Why is My Off-Grid Inverter Beeping?
Some folks called us to diagnose their off-grid solar installation, where the inverters were beeping non-stop, and the system barely generated enough power to keep the inverter beeping.
It is somewhat unnerving and annoying when the inverter whines all day. What’s wrong, and what can you do to fix the issue?
What causes the inverter to beep?
These three root causes cover almost all the scenarios:
A low-battery event. You have consumed more than your system can generate (solar production limit) or store (battery limit).
An overcurrent event. You have an appliance that consumes substantial current, with a multi-second burst (e.g., a slow-starting water pump) or a sustained draw (e.g., a water heater).
An over-temperature event. You draw a large current below the threshold but long enough to generate excessive heat.
The quick fix and the long-term fix
If you wake up to a beeping inverter, the battery is likely depleted overnight, and the inverter fails to reset after the sun comes out. Rebooting the inverter (turning it off for a few seconds and back on) should allow the system to resume solar production.
If the issue occurs often, you may investigate whether your panels produce enough electricity and your battery stores enough power.
When your battery is fully charged, does it store enough power to take you through the night?
If the answer is yes, your battery capacity is not the bottleneck. You may need to increase your power production by adding more solar panels or adjusting the panels’ elevation and azimuth to charge your batteries fully before the sun goes down.
If the answer is no, you should increase your battery capacity or lower your overnight consumption. A little sleuthing goes a long way to identify unnecessary power draw.
For example, if your water pump turns on at night to fill your gravity tank, use a timer so it turns on during the day. The same goes for the water heater. Why heat water at midnight when everyone is sleeping? Use a timer to control the power usage pattern.
You may also look for energy vampires lurking in your house. Do you have a 20-year-old fridge or freezer humming in the basement or garage? Older appliances may be bad news because their energy efficiency is often low and can draw down your battery quickly.
If you can’t find any way to trim down your overnight consumption enough, you may invest in more battery capacity.
Dimensioning a battery bank can be tricky, yet not investing the effort could cost you thousands in battery capacity you don’t need. We advocate an iterative approach where you’d add one battery module at a time until you’ve found the sweet spot. Our modular battery design makes adding capacity a breeze without any disruption.
Some people face a dilemma — they have an existing lead-acid battery bank. Even though they understand lead-acid batteries are costly, toxic, and inefficient, they don’t want to let the many thousands of dollars they recently invested in the batteries go to waste.
The good news is that our proprietary technology makes it possible to mix lead-acid with lithium batteries. For a client who wanted to transition from lead-acid to lithium chemistry, we built a custom battery solution with lithium iron phosphate (LFP) cells, and our software makes the two battery types get along.
Data insights make diagnosing issues a lot easier
So, how do you know your battery bank’s capacity and whether your solar production is sufficient to keep it fully charged?
The answer is simple if you have a solar charge controller (SCC) or battery management system (BMS) with smartphone apps (like our preferred equipment brands). They can show your solar production, whether your batteries are topping off nicely, how much charge remains in your battery, and how fast it’s discharging.
Other SCC and BMS solutions may also provide data with different levels of granularity. We can’t cover all of them here, so give us a shout to schedule a diagnostic. We can see what data your system collects, perform real-time measurements to understand your battery bank’s state of health (SoH), and crunch some numbers to find the bottleneck.
