You finally install solar, expecting your ZESA bill to shrink. But then, a surprise your ZESA units are disappearing faster than before. It feels confusing and frustrating. Isn’t solar supposed to reduce costs?
The truth is, if your ZESA units are vanishing quickly after solar installation, there’s usually a clear reason. Let’s break down the most common causes—and how to fix them.
- Charging Your Batteries on ZESA at Night
This is the biggest culprit. If your solar system doesn’t have enough panels, the inverter may default to charging the batteries from ZESA at night. Charging large batteries consumes huge amounts of units, leaving you wondering where all your credit went.
Solution:
Have an energy audit done to confirm if your solar panels are enough for your load. In many cases, adding more panels ensures the batteries are fully charged during the day, so they don’t draw from ZESA at night.
- Wrong Inverter Programming
Sometimes the inverter is set up incorrectly. For example, if the priority is set to “utility first,” the system will favor ZESA instead of using your solar panels. This means you’re still running mostly on ZESA without realizing it.
Solution:
Reprogram the inverter to prioritize solar first, then batteries, and only fall back on ZESA when necessary.
- Phantom Loads During the Night
Appliances like fridges, Wi-Fi routers, security lights, and TVs on standby continue to draw power even when you think everything is off. If the solar batteries drain by midnight, the inverter silently switches to ZESA and carries these loads until morning. That eats into your units.
Solution:
Either increase your battery capacity, or program your inverter to power only critical loads at night.
- Voltage Fluctuations and AVS Cut-Offs
Sometimes your Automatic Voltage Switch (AVS) or inverter protection settings reject ZESA during the day due to low/high voltage. If the solar doesn’t cover your needs, the inverter may switch back to ZESA when voltage normalizes, and you unknowingly burn units.
Solution:
Have a technician review your AVS and inverter settings to ensure they’re balanced between protection and practicality.
- Misunderstanding the Balance Between Solar and ZESA
Many people expect solar to eliminate ZESA use completely. But if your system is under-sized—too few panels, too small a battery bank—you’ll still use ZESA heavily. This isn’t a fault, but a design issue.
Solution:
Make sure your system is designed around your actual load profile. A daytime salon and a night-heavy poultry farm need completely different solar setups.
Final Word
If your ZESA units are vanishing faster after going solar, it doesn’t mean your system has failed. It usually means the system isn’t sized or programmed correctly. The good news? These issues are fixable.
At Infinity Solar, we’ve helped countless Zimbabwean households and businesses fine-tune their systems to maximize solar savings. From adding the right number of panels to reprogramming inverters, our team makes sure solar truly cuts your ZESA costs.
Don’t let disappearing units frustrate you. Get in touch with Infinity Solar today and let’s make your system work smarter, not harder.