Solar Panels

[domo]

can anyone tell me why the replacement inverter a sunnyboy 5000tl produces less than my samil 5860 on a 4kw systemS

 

[Earthstore]

They are both too big for a start, who on earth have you got as an installer, you need something like a 3600TL inverter for a 4KW system, sorry but I am not going into all the ins and outs of why, but it is called system design also you should have had G59 approval from the DNO, as it can not be installed and connected to the grid under the easier G83 regulation, Do you have this approval?

 

[domo]

no not as far as I know its a split east west system eight panels on each side I don't know if this makes a difference what is dno

 

[SpitfireW'sale]

Can the company who replaced the unit not answer these questions?

 

[Ian-LS]

if the east and west roofs are steep enough you could have also used a 3 kW dual MPPT inverter......

 

[Earthstore]

You have two posts running on the same topic, however, as stated your inverter is way too big for an east/west split system if it is 4kwp in total, if this is the case then your installer really has not got a clue, sorry to be so direct.

 

[domo]

thanks for replying will the sunnyboy 5000tl cause any problems on my 4kw system east west split on two strings and will it produce the same kw output as a smaller inverter . thanks for everybodys help struggle with computer as you can probably see.

 

[FB.]

As said above: a 4kWp East/West split system is not often going to peak much above 3-3.25kW output. If it was all on one of your roofs facing the sun at the same time it would peak around 4kW output (although inverters are supposed to be capped at 3.68kW output; 230V @ 16A which slightly reduces the efficiency of full size systems).
An optimal South-facing 4kWp array might reach 4.5kW output, but, again, is likely to have been capped at 3.68kW output.

If the inverter is too big it's not going to be as efficient as an optimal sized inverter: you don't put the engine of a lorry into a small car because it's wasteful.
Similarly you don't put a car engine into a lorry and expect normal performance.
A big inverter will be optimised to receive big power inputs and will not run as efficiently with lower inputs. Manufacturers often supply an "efficiency curve" chart which shows where their inverter is at its optimum.

I would be contacting the installer and asking for an inverter that was "fit for purpose" and optimised for peak power in the 3-3.4kW range which would better suit your system.

Of course: some of the apparent difference might just be the weather, or minor calibration differences in any add-on device which measures the generation.

 

[domo]

thanks for the advice

 

[James Anderson]

Definitely a bad design. I would be contacting the installer sb4000tl would be the maximum size of inverter for this install or as earthstore says 3600 would be ideal