---
title: "SolarEdge SE66.6K (Synergy, 380/400V) vs SolarEdge SE66.6K (K66.6SE) - Secondary unit - Inverter Comparison | ComparePV"
description: "Compare SolarEdge SE66.6K (Synergy, 380/400V) vs SolarEdge SE66.6K (K66.6SE) - Secondary unit side by side: what actually differs, efficiency, MPP trackers, battery input and the full specification."
source: "https://comparepv.com/compare-inverters/solaredge-se66-6k-synergy-380-400v/solaredge-solaredge-se66-6k-k66-6se-secondary-unit"
updated: 2026-01-16
---

# SolarEdge SE66.6K (Synergy, 380/400V) vs SolarEdge SE66.6K (K66.6SE) - Secondary unit

SE66.6K (Synergy, 380/400V) leads on the differences that matter

The largest is max pv power: 26.55 kW apart. 12 of 20 comparable parameters are identical, with 12 more left out because at least one datasheet does not publish them.


## The two inverters


| Attribute | A | B |
| --- | --- | --- |
| Inverter | [SolarEdge SE66.6K (Synergy, 380/400V)](https://comparepv.com/inverter/solaredge-se66-6k-synergy-380-400v) | [SolarEdge SE66.6K (K66.6SE) - Secondary unit](https://comparepv.com/inverter/solaredge-solaredge-se66-6k-k66-6se-secondary-unit) |
| Manufacturer | SolarEdge | SolarEdge |
| Rated AC power | 66.6 kW | 66.6 kW |
| Type | Grid-tie | Grid-tie |


## Where they differ

Ranked by how much the difference matters, not by datasheet order.


| Parameter | SE66.6K (Synergy, 380/400V) | SolarEdge SE66.6K (K66.6SE) - Secondary unit | Difference |
| --- | --- | --- | --- |
| Max PV power | 116.55 kW | 90.00 kW | 26.55 kW apart |
| DC/AC ratio | 1.75 | 1.35 | +0.40 for SE66.6K (Synergy, 380/400V) |
| Weight | 32.0 kg | 45.0 kg | -13.0 kg for SE66.6K (Synergy, 380/400V) |
| Noise | 67 dB | 60 dB | -7 dB for SolarEdge SE66.6K (K66.6SE) - Secondary unit |
| Nominal AC voltage | 400 V | 480 V | 80 V apart |
| Max AC current | 96.5 A | 80.0 A | 16.5 A apart |
| Max efficiency | 98.3 % | 98.1 % | +0.2 pp for SE66.6K (Synergy, 380/400V) |
| Dimensions | 558x328x273 mm | 540x315x260 mm | 558x328x273 mm vs 540x315x260 mm |


## Every compared parameter


| Parameter | SE66.6K (Synergy, 380/400V) | SolarEdge SE66.6K (K66.6SE) - Secondary unit |
| --- | --- | --- |
| Rated AC power | 66.60 kW | 66.60 kW |
| Max AC power | 66.60 kW | 66.60 kW |
| Grid connection | 3-phase | 3-phase |
| Nominal AC voltage | 400 V | 480 V |
| Max AC current | 96.5 A | 80.0 A |
| Max PV power | 116.55 kW | 90.00 kW |
| DC/AC ratio | 1.75 | 1.35 |
| Max DC voltage | 1000 V | 1000 V |
| MPPT voltage range | 680-1000 V | - |
| Start voltage | - | - |
| MPP trackers | - | - |
| Strings per tracker | - | - |
| Max input current per tracker | - | - |
| European efficiency | 98.0 % | 98.0 % |
| Max efficiency | 98.3 % | 98.1 % |
| CEC efficiency | - | - |
| Battery input | - | - |
| Battery voltage | - | - |
| Max charge current | - | - |
| Backup power | - | - |
| Weight | 32.0 kg | 45.0 kg |
| Weight per kW | 0.5 kg/kW | 0.7 kg/kW |
| Dimensions | 558x328x273 mm | 540x315x260 mm |
| Ingress protection | IP65 | IP65 |
| Cooling | forced-air | forced-air |
| Noise | 67 dB | 60 dB |
| Max operating temperature | 60 °C | 60 °C |
| Wi-Fi | Yes | - |
| Ethernet | Yes | Yes |
| Arc fault protection | Yes | Yes |
| Integrated DC switch | Yes | Yes |
| Warranty | 20 yrs | - |


## Related comparisons

- [SolarEdge SE66.6K (Synergy, 380/400V) vs SolarEdge SE66.6K (K66.6SE)](https://comparepv.com/compare-inverters/solaredge-se66-6k-synergy-380-400v/solaredge-solaredge-se66-6k-k66-6se) - 7 differences, the largest is max pv power
- [SolarEdge SE66.6K (Synergy, 380/400V) vs SolarEdge SE66.6K (K66.6SE) - Primary unit](https://comparepv.com/compare-inverters/solaredge-se66-6k-synergy-380-400v/solaredge-solaredge-se66-6k-k66-6se-primary-unit) - 9 differences, the largest is max pv power
- [SolarEdge SE66.6K (Synergy, 380/400V) vs SolarEdge SE66.6K (Synergy, 277/480V)](https://comparepv.com/compare-inverters/solaredge-se66-6k-synergy-380-400v/solaredge-solaredge-se66-6k-synergy-277-480v) - 7 differences, the largest is max pv power
- [SolarEdge SE66.6K (K66.6SE) - Secondary unit vs SolarEdge SE66.6K (Synergy) - secondary unit (physical)](https://comparepv.com/compare-inverters/solaredge-solaredge-se66-6k-k66-6se-secondary-unit/solaredge-solaredge-se66-6k-synergy-secondary-unit-physical) - The same specification on paper


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Source: https://comparepv.com/compare-inverters/solaredge-se66-6k-synergy-380-400v/solaredge-solaredge-se66-6k-k66-6se-secondary-unit

Not in this file, on the page: a written summary generated on request.