833 Gallium panels??

pigglypots

Was just wondering if anyone has experience of 833 Gallium 250W panels?
Have been offered a very good price for 10+6 split roof install (ESE/WNW).
But likely with Solaredge optimizers and inverter (shading problems)
Any input from forum members who have them would be greatly appreciated?
Thank you

tunnel

How good a price are you talking here?
Been looking at prices for these and they're around 10-15% higher cost to other similar panels.

pigglypots

Hi
£4750..but includes a bit of a discount (£200) as they want to do a 'bit of a study' on them so pics and monthly generation numbers...think that's pretty good. But still some discussion as they are a 96-cell panel and much higher voltage (48V+) so jury is out on which optimiser (should be P500) and then which inverter? Waiting to hear tomorrow.

Martyn1981

My Jetion panels are 96 cell and ~50V. I can't remember which POs were used, but the P500 sound right, and are the same cost as the other PO's (60 and 72 cell versions).

Great price, especially for a split system with shade mitigation. Well done.

Mart.

pigglypots

Hi Martyn
Which inverter did they use? That for me is the problem as it seems the number of panels would easily max out the voltage (as data sheet)? Solar edge seem to have 500V max?...any guidance from your experience would be great...and I would know it works!! To be honest I still don't quite understand the effect of PO's and then into the inverter etc, regarding voltage anyway.
Thanks..

Martyn1981

pigglypots wrote: »

Hi Martyn
Which inverter did they use? That for me is the problem as it seems the number of panels would easily max out the voltage (as data sheet)? Solar edge seem to have 500V max?...any guidance from your experience would be great...and I would know it works!! To be honest I still don't quite understand the effect of PO's and then into the inverter etc, regarding voltage anyway.
Thanks..

Hiya Piggly, I have to admit to being as confused as you. My inverter is the SE2200 model, it's also rated at 500V so can cope with 8 50V panels easily.

However, looking at the inverter specs, even the SE6000 is 500V. 6000W would be about 24 panels, so even at 30V that's 720V. So clearly there's a lot more going on here.

Now, Solaredge with PO's is a different kettle of fish to normal string inverters, so I assume that the voltage seen at the PO, is not necessarily the same as the voltage sent to the inverter. But I'm really guessing now. Looking at the P500 specs it says it has a maximum input current (Amps) of 10, but a maximum output of 15. So ...... (boy I'm digging myself a deep hole here) if the 250W is coming in at 50V, then it must be at 5A (W=VxA), so if the PO sends the wattage on to the inverter at 15A, then the voltage could now be down to 17V. 16panels x 17V = 272V.

Please understand though that I've just made that up on the spot, and don't actually know exactly what the PO's do.

It's raining here at the moment, and it's too early, but if it gets sunny in the early afternoon, and my 2kWp WNW is pushing out 50%+ I'll have a look at the menu screens and see what voltage (DC) the inverter is registering.

When you said "and then which inverter?", I actually thought you meant which size to best suit your install. The SE4000 16A capped would work fine, but as you have a split system that will never run at full peak, the smaller SE3500 might be better, not really sure, and the prices are almost identical.

Mart.

Martyn1981

Martyn1981 wrote: »

It's raining here at the moment, and it's too early, but if it gets sunny in the early afternoon, and my 2kWp WNW is pushing out 50%+ I'll have a look at the menu screens and see what voltage (DC) the inverter is registering.

Quick update. It's still too early for my SE system, but I had a quick look and it's producing approx 250W and has an input voltage of 349V (DC).

That figure rang a bell, and checking the inverter specs it states a nominal DC input voltage of 350V for all the models.

So the 349 figure may be a complete coincidence (we'll see later) or the PO's are trying to maintain a sweet spot (DC voltage wise).

Mart.

Martyn1981

Further update. The weather is mixed so generation is fluctuating, but with AC output (generation) of 250W, 350W, 500W and 1,300W the inverter is still reporting DC voltage in the 345V to 355V range.

I suspect therefore that the inverter sees the voltage sent by the PO's, not the voltage given off by the panels.

So, the inverter should be sized to match expected generation, and the PO's matched to the voltage of the panels.

Mart.

EricMears

Surely, if the voltage of a string of panels turned out to be greater than the inverter could accept, it should be possible to rewire them such that two strings of half the number were combined in parallel ?

pigglypots

Thanks guys...we were still waiting to see what Solaredge techies recommend, installer is doing a bit of a check through with them..will add their input when we know. Just trying to get the best out of the panels...

ely_ellis

Hi all, just catching up after a failed Windows 10 update.

I have the 8.33 Eternity panels, although they are not the same as the Gallium so cannot offer much there.

Although I have no where near the experience of Martyn (with a Y) I think he is spot on.
The PO's do the tracking, so it is down to the PO's input rating for the higher output voltage of the panels.

The PO's present a nominal voltage to the inverter which I understand does not actually contain a tracker at all.

My system presents between 365vdc to 375vdc to the inverter from the PO's. This voltage remains pretty constant regardless off the voltage of the panels. The current varies massively depending upon sunshine / cloud / rain etc.

So in short, the PO's input rating has to match the panel rating. Don't worry about the inverter.

You wouldn't believe the amount of time I spend looking at all the graphs and charts of my SE system. It is very interesting (to me).