Claiming a module or inverter warranty without losing the argument

A module fails in year four. The customer expects a free replacement within the week. What actually happens depends almost entirely on paperwork created on the day it was installed.

Two warranties, and customers conflate them

Product warranty covers defects in the module itself: delamination, junction box failure, frame or glass defects. It typically runs ten to fifteen years depending on manufacturer.

Performance warranty covers output, usually as a guaranteed percentage of rated power at year twenty five, with a permitted annual degradation rate. It does not cover a module that is merely dirty, shaded, or in a system with a fault elsewhere.

A customer saying "twenty five year warranty" almost always means the performance warranty, and almost always believes it covers everything. Correcting that at the proposal stage costs one sentence. Correcting it at failure costs the relationship.

What a claim actually requires

Most rejected claims are rejected on evidence, not on merit. Collect these at installation, not at failure:

• Serial numbers, recorded against their position in the array. A claim for "a module in row three" is not a claim.
• The purchase invoice, showing the model and the batch.
• The commissioning record, including string level measurements taken on the day: open circuit voltage and short circuit current per string, and the date.
• Photographs of the installation, including the mounting, the clamping and the DC connections before they were closed.
• The warranty document as it existed at purchase. Terms change between versions, and the one that applies is the one current at purchase.

Then at failure, add: the measured output of the affected string or module, a clear photograph of the defect, the inverter's error log, and the date the fault was first observed.

The two exclusions customers never expect

Freight and labour. Most manufacturer warranties replace the defective part. They frequently do not pay for shipping it, removing the old one, or installing the replacement. So a "free replacement" arrives with a bill for the work, and the customer is surprised by it.

Decide your position on this before it happens and write it into your proposal: either you carry it for a defined period, or the customer does. Either is defensible. Silence is not.

Installation caused damage. Micro cracks from someone standing on a module, cracked glass from over-torqued clamps, water ingress from a mishandled junction box. These are your workmanship, not the manufacturer's defect, and a manufacturer with good forensic capability will identify them.

Which is why the photographs taken during installation protect you as much as they protect the customer.

Inverters are a different process

Inverter warranties are usually shorter than module warranties, often five to ten years with paid extensions available, and the process runs through the manufacturer's service network rather than through the distributor.

Three practical points:

• Register the unit if the manufacturer requires registration for full coverage. Unregistered units sometimes receive a shorter standard term.
• Keep the error log. Most claims are diagnosed remotely from it, and a unit that was power cycled repeatedly before anyone recorded the fault is harder to diagnose.
• Ask about turnaround and replacement stock before you specify a brand. A twelve year warranty from a company with no Indian service presence is worth less than an eight year warranty with a spare on a shelf in the next city.

That last point belongs in your procurement decision, alongside the module technology question in TOPCon, bifacial, and what actually belongs on a rooftop.

Who owns the claim

Say so in writing, because ambiguity here is where relationships break.

The common and sensible arrangement is that you facilitate: you diagnose, you file, you pursue, you fit the replacement, and the customer understands that the manufacturer decides. Your AMC can state this explicitly, as in an annual maintenance contract a customer will actually buy.

What you should not do is imply that you guarantee the manufacturer's decision. You do not control it, and promising it converts every manufacturer refusal into your liability.

What to put in the proposal

Four lines: module product warranty term, module performance warranty term with the guaranteed output, inverter warranty term, and your own workmanship warranty with its scope.

Then one sentence naming who handles claims and what the customer pays for during a replacement. It reads as thoroughness at proposal stage. Four years later it reads as the reason there is no argument.

The short version

• Product warranty covers defects. Performance warranty covers output against a degradation curve. Customers mean the second and assume it covers the first.
• Collect serial numbers by position, the invoice, commissioning measurements, installation photographs and the warranty document as it stood at purchase.
• Most warranties exclude freight and labour. Decide who pays and write it in the proposal.
• Installation damage, including micro cracks and over-torqued clamps, is your liability, not the manufacturer's.
• Register inverters, keep the error log, and weigh service presence over headline warranty length.
• State that you facilitate claims. Do not imply you guarantee the manufacturer's decision.