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Deye 5Kw Install - Can you help a newbie with solar panel advice?

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Hi everyone,

I've recently installed a 5Kw Deye inverter (spec sheet attached) onto my DB along with 2 x 5Kw Vestwoods batteries. The setup works great and our entire house runs fine during load shedding.

My stove is gas. My geyser and aircons are isolated so we are good.

I have recently ordered 8 x Longi Solar Panels 555w for my roof (Spec sheet attached) from a supplier.

I contacted my installer and he mentioned that I might have an issue with my input voltage on the MPPT that I the panels will be installed on.

He said I might want to return the panels.

Does anyone have any advice for me regarding this? I would like to use these panels and get the best efficiency out of them if possible butt he installer has cast some doubt?

I'm totally new to this and would welcome any advice.

deye specs.jpg

Longi 555W Panels Spec Sheet_opt.pdf

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Those panels will work perfectly on that inverter.
You can run them 4 in series X 2 strings i.e. 4 panels in series onto each mppt input at the inverter.

When budget allows add at least another 4 panels,  2 onto each string to bring you closer to the optimal voltages.

Or if your roof space allows it then put all 8 onto 1 mppt that should be pretty much close to the sweet spot for efficiency.
Then you have the other mppt to add more panels later.

Edited by WannabeSolarSparky
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6 hours ago, CyberStorm said:

@WannabeSolarSparky - Thank you for the information. I'm new to solar and am learning each day, so I really appreciate your advise.

I have another question, what do I need to look at on my inverter specs list and the solar panel spec list to determine if panels will or wont work perfectly?

Inverter spec sheet you show and the panels spec sheet gives the info needed:

On the Inverter you would look at the mppt/solar PV specs - MPPT Voltage range ( V ) 370V ( 100 - 500 ) - means the optimal voltage ( sweet spot ) for efficiency is 370V
On the panels - Panels as per STC specs: 42.1V Vmp/V and 13.19A X 8 = 336V so just a bit lower than the inverters sweet spot
The theoretical test values as per the panels spec sheets give you VOC 49.9V X 8 = 399V still below the safe value and gives some margin for cold cloudy days where the voltages could spike higher, but should still be safe.
In real life on average the values you will get from the panels will be closer to the NOCT values, but for your question work on the STC values to be safer.

So based on the spec sheets those panels installed in 8s configuration on one mppt will almost be perfect.

Not sure why the supplier is telling you they are not suitable and to send those back. From my side they look like a perfect match for that inverter in an 8s.

Edited by WannabeSolarSparky
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  • 2 weeks later...
On 2023/05/18 at 1:18 PM, Dani said:

@WannabeSolarSparky are the panel specs for amperage not too high 13a vs 11a?

Not fatal but there will be "clipping" 

The sunsynks on latest firmwares take 13 amps no problem. I personally do not mind some clipping. Winter months are always better with over speced panel arrays :) So the bit you lose in summer does not matter :) as it is super helpful in winter.

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