Just now, Nexuss said:

Yes that is perfectly safe and its what i am running currently. Heres the specs from the inverter right now.

PV1

289.60V

10.70A

3.058kW

PV2

297.20V

10.70A

3.123kW

Thanks!

Soooo, a friend of mine has been able to source some 540w for R6.60 per watt. (compared to the R6.90 for the 455w

Knowing this, would it be a good idea to get the 540w?

If I get 12 x 540w, the voc will be 297v per string. (6 panels per string) 

If I get 14 x 445w the voc will be 376v per string. (7 panels per string). 

I know with the 540w, the voltage will be on the low side. Im thinking if I add another 2x540w (total 14) at a later stage then I will have more production in winter. This might be better than having 16 x 455w.

Or will having 14x540w (7560w) be a waste because I only have a 5kw inverter. 

Thoughts please

think about it in terms of an inverter upgrade down the road, 14x 540w will be wasted now but if and when you get an 8kw inverter, your almost there

it may not seem like it now, but that itch will likely come up needing scratching...

12x 540w will put you at 6480w with little to no wastage, keep in mind your actual pv wattage could easily be 75% - 90% of name plate.

75% odd with no cleaning of panels, soiling, bird debris etc. around 90% if you do the maintenance. even so, 75% of 6480w puts you at 4860w actual.

with that price just go for it, and get the firmware upgrade

just make sure you can get the panels again in the future if an upgrade could occur, supply is sometimes sketchy.

Edited January 13, 20224 yr by Nitrious

12 minutes ago, Terminal3k said:

Soooo, a friend of mine has been able to source some 540w for R6.60 per watt. (compared to the R6.90 for the 455w

Knowing this, would it be a good idea to get the 540w?

If I get 12 x 540w, the voc will be 297v per string. (6 panels per string) 

If I get 14 x 445w the voc will be 376v per string. (7 panels per string). 

I know with the 540w, the voltage will be on the low side. Im thinking if I add another 2x540w (total 14) at a later stage then I will have more production in winter. This might be better than having 16 x 455w.

Or will having 14x540w (7560w) be a waste because I only have a 5kw inverter. 

Thoughts please

14 of the 540w panels will be great , go for it  !

10 minutes ago, Nitrious said:

think about it in terms of an inverter upgrade down the road, 14x 540w will be wasted now but if and when you get an 8kw inverter, your almost there

I dont think it will be wasted , cloudy days and in winter will balance out the excess of the summer. I also dont think an 8kw inverter would make sense as you are extending the payback period of the system considerably. You need to be above the 5kw threshold a big amount of time to justify the costs of the 8kw inverter . I produced 50kwh today and bought only 5kwh with my 5kw sunsynk. 

Nexuss has a point, 14x 540w will cover you better in winter and cloudy days. 

I'm actually wondering if 2x 5kw inverters dont make better sense than 1x 8kw inverter

you get more capacity, more mppt's, price point is similar, but thats a whole other conversation

The 540’s will be easier to find in the future as the 455’s become obsolete like the 300 plus watt panels anymore

Thanks all. Makes sense. I will go for 12 x 540w then get another 2 at a later stage. 

1 hour ago, Tariq said:

The 540’s will be easier to find in the future as the 455’s become obsolete like the 300 plus watt panels anymore

lol, my first solar system was 12x 245w and a infiniti grid tie inverter with 8x sla batts, talk about the old days, and it just never seemed to make enough power, ever

but I got it free, so at least, was part of testing out a green estate solar installation about 5-7years ago, the methodology the installers wanted to use was very much in question, all the time, and they pivoted like nobody's business, the math just didn't ever make sense though.

these days everything is different of course, and 700w panels are already available as an example, nevermind li ion batteries as well, at that time li ion was still in its infancy, with prices to match.

and "creaming" the power requirements of complexes/estates has become commonplace, for "free", but the generated unit prices track eskom so yearly increases are guaranteed. an obvious but huge scam imo.

got tied up in giving the go ahead for another 17 complexes/estates on about at the time, told everyone to wait, prices will come down (solar not eskom), and pointed out the ongoing loss of value yearly, first/second years were great, but quickly became an issue after that.

Edited January 13, 20224 yr by Nitrious

2 hours ago, Terminal3k said:

Soooo, a friend of mine has been able to source some 540w for R6.60 per watt. (compared to the R6.90 for the 455w

Knowing this, would it be a good idea to get the 540w?

If I get 12 x 540w, the voc will be 297v per string. (6 panels per string) 

If I get 14 x 445w the voc will be 376v per string. (7 panels per string). 

I know with the 540w, the voltage will be on the low side. Im thinking if I add another 2x540w (total 14) at a later stage then I will have more production in winter. This might be better than having 16 x 455w.

Or will having 14x540w (7560w) be a waste because I only have a 5kw inverter. 

Thoughts please

This is exactly what I was alluding to earlier, my apologies if I wasn't clear enough.

I have never yet met anyone who ever bought too many solar panels. The majority (myself included) have always ordered another 4-10 panels within the first 6 months. So unless you have maxed out all your MPPTs (and possible Aux inputs) I would suggest planning for it upfront, ensure that placement, spacing and fixtures of panels, as well as wiring quality and thicknesses take into account future expansion needs.

Even if you have maxed the MPPTs, who knows, your needs may change because an elderly parent or two may join the household tomorrow, or a destitute brother or sister-in law, and you may need to add another inverter in parallel.

Planning for it upfront means less waste in 3-6 months time.

