Astronergy · Growatt
Astronergy ASTRO N7 CHSM66RN(DG)/F-BH-640 + Growatt MOD 10KTL3-XH: how many panels per string
From 4 to 19 Astronergy ASTRO N7 CHSM66RN(DG)/F-BH-640 panels per string on an MPPT input of the Growatt MOD 10KTL3-XH inverter — in any climatic region of Ukraine. Below: the window for each region, the input currents and example plants laid out by the Solispec engine.
- Panels per string
- 4–19pcs
- Input V_max
- 1,100V
- MPPT window
- 140–1,000V
- Panel I_sc
- 16.42A
- MPPT input I_sc
- 20.0A
- Panel V_mp in heat
- 35.8V
Ground frame designer
A ground plant with Astronergy ASTRO N7 CHSM66RN(DG)/F-BH-640
The builder opens with this panel and the Growatt MOD 10KTL3-XH inverter: Solispec lays out the strings itself.
- No sign-up
- Snow and wind check
- Drawings and estimate
String by climatic region
T_min per ДСТУ-Н Б В.1.1-27:2010, табл. 1; open-circuit voltage at T_min: K_U = 1 + α·(T_min − 25)/100 = 1.17 (α -0.25 %/K, T_min -42 °C; Annex B).
| Region | T_min | Panel U_oc at T_min, V | Min per string | Max per string | String U_oc at max, V (≤ 1,100) |
|---|---|---|---|---|---|
| Region I | -40 °C | 57.63 | 4 | 19 | 1,094.9 |
| Region II | -42 °C | 57.87 | 4 | 19 | 1,099.6 |
| Region IIIA | -38 °C | 57.38 | 4 | 19 | 1,090.2 |
| Region IIIB | -32 °C | 56.63 | 4 | 19 | 1,076.0 |
| Region IV | -20 °C | 55.15 | 4 | 19 | 1,047.8 |
| Region V | -27 °C | 56.01 | 4 | 19 | 1,064.3 |
The minimum per string keeps the string voltage in heat (panel V_mp 35.8 V) above the MPPT window (140 V).
Input currents
| Panel I_sc / MPPT input I_sc, A | 16.42 / 20.0 |
|---|---|
| Panel I_mp / MPPT input I_mp, A | 15.24 / 16.0 |
| Parallel strings per MPPT | 1 |
| MPPT inputs | 2 |
- I_SC MAX above the input currentUnder DSTU HD 60364-7-712 the design current I_SC MAX = 1.25·I_SC of the panel is above the inverter's input current. Check in the inverter's datasheet how its input is rated.
Example plants
The Solispec engine laid out the strings for plants of several sizes with this inverter at the lowest T_min; only those that pass the checks with every panel placed are shown.
| Plant | Panels | kW DC | Inverters | Strings | DC/AC |
|---|---|---|---|---|---|
| ≈ 5 kW | 8 | 5.12 | 1 | 8 pan. × 1 — inv. 1, MPPT 1 | 0.51 |
| ≈ 10 kW | 16 | 10.24 | 1 | 16 pan. × 1 — inv. 1, MPPT 1 | 1.02 |
| ≈ 15 kW | 24 | 15.36 | 2 | 12 pan. × 1 — inv. 1, MPPT 1; 12 pan. × 1 — inv. 2, MPPT 1 | 0.77 |
- I_SC MAX = 1.25·I_SC = 20.5 A > 20 A input — check how the inverter datasheet rates the input (712.512.1.2)
- DC/AC 0.51 — inverter oversized
A preliminary calculation; a design needs an engineer's check. Solispec engine 0.12.0.