sma overvoltage

[jimbo1]

Hello, i am new to forum just need a bit of advice, installation of a 3600tl sma inverter going in to lockout overvoltage first thing in mornings been ok up until nw 3 months old, panels are 250 x16 on single string is this the problem should it be 2 string has shown up to 630v dc max at moment but is in lockout mode any help??

 

[Earthstore]

The max DC voltage is 750V for the 3600tl, are you sure it is not the AC that is going overvoltage?

This is a common install problem if the AC cable is too small that connects the inverter to the supply, even more so if it is a long run.

 

[jimbo1]

The ac cable is 2.5mm and 2mtrs from supply ac showing between 244-249v sma stated that this inverter will only accept 550v from 16 panels although no ane has factored in 10% for cold panels am i right in saying it is overheating from 1 string setup.

 

[SolarCity]

I don't have the spec sheet in front of me but I would have thought the upper limit on the MPPT would be less than 750v.

The voltage will be quite high on the last few mornings as we have had lots of sunshine and very cool temperatures - perfect conditions for high voltages.

What error message are you getting exactly? Are you sure that the inverter is set up for G83?

 

[SolarCity]

550v sounds more like it. Therefore you're going way above voltage - possibly damaging the inverter. What panels are you using?

 

[Earthstore]

SUNNY BOY 3000TL / 3600TL / 4000TL / 5000TL with Reactive Power Control. SMA UK

Here is the spec.

 

[jimbo1]

sma checked serial number and say it is setup for g83, inverter states this also panels are ja 250 can it be that dc input needs to be raised/adjusted from initial commisioning

 

[SolarCity]

Okay, looks like you're within spec - which is surprising.

What error message are you getting? And code?

 

[jimbo1]

error message is overvoltage code 34

 

[jimbo1]

can the perameters be altered or should they have been checked on commisioning?

 

[ExtremePV]

If its 3months old then its probably a SB3600TL-20 which has a 550VDC max input voltage. The SB-3600TL-21 released turn of the year has a higher input voltage.
Isolate the DC (dc isolators or the ESS handle) until it can be split into 2 separate strings. Overvoltage can damage the inverter, and over voltage isn't covered by warranty!

You need to get it put into 2 strings!

Ken

 

[Gavin A]

Hello, i am new to forum just need a bit of advice, installation of a 3600tl sma inverter going in to lockout overvoltage first thing in mornings been ok up until nw 3 months old, panels are 250 x16 on single string is this the problem should it be 2 string has shown up to 630v dc max at moment but is in lockout mode any help??

SMA 3600TL-21 or -20?

If it's a 21 then it's the higher voltage model then it should be fine as even at -10deg the Voc should be around 698V vs 750Voc maximum on the inverter.

I suspect thought hat it might be an 3600TL-20, which has 550Voc max and 440V max MPPT voltage, and you've been just skirting inside those limits until it's got a bit colder (the voltage is reduced at lower light levels and in higher temperatures, so the combination of the 2 might have just kept you inside the limits).

I did find out recently that some of the chinese panels are coming with +/- 10% variation on the voltage, which could also explain this.

Either way, it looks like the string is going to have to be split as one way or another it's going over voltage whatever the calcs say.

 

[jimbo1]

very helpfull ken , i thought i was getting there with 1or 2 string configuration but will it still work in 2 strings if you have 16 panels with no shading ssw 45 deg roof,

 

[jimbo1]

is this a speck error /installer or both

 

[Ian-LS]

installer error I would have thought. Simple enough to use SMA sunny design to make sure the system is designed correctly