> ## Documentation Index
> Fetch the complete documentation index at: https://installerguides.lunarenergy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Stringing Requirements

<img src="https://mintcdn.com/lunarenergy/9SpEOi1RhVKSku07/images/pv-config.png?fit=max&auto=format&n=9SpEOi1RhVKSku07&q=85&s=0c3eaea1e4bb640301bff148987bbbc7" alt="" width="2385" height="902" data-path="images/pv-config.png" />

## PV Module Requirements

| Requirement                         | 650W Maximizer | 420W Maximizer |
| :---------------------------------- | :------------- | :------------- |
| Maximum Rated Power Output          | 650 W          | 420 W          |
| Maximum Short Circuit Current (Isc) | 20 A           | 20 A           |
| Maximum Open Circuit Voltage (Voc)  | 75 V           | 60 V           |

## Series String Requirements

| Requirement                                                                | 650W Maximizer                                                                                                                                                                    | 420W Maximizer                                                                                                                                                                    |
| :------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Maximum # of PV Modules per String                                         | Typical site: 20 recommended<br />Shaded PV: 24                                                                                                                                   | 20                                                                                                                                                                                |
| Minimum # of PV Modules per String                                         | 9                                                                                                                                                                                 | 9                                                                                                                                                                                 |
| Minimum # of PV Modules within +/- 5° pitch and azimuth                    | <Tooltip tip="Remaining PV modules of the same string can be on different planes and orientations.">7</Tooltip>                                                                   | <Tooltip tip="Remaining PV modules of the same string can be on different planes and orientations.">7</Tooltip>                                                                   |
| Maximum Usable Power per String                                            | 6.6 kW                                                                                                                                                                            | 6.6 kW                                                                                                                                                                            |
| Maximum DC Current per String                                              | 16 A                                                                                                                                                                              | 16 A                                                                                                                                                                              |
| Recommended Max STC Nameplate Power per String<br />for un-shaded PV sites | <Tooltip tip="Based on site specific pitch, azimuth, shade, and weather conditions, Maximizers will curtail power if real world power exceeds 6.5kW per string.">8.4 kW</Tooltip> | <Tooltip tip="Based on site specific pitch, azimuth, shade, and weather conditions, Maximizers will curtail power if real world power exceeds 6.5kW per string.">8.4 kW</Tooltip> |

## Parallel String Requirements

| Requirement                                  | 650W Maximizer                                                                                                                                                                                                                                                                                      | 420W Maximizer                                                                                                                                                                                                                                                                                      |
| :------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| # of Parallel Strings Allowed                | 3                                                                                                                                                                                                                                                                                                   | 3                                                                                                                                                                                                                                                                                                   |
| Uneven String length Allowed                 | <Tooltip tip="Each string in parallel can have different number of PV Modules/Maximizers.">Yes</Tooltip>                                                                                                                                                                                            | <Tooltip tip="Each string in parallel can have different number of PV Modules/Maximizers.">Yes</Tooltip>                                                                                                                                                                                            |
| Maximum Total DC Current from PV to Inverter | 37.5 A                                                                                                                                                                                                                                                                                              | 37.5 A                                                                                                                                                                                                                                                                                              |
| Maximum Total Usable Power                   | <Tooltip tip="The inverter will curtail power if real world power exceeds 15 kW for all strings combined. Note that curtailment is unlikely to occur at 15kW STC with Lunar 9.6kW inverter as the battery charge power plus the inverter output power is capable of handling 15kW.">15 kW</Tooltip> | <Tooltip tip="The inverter will curtail power if real world power exceeds 15 kW for all strings combined. Note that curtailment is unlikely to occur at 15kW STC with Lunar 9.6kW inverter as the battery charge power plus the inverter output power is capable of handling 15kW.">15 kW</Tooltip> |

## Communication Distance

Each Maximizer only needs to be in the communication range of a single Maximizer (or Maximizer Hub) to communicate with the Lunar System.

| Environment    | Wifi Mesh Communication Range (point to point) |
| :------------- | :--------------------------------------------- |
| Metal Roof     | 30 ft (9 m)                                    |
| Any other roof | 60 ft (18 m)                                   |
| Free Air       | 100 ft (30 m)                                  |

<Note>
  420W Maximizers and 650W Maximizers are allowed on the same PV string.
</Note>

<Note>
  Refer to the [Lunar System PV Installation and Troubleshooting Guide](https://documents.lunarenergy.com/pv-installation-and-troubleshooting-guide) for detailed rooftop design and diagnostics instructions.
</Note>

<Note>
  Output voltage from each PV module is individually controlled per each Maximizer to stay within the inverter operating input range. Do not apply string inverter design rules to planning module-level MPPT systems.
</Note>