Can I pick your brains?

[Somecamel]

Hi,

Run into a strange problem today, could be something simple but for the life of me couldn't work it out.

Finished off fitting a 2.45kW PV job today, electrician came last Saturday to do the AC connection etc. (CU is being changed this weekend as not in regs)

It's 10 Canadian 245 with a Power One Uno 2.5 (2 strings of 5)

All connected up to inverter but inverter wouldn't kick in. (LED backlight came on but thats all, no data on screen) Tried another Uno I had in the van and again same problem.

Popped a steca 3.6 on to see if it was the powerone's (same batch) but no AC voltage was coming through.

Checked AC isolator and showed 247v coming in so somewhere between the AC isolator and the inverter (had bypassed the Gen meter to test) it cant get the grid voltage.

Could it be the old CU? I cant work out how I can get 247 from the isolator but the 3 inverters I tried it with don't see it.

 

[dansk]

Did you check for 247 on the inverter terminals?

 

[Somecamel]

Did you check for 247 on the inverter terminals?

You know what I can't remember I'm sure I must have done, if I didn't could be a dodgy Isolator maybe, it's been one of them days

Edit:- The inverter did power up though so maybe I didn't

 

[dansk]

Thats what it sounds like to me - 247 "in the iso" but not 247 "out of iso" so maybe?

- - - Updated - - -

Tell you what ive had in the past - wires appear clamped in the iso - when in fact they are tucked behind the clamp, easy to do on some of them.

 

[Somecamel]

But would the inverter start up if it was done like this?

 

[dansk]

Nope because it hasnt a positive connection, or in other words the wiring isnt making a strong contact.

 

[Gavin A]

I'd expect it's a start up voltage issue as the standard start up voltage is 200V.

You can reduce the start up voltage down to 120, but you'd be much better running it in a single string of 10 panels, as this is far closer to the peak efficiency point on the voltage curve.

 

[Somecamel]

This is the problem though, the Steca I tried started up but couldnt find the grid

 

[Somecamel]

I'd expect it's a start up voltage issue as the standard start up voltage is 200V.

You can reduce the start up voltage down to 120, but you'd be much better running it in a single string of 10 panels, as this is far closer to the peak efficiency point on the voltage curve.

But surely the inverter should have the info on the LCD display? there was nothing on the PO Uno display

 

[Gavin A]

oh, well then it sounds like you've got a faulty ac isolator or something, and just need to trouble shoot the AC circuit to find the fault.

but then when you've done that you'd still be a lot better off running it as a single string IMO.

 

[dansk]

Good job Gavins about - which Canadian model were they?

 

[Gavin A]

But surely the inverter should have the info on the LCD display? there was nothing on the PO Uno display

if you've got a combination of no AC, and DC under voltage then it probably won't fire up at all.

Which sounds like what you've got going on... have you been walking under ladders / smashing mirrors recently?

 

[Somecamel]

Fair do's, put them in 2 strings due to shading, they're the CS5P-245M

- - - Updated - - -

if you've got a combination of no AC, and DC under voltage then it probably won't fire up at all.

Which sounds like what you've got going on... have you been walking under ladders / smashing mirrors recently?

No I started a solar company a few years ago Im doomed

 

[dansk]

I just checked also as i started to doubt myself 2 x parallel is spot on according to the PO sizing tool - i would say AC Iso.

 

[Somecamel]

To be fair, I don't think the voltage went above 173v today (when tested)- crappy weather, so could be this.