1. for Starting Bank 2 for Domestic. I do have A large switch under the Helm to select 1 1+ 2 & 2 this is for the 2v System.
I Cannot Scroll down to the section where you mentioned about a Fuse Near the batteries DO I need this ? I hope to have 4 Flexible Solar panels (Struggling for replies in Italy or even UK, Boat is in Sardinia, I will obtain the relevant MPPT or More if necessary Probably need two Also a Victron Energy BMV 712 display and Global link 520 (Like a transmitter) hopefully will reach UK. What are thses Shunts? Off to Alghero Back later thanks graham

if a 12v system then yes start current may be very large. Yes conceivable that boat has a very simple system of one battery (4in parallel) for engine start and services. This may work out OK if you are diligent in not discharging batteries too much when sailing or over night. Save some charge for starting engine to recharge.
If you over do it especially if batteries are old you are really stuck with no engine start.
The better way to do it is to have optimised battery type for engine start isolated from, all other loads. Then you have optimised deep cycle batteries for domestic loads that are isolated from engine start batteries. There are then various ways to charge both battery systems when the engine is running.
OP may have this and be unaware or perhaps not. Dual batteries not only reduces worry about deep discharge with fridge etc but also gives an additional battery system for jump start when and if engine battery dies.
It does seem OP needs to research his system he has, then ask more questions here on way forward.
Certainly almost any small PV panel will aid in keeping batteries alive in long period of inactivity. ol'will

 

[Tranona]

Your system is what would be considered rather old fashioned these days. normally position 1 would be the engine bank and in this position all loads including the house would come from this battery - that is why they fitted twice the size of what is strictly needed to start the engine. when the engine is running only this bank is charged. Position 2 will be the bigger house bank but you can also use it to start the engine. again only this is charged from the engine. Both turns all the batteries into one big bank which is charged by the alternator. Nowadays it is common to keep the 2 banks independent and use a split charge device to charge from the alternator. There are choices about which position you use for what, but starting on 1 then switching to 2 is common so that you house loads don't deplete your engine battery. You solar should be connected direct to the house bank as that is the one that feeds all the heavy loads like fridge. The shunt is fitted between the house negative terminal and the cable as it measures all the loads going out to provide the data for your monitor.

You don't say what your windlass and thruster are powered by. They do not consume much in terms of amps but do have high loads for short periods and it is common to power them from the engine bank and run the engine when using them so effectively powering them by the input from the alternator for the short periods they are in use.

 

[graham460]

Hello Tranona Thanks fr the reply Appreciated.. I'm a little confused about Charging..

So When the Solar system is finally installed -(I taly Not getting many answers about solar panel sizes)


YOUR TEXT
When the engine is running only this bank is charged.

Position 2 will be the bigger house bank but you can also use it to start the engine. again only this is charged from the engine. Both turns all the batteries into one big bank which is charged by the alternator. Nowadays it is common to keep the 2 banks independent and use a split charge device to charge from the alternator.




When RUNNING ENGINE I want to charge ALL the Batteries How do i do this,

I have the Big Orange 12v Switch 1 1+2 and 2. What Setting do I have it one Once the Engine is Running to charge all the batteries.?? I just thought the Alternator charged both.


SOLAR Will this charge the Domestic as well as the Engine Starter Batteries.

Not too Sure How the Cables are connected from Bank 1 (starter) to Bank 2 (Domestic) I'll have to check Make a sketch - there is a Buzz bar in the Boxes.
Thanks Graham

 

[pmagowan]

I think you need to draw out and understand the basics of your electrical system. It may be worth simplifying also. I see no fuses on your battery terminals but I see quite a few cables connecting to one terminal. There are a number of approaches including manual 1/2/B switches and automatic VSR battery combiners. The former relies on you to understand how your system is wired and to move the switch to the appropriate setting. In simple systems with one engine, 1 starter battery and 1 house battery the switch connects the engine to 1 : starter battery, 2: house battery and B: both. In normal operation to start the engine you switch to 1 and the starter battery is connected. If the starter is depleted for whatever reason you can move to 2 and start off the house battery or both. The alternator will only charge the connected battery. So if you leave it on 1 only the starter will receive charge, if 2 the house and if B both. Normally people switch to B to charge both and then have to remember to switch off to avoid depleting the starter when house loads are running and the engine is off. You MUST never switch off when engine running or the alternator may die.

Every wire needs a fuse. For starter motor this is strictly not required but an oversized fuse is a good safety precaution. Solar panels wires are also a potential exception as they are sized above a direct short of the panel.

The simple answer to your question is 1+2 should charge both.

 

[graham460]

Your system is what would be considered rather old fashioned these days. normally position 1 would be the engine bank and in this position all loads including the house would come from this battery - that is why they fitted twice the size of what is strictly needed to start the engine. when the engine is running only this bank is charged. Position 2 will be the bigger house bank but you can also use it to start the engine. again only this is charged from the engine. Both turns all the batteries into one big bank which is charged by the alternator. Nowadays it is common to keep the 2 banks independent and use a split charge device to charge from the alternator. There are choices about which position you use for what, but starting on 1 then switching to 2 is common so that you house loads don't deplete your engine battery. You solar should be connected direct to the house bank as that is the one that feeds all the heavy loads like fridge. The shunt is fitted between the house negative terminal and the cable as it measures all the loads going out to provide the data for your monitor.

You don't say what your windlass and thruster are powered by. They do not consume much in terms of amps but do have high loads for short periods and it is common to power them from the engine bank and run the engine when using them so effectively powering them by the input from the alternator for the short periods they are in use.

Hello Tarona Oops I forgot your Question.

BOW THRUSTER Powered By the Domestic Batteries THAT IS the GREEN cable runs from Domestic Batteries through the boat to the BOW where is connects to a Battery and Battery Charger. The Green Cable is Only used to Charge the Battery in the Bow.
It was installed 2017 In Torreveja as the old one Corroded off.. The Mechanic that installed the New one Did not provide enough Power he installed 2 x 15mm Cable It blew the 500amp fuse a few times - So in PALMA a Company installed a Battery and Battery charger in the BOW

WINDLASS I have only ever used the Anchor Once.
YES it draws a lot of Energy I kept the Engine Running The Battery charger 9Sterling Power then works overtime)

 

[B27]

....

The simple answer to your question is 1+2 charges both.

I'd be careful making simple statements like that, there could be all sorts going on, on a boat of this vintage that's been modified over the years.