Mike's (non-Sunsynk) System

As long as I've hijacked this thread... Is there any downside to having 10 x 545W panels rather than 10 x 455W panels, assuming your invertor can handle it, other than the price difference?
 
On the subject of asking about downsides, I see one more be able to get 2 5kw units for about the price of one 8kw unit.

What would be the downsides of going two parallel, or the benefit of a single unit?
 
hj2k_x said:
As long as I've hijacked this thread... Is there any downside to having 10 x 545W panels rather than 10 x 455W panels, assuming your invertor can handle it, other than the price difference?
Click to expand...
I'd go with the higher value panels if you can place them on the roof. More output is always a good choice.
They'll be physically larger assuming they're the same efficiency as the 455w panels.

I'm not sure your inverter will handle 10x545w though in series, i think 9S might be the limit, as the max system voltage should be 450v. 10 would put it over, unless you're going to run in a different way eg 5S2P on an MPPT string.

S = Series
P = Parallel
 
Mosgi said:
On the subject of asking about downsides, I see one more be able to get 2 5kw units for about the price of one 8kw unit.

What would be the downsides of going two parallel, or the benefit of a single unit?
Click to expand...
You still need to add in additional DC breakers and other wiring which will bring the cost over.

If you go with multiple units, need to keep firmwares identical, and possibility of software issues that others don't have. I suspect multiple units software isn't tested as well as single units, as less people go with multiple units...

If you're looking at say deye or its variants (sunsynk) - they have 5kw, 8kw, and 16kw units available.

Have a look at your equipment in use, and work out if you really need that much power at once.
I'd consider moving to a gas stove to avoid needing 2-3KW of electricity for cooking, that will bring your max load down.

Reducing Geysers use is another option, as those can chow 3-4KW. A number of different methods available - heat pumps, solar hot water systems, changing element to a DC element and driving directly from panels, or putting in a 2kw AC element instead of the existing 4kw to drop peak usage etc etc.

Once you've done that, the only other major load in the house will be your geyser, and sporadic stuff like kettles or washing machine. A 5kw on its own would probably be fine in that instance, and would be fine in a 3 bedroom if you got rid of the larger single loads (cooker or geyser - or both!)

If you have multiple geysers or a larger house eg a 5 bedroom family, then go with a larger inverter 8kw or 2 x 5kw, or look also at getting the geysers offgrid with solar hot water, or maybe a heat pump.

If you have an electric car, a large roof and lots of play money, I'd go with a 16kw and overspec the crap out of generation.


How big is your household?

Is the significant other or other household residents big users of heavy power items - kettle, hair dryer, washing machine, dish washer, cooking (anything that generates heat chows electricity hard when in use...).

Always mitigate first as its the cheaper option. The less you use, the less you need to spend overall on the solar system.
move - cooking -> gas. Halogens -> bin (replace with decent LED), Geysers -> SHW or Heat Pump etc
Older fridges -> A++++ models
 
Last edited:
itareanlnotani said:
I'd go with the higher value panels if you can place them on the roof. More output is always a good choice.
They'll be physically larger assuming they're the same efficiency as the 455w panels.

I'm not sure your inverter will handle 10x545w though in series, i think 9S might be the limit, as the max system voltage should be 450v. 10 would put it over, unless you're going to run in a different way eg 5S2P on an MPPT string.

S = Series
P = Parallel
Click to expand...
I agree. 9 in series in what I would do. 10S is pushing it to the limit. The spec sheet says it can handle 500V though.

1651128750478.png
 
ADrunkTeddyBear said:
I agree. 9 in series in what I would do. 10S is pushing it to the limit. The spec sheet says it can handle 500V though.

