How to plan a solar system

British Red

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good question. 12v power for charging batteries to power my laptop and lights in my tent. x
Okay. What you have are 6 panels. They are, nominally 12V panels that, in reality run a bit higher on Voltage. They have MC4 leads on them In order to make them work, you will need a bunch of MC4 leads, a charge controller & one or more 12V batteries. I suggest Lithium Iron Phosphate batteries. Do you want me to suggest wiring arrangements etc.?
 

demented dale

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Dec 16, 2021
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Okay. What you have are 6 panels. They are, nominally 12V panels that, in reality run a bit higher on Voltage. They have MC4 leads on them In order to make them work, you will need a bunch of MC4 leads, a charge controller & one or more 12V batteries. I suggest Lithium Iron Phosphate batteries. Do you want me to suggest wiring arrangements etc.?
yes please. tell me are the mc4 leads universal? and what is a good charge controler to get . thanks xxx
 
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British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
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yes please. tell me are the mc4 leads universal? and what is a good charge controler to get . thanks xxx
Mc4 extension leads are pretty much universal but you can make your own too. MC4 is just a universal plug on a wire.

If we read your plate your panels are putting out about 6A. There is some advantage in keeping everything 12V. If you wire the panels in parallel, the Voltage stays the same, but you add 6A extra for each panel. If you use standard 6mm cables you are limited to 30A so a 5 panels.

To wire 5 panels in parallel you need one of these adapters

You will probably need some 6mm2 extension cables to connect pannels to the 5 to 1 plug


Renogy make decent charge controllers. Something like this


You would then need a few leads to connect the combiner plug to the charge controller (Mc4 to bare wire) and the charge controller to the batteries (bare wire to crimped battery lug). It's best to tin the wires with a soldering iron.
 

demented dale

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Dec 16, 2021
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Mc4 extension leads are pretty much universal but you can make your own too. MC4 is just a universal plug on a wire.

If we read your plate your panels are putting out about 6A. There is some advantage in keeping everything 12V. If you wire the panels in parallel, the Voltage stays the same, but you add 6A extra for each panel. If you use standard 6mm cables you are limited to 30A so a 5 panels.

To wire 5 panels in parallel you need one of these adapters

You will probably need some 6mm2 extension cables to connect pannels to the 5 to 1 plug


Renogy make decent charge controllers. Something like this


You would then need a few leads to connect the combiner plug to the charge controller (Mc4 to bare wire) and the charge controller to the batteries (bare wire to crimped battery lug). It's best to tin the wires with a soldering iron.
Thankyou. My brain is spannered with all that. Can I ask a question at a time please and write it down
1. Each panel is 6 amps at 12v and if i go above 30 amps then I need thicker wires? have I understood that bit right? thanks x
 

British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
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Thankyou. My brain is spannered with all that. Can I ask a question at a time please and write it down
1. Each panel is 6 amps at 12v and if i go above 30 amps then I need thicker wires? have I understood that bit right? thanks x
Quite right IF you wire the panels in parallel. You could wire in series which would increase the voltage rather than the current but with 12V panels I wouldn't
 

demented dale

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Dec 16, 2021
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Thankyou. My brain is spannered with all that. Can I ask a question at a time please and write it down
1. Each panel is 6 amps at 12v and if i go above 30 amps then I need thicker wires? have I understood that bit right? thanks x
I have decided to do two set ups. a four panel and a two panel on my van. Tell me is this what I want for the four panel set up please? x
 

demented dale

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Dec 16, 2021
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Quite right IF you wire the panels in parallel. You could wire in series which would increase the voltage rather than the current but with 12V panels I wouldn't
no you are right and i think i will just use 4 panels and keep the other two for the van for now. i found some 4 to 1 connecters and posted link below, are these what i want? ps thank you for helping me x
 
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demented dale

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I found this one
I found this controller https://www.ebay.co.uk/itm/124898733875
and this one
i want one that can live outside. i will try to box it in but basically it will be outdoors. what do you think? any good ? x
 

British Red

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Dec 30, 2005
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ah ok. so I have got my 4 in 1 connectors boxed off and now I am onto the controller. I have looked up two 30 amp models and sent links asking you what you think. sorry i should have explained. x
The great advantage of sticking to 12V & wiring in parallel is that you can use the cheaper PWM controllers like these. Personally I would like to Victron models but the Bateria model I have has been good too. They do PWM 12V 30A controllers for a decent price ready wired for MC4 so you can plug your adapters straight im

 

demented dale

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The great advantage of sticking to 12V & wiring in parallel is that you can use the cheaper PWM controllers like these. Personally I would like to Victron models but the Bateria model I have has been good too. They do PWM 12V 30A controllers for a decent price ready wired for MC4 so you can plug your adapters straight im

i think i wll get that, thank you. all i need now is the single cables that go from the 4 into 1 and continue into the charge controller. what are they please? x
 
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British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
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i think i wll get that, thank you. all i need is the single cables that go from the 4 into 1 and continue into the charge controller. what are they please? x
The 4 in 1 should plug directly into the MC4 plugs on the charge controller.

You will probably need some MC4 extension leads to extend the leads on the panels to reach the 4 in 1. You will need to lay your panels out & measure the length you need. I would make a waterproof housing for the charge controller & battery but that's super easy.
 

British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
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i think i wll get that, thank you. all i need now is the single cables that go from the 4 into 1 and continue into the charge controller. what are they please? x
Your best bet for cables is just to make them to the right length. Bateria sell a kit & it's super easy (I will do a quick video soon)


They also do the 4 in 1 connections

 

demented dale

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The great advantage of sticking to 12V & wiring in parallel is that you can use the cheaper PWM controllers like these. Personally I would like to Victron models but the Bateria model I have has been good too. They do PWM 12V 30A controllers for a decent price ready wired for MC4 so you can plug your adapters straight im

BR i am about to order this. Am I doing right? dont want bluetooth anything xx

 

British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
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BR i am about to order this. Am I doing right? dont want bluetooth anything xx

It sounds like the sort of thing you need & you can always send it back!
 

demented dale

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Dec 16, 2021
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Your best bet for cables is just to make them to the right length. Bateria sell a kit & it's super easy (I will do a quick video soon)


They also do the 4 in 1 connections

Thank you. Ref;the 4 into 1 leads. I cant work it out though if you get 2 leads (enough to connect four panels) or just one for £19. I am very nearly there now. xxx
 

Moondog55

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Sep 17, 2023
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My Australian experience is that you are best to keep your 12V systems separate from your house system. The car based system is a quad of 100Watt panels a controller and two 120AH Lithium Ion Phosphate batteries.
The house system is 3 banks totaling 12.6KVA running through a 240V converter and grid connected, we are saving for a house battery but we need about $16k- for that. We are in a marginal area and need 12.6 to get enough power in winter. In summer we could export 30 to 40 Kv to the grid on a good day if we were allowed but in winter we really need another bank of panels that could be disconnected in summer
Melbourne Victoria if you want to check out the insolation data for this area
 
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