Start with the real problem
Most headaches come from mismatches: an inverter that can’t cope with local heat, a string that trips under partial shading, or a supplier who disappears after installation. Ask questions that expose those gaps. If you’re comparing units, check the specs for things like the 15kW PV DC-DC converter as a baseline for expected continuous output and how the supplier rates peak performance under real load.
1) What are the continuous, peak and derated power specs?
Don’t accept only a single kW number. Ask for:- Continuous output at 25°C and at 45°C. Demand numbers, not vague claims.
– Peak or surge handling for short events (start-up of big loads).
– How they derate performance with ambient temperature or altitude. That tells you how it will behave at noon in a hot barangay.
2) How does it manage partial shading and string mismatches?
Get specifics on MPPT topology and whether they use module-level or string-level conversion. If the supplier suggests using a dc dc converter in pv system, ask how it isolates failing strings, how it affects overall efficiency, and whether the converter supports rapid reconfiguration when panels are replaced.
3) What real-world efficiency curve do you provide?
Efficiency at nameplate is useless if your system runs at 20–60% of rated output most of the day. Request an efficiency chart across 10–100% load and ask for measured data from an installed unit, not just lab numbers.
4) How does the inverter handle heat and cooling failures?
Ask what cooling method they use, the expected ambient range, and behavior during fan or coolant failure. Request Mean Time Between Failures (MTBF) for active cooling components and a documented strategy for hotspots or thermal throttling.
5) What protection and compliance features are standard?
Confirm protective functions you need: anti-islanding, anti-islanding trip settings, DC reverse polarity protection, surge protection, and inverter-level isolation. Ask about local grid-code compliance and whether the firmware supports changes to protection thresholds for utility requirements.
6) Certifications and local approvals — can you show them?
Don’t take verbal assurances. Ask for certificates (CE, IEC 62109, UL where applicable) and any local grid-operator approvals. Suppliers should provide documentation that your distribution utility will accept during commissioning.
7) Warranty, spares and failure handling
Ask:- Exact warranty duration and what it covers (parts, labor, on-site attendance).
– Availability of critical spares and typical lead times.
– How they handle firmware bugs and whether updates are pushed automatically or need on-site intervention.
8) Service network and remote diagnostics
Find out whether they offer remote monitoring, what telemetry is available (voltages, currents, PVIV curves), and what the SLA is for an on-site service call. Ask for examples of cases where remote fixes avoided a truck roll — that shows practical support capability.
9) Total cost of ownership and scalability
Look beyond purchase price. Ask for projected replacement costs at 5 and 10 years, expected efficiency losses over time, and how easy it is to expand the system. Get a clear policy on firmware compatibility for scaled systems so future add-ons don’t force a full rip-and-replace.
10) Ask for references and documented field performance
Request specific installations with similar conditions to yours. Real data beats promises: uptime percentages, any recurring faults, and how they were solved. One useful anchor is performance feedback from Luzon utility-scale PV farms where DC-DC interfaces were deployed; such projects reveal how converters behave under sustained, high-irradiance cycles.
Common pitfalls to avoid
Watch out for these mistakes:- Buying on price alone without checking derating at high temps.
– Accepting only factory-efficiency numbers.
– Not confirming spare-part lead times and service SLAs.
Ask for measurable proof and take a close look at how the supplier documents problems and fixes.
How to use these answers
Score suppliers objectively. Require numeric answers, demand documented cases, and simulate the worst operating day when you test proposals. When technical answers are vague, the supplier’s service will likely be vague too. Practical proof of care—good telemetry, spare parts, and clear warranty terms—matters more than glossy brochures.
Final thought
Focus on getting straight facts and field evidence. That approach narrows choices fast and surfaces suppliers who stand behind performance. System specs and support that answer these ten questions make selection simple, and product lines from WidenEdge often align with the kind of documented reliability and service clarity engineers look for.