View attachment 1299588
Click to expand...
Should still be okay, VOC of a JA solar 545w Panel is 49.75VOC so 10 panels would ideally be below the 500VOC, Perhaps beyond this would make it go poof, But the panels would always be under load so the actual voltage from the panels or VMPP (Max Power Point Voltage) for these same panels would be 41.8V so you would be below the 425V mark
 
Following on from the above with regards to wiring in series. If wiring in series and within the limits of the inverter, is it still needed to include a PV combiner box? As I understand that is an advantage of having a 500VOC inverter vs a ~145VOC, as the combiner box is around R2800
 
ands45 said:
Following on from the above with regards to wiring in series. If wiring in series and within the limits of the inverter, is it still needed to include a PV combiner box? As I understand that is an advantage of having a 500VOC inverter vs a ~145VOC, as the combiner box is around R2800
Click to expand...
You don't need a combiner box for the sunsynk.

It has 2 sets of connections for each MPPT. You just need to run 8 cables to the inverter if you have 4 strings.
 
AchmatK said:
You don't need a combiner box for the sunsynk.

It has 2 sets of connections for each MPPT. You just need to run 8 cables to the inverter if you have 4 strings.
Click to expand...
Thanks, I am looking at 8x460w panels to start, so assume I would be able to wire these all in series (1 string) and connect to 1 MPPT. As the inverter I am looking at (Luxpower) is max 500v and 4000w per MPPT. This would all be done by an installer but I just want to make sure I understand how it works before
 
DuracellBunny said:
Should still be okay, VOC of a JA solar 545w Panel is 49.75VOC so 10 panels would ideally be below the 500VOC, Perhaps beyond this would make it go poof, But the panels would always be under load so the actual voltage from the panels or VMPP (Max Power Point Voltage) for these same panels would be 41.8V so you would be below the 425V mark
Click to expand...
Nope, it would be very much NOT ok.

9 in series would be max.

Overcast/cloudy conditions can peak past VOC, so 10 panels will DEFINITELY go over, and release the magic smoke from the inverter.

Do NOT do that!
 
ands45 said:
Thanks, I am looking at 8x460w panels to start, so assume I would be able to wire these all in series (1 string) and connect to 1 MPPT. As the inverter I am looking at (Luxpower) is max 500v and 4000w per MPPT. This would all be done by an installer but I just want to make sure I understand how it works before
Click to expand...
Go with 9. Labour is the main cost, mounting costs are marginal for 9 vs 8
Having another panel of output is more important in the longer term.

The inverter will clip if too much power is being generated in summer, so no worries about that. Its winter that you want as much output so that extra panel will be a huge help.
 
itareanlnotani said:
Go with 9. Labour is the main cost, mounting costs are marginal for 9 vs 8
Having another panel of output is more important in the longer term.

The inverter will clip if too much power is being generated in summer, so no worries about that. Its winter that you want as much output so that extra panel will be a huge help.
Click to expand...
Or I am considering if I should rather just go for the 545w panels, they are R400/500 rand a panel more but might be worth it
 
itareanlnotani said:
Nope, it would be very much NOT ok.

9 in series would be max.

Overcast/cloudy conditions can peak past VOC, so 10 panels will DEFINITELY go over, and release the magic smoke from the inverter.

Do NOT do that!
Click to expand...
I considered 9 but installed 8 to avoid worst case scenario.

But really tempted to install a 9th JA 545 panel.
 
Mike Hoxbig said:
I would go as big as possible within the inverter's spec. Should save yourself some roof space in the long run...
Click to expand...
Ya, just waiting on the install quote to see what the budget allows. The inverter can take 8000w total so plenty. Was going to add the 8 460 now on the 1 mppt and then hopefully do another 8 on the other 1 later. But might make more sense to just go bigger now, then add a few more later down the line if needed
 
ands45 said:
Ya, just waiting on the install quote to see what the budget allows. The inverter can take 8000w total so plenty. Was going to add the 8 460 now on the 1 mppt and then hopefully do another 8 on the other 1 later. But might make more sense to just go bigger now, then add a few more later down the line if needed
Click to expand...
The 8000W is the AC output to power your load.

The DC input limitation is governed by the total voltage of your panels...
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X