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Best electrical systems/solar systems


Sandra Bailey

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It will depend on whether you are low, medium or high users of electricity, what other generating capacity you have, and how large your battery bank is(along with what type).

Many other factors such as what roof space(narrow or widebeam), where moored, or CCing, etc etc

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2 hours ago, Sandra Bailey said:

Hi,

We are new to boating and are about to have our boat fitted out. Can anyone give us suggestions please as to which solar system to use?

 

thanks

 

I've gone with Renogy panels and MPPT charge controller. These seem to be of a decent quality. But what would you like the system to do? How much space do you want to give up on the roof, and for what sort of size boat. 

 

 

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3 hours ago, matty40s said:

It will depend on whether you are low, medium or high users of electricity, what other generating capacity you have, and how large your battery bank is(along with what type).

Many other factors such as what roof space(narrow or widebeam), where moored, or CCing, etc etc

 

And how much you wish to  spend

Also be aware that any 20 year guarantee tends only to be that the panels will have 80% of their rated output over 20 years, nothing more, so read the small print.

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I have to say that there are loads of members here who have forgotten more than I will ever know about solar systems, but I can give you my personal viewpoint, and how I approached it as a CCing liveaboard boater for the last year or so. 

 

The critical question is whether you plan to live aboard, or use the boat for holidays/breaks etc? 

I think holiday/part time boaters tend to cover more miles cruising during the times they are aboard, so their engines are doing much more charging, and solar is less important.

(So do please give a bit more detail on this point.) 

 

However, if you live aboard full time, it might be that you cruise for fewer hours per week than someone who uses their boat for breaks etc.

In that scenario your engine is being used less, and is doing less charging, so it needs to have a good charging capability, particularly in winter when there is very little solar.

So this is just a thought, but do not neglect the charging capability of your alternator.  

Mine charges at a very poor 40 amps, which in winter means I have to run the engine for 3 hours each day to generate the electricity I need- and that expends lots and lots of diesel, and adds many hundreds of hours running time to the engine, adds to servicing costs, etc. 

 

From mid-March to October, solar starts to come into its own, and the engine charging becomes less important.

My boat came with 660 watts of solar, but the panels were limited by the fact that my tired lead acid batteries were not able to store enough charge to get me through the night and, still be perky enough to run the diesel CH on a chilly Sept morning (i.e. before you are using the coal stove). 

 

My response to my batteries being poor was to install lithiums, and what I found (that is of relevance to your thread) was that the lithiums seemed to work a lot better with the solar.

I dont know the technical reasons or language, but my lead acids seemed to have some level of resistance to being charged, but the lithiums seem to soak up every bit of energy that the panels give them.

So if you are speccing out a charging system from scratch, give at least a thought to the idea of installing lithium house batteries. 

 

I've so far experienced living aboard with effectively no solar (when I had the knackered lead acids), then with 600 watts, and now I have 1.4 kw. 

Very broadly speaking, my impression is that in June and July, 660 watts will run your fridge and light electrical systems, and you wont often need to run the engine to charge.

In March, May, Aug and Sept, 660 watts is enough on some days, but on maybe 60% of the days its not quite enough, and a bit of engine running is needed to top up your batteries (which you might do anyway to get hot water).

 

What I'm finding at the moment (i.e. in the week since I upgraded my solar to 1.4kw) is that I always have enough power to run the boat systems, and I never need to run the engine unless I moor right under trees. 

This afternoon was pretty overcast, and was still getting 28 amps of charge in for a few hours. On sunny days in June/july, with 1.4kw, there will be enough power to heat the water as well as running the boat. 

 

One thing to bear in mind is dont get panels wider than 1metre, or 80cm if you're nervous. This allows you to still walk along the roof to reach the odd lock ladder that you cant step on to from the stern deck. 

 

I dont know if there is a major quality difference between panel manufacturers. My new set are supposed to be 750 watts, but they put out a bout the same power as my original set (rated at 660 watts, but also 5 years old)- so maybe quality is a thing. 

 

In terms of MPPT charge controllers, my new one is a victron, which is a bit more expensive but allows control via a phone app. And after you're wrestled with EPever's PC application and tried to configure things for a few hours, the simple victron phone app has a real appeal 

Solar is a huge subject to be fair, those are just some random thoughts based on my own experiences over the last year or so. 

 

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6 minutes ago, Tony1 said:

My new set are supposed to be 750 watts, but they put out a bout the same power as my original set (rated at 660 watts, but also 5 years old)- so maybe quality is a thing. 

 

My experience is that different brands notionally the same power can be substantially different in power output. 

 

As an example, I had one 100W Vikram panel on one of my boats which could not quite keep up with the fridge consumption. So I bought two more Victron brand 100W panels from Midland Chandlers. Surprisingly, with nominal 300W of panel now instead od 100W, the charging current less than doubled. 

 

Experiments revealed disconnecting the two x 100W Victrons results in the charge current falling by less than 50%, so I conclude the 200W of Victron panel has less output than the 100W of Vikram panel on a sunny summer's afternoon. 

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21 minutes ago, MtB said:

 

My experience is that different brands notionally the same power can be substantially different in power output. 

