Over driving SMA Sunny Boy 1.5

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bpabpa
Posts: 12
Joined: Tue Jan 11, 2022 7:54 pm

Over driving SMA Sunny Boy 1.5

#1

Post by bpabpa »

Hi

I have a Sunny Boy 1.5 inverter with 8 x 120 watt panels totalling 960 watts.
I have on order 4 x JA 545 watt panels that I can just fit in place of the old panels.
IMPP: 13.04 A
Isc: 13.93 A

The position and angle of the panels is poor and the peak output of the 960 watt panels was 750 watts in June of this year.
The Sunny Boy manual states maximum DC power at cos φ = 1 1600 W.
Maximum input current 10 A
Maximum short-circuit current* 18 A

Can I safely connect the new panels to the Sunny Boy? My calculation is the peak could be 1700 watts.

I was going to fit a new Solis 2.0kW Mini S6 inverter but that is a lot more work and expense.

I am know thinking of just replacing the panels and only if there are any problems replacing the Sunny Boy.

Regards

Ian
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nowty
Posts: 5576
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Over driving SMA Sunny Boy 1.5

#2

Post by nowty »

No problem whatsoever, its very common to load up inverters well beyond their max input / output. The Sunny Boy will just current limit its input at 10A or even lower if it reaches the max 1.5kW output first. And if the angle of the panels is poor you might end up with less efficiency with a larger inverter.

The main thing that kills inverters is overvoltage and you will be on the lower end of that.

The Sunny Boy manual stating "the maximum DC power at cos φ = 1 1600 W" is simply the max amount of power that will be absorbed by the inverter from the panels at the max 1.5kW AC output of the inverter.
Last edited by nowty on Sat Oct 22, 2022 6:00 pm, edited 1 time in total.
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Tinbum
Posts: 1073
Joined: Mon May 31, 2021 9:55 pm

Re: Over driving SMA Sunny Boy 1.5

#3

Post by Tinbum »

I have 9kW on a SMA sunny boy 4000 that runs with no problems at all.
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
bpabpa
Posts: 12
Joined: Tue Jan 11, 2022 7:54 pm

Re: Over driving SMA Sunny Boy 1.5

#4

Post by bpabpa »

Many thanks.

Solis cancelled!
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