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Appropriate solar


captain flint

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I sent an enquiry to the folks at bimble and they sent me a link to a basket with what they reckon I need. 

 

http://click.bimblesolar.com/wf/click?upn=iQzGkz6GwKVnjfYsDWtViS2nqVxY6VvxNw3lGNx4-2FSS5-2FooTxOXPgD6ejIPYyrmOO-2F-2FZ9xYviClY3yc7fPSwgYdn3j28D5kwRIB1TDukDOfJTO0LHjjReHbhMPS-2F4d7lw8YD-2FZNn7wfY-2FuHioeMxRf1n6w3UPQLSU-2BgwIjUuPayAW9qXGLeauPGV51VM7TBR_tAklq2Mf0C5rGjkiXwrtnd0CGG1CAI4n3pvBY9TfcvPynr12LTN7dQpzhddiMahP-2FeHGrsm-2BVoV3L6MZVKN3jgyurf1Q6xw0Azy6NllaSDqthUkJwFeDr9BRxBMgj-2F7cNAlemWOHpL11pBVtXjj5c60HRFW5Kv-2FPOAj4TkgkcehrrJ5sg8SFq8QoWnyTN1rXf7KQtbRQeOE6acyUF45ObA-3D-3D

 

Does it look OK? Seems OK to me but being ill informed and slightly thick I thought I should check. 

 

I want a little solar as back up and support rather than expecting too much from it. Prefer walk on for various reasons. Main thing is there's a little 12v computer fan vent in the toilet that needs to run. I am getting a low voltage cut off fitted, too, so hopefully won't have any nasty surprises. 

Edited by captain flint
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Looks OK. Monitor and controller matched to the capacity of the panels. All the connectors splitters, wires and cable glands you are likely to need for a neat installation. How are you planning to split the panels, series, parallel, mixed series and parallel? It'll probably need a few other connectors for the connection to batteries.

 

Jen

Edited by Jen-in-Wellies
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personally i would forget the DIN rail and the MCB and instead fit an automotive blade fuse Y holder. I assume this is for the controller to battery lead and if so it needs to be near batteries and that location may well  get damp, under a cruiser stern running with condensation damp!

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1 hour ago, Tony Brooks said:

personally i would forget the DIN rail and the MCB and instead fit an automotive blade fuse Y holder. I assume this is for the controller to battery lead and if so it needs to be near batteries and that location may well  get damp, under a cruiser stern running with condensation damp!

My guess is that Bimble specify it as a kind of on/off switch for the panels and, if so, it isnt actually necessary at all. I've got one of these:

 

https://www.12voltplanet.co.uk/waterproof-switchable-surface-mounted-circuit-breakers.html

 

and find it handy if I want to switch the solar off - yesterday I wanted it off to have some welding done in the engine space.

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On 14/07/2018 at 12:01, Jen-in-Wellies said:

Looks OK. Monitor and controller matched to the capacity of the panels. All the connectors splitters, wires and cable glands you are likely to need for a neat installation. How are you planning to split the panels, series, parallel, mixed series and parallel? It'll probably need a few other connectors for the connection to batteries.

 

Jen

I wish I knew! 

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4 hours ago, captain flint said:

I wish I knew! 

Each panel will have up to 48V on it when unloaded, but up to around 36V at optimum power. If all the panels are in series, then the total will be between 36x4 = 144V and 48*4 = 192V. However the solar controller has a maximum input voltage of 150V, so there is a high risk of exceeding this, or pushing towards the maximum and damaging the controller.

If the panels are in parallel, then the voltage will be that of one panel, 36 to 48V in bright sun. However the current through the wires will be four times as high and can lead to resistive losses.

A mix of series and parallel will give a voltage of 72 to 96V and mid range in the current. This is what I would go with if it was me setting up this array. Pics below. Note that some of these voltages are enough to give you quiet a jolt. Do your wiring with good opaque blankets covering the panels and take precautions.

 

Jen

 

 

parallel.png

series.png

mixed.png

Edited by Jen-in-Wellies
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I have a pair of circuit breakers, on Bimble's advice. You can see the DIN rail towards the end of these photos.  It's inside, not in the wet.

It's quite handy to be able to turn the solar panels off safely, the connectors do say "not to be disconnected under load"....  The other gadget I have just added is a temperature sensor that measures the termperature of the battery compartment. I would advise buying a crimping tool for the MC4 connectors, though youtune suggests you can manage without!

https://nbsg.wordpress.com/2018/04/23/fitting-the-solar/
 

dsc_4370.jpg

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For big installs there's double pole solar DC isolators available:

 

https://www.electricalguys.co.uk/salzer-dc-isolator-for-solar-installs-h226-81400-710n1.html

 

If you squint at the pic you can just make out that each pole uses 2 contacts in series, I guess it's just a 4 pole switch rewired appropriately. For a modest 36V or 72V install a standard 2 pole MCB might work just fine.