35 minutes ago, YellowTapemeasure said:

This is exactly what I was alluding to earlier, my apologies if I wasn't clear enough.

I have never yet met anyone who ever bought too many solar panels. The majority (myself included) have always ordered another 4-10 panels within the first 6 months. So unless you have maxed out all your MPPTs (and possible Aux inputs) I would suggest planning for it upfront, ensure that placement, spacing and fixtures of panels, as well as wiring quality and thicknesses take into account future expansion needs.

Even if you have maxed the MPPTs, who knows, your needs may change because an elderly parent or two may join the household tomorrow, or a destitute brother or sister-in law, and you may need to add another inverter in parallel.

Planning for it upfront means less waste in 3-6 months time.

Makes a lot of sense, but hoping I'm not getting an extra family member anytime soon xD

Thanks for your input 

ART Solar(in Durban) has quoted me R6,8 / watt on their 550 watt panels, has anyone got any experience with their panels, also looking at 12 panels(6 east and 6 west) with an 8kw Sunsync? Attached datat sheet on the panelsART550 Panels.pdf

I run 2 strings of 4 panels 495w JA solar on my 5kw Axpert - rather happy with them, they work great even in rainy low light conditions.

1 hour ago, John Know said:

has anyone got any experience with their panels

I had Art Solar panels installed at my previous house. I never had any issues with them and they performed well, exceeding their rate output power on many occasions.  

Thanks Don, I like they are local to me so there is someone I can physically go see at the factory if I have any issues

3 hours ago, John Know said:

ART Solar(in Durban) has quoted me R6,8 / watt on their 550 watt panels, has anyone got any experience with their panels, also looking at 12 panels(6 east and 6 west) with an 8kw Sunsync? Attached datat sheet on the panelsART550 Panels.pdf

thats a good price. Did they say if they had other high watt panels in stock?

Not sure but I went to their factory in Durban there is alot of stock in there so assume so 

Don't forget to count the cost of the mounting system.  This is typically some cost per panel, irrespective of the panel size.  The calculation can look very different if your mounting system is suddenly 20% more expensive because you picked more, lower yielding panels.

Some practical feedback from my similar solar panel setup. The theoretical values you will never achieve. Your fixed azimuth and tilt of your installation will also have a big influence on the actual values achieved.
My system consists of 12 X JA 535W panels in 2 X 6 strings. The 535W and 540W panels are near identical in VOC and Amps. My roof is a 30deg pitch and my house faces around 20deg North East. Thus my maximum solar radiation occurs before the sun is at it's highest point. 
My two strings on average give me between 265 -280V each on a clear sunny day.
I have never ever had more than 4,8kW from the panels when using the 5kW limit of my Growatt 5000ES whilst the batteries are charging. 
So either the MPPT is limiting this or the fixed solar installation is just what it is. No more to be expected. I use the free version of the Solcast forecasting tool and that in general is pretty accurate in terms of what I actually get out of the system and what they calculate it would/should be.
My single Hubble AM2 is normally full by 08:30 -09:00 depending on solar radiation. The battery on average is between 30-40% SOC before recharge starts.
My household has never been a power hog. My monthly usage before I installed the system last year was 180-250kWh.
Now I run mostly off Grid just with the solar and tend to not be so stingy anymore. The system was installed as an off grid and I have a change over at my DB board to select either Solar or Grid. 
The only thing I am considering is another Battery. But the finances for that are another story.
 This is the summary for the time period since I got Solar Assistant.

Also a snip of the Solcast tool forecast based on my system info. The forecast is limited to 3 days for the free version. 

Edit: The reason my normal usage is on the low side is that I have had a gas stove for a long time already and I also have a flat panel solar geyser conversion. Yes I do use my solar panels now in the mornings on the geyser element too. 

Edited January 26, 20224 yr by zsde

19 hours ago, zsde said:

Some practical feedback from my similar solar panel setup. The theoretical values you will never achieve. Your fixed azimuth and tilt of your installation will also have a big influence on the actual values achieved.
My system consists of 12 X JA 535W panels in 2 X 6 strings. The 535W and 540W panels are near identical in VOC and Amps. My roof is a 30deg pitch and my house faces around 20deg North East. Thus my maximum solar radiation occurs before the sun is at it's highest point. 
My two strings on average give me between 265 -280V each on a clear sunny day.
I have never ever had more than 4,8kW from the panels when using the 5kW limit of my Growatt 5000ES whilst the batteries are charging. 
So either the MPPT is limiting this or the fixed solar installation is just what it is. No more to be expected. I use the free version of the Solcast forecasting tool and that in general is pretty accurate in terms of what I actually get out of the system and what they calculate it would/should be.
My single Hubble AM2 is normally full by 08:30 -09:00 depending on solar radiation. The battery on average is between 30-40% SOC before recharge starts.
My household has never been a power hog. My monthly usage before I installed the system last year was 180-250kWh.
Now I run mostly off Grid just with the solar and tend to not be so stingy anymore. The system was installed as an off grid and I have a change over at my DB board to select either Solar or Grid. 
The only thing I am considering is another Battery. But the finances for that are another story.
 This is the summary for the time period since I got Solar Assistant.

Also a snip of the Solcast tool forecast based on my system info. The forecast is limited to 3 days for the free version. 

Edit: The reason my normal usage is on the low side is that I have had a gas stove for a long time already and I also have a flat panel solar geyser conversion. Yes I do use my solar panels now in the mornings on the geyser element too. 

thanks, good info there! I have ordered 12 x 540W JA

Edited January 27, 20224 yr by Terminal3k