How much solar do you have?

[Pete7]

thank you both.
I was wondering also about cable sizing and connection types when fitting a replacement/upgrade set of panels.
if you are on shorepower as well, what is the best way of prioritising your solar input over shorepower input?

This is worth a read:

https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/reference/20010.pdf

Comes from this site and has some other interesting articles:

Reference - Blue Sea Systems

 

[noelex]

Hi,
Any tips on doing this? What are the quick wins/max attention areas, to get this right?

It is a huge subject, but there are few fundamental areas to look at:

Equipment choices:
There is often a significant difference in in the power draw between otherwise similar equipment. When purchasing equipment consider the power draw as a factor. As B27 suggests, this is most critical for the devices that draw the most power (fridge/freezer, autopilot, etc).

Equipment optimisation:
Devices such as fridges can be modified or adjusted to reduce the power draw with extra fans and insulation. How the equipment is operated can be important, for example my chart plotter uses significantly less power when the brightness is dimmed even slightly to around 80%. Surprisingly, reducing the brightness further only makes a small difference to the power consumption. Knowing how the power consumption varies is helpful.

Parasitic consumption:
A lot of equipment consumes some power when turned "off". If you can disconnect the actual power supply, consumption can be reduced. It helps to have seperate switches or circuit breakers to disconnect the power completely from offending equipment. Inverters often have a high parasitic consumption, but the small amounts from other equipment adds up over a 24 hour period.

”A penny saved is a penny earned" applies even more to power management than to economics.

 

[john_morris_uk]

Solar should suit your load and use. No point in having solar you can't or won't use.
My first boat was very simple. A 27ft boat used for weekend sailing and summer hols. It was kept on a mooring and the solar ensured the batteries were full when we arrived on a .Friday night . We would go home on the Sunday with depleted batteries but they were charging all week. A tiny fridge gave us fresh stuff to eat. We didn't need any more. No we liveaboard we have very different requirements. We spend more time on our boat than in our house by a considerable margin. Having some of the comforts of home that a large solar array provides us is very pleasant

Short of throwing money at our boat with a complete redesign of the back end with an arch and panels mounted etc we have the max solar we can fit. I suppose we could try adding some flexible panels to the bimini but they’d be shaded by the boom a lot of the time. However our panels ‘just’ keep up with demand when we’re at anchor so I’m not to worried.

Making water usually means running the generator but that has the added bonus of giving us a tank of hot water.

 

[ghostlymoron2]

On my last 2 little boats I've had 20w semi flex panels which keep my batteries charged and allow use of lights, nav, some autopilot and vhf. I don't have heating and just a cool box. I prefer to have panels permanently mounted rather than fly leads - who's going to be fiddling with different positions all the time? I have to accept that some shading occurs but not much of a problem and compensated by generation whenever daylight whether anchored or sailing.

 

[B27]

On my last 2 little boats I've had 20w semi flex panels which keep my batteries charged and allow use of lights, nav, some autopilot and vhf. I don't have heating and just a cool box. I prefer to have panels permanently mounted rather than fly leads - who's going to be fiddling with different positions all the time? I have to accept that some shading occurs but not much of a problem and compensated by generation whenever daylight whether anchored or sailing.

I have a 'permanently' mounted panel on the stern rail.
I'm not going to mone it around during the day, I don't want wires trailing, I don't want to remove it or move it to go sailing.
I might augment this with some demountable panels.

With portable panels, storage on a small boat is an issue. They are big and not infinitely robust. The rigid ones are quite heavy and have sharp corners, they can do damage to other stuff.

It's bad enough that 70s and 80s yacht designers never designed in a place to keep the washboards...
Where will people keep there panels in the 2020s? wasn't asked!

 

[Kelpie]

we could try adding some flexible panels to the bimini but they’d be shaded by the boom a lot of the time.

Most of our panels *are* the bimini.
If power is marginal I swing the boom out. Preventer is always ready to rig so it's a two minute job. Also handy for deploying the flopper stopper. And keeps the boat boys at a safe distance, on one side at least.

 

[davethedog]

We have 620W of solar in the following configuration:

1. 1 hard panel on each rear side (modified rear sides to solid 25mm tubing).
2. 2 x semi flexible on the rear deck above the aft cabin (we are a centre cockpit vessel).
3. 2 x semi flexible on the bimini.

On a good day this will keep up with our usage (including running the 12V DC watermaker for a few hours if needed) but if overcast etc we think about running the generator for an hour or 2 to top the batteries up, or just not fully charge the 510Ah 12V Trojan Gel domestic battery bank every day. Would like more solar or even lithium batteries but have to draw the line somewhere.

 

[rotrax]

I installed 400W of rigid solar to our large pilothouse roof 12th May 2022. The roof is big enough to take our Talamex Superlight dinghy as well.

The controller is an EPever 30W unit, mounted to allow the shortest cable runs possible.

Since installation we have not used shorepower to charge the batteries. The solar and main engine when motoring is more than enough. We have 6 X 110W AGM's, all with spiral wound technology. The house bank is 4 top quality Lifelines, fitted in 2016 by the previous owner. The starter battery is a cheaper Chinese AGM and the Genset start battery a Lifeline, OE from when the boat was new in 2008.

When aboard or sailing we have two refrigerators and a Dometic 40 litre freezer box running 24/7. The refrigerators are keel cooled.

I installed a 3000W inverter - 1500W continuous - early this year. Our electric flat grill, Instant Pot cooker, small washing machine and mains hand held vacuum cleaner all work from this perfectly. Devices are charged from the inverter when no shorepower is available.

IMHO, it is the way to go.

More sophisticated systems would be even better.

After two hours draw using the Instant Pot using the inverter the battery voltage was 12.3 V on a dull, rainy day. Two hours later back to 12.9V.

I used Craig Solar as a supplier. Good kit, well priced, super service.