The Big Solar Install

[Alan de Enfield]

5 minutes ago, ASupertramp said:

Ok so, if a 60a controller will suffice, can I simply use one of my 30a controllers (that I already have) wired into two panels (800) and the other taking a feed from the other panel? 
 

 

 

Also consider which panels you buy - I have 120v panels (many are just 19v, or 30 volt) this means that (in theory) for every amp coming out of the panel I get 10 amps going into the batteries - In reality due to losses, and charging at 14+ volts,  and not always having enough Sun to make 120v, I usually get 7x or 8x rather than 10x.

 

If you use (say) 19v panels you get roughly 1.5x the panel current going into your batteries.

 

You will be gald of MPPT controlers at each end of the season' as test suggest that you actually get 30%more output than with PWM controllers, so in October - you may get 4 amps instead of 3 amps

[ditchcrawler]

36 minutes ago, Tony Brooks said:

 

And in addition to Dora's point it helps them sell punter more expensive equipment.

 

Yes, but have you looked into series panel  connection? Not only starting to charge sooner but thinner cabling required so may be cheaper cables.

There is also a school of thought that paralleled is better and that series doesn't offer any advantage

[robtheplod]

1 hour ago, Loddon said:

If panels are flat you only lose 10% compared to having them angled at 30deg.

The bonus being you get sun from any direction not just the one that the panel is pointing in.

Those panels the OP is looking at would look really nice flat also!

[ditchcrawler]

Just had to post this 

[IanD]

1 hour ago, Loddon said:

If panels are flat you only lose 10% compared to having them angled at 30deg.

The bonus being you get sun from any direction not just the one that the panel is pointing in.

Loss is a bit more than that -- yield in the UK for flat-mounted panels is 84% of that for south-facing ones at 35 degrees.

 

But no need to move them, or hope that the boat won't  be moored N-S...

[GUMPY]

I did originally think 15% but this persuaded me otherwise.

 

 

 

 

Edited June 16, 2022 by Loddon

[Tony Brooks]

33 minutes ago, ditchcrawler said:

There is also a school of thought that paralleled is better and that series doesn't offer any advantage

 

Agreed, but the OP showed no signs that he had even considered series connection. All I am suggesting is that he does a bit of research about it.

[ASupertramp]

1 hour ago, Tony Brooks said:

 

Agreed, but the OP showed no signs that he had even considered series connection. All I am suggesting is that he does a bit of research about it.

I had considered series but discounted it for the previously mentioned concern regarding shading.

 

As a happy compromise, it looks like a 100/50 to run 2x400w and a 100/30 for the other panel seems like a nice setup, ticking the cost box and adding in some redundancy. 

[IanD]

2 hours ago, Loddon said:

I did originally think 15% but this persuaded me otherwise.

 

 

 

 

 

or alternatively, averaged over the year in the Midlands...

[GUMPY]

5 minutes ago, IanD said:

 

or alternatively, averaged over the year in the Midlands...

The last bit convinces me that flat panels on a boat will out perform angled panels as you will get a constant 84%, you will get longer hours of charging*  and not have to worry about which way the boat is pointing.

 

* My panels at home face due south and don't produce more than 50% of rated output before 9am or after 5pm due to the movement of the sun, I need to have a chat with the chap up the road that had panels split 50/50 on an East / West facing roof to see what his output is.

 

[IanD]

18 minutes ago, Loddon said:

The last bit convinces me that flat panels on a boat will out perform angled panels as you will get a constant 84%, you will get longer hours of charging*  and not have to worry about which way the boat is pointing.

 

* My panels at home face due south and don't produce more than 50% of rated output before 9am or after 5pm due to the movement of the sun, I need to have a chat with the chap up the road that had panels split 50/50 on an East / West facing roof to see what his output is.

 

The figures include the effect of not just average power over the day but also clouds, radiation from the sky as well as the sun, what happens in mornings and evenings, and what happens over the year.

[ASupertramp]

Now that the MPPT issue has been cleared up, I've had a look at my space for mounting everything, seems like it should be enough. I'll put a piece of ply over the tongue and groove so that there is a little more depth to screw in to.

 

 

[Alan de Enfield]

 

 

O' dear I spy Twin and earth grey cable .

 

THATS A HUGE NO NO for boat wiring.Hopefully you know that and its not some thing that you installed.

 

If you are doing the rewiring yourself then make sure you use cables and installation practices to ISO 13297:2020 which covers 'small craft wiring'.

 

 

 

 

Edited June 16, 2022 by Alan de Enfield

[ASupertramp]

3 hours ago, Alan de Enfield said:

 

Also consider which panels you buy - I have 120v panels (many are just 19v, or 30 volt) this means that (in theory) for every amp coming out of the panel I get 10 amps going into the batteries - In reality due to losses, and charging at 14+ volts,  and not always having enough Sun to make 120v, I usually get 7x or 8x rather than 10x.

 

If you use (say) 19v panels you get roughly 1.5x the panel current going into your batteries.

