Hi There

Would it be fine if I add 10 x 545w Canadian panels in 2 strings of 5 panels each to a 5KW Deye hybrid inverter? Looks like max PV is 6500W in the manual

Edited March 3, 20233 yr by krugerjq
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I think that's your most realistic option, and leaves some room for some extra panels to be added per string. Voc of those panels is just short of 50V, and Ioc is 14A. That inverter probably has a max PV amp of 13A and volt per series of 450V. Your other option would be to use one less panel and have one 9-panel string (if all facing the same way), which might be more efficient than 2 smaller strings that are both far off the MPPT sweet spot with their respective low string voltages. Perhaps others with first hand experience will chime in on these two options. However, if using only one string (assuming that works optimally for your roof), you may be limiting yourself for further expansion on the unused string, or would need to re-cable later. 

Agree with @Kalahari Cruiser Rather put 1 string with 8 or 9 panels. Do the exact math to make sure you stay under the 450V limit of the MPPT

I was going to use both MPPT's on the inverter 

Is there like a specific series Voltage to aim for? I just thought to not overload one and split them equal on both MPPT's

Edited March 3, 20233 yr by krugerjq
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A few considerations (while roof direction, sun, shading etc) all play an important role. But in terms of the basic specs (including some double-counting here):

1. check inverter max PV input (6600W?)

2. check MPPT voltage limit (absolute max I think is 500V on yours)

3. check the MPPT input spec and range: (think yours is 370V (100V-500V).

4. voltage sweet spot is (I think) 370V, give or take. Absolute max is 500V, but your string sizing working max would leave some room for spikes, i.e. 450V, i.e. do not add 10 panels in series with a VoC of around 50V. 

5. divide your panel's open circuit volt spec into this number (i.e. 450/49.5 = 9 panels). that's max string size. 

6. actual power and current will be less, but the above is for planning / sizing purposes. 

7. look at the minimum voltage required (seems like 100V). That means your realistic minimum size string is 3+ if you split your array

8. so yes, 2 strings of 5 panels will work, each string Voc spec will be around 250V each (but actual considerably lower), but the question then is: you're far off the MPPT sweet spot of 370V, will you be getting more out of your two strings than if you rather go for a single 9-string setup. But as mentioned earlier, while you can oversize the total array (but I don't know by how much, on your inverter), you "may" be better off starting off with 9 panels on one string, and then if and when you expand, to perhaps go for 2 strings of 6-7 panels each. Of course, if the intention is to perhaps add another panel or two per string soon, then you may as well start off with the 2x 5S setup that you proposed.  Array output oversizing may give you better returns on marginal days, but how much you can oversize the total array by, others will be in a better position to say. 

Thank you guys for the information.  I also forgot to mention Budget and panel availability.....😀

7 hours ago, Kalahari Cruiser said:

4. voltage sweet spot is (I think) 370V, give or take. Absolute max is 500V, but your string sizing working max would leave some room for spikes, i.e. 450V, i.e. do not add 10 panels in series with a VoC of around 50V. 

5. divide your panel's open circuit volt spec into this number (i.e. 450/49.5 = 9 panels). that's max string size. 

MPPT Voltage range is stated as 150-425V. So I would try to not exceed 425V. Usually the MPPT derates above that. I would probably start with 8 panels and see how my string voltage performs for a while. Alternatively there is a calculation tool from Victron somewhere online that you can do detailed calcs with based on your panels specs, expected temperatures, etc.

7 hours ago, Kalahari Cruiser said:

Array output oversizing may give you better returns on marginal days, but how much you can oversize the total array by, others will be in a better position to say. 

Oversizing should only be done on Amps, not Voltage. If you exceed the MPPT voltage, it will ' go poof'

So yes, try to get to the 425V as close as possible, but make sure that never ever you could exceed 500V (e.g. sunny days in cold weather)

2 hours ago, wolfandy said:

MPPT Voltage range is stated as 150-425V. So I would try to not exceed 425V. Usually the MPPT derates above that. I would probably start with 8 panels and see how my string voltage performs for a while. Alternatively there is a calculation tool from Victron somewhere online that you can do detailed calcs with based on your panels specs, expected temperatures, etc.

Oversizing should only be done on Amps, not Voltage. If you exceed the MPPT voltage, it will ' go poof'

So yes, try to get to the 425V as close as possible, but make sure that never ever you could exceed 500V (e.g. sunny days in cold weather)

https://www.victronenergy.com/mppt-calculator

We always read about the derating outside the sweet spot. 

Have anyone seem test's showing what % the derating is?

Edited March 3, 20233 yr by Scorp007

11 minutes ago, Scorp007 said:

We always read about the derating outside the sweet spot. 

Have anyone seem test's showing what % the derating is?

To my understanding the derating is not outside a sweet spot - but if you exceed the MPPT voltage range. In this case the upper limit of the voltage range is 425V and the hard limit is 500V.

@Coulomb at one point explained this in more detail for an Axpert, but I cannot remember exactly where...

3 hours ago, wolfandy said:

To my understanding the derating is not outside a sweet spot - but if you exceed the MPPT voltage range. In this case the upper limit of the voltage range is 425V and the hard limit is 500V.

@Coulomb at one point explained this in more detail for an Axpert, but I cannot remember exactly where...

My question was if you are over 425V but below the hard and fatal limit of 500V. We might be breaking our necks to stay below 425V when in fact the derating might be like 5%.

I have found my Axpert does work very well even below the minimum voltage input from PV. The same might happen over the MPPT high sweet spot. Again below the Voc level 

23 hours ago, krugerjq said:

Thank you guys for the information.  I also forgot to mention Budget and panel availability.....😀

If you find those panels in stock anywhere please let me know

On 2023/03/04 at 10:15 AM, Chris_S said:

If you find those panels in stock anywhere please let me know

Where are you located?

20 hours ago, krugerjq said:

Where are you located?

East London 

Is the Canadian 545 watt panes ( 8 in series) compatable with the Growatt SPF5000 ES inverter?

1 hour ago, BHH said:

Growatt SPF5000 ES inverter?

The Max VOC is 450V. The documented PV array MPPT Voltage range is 120Vdc - 430Vdc
If those panels in theory have a max VOC of 50V, then 8 X 50V = 400Vdc.
So 8 panels will be good.