Huawei MERC-1100W-P (short input cable)1100W module optimiser, short input cable version

Overview

The MERC-1100W-P is the 1100W member of Huawei's MERC optimiser family, intended for PV modules of up to 605W at STC, with 1155W maximum input power. Like the 1300W model it accepts 125V and 20A short-circuit current, tracks between 12.5V and 105V and drops to 1V output when the inverter stops. This is the short input cable version, with a 0.1m input lead and 0.1m (+) and 5.1m (–) output leads. It is used in full optimiser configuration only, with 8 to 25 units per string.

• 1100W and 1300W rated input, up to 1430W
• For modules up to 605W or 800W at STC
• 125V max. input, 20A Isc, 22A output
• 1V output per optimiser when shut down
• 99.5% max. efficiency, IP68, -40…+85°C
• Full optimiser configuration only, 8–25 per string

How it works

MERC optimisers are DC/DC converters mounted behind each PV module. Each one tracks the maximum power point of its module between 12.5V and 105V, so shading, soiling or mismatch on one module does not pull down the whole string. Output is limited to 80V and 22A per unit, and when the inverter is off or the optimiser is disconnected from it, the output drops to 1V, which keeps the string at a safe voltage for installers and firefighters.

The MERC-1100W-P takes modules of up to 605W at STC and the MERC-1300W-P modules of up to 800W; the 1300W model has no output power limit with modules up to 715W at an ambient temperature of 60°C or less. The input accepts up to 125V and 20A short-circuit current. An optimiser that fails is bypassed, so the rest of the string keeps working.

Installation and compatibility

MERC optimisers are designed for full optimiser configuration only: every module under the same inverter needs one, and they cannot be mixed with SUN2000-450W-P2 or SUN2000-600W-P units. The datasheet allows 8 to 25 optimisers per string (20 on the SUN2000-50KTL-M3) and 20kW per string, and recommends equal string capacities, with no more than 2kW difference between strings on one inverter.

Listed compatible inverters are the SUN2000-8/10/12/15/17/20KTL-M2, SUN2000-12/15/17/20/23/25KTL-M5 and SUN2000-30/36/40/50KTL-M3, and the SUN2000-12/15/17/20/25K-MB0 datasheet also names both MERC models. The short input cable version has a 0.1m input lead and 0.1m (+) and 5.1m (–) output leads with Staubli MC4 connectors; a long input cable version for split junction boxes is available on request.

Monitoring and protection

Each optimiser reports to the inverter, so module-level data and open-circuit faults can be located in FusionSolar, and the physical layout of the optimisers can be mapped in the app. The 149×104×49mm, 1.0kg housing is rated IP68 and operates from -40°C to +85°C; between 70°C and 85°C it may shut down for over-temperature protection and restarts automatically once it cools.

Questions and answers