Tongwei · Growatt
Tongwei TNC 3.0 TWMNH-66QD660 + Growatt SPF 5000 ES: how many panels per string
From 4 to 7 Tongwei TNC 3.0 TWMNH-66QD660 panels per string on an MPPT input of the Growatt SPF 5000 ES 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
- 4–7pcs
- Input V_max
- 450V
- MPPT window
- 120–430V
- Panel I_sc
- 16.50A
- MPPT input I_sc
- 22.0A
- Panel V_mp in heat
- 35.9V
Ground frame designer
A ground plant with Tongwei TNC 3.0 TWMNH-66QD660
The builder opens with this panel and the Growatt SPF 5000 ES 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 = 1.15 (α -0.22 %/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 (≤ 450) |
|---|---|---|---|---|---|
| Region I | -40 °C | 57.74 | 4 | 7 | 404.2 |
| Region II | -42 °C | 57.97 | 4 | 7 | 405.8 |
| Region IIIA | -38 °C | 57.52 | 4 | 7 | 402.7 |
| Region IIIB | -32 °C | 56.86 | 4 | 7 | 398.0 |
| Region IV | -20 °C | 55.52 | 4 | 8 | 444.2 |
| Region V | -27 °C | 56.30 | 4 | 7 | 394.1 |
The minimum per string keeps the string voltage in heat (panel V_mp 35.9 V) above the MPPT window (120 V).
Input currents
| Panel I_sc / MPPT input I_sc, A | 16.50 / 22.0 |
|---|---|
| Panel I_mp / MPPT input I_mp, A | 15.68 / 22.0 |
| Parallel strings per MPPT | 1 |
| MPPT inputs | 1 |
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 | 8 | 5.28 | 2 | 4 pan. × 1 — inv. 1, MPPT 1; 4 pan. × 1 — inv. 2, MPPT 1 | 0.53 |
| ≈ 10 kW | 16 | 10.56 | 3 | 6 pan. × 1 — inv. 1, MPPT 1; 6 pan. × 1 — inv. 2, MPPT 1; 4 pan. × 1 — inv. 3, MPPT 1 | 0.70 |
| ≈ 15 kW | 23 | 15.18 | 4 | 6 pan. × 1 — inv. 1, MPPT 1; 6 pan. × 1 — inv. 2, MPPT 1; 6 pan. × 1 — inv. 3, MPPT 1; 5 pan. × 1 — inv. 4, MPPT 1 | 0.76 |
- DC/AC 0.53 — inverter oversized
- DC/AC 0.66 — inverter oversized
A preliminary calculation; a design needs an engineer's check. Solispec engine 0.12.0.