Keep Your Solar Battery Healthy: The Monthly Deep Cycle You Shouldn’t Skip
If you’ve invested in a solar energy storage system with batteries — especially LiFePO₄ (LFP) backup batteries — congratulations: you now have the power to store energy, reduce grid reliance, and protect your home in outages. But like any investment, it will serve you best if you treat it right.
One important maintenance step many owners overlook: performing a monthly deep cycle. Doing it takes only a few minutes, but can pay off in longer battery life, better performance, and fewer surprises.
Why a Monthly Deep Cycle?
When your battery bank sits at 100% state-of-charge for long periods, or gets little variation in its usage (always full, never discharged), a few issues can arise:
The battery’s monitoring, balancing and calibration can drift, meaning the system’s estimate of remaining capacity might become less accurate.
While LFP chemistry is more forgiving than many others, keeping it constantly at full charge or at extreme states (very high for long, very low for long) can still reduce useful cycle life.
In a backup-mode system (i.e., it’s ready for a power outage but not daily used), the battery may rarely discharge, so bringing it down periodically helps “exercise” the battery and allows the system’s monitoring to verify everything is working.
In short: a monthly intentional “charge up → discharge down → recharge” keeps the battery in better shape, ensures your monitoring stays accurate, and preserves long-term health.
How to Do It — A Simple Process
Here’s a step-by-step you can follow. Most good energy-storage system (ESS) setups will allow you to configure these easily.
Step 1: Set your system into “self-consumption” or manual discharge mode.
Switch your battery mode so that it discharges at night (or some period of low solar input) down to a predefined limit (e.g., 10%).
Many systems let you set a “minimum discharge SoC” (state-of-charge) of ~10 % for this purpose.
Step 2: Let the battery discharge to ~10%.
Overnight or during the configured period, let your battery drop from its usual high charge (say 90-100 %) down to around 10%.
⚠️ Note: Do not fully drain it to 0%; most LiFePO₄ systems advise staying above ~5-10 % SoC.
Step 3: The next morning (or soon after) charge the battery back up to ~90-100%.
Switch the system back into normal or “backup ready” mode so the battery returns to full, ready for the next event.
Step 4: Confirm the cycle is recorded/visible.
Check your system monitoring to see that the battery went from ~100 % down to ~10 % and back up. This not only verifies your system is working, but also helps keep the calibration of the battery management system (BMS) accurate.
Step 5: Set a monthly reminder/alarm.
To make this easy and reliable, set a calendar reminder or alarm (e.g., first Sunday of each month) titled:
“Perform monthly battery exercise: discharge to 10 %, recharge to 100 %.”
That way you don’t forget it — and you build good maintenance discipline.
Why These Specific Numbers?
Charge to ~90–100 %: For many LiFePO₄ systems, periodically reaching full charge is useful to allow the BMS to balance cells and recalibrate. Some sources say that holding constantly at 100 % isn’t ideal, but a periodic full charge is fine.
Discharge down to ~10 %: Most guidance says avoid very deep discharge to 0 % habitually; keeping above ~5-10 % helps protect the battery.
Every month: Because your system likely sits mostly idle (in backup mode), a monthly cycle is frequent enough to exercise the battery and monitor performance, without heavy wear.
What to Avoid
Never keep the battery at 100% SoC all the time without ever discharging. While LiFePO₄ is more robust here than many chemistries, prolonged full state of charge without variation can accelerate aging.
Avoid frequent deep discharges beyond your system’s design. Regularly discharging to extremely low SoC (near 0 %) or at very high discharge rates can reduce lifespan.
Don’t ignore the BMS or manufacturer instructions. Always use the system charger/profile recommended for your battery type, and follow any special instructions the manufacturer gives.
Sample Monthly Battery Maintenance Calendar
Day Action Day 1 At dusk: Enable “Discharge mode – Minimum SoC = 10%.” Day 2 (morning) At sunrise or first daylight: Switch back to “Backup mode – Target SoC = 90–100%.” Confirm charge back up. Day 2 Check system monitoring: confirm discharge and recharge. Log any discrepancies. Day 3–30 Normal backup operation. Set next reminder in calendar for next month.
Final Thoughts
Your solar-battery system is only as strong as how well you maintain it. By including a simple monthly exercise cycle (discharge to ~10%, recharge to ~90–100%), you’ll help ensure optimal performance, extend battery life, and keep your system ready for action when you need it most.
If you ever notice: unusually slow charging, unusually fast drop in SoC, or your monitoring doesn’t show the expected drop → rise pattern in your monthly cycle, it’s a good signal to contact your installer or the battery manufacturer.
At [Your Company], we recommend you make this step part of your routine — just like changing the air filter or scheduling your annual service. A ten-minute monthly check now can save you big headaches later.
