Solar panel installation typically does not void a roof warranty if the racking system and fasteners are installed correctly. However, the warranty may be void if the roof is damaged during the installation. Common issues that will void your roof warranty include:
Solar panel installers causing roof damage, liked cracked tiles or shingles
Racking system installed without suitable waterproof sealant
Racking system is substandard and doesn't include waterproofing features
Wrong fasteners used in the installation
Installers drill holes in your roof and compromise the roof membrane or decking