Sunny island help

[Kirk]

Have 12kw system, 2 SMA 6000, 2 sunny islands, after hookup was told that it would not support my AC unit pulling 90 amp critical load panel. After hookup was told that it would not support over 60amps. Any comments. Should I have used Zantac or outback or other.

[solar pete]

Have 12kw system, 2 SMA 6000, 2 sunny islands, after hookup was told that it would not support my AC unit pulling 90 amp critical load panel. After hookup was told that it would not support over 60amps. Any comments. Should I have used Zantac or outback or other.

Hi Kirk,

You might find that your AC is three phase?In which case your going to struggle solar dont do 3 phase very well, you basically have to run three systems. So not sure another brand would be any help at all, cheers and good luck with it

[JFinch57]

Have 12kw system, 2 SMA 6000, 2 sunny islands, after hookup was told that it would not support my AC unit pulling 90 amp critical load panel. After hookup was told that it would not support over 60amps. Any comments. Should I have used Zantac or outback or other.

Not sure if it can be purchased separately, or if it will work with your AC unit. Waterfurnace has an option called IntelliStart, that reduces the starting current by ramping up the voltage. See http://www.waterfurnace.com/literatu...l/BR1629MW.pdf . One of the benefits is listed as "Implement off-the-grid power technologies like Solar PV and Wind more easily".

[inetdog]

Have 12kw system, 2 SMA 6000, 2 sunny islands, after hookup was told that it would not support my AC unit pulling 90 amp critical load panel. After hookup was told that it would not support over 60amps. Any comments. Should I have used Zantac or outback or other.

There are three separate problems here:
1. Can you run the A/C on the two SIs alone (i.e. at night or in bad weather). Since you did not specify the size of your SIs, I can't tell the answer to this one.
2. Can you run the A/C on the four inverters together during peak production hours.
3. Can you start the A/C in each of these cases (looking at a starting surge that could easily be six times the normal running current).

Your system is 12kW on the panel side, I assume. That would give you 50A at 240V, which is probably how your A/C load is specified.
To get to 90 you would have to also be pulling from your battery bank with the SIs at the same time. If you want a sustainable system, SMA may be telling you that you should not go beyond the capability of the SBs alone.

But I strongly suspect that the problem is the starting surge, and SMA has made some assumptions and looked at the surge output capacity of the SIs in forming their opinion.

Other types of standalone inverters might have a proportionally greater surge capacity, depending on their design.
Grid tie inverters have no surge capacity at all.

[JFinch57]

3. Can you start the A/C in each of these cases (looking at a starting surge that could easily be six times the normal running current)...

But I strongly suspect that the problem is the starting surge, and SMA has made some assumptions and looked at the surge output capacity of the SIs in forming their opinion.

Other types of standalone inverters might have a proportionally greater surge capacity, depending on their design.
Grid tie inverters have no surge capacity at all.

The Waterfurnace IntelliStart is specifically designed to reduce the starting surge current!