My Axpert mks 5000kva Inverter got power surge damage. I replace it with 2 Mecer 5000kva inverters. They will be running in parrelel in 2 weeks time. My new inverters solar aray volt is from 120 volt to 430 volt with a VOC of 450. The one inverter is getting 258 volt at 6 amps. I must buy new panels for the second inverter. But high voltage panels are so much more expensive. So do i go for the same kind of voltage and amps or do i go for 360 volt at 6 amps with cost almost double. What would you guys do ?;

6 minutes ago, vulgrim said:

But high voltage panels are so much more expensive.

? You use exactly the same panels but in series rather than series/parallel.

For the same power, higher voltage costs the same.

No i cannot get to that voltage even if i put them in series. If you take the max amount of watt that your inverter can take (4500 watt.)And devide that into your solar panels (325 w) you get 14 panels using 2 arays you can only get to 260 volts. If you put more in series you cannot use all 14 panels.

22 minutes ago, vulgrim said:

So do i go for the same kind of voltage and amps or do i go for 360 volt at 6 amps with cost almost double.

If you can get your working voltage at above 330 volt dc, the inverting to 230Vac will be the most efficient. You can use normal panels and add it up to till you get 330plus volts.  

24 minutes ago, vulgrim said:

you get 14 panels using 2 arays you can only get to 260 volts.

I looked at your situation again and with the panels available right now you will not reach 4500 at the correct voltage, its going to be a trade off, either high voltage at 3015 watt or 4500 watt at a lower voltage. Your calculation is correct at 260 Vmpp for 7 in series, but 9 in series will give a Voc of 412 and a Vmpp of 336V. (3015Watts)

I worked on 335 watt panel as this is the only size currently available from my supplier in Canadian solar, rest expected in MAy. 

4500 w divide by 325 give you14 panels Voc-45.5  volts . Vic -37 volts.

Voc.  7X45.5 = 318 volts.  9X45.5= 409 volts.

Vic.   7X37 = 259 volts.   9X37=333 volts.

Using 9 panels yo get to 333 volts. But then i am losing out on 1575 watt.

4500-2925=1575

 

 

 

 

28 minutes ago, vulgrim said:

14 panels using 2 arays you can only get to 260 volts

? You have two inverters, each of which has an MPPT, correct? So you have a maximum of 4500 W per inverter, or 9 kW max for the two.

But a typical 325 W panel has a Voc of over 46 V @ 25 °C, nearer 50 V at 0 °C, so to stay under 450 V, you'll need a maximum of 9 panels in series; possibly 8 if it gets colder or your panel specs are different to my assumptions (the first 325 W panel I found with a quick search).

If the Vmppt is around 35 V at NOCT, 8S or 9S will give 280 or 315 V. It will be difficult to get the Vmppt higher than that without exceeding the Voc at low temperatures.

7S will still give 245 V, which is perfectly reasonable. You could start with as few as 4S (140 V).

3 minutes ago, vulgrim said:

But then i am losing out on 1575 watt.

If you really needed to max out one of the MPPTs, you could use 2P of panels with lower Imppt (e.g. ~200 W panels).

But with 9 kW between the two inverters and therefore two MPPTs, I don't see the need for this, especially when these two inverters replace one.

4 minutes ago, Coulomb said:

7S will still give 245 V, which is perfectly reasonable.

I agree, nothing wrong with that.. 

 

This is the specs of the high voltage panels.

Jaco de Jongh  do you sell solar panels ?

3 minutes ago, vulgrim said:

Jaco de Jongh  do you sell solar panels ?

I can help you find some panels, PM me your requirements. 

1 hour ago, vulgrim said:

This is the specs of the high voltage panels.

Ah! I'd never heard of them. Thanks. But there is no need to use them just because you have higher voltage solar charge controllers now.