 

More info: http://www.plctalk.net/qanda/showthread.php?t=95968

 

Edit: Squinting at the above pic in this topic it looks like the breakers are rated 125V DC so that should be fine for the solar side.

Edited by smileypete
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On 14/07/2018 at 11:51, captain flint said:

 

I want a little solar as back up and support rather than expecting too much from it. Prefer walk on for various reasons

£600 quid for that purpose seems hugely over the top to me.  Walk on panels are higher cost - lower output. Why not consider a narrow standard panel - easily available from about 2' wide or a little more, so you can just walk past it.

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49 minutes ago, Sea Dog said:

£600 quid for that purpose seems hugely over the top to me.  Walk on panels are higher cost - lower output. Why not consider a narrow standard panel - easily available from about 2' wide or a little more, so you can just walk past it.

Also walk on, really means in soft shoes.   Just because you can walk on them, doesn't really mean you should.

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5 hours ago, Robbo said:

Also walk on, really means in soft shoes.   Just because you can walk on them, doesn't really mean you should.

I wasn't planning on walking on them, but it's good to know if you happen to misplace a foot it shouldn't matter, plus no trip hazard. Main thing is that I've heard of regular panels being nicked. Then again, I do have insurance, I guess... 

Thanks for all the help everyone, appreciated. 

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21 minutes ago, captain flint said:

Main thing is that I've heard of regular panels being nicked. Then again, I do have insurance, I guess... 

With the low price of panels these days, unless you have 'mega-watts' their value is probably less than your Insurance Excess, &/or the amount your premium will increase by over the next few years because of a claim.

With panels that can be obtained at under 50p per watt, they are not really worth stealing because of the size and the likely hood they are miles from anywhere and cumbersome to carry to a truck (they won't fit in a car).

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11 minutes ago, Alan de Enfield said:

With the low price of panels these days, unless you have 'mega-watts' their value is probably less than your Insurance Excess, &/or the amount your premium will increase by over the next few years because of a claim.

With panels that can be obtained at under 50p per watt, they are not really worth stealing because of the size and the likely hood they are miles from anywhere and cumbersome to carry to a truck (they won't fit in a car).

Didn't @leeco panels get knicked over winter tho, so yes it does happen.

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I have heard the life expectancy of walk on / stick on panels is low a couple of years seems typical, mainly due to temperature ageing by being on a hot steel roof.  They also perform poorly on sunny days because they get too hot, high temperature can halve the theoretical output. Rigid panels also drop amps when hot but being better ventilated you are looking at a 10%  drop.

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32 minutes ago, rusty69 said:

No. 

 

Although i do have a flexible panel too. 

Then you missed my point,  oh corroded one, which was that flexi walk ons, size for size and pound for pound, produce less than normal panels whilst creating a (potential) rust trap. That's not to say they don't have their place, and they can look better too.

 

What's your flexi doing - BT and/or engine start?

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20 hours ago, Detling said:

I have heard the life expectancy of walk on / stick on panels is low a couple of years seems typical, mainly due to temperature ageing by being on a hot steel roof.  

Two years?? Right. That's certainly got me thinking. The rust issue, too. 

 

The fact the walk on ones look better was a factor, as well as the other things I mentioned. 

 

I don't necessarily mind if they are pound for pound less powerful and more expensive if they look better and are less delicate and it's a one off expenditure. Or at least, one that comes round a lot less often than every two years! Does that really sound about right? That would draw a line under the whole thing. 2 years would be way too short a life expectency to get my vote (and bucks)

Edited by captain flint
Typos. Oh, and one too many - even for me - exclamation marks
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24 minutes ago, captain flint said:

Two years?? Right. That's certainly got me thinking. The rust issue, too. 

 

The fact the walk on ones look better was a factor, as well as the other things I mentioned. 

 

I don't necessarily mind if they are pound for pound less powerful and more expensive if they look better and are less delicate and it's a one off expenditure. Or at least, one that comes round a lot less often than every two years! Does that really sound about right? That would draw a line under the whole thing. 2 years would be way too short a life expectency to get my vote (and bucks)

Add in having to re-paint your roof every time (2 years ??) that you replaced the panels

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22 minutes ago, captain flint said:

Two years?? Right. That's certainly got me thinking. The rust issue, too. 

 

The fact the walk on ones look better was a factor, as well as the other things I mentioned. 

 

I don't necessarily mind if they are pound for pound less powerful and more expensive if they look better and are less delicate and it's a one off expenditure. Or at least, one that comes round a lot less often than every two years! Does that really sound about right? That would draw a line under the whole thing. 2 years would be way too short a life expectency to get my vote (and bucks)

Rigid silicon panels from the major manufacturers have a life expectancy of at least 20 years. No one really knows for sure just how long they'll last, but that is the timescale used for calculating payback on big solar power installations. The oldest of mine are over ten years now.

 

Jen

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