Should you wash your solar panels?
Points and comments are a snapshot, not live.
Washing a small solar farm yielded a 2%-5% power increase, worth about £60-£150 per year.
The author cleaned one bank of 16 panels on their small solar farm and measured the ratio of power output between cleaned and uncleaned banks. The results showed a temporary 2%-5% improvement, worth roughly £60-£150 annually, decaying to zero over a few years. The author also felt a tingle while cleaning panels, likely from capacitive leakage from a transformerless inverter. Upgrading the 15-year-old system is unattractive because the old feed-in tariff pays for generated electricity at a high rate, while new capacity would revert to a much lower present-day tariff.
What commenters are saying
Commenters debated the safety of the tingle the author felt. Several emphasized that panel frames and racking must be bonded and grounded per code, and that a supplementary ground rod near the panels can mitigate touch potential. Others noted that DC voltages of 300-600V can cause burns but are easy to let go of. On cleaning, some argued rain is sufficient in many climates, while others pointed out that arid regions with heavy dust benefit from washing. A separate point: roof panels are more dangerous to clean than ground-mounted ones, and ladders or scaffolding may be legally required in some countries.