Solar power, seeking forum input please.

[harvey38]

With nothing on the boat switched on apart from a WiFi router and security camera plus Victron battery charger, I am using roughly £1 a day when we are not on the boat, far too much to my miserly mind.

My thought is to install a solar system than will run the above, leaving the 3000A inverter on to power the camera/router or maybe just find a way to run them on 12V.

I have 6 x 110A SLA house batteries and 2 x 110A SLA engine start batteries, I assume if I use some kind of solar panel controller, I could ditch the Victron 50A charger which would suit me as its badly sited and would give me some much needed room back in a cupboard.

When we are onboard in port, I would leave the shore power plugged in and have a 2.5kva genset when at anchor so not reliant on battery power, I just want the battery bank to be well maintained and not be paying £1 a day for electricity.

How would I wire the system up and what size solar panel would I need?

Many thanks,
Rob

 

[PaulRainbow]

If you get rid of the mains charger there is little point being plugged into shore power, as all of your DC systems will drain the batteries, unless the solar panel/s are big enough to keep up.

Using a 3000w inverter to run a router and security camera is wasteful. The inverter will have a .5a or so overhead just for being on, plus what is actually uses, with an additional hit of 10% due to inefficiency.

Plenty of 12v wifi routers out there, ditto security cameras. Check that what you have aren't DC, with 240v power supplies.

You would connect the solar panel to a controller and then to the domestic bank, fused close to the batteries. Fit as much as you have space for.

 

[[70521]]

I'd start with understanding your daily power requirements when not on the boat.

Having installed a Victron SmartShunt over the winter I can see what power is being used via their app on my phone, if I was feeling really geeky I could pass that data to a spreadsheet.

Once you understand your needs you can size the system.

 

[harvey38]

If you get rid of the mains charger there is little point being plugged into shore power, as all of your DC systems will drain the batteries, unless the solar panel/s are big enough to keep up.

Using a 3000w inverter to run a router and security camera is wasteful. The inverter will have a .5a or so overhead just for being on, plus what is actually uses, with an additional hit of 10% due to inefficiency.

Plenty of 12v wifi routers out there, ditto security cameras. Check that what you have aren't DC, with 240v power supplies.

You would connect the solar panel to a controller and then to the domestic bank, fused close to the batteries. Fit as much as you have space for.

When in port we use 240v for toaster, kettle, microwave, Sonos system, etc so plenty of point being on shore power. I get the idea of running the camera/router via 12v which you pointed now I understand the inverter loss.

I still don't see the need for a 240v charger if I have 2 x 80A alternators when underway and genset when at anchor.

I have plenty of space, 4m2 but I'm sure I don't need a panel that big to keep the batteries topped up whilst not on the boat?

 

[harvey38]

I'd start with understanding your daily power requirements when not on the boat.

Having installed a Victron SmartShunt over the winter I can see what power is being used via their app on my phone, if I was feeling really geeky I could pass that data to a spreadsheet.

Once you understand your needs you can size the system.

Daily requirement is just to keep the batteries maintained when not on the boat

 

[PaulRainbow]

When in port we use 240v for toaster, kettle, microwave, Sonos system, etc so plenty of point being on shore power. I get the idea of running the camera/router via 12v which you pointed now I understand the inverter loss.

I still don't see the need for a 240v charger if I have 2 x 80A alternators when underway and genset when at anchor.

I have plenty of space, 4m2 but I'm sure I don't need a panel that big to keep the batteries topped up whilst not on the boat?

I meant little point, with regard to your DC systems. Without the mains charger, will your batteries stay charged when on shore power, using lights and other DC equipment ?

You can fit panels big enough to run the router and camera only, or you could fit more and be a little less reliant on other power sources.

Just for the router and camera, plus natural depletion, 100w is probably enough if you get a reasonable amount of Sunshine, more if not so much Sun, or in the Winter.

 

[harvey38]

I meant little point, with regard to your DC systems. Without the mains charger, will your batteries stay charged when on shore power, using lights and other DC equipment ?

You can fit panels big enough to run the router and camera only, or you could fit more and be a little less reliant on other power sources.

Just for the router and camera, plus natural depletion, 100w is probably enough if you get a reasonable amount of Sunshine, more if not so much Sun, or in the Winter.

Good point Paul,

DC usage is lighting, water pump, 2 x electric toilets, shower etc so good call, I hadn't considered those at all Looks like the 240v charger will be staying but the 100w solar output is very much appreciated, we're in Ramsgate but as long there is sufficient charge to maintain the batteries whilst we're not there, I'll be happy

 

[PaulRainbow]

Good point Paul,

DC usage is lighting, water pump, 2 x electric toilets, shower etc so good call, I hadn't considered those at all Looks like the 240v charger will be staying but the 100w solar output is very much appreciated, we're in Ramsgate but as long there is sufficient charge to maintain the batteries whilst we're not there, I'll be happy

If you want to reclaim some cupboard space, you could swap the 50a charger for a BlueSmart 30a model, check out the specs, it might be a worth while space saver ?

Blue Smart IP22 Charger - Victron Energy

 

[William_H]

If OP has 4 square metres of space for solar panel then look for a domestic PV solar panel. Assuming your space is a roughly rectangular so could handle a 1 x2m panel. Domestic PV is rife here. (I have just signed up for household electricity costs based on time. Super cheap 9AM to 3PM cos every one is pumping solar power into grid)
Local PV supplier is claiming 380/425w from a single panel. compared to 180w from same size 10 years ago. Domestic PV panels are usually40v or higher so require an MPPT controller. These panels should be cheap due to huge numbers being made. ol'will

 

[dukeofted]

And if you look on ebay or facebook market place there are loads of ex solar farm panels being sold cheap. These are usually around 250w per panel and about £60. If you have room for a panel that big they are a great option. They are about 1.5m x 1m ish in size. I would fit as much solar as you can comfortably fit as who wants to be sat at a nice quiet anchorage listening to the lovely sound of a genset?

 

[Refueler]

Most Routers and Cameras use adaptors dropping the 240v to 12v ... so router and camera can run direct of the batterys on board. It may be idea to have a voltage regulator to stop the higher alternator voltage though.

I'm with Paul - ditching mains powered charger is not a good idea even if not used all time.

I have vastly less battery and reqt's - but principle is same :

I intend this year to have Solar charge to my two in board batterys. With engine alternator while on passage etc.
The Mains Charger on board will stay on board ready to be put into play if needed. If I am alongside and using gear - that Mains Charger will certainly be plugged in.

Why get rid of it ??