# Solar edge inveter cal

#### hhsting

##### Senior Member
I have solar edge.SE 43.kKUS has following string input from DC side:

1. 3 strings of 18 modules, 9 optimizers per string
2. 3 strings of 18 modules, 9 optimizers per string
3. 1 string of 17 modules, 9 optimizers per string

Optimizer used is P800P whose max ouput amps and volts is 18A, 85V.

Module power is 360W model SPR-X22-360-COM.

Inveter Spec SE43.2KUS says max input DC kw at STC/unit: 58.2kw/19.4kw

Question: I have total 63 optimizer whose max output power is 63x18x85 =96.39kW would that not exceed max input power 58.2kW inverter spec? Am I wrong?

#### Carultch

##### Senior Member
Add up module nameplate Watt ratings at STC. That value shall not exceed 19.4 kWdc per power stage on this inverter, per Solaredge's requirements. There's also a power limit per string, you'll find on the optimizer datasheet. Again, it also refers to module nameplate power.

Optimizers cannot produce new power. They only reformat power already available to them from the module(s).

#### hhsting

##### Senior Member
Add up module nameplate Watt ratings at STC. That value shall not exceed 19.4 kWdc per power stage on this inverter, per Solaredge's requirements. There's also a power limit per string, you'll find on the optimizer datasheet. Again, it also refers to module nameplate power.

Optimizers cannot produce new power. They only reformat power already available to them from the module(s).
I have total 125 modules at stc each module is 360W. So 125x360 = 45kw. Please correct me if I am wrong. Is it 19.2kw or 58.2kw that I should be comparing?

#### Carultch

##### Senior Member
I have total 125 modules at stc each module is 360W. So 125x360 = 45kw. Please correct me if I am wrong. Is it 19.2kw or 58.2kw that I should be comparing?
19.4 kW applies for the modules you connect to each power stage. 3*19.4 kW = 58.2 kW. There are no paralleling jumpers on the DC side paralleling the three power stages, so they each have to comply with this limit independently. At 360W each, that's 53 modules on a stage, or up to 159 modules on the whole inverter. A 54th module would be the proverbial "last straw", even if your other stages have a lot fewer than 53 modules. 53 is not divisible by 3, so it would mean a mixed string size array (which SolarEdge optimizer strings allow) if you sourced that particular power stage to the max.

#### pv_n00b

##### Senior Member
The best way to tell if your design meets SolarEdge requirments is to run it through their Designer software. I'll do this without going into a lot of site detail, just put in the basics for the modules, optimizers, and inverters and see if it spits out an option that is the same as what you want to do.