 

As an example, I had one 100W Vikram panel on one of my boats which could not quite keep up with the fridge consumption. So I bought two more Victron brand 100W panels from Midland Chandlers. Surprisingly, with nominal 300W of panel now instead od 100W, the charging current less than doubled. 

 

Experiments revealed disconnecting the two x 100W Victrons results in the charge current falling by less than 50%, so I conclude the 200W of Victron panel has less output than the 100W of Vikram panel on a sunny summer's afternoon. 

 

Apologies for asking the obvious, but just to make sure- were they connected in series or parallel? 

After some youtube research I came to the conclusion that parallel was better when one panel or part of a panel was obscured by tree shadow (which seems to happen to me a lot).

But it also meant that all the panels performed to the level of the weakest one. 

But with that said, if you disconnect 66% of your panels and the charge current only falls by say 45%, that seems a pretty compelling argument that the new guys are not really pulling their weight. Its kind of surprising though, because you normally associate victron with higher quality, better results, and fewer compromises. 

 

For me, its a cost/benefit question- my 375 watt panels cost £140 or so each, and they yield only about 5% more charge than my older panels of 660 watts .

But for me to buy a recognised quality brand like LG would have cost double, and I expect would have yielded maybe a 10% increase in output.

Some people will pay that premium happily for the extra 10-15%, but for me it was a step too far. 

 

I did get a victron MMPT but that was only because I spoke to 2 installers  and both said victron was the brand they strongly preferred. 

 

2 out of 2 marine electricians is not as statistically impressive as say, 8 out of ten cats, but the buggers convinced me to go victron. Well that, and the fact that the victron was only another 50 quid, as opposed to costing another 500 quid as their gear usually does.

 

 

 

Edited by Tony1
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5 minutes ago, Tony1 said:

Apologies for asking the obvious, but just to make sure- were they connected in series or parallel? 

 

Series, so the sum of the voltages is presented to the controller.

 

Victron controller too, capable of handling 100Vdc.

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8 minutes ago, Tony1 said:

 

Apologies for asking the obvious, but just to make sure- were they connected in series or parallel? 

After some youtube research I came to the conclusion that parallel was better when one panel or part of a panel was obscured by tree shadow (which seems to happen to me a lot).

But it also meant that all the panels performed to the level of the weakest one. 

But with that said, if you disconnect 66% of your panels and the charge current only falls by say 45%, that seems a pretty compelling argument that the new guys are not really pulling their weight. Its kind of surprising though, because you normally associate victron with higher quality, better results, and fewer compromises. 

 

For me, its a cost/benefit question- my 375 watt panels cost £140 or so each, and they yield only about 5% more charge than my older panels of 660 watts .

But for me to buy a recognised quality brand like LG would have cost double, and I expect would have yielded maybe a 10% increase in output.

Some people will pay that premium happily for the extra 10-15%, but for me it was a step too far. 

 

I did get a victron MMPT but that was only because I spoke to 2 installers  and both said victron was the brand they strongly preferred. 

 

2 out of 2 marine electricians is not as statistically impressive as say, 8 out of ten cats, but the buggers convinced me to go victron. Well that, and the fact that the victron was only another 50 quid, as opposed to costing another 500 quid as their gear usually does.

 

 

 

But depending on the state of the batteries you can get to the point of no matter how many panels you connect you wound have any more flow going into the batteries

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When connecting dissimilar panels in series you have to make sure that that they have similar maximum power currents because if one panel has a lower maximum power current it can throttle the other panels. If the different panels have their maximum power points at different currents, the MPPT controller can not get all the panels working simultaneously at the individual maximum powers, it has to run at a single current and at least one panel will be away from its maximum power.

 

The same applies for dissimilar panels connected in parallel, but in this case it is the maximum power voltages that should match closely.

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19 hours ago, Jen-in-Wellies said:

Don't get stick on flexible panels. If you do, don't stick them to the roof. They only seem to last a few years for many people. Get rigid panels. These should have a life of many decades. No one is entirely sure how many decades yet!

The flexi-panels I installed only lasted a year. However, that's because the roof blew off.

 

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Just now, Jen-in-Wellies said:

To be fair, rigid ones would have suffered the same fate!

The rigid ones that replaced them once the roof had been found floating a couple of km down the canal have done three years now. I think they'd sink the roof if it blew off again though...

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Shared a lock with a CC'er and asked over the 6 six years what he would change on his boat. He said the flexible solar panels were awful and were put on when his boat was built (Aintree). They pushed for flexible panels as he felt they thought it made their boat look good. He replaced with rigid and now enjoys more power and they'll last longer.....

Edited by robtheplod
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4 hours ago, robtheplod said:

Shared a lock with a CC'er and asked over the 6 six years what he would change on his boat. He said the flexible solar panels were awful and were put on when his boat was built (Aintree). They pushed for flexible panels as he felt they thought it made their boat look good. He replaced with rigid and now enjoys more power and they'll last longer.....

Also flexible panels cost about 7x more per kW than rigid ones -- together with the short lifetime, this makes them a very expensive way of generating power...

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