 

You will be gald of MPPT controlers at each end of the season' as test suggest that you actually get 30%more output than with PWM controllers, so in October - you may get 4 amps instead of 3 amps

 

Here are the panel specs:

Watts	400
Maximum Power Voltage - Vmpp(V)	41
Maximum Power Current - Impp(A)	9.76
Open Circuit Voltage - Voc(V)	49.5
Short Circuit Current - Isc (A)	10.12
Panel Efficiency (%)	21.3
Height (mm)	1646
Width (mm)	1140
Thickness (mm)	30
Weight (KG)	19
Cell Type	Mono Percium

 

 

So 41v?

Just now, Alan de Enfield said:

 

 

 

O' dear I spy Twin and earth grey cable .

 

THATS A HUGE NO NO for boat wiring.Hopefully you know that and its not some thing that you installed.

 

If you are doing the rewiring yourself then make sure you use cables and installation practices to ISO 13297:2020 which covers 'small craft wiring'.

 

 

 

 

 

The boat was full of grey twin and earth when I bought it, couldn't work out what was 12v and what was 230v, all been ripped out since. I think that's probably the last remaining remnant. 

That's the plan and is why the solar installation has expanded somewhat to include rewiring the batteries, shore power etc as I'm fairly certain it's all on the cusp of being unsafe. 

[Alan de Enfield]

1 minute ago, ASupertramp said:

 

Here are the panel specs:

Watts	400
Maximum Power Voltage - Vmpp(V)	41
Maximum Power Current - Impp(A)	9.76
Open Circuit Voltage - Voc(V)	49.5
Short Circuit Current - Isc (A)	10.12
Panel Efficiency (%)	21.3
Height (mm)	1646
Width (mm)	1140
Thickness (mm)	30
Weight (KG)	19
Cell Type	Mono Percium

 

 

So 41v?

 

 

No,

VoC is 49.5V

[ASupertramp]

Solar panels are arriving on Tuesday. The rest of the equipment on Monday. Just need to size the correct cabling and order. 
 

Any thoughts of BMV’s? I’m aware they can’t be taken as gospel. 

[Tony Brooks]

1 hour ago, ASupertramp said:

Solar panels are arriving on Tuesday. The rest of the equipment on Monday. Just need to size the correct cabling and order. 
 

Any thoughts of BMV’s? I’m aware they can’t be taken as gospel. 

As long as you ignore the % charged and use tail current to know when the batteries are fully charged they are probably all as accurate as each other. Some are easier to read than others.

[Sea Dog]

16 hours ago, Tony Brooks said:

As long as you ignore the % charged and use tail current to know when the batteries are fully charged they are probably all as accurate as each other. Some are easier to read than others.

Agree - although he should take into account the maximum current capacity of the shunt. 

[ASupertramp]

20 hours ago, Tony Brooks said:

As long as you ignore the % charged and use tail current to know when the batteries are fully charged they are probably all as accurate as each other. Some are easier to read than others.

 

4 hours ago, Sea Dog said:

Agree - although he should take into account the maximum current capacity of the shunt. 

Noted, thank you. Shunt is 500amps. 
 

 

Victron Multiplus II 3000 ordered, additional cabling ordered. Picked up the ply today so that I can start laying out the board on Monday. 

Edited June 18, 2022 by ASupertramp

[ASupertramp]

 

Crude wiring diagram but helps me start thinking about how things will look. 

[Tony Brooks]

Please will you give me a link to the Cyrix unit. As far as I can see they are just voltage sensitive relays so would just link two batteries. Yours seem to be linking a number of charge sources.

[ASupertramp]

5 minutes ago, Tony Brooks said:

Please will you give me a link to the Cyrix unit. As far as I can see they are just voltage sensitive relays so would just link two batteries. Yours seem to be linking a number of charge sources.

Do you mean the box in the middle? It’s a Lynx Power in, effectively just a bus bar with fuses…

[blackrose]

On 16/06/2022 at 16:01, Alan de Enfield said:

 

 

O' dear I spy Twin and earth grey cable .

 

THATS A HUGE NO NO for boat wiring.Hopefully you know that and its not some thing that you installed.

 

If you are doing the rewiring yourself then make sure you use cables and installation practices to ISO 13297:2020 which covers 'small craft wiring'.

 

How do all those loose cables flapping around pass any BSS inspection? Shouldn't they be clipped to a bulkhead, etc, not just cable tied in a big bunch and left loose? 

[Tony Brooks]

1 minute ago, ASupertramp said:

Do you mean the box in the middle? It’s a Lynx Power in, effectively just a bus bar with fuses…

 

Thanks, that explains it.

[ASupertramp]

2 minutes ago, blackrose said:

 

How do all those loose cables flapping around pass any BSS inspection? Shouldn't they be clipped to a bulkhead, etc, not just cable tied in a big bunch and left loose? 

Absolutely no clue how it passed, hence my now 2 year effort to rebuild, finishing with the engine room electrics!