Question about solar panel setup and garden lighting - Is this setup Right?

[Earunder]

Hi all,

Completely new to the solar panel era and am pretty much a novice in electrical circuits but love learning new things and am fascinated by how things work and run.

From my very basic reading up so far I've decided to go out and purchase a little setup to ween myself into this easily.

I've just bought:
1 x 60W Solar Panel
1 x 20Amp Charge Controller
1 x 90Ah 12v Battery
1 x 400w 12v -> 230 240v inverter
1 x 8 Way Extension Lead Surge Protector ( 13A Fused )
6 x 5w Garden Lights w/Bulbs

The solar panel stats are:
Voc: 21.6V
Vpm: 18V
Short circuit current (Isc): 3.05A
Working current (Ipm): 2.77A
Output Tolerance: ±3%

Question 1) Would 5.75amp 12v wire running from the panel to the charge controller be ok?
I was thinking of going upto 20 to max with the controller input, but for now I was just going to use what I have laying about.

Question 2) Would a standard car battery cable set from the charge controller to the battery suffice? I can't imagine

Question 3) IS the final setup below correct or am I missing something or anything?

Thanks in advance!

 

[ban-all-sheds]

Why not just use 12V lights?

 

[Earunder]

Thanks for the reply!

Sorry I forgot to explain the light setup.

4 of the lights are going to be over 30m from the extension. 2 within 5m

Wouldn't it lose power over that distance on a 12v feed? Another reason why I'm running each light off separate plugs. Unless I'm wrong or I've not understood something?

 

[winston1]

Wouldn't it lose power over that distance on a 12v feed?

Just use thicker cable. Cheaper than an inverter.

 

[JohnW2]

Just use thicker cable. Cheaper than an inverter.

Agreed, but it appears that the OP has already bought the inverter.

Kind Regards, John

 

[ban-all-sheds]

Wouldn't it lose power over that distance on a 12v feed?

Not significantly with the low currents involved.

Another reason why I'm running each light off separate plugs.

Not necessary.

 

[JohnW2]

Not significantly with the low currents involved.

That obviously depends upon the size of cable the OP was thinking of using.

We appear to be talking of what would be about 2.5A at 12V. If, say, 1mm² cable were used, that would, by my reckoning, be a voltage drop of about 3.3V over 30m - pretty significant with a 12V supply.

Kind Regards, John

 

[ban-all-sheds]

I guess it would have helped if I'd thought about a 30W load, not 5W.

Although it's the old multi-drop problem - over the last segment the load is only 5W.

 

[JohnW2]

I guess it would have helped if I'd thought about a 30W load, not 5W. Although it's the old multi-drop problem - over the last segment the load is only 5W.

Yes, but ....

4 of the lights are going to be over 30m from the extension. 2 within 5m

... so 'over 30m' of cable is going to be carrying at least two-thirds of the total current. I would think that he would probably have to be looking at a very minimum of 2.5mm² cable.

Also, if the 'bulbs' happen to be LEDs with appalling PF's, the current could actually be a lot higher than we are estimating.

Kind Regards, John

 

[Earunder]

Good morning gents.

Thank you for your replies.

Yes, but ....
... so 'over 30m' of cable is going to be carrying at least two-thirds of the total current. I would think that he would probably have to be looking at a very minimum of 2.5mm² cable.

Also, if the 'bulbs' happen to be LEDs with appalling PF's, the current could actually be a lot higher than we are estimating.

Kind Regards, John

The 4 lights that are over 30m in total distance are : 4 x 5w (40w EQV) 6500k Cool White Auraglow LED Light Bulb - Operating Voltage: 220-240v (https://goo.gl/gwYuuY)

Maybe I've gone OTT but just got a £6 safety adaptor RCD for the 4 that I'll link in parallel.

Might need to go and get some bigger cable then to run the 4. Any recommendations on cable for underground?

Again maybe OTT but should I add a junction box at the end? I plan on adding more in the future when / if I upgrade the system. If it works good enough that is.

 

[JohnW2]

Maybe I've gone OTT but just got a £6 safety adaptor RCD for the 4 that I'll link in parallel.

If the circuit you're running these lights from is already RCD-protected, there's no real need/point in adding another (except as a 'backup' in case the primary RCD becomes faulty), but it won't do any harm.

Might need to go and get some bigger cable then to run the 4.

I'm afraid you have been a bit confused by people talking about 12V lights. If, as is the case with yours, they are mains voltage ones, then virtually any size cable would be adequate.

Any recommendations on cable for underground?

In practice, about the only acceptable cable for burying underground is Steel Wire Armoured ('SWA') cable. Connecting to it ('terminating the cable' in electrician-speak) requires some skill/experience, and if you don't have that, you would be advised to employ an electrician.

Again maybe OTT but should I add a junction box at the end? I plan on adding more in the future when / if I upgrade the system. If it works good enough that is.

That would do no harm - it's up to you. Again there would be the issue on terminating the SWA into the junction box.

Kind Regards, John

 

[Earunder]

Just use thicker cable. Cheaper than an inverter.

Wouldn't I have needed a transformer, or could I have just connected directly to the battery using a connector? This is a "testing / bedding in attempt" to check on power usage, etc. I will actually require around 30 lights in the long run if this goes well, so it'll probably be 8-10 on each link.

Although I managed to get the inverter as above for £25 and the lamps I plan to add to the link are:
(4 x 5w (40w EQV) 6500k Cool White Auraglow LED Light Bulb - Operating Voltage: 220-240v (https://goo.gl/gwYuuY))

 

[Earunder]

.
I'm afraid you have been a bit confused by people talking about 12V lights. If, as is the case with yours, they are mains voltage ones, then virtually any size cable would be adequate.

Ah ok! Thank you for clearing that one up

.
In practice, about the only acceptable cable for burying underground is Steel Wire Armoured ('SWA') cable. Connecting to it ('terminating the cable' in electrician-speak) requires some skill/experience, and if you don't have that, you would be advised to employ an electrician.

Ok, I'll give the installation a pass and will get an electrician if it all goes as plan to wire them in outside.

Thanks again for your response John!

 

[JohnW2]

Wouldn't I have needed a transformer, or could I have just connected directly to the battery using a connector?

No. If you had been using 12V bulbs, you could just have connected them straight to the battery.

This is a "testing / bedding in attempt" to check on power usage, etc. I will actually require around 30 lights in the long run if this goes well, so it'll probably be 8-10 on each link.

What do you mean by 'each link'? If the ultimate plan is to have that many lights, then the 12V option would have been even more problematical (in terms of cable size).

Kind Regards, John

 

[JohnW2]

Ok, I'll give the installation a pass and will get an electrician if it all goes as plan to wire them in outside.

That makes sense if you have no experience of using SWA. If you are interested in knowing what would be involved in 'terminating' it, you could look at our wiki - (click here) .

One issue you'll need to discuss with your electrician is the suitability of the lights you have for direct connection to SWA cable - it could be that some 'workarounds' (maybe involving junction boxes) might be necessary.

Kind Regards, John