REC · Growatt
REC Alpha Pure-RX REC470AA Pure-RX (HJT) + Growatt MOD 5KTL3-X: how many panels per string
From 3 to 14 REC Alpha Pure-RX REC470AA Pure-RX (HJT) panels per string on an MPPT input of the Growatt MOD 5KTL3-X 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
- 3–14pcs
- Input V_max
- 1,100V
- MPPT window
- 140–1,000V
- Panel I_sc
- 8.95A
- MPPT input I_sc
- 16.0A
- Panel V_mp in heat
- 47.2V
Ground frame designer
A ground plant with REC Alpha Pure-RX REC470AA Pure-RX (HJT)
The builder opens with this panel and the Growatt MOD 5KTL3-X 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 = 1.16 (α -0.24 %/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 | 75.95 | 3 | 14 | 1,063.3 |
| Region II | -42 °C | 76.26 | 3 | 14 | 1,067.7 |
| Region IIIA | -38 °C | 75.63 | 3 | 14 | 1,058.9 |
| Region IIIB | -32 °C | 74.69 | 3 | 14 | 1,045.6 |
| Region IV | -20 °C | 72.80 | 3 | 15 | 1,091.9 |
| Region V | -27 °C | 73.90 | 3 | 14 | 1,034.6 |
The minimum per string keeps the string voltage in heat (panel V_mp 47.2 V) above the MPPT window (140 V).
Input currents
| Panel I_sc / MPPT input I_sc, A | 8.95 / 16.0 |
|---|---|
| Panel I_mp / MPPT input I_mp, A | 8.49 / 13.0 |
| Parallel strings per MPPT | 1 |
| MPPT inputs | 2 |
No cautions about the currents.
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 | 11 | 5.17 | 1 | 11 pan. × 1 — inv. 1, MPPT 1 | 1.03 |
| ≈ 10 kW | 22 | 10.34 | 2 | 11 pan. × 1 — inv. 1, MPPT 1; 11 pan. × 1 — inv. 2, MPPT 1 | 1.03 |
| ≈ 15 kW | 33 | 15.51 | 3 | 11 pan. × 1 — inv. 1, MPPT 1; 11 pan. × 1 — inv. 2, MPPT 1; 11 pan. × 1 — inv. 3, MPPT 1 | 1.03 |
A preliminary calculation; a design needs an engineer's check. Solispec engine 0.12.0.