Hi everyone,

On the deye hybrid 8kw, there are 2x mppts with connection for 4 strings.

I have 4 strings in series into the 2 x mppts.

When wiring 2 strings in series into mppts 1, do they connect internally together? Which would make them a parallel connection?

Reason I ask, Tigo optimisers tech help tell me it does turn string into a parallel connection, there by allowing unwanted reverse DC voltage to interfere with the optimisers!! 

Because of this, I put 2 strings into 1 string into mppts 1 but noticed that the voltage went higher and the output dropped lower!

I was also wondering if I installed a blocking diode on each string after the isolators if that would cure the issue assuming it is coming from tge inverter.

Any knowledge of this would be grateful.

 

Thank you 

47 minutes ago, AndyH said:

Hi everyone,

On the deye hybrid 8kw, there are 2x mppts with connection for 4 strings.

I have 4 strings in series into the 2 x mppts.

When wiring 2 strings in series into mppts 1, do they connect internally together? Which would make them a parallel connection?

Reason I ask, Tigo optimisers tech help tell me it does turn string into a parallel connection, there by allowing unwanted reverse DC voltage to interfere with the optimisers!! 

Because of this, I put 2 strings into 1 string into mppts 1 but noticed that the voltage went higher and the output dropped lower!

I was also wondering if I installed a blocking diode on each string after the isolators if that would cure the issue assuming it is coming from tge inverter.

Any knowledge of this would be grateful.

 

Thank you 

Just to clarify the series and parallel connections. There are only 2 parallel strings into each MPPT I guess. I guess the optimiser will be wired as per sketch. I have no experience on their wiring. 

The thick lines are connections inside the inverter. The terminals are marked as MPPT1-4. The 2xMPPTs in the sketch is just to indicate that there are 2 independent MPPTs. 

Not sure if the 2 strings in parallel are wired to 1 optimiser? 

 

Edited April 1, 20242 yr by Scorp007

Hi, each panel has an individual Tigo optimiser, the inverter image shows how the panels connect, I assume that on one mppts the 2 strings do somehow link inside as there is now less amps on the readout.

This is the manual.

https://www.deyeinverter.com/deyeinverter/2020/12/29/502012022【a】储能单相说明书sun-5-8k-sg01lp1-useu-ver2.0-deye.pdf

 

Many thanks 

 

Yes all panels are in series with each going through an optimiser, then suspect they go parallel when meeting  in the inverter.

Tigo install image attached

https://assets-global.website-files.com/5fad551d7419c7a0e9e4aba4/600ef20aa9acd8bc2a054520_Quick Start Guide - TS4-A-O.pdf

 

@AndyH I don't want to be bearer of bad news but read this article below it was posted 2019 but maybe you need software update as explained in this article. 

https://mcelectrical.com.au/tigo-optimiser-recall/

26 minutes ago, TaliaB said:

@AndyH I don't want to be bearer of bad news but read this article below it was posted 2019 but maybe you need software update as explained in this article. 

https://mcelectrical.com.au/tigo-optimiser-recall/

. Thanks for the link

Thanks for the article, interesting, I luckily have the equipment installed to allow updates, and my units are 2023 versions, Tigo engineers have been on my system many times with my parallel issue.

Since yesterday , I heard back from Deye inverter people, as expected, the inverter unfortunately changes series connected strings to parallel! That's the issue for the optisers. 

8 minutes ago, AndyH said:

, I heard back from Deye inverter people, as expected, the inverter unfortunately changes series connected strings to parallel! That's the issue for the optisers. 

Most inverters with strings entering the Mppt with multiple inputs are paralleled. You should think that this would have been taken into account when designing the optimizers.

I don't want to be pessimistic about optimizers in general but a few years ago i tried to optimise strings from diffrent orientations but wasn't successful. It seems that impedance matching is not quite what is promised by the manufacturer. I did not test the Tigo optimizers, we used Inge and Solar Edge optimizers but like i said couldn't get them to work efficiently. Maybe we had the same issue you are experiencing with string in parallel entering the mppt. Interesting.

Would be interesting to see what the DEYE optimizer would do with the Deye inverter.  I would think that it would seamlessly integrate with the inverter and that the communication protocols would solve some of the issues regarding voltage/power and PV panel control. 

【B】单页 SUN-XL02-A (deyeinverter.com) 

Yes I bet they would be a decent unit, not seen them before, Tigo very similar to these in functionality and form.