Understanding Tare Loss in Home Battery Systems & Why It Matters
Introduction
When homeowners invest in a battery storage system, most focus on total capacity, efficiency, and backup capabilities. However, one often-overlooked aspect is tare loss, also known as standby loss. This is the energy a battery consumes simply to stay operational — keeping its electronics, inverters, communication systems, and safety protocols online. While it may seem small on a daily basis, over time it can subtly impact your energy savings and system design.
At Spectrum Energy, we make it a priority to educate clients about tare loss and show how smart system design can mitigate its effects, especially when pairing a battery with a solar array.
What Is Tare Loss?
Tare loss is the baseline energy a battery consumes when it’s idle but ready to operate. Every battery system has some standby draw — it’s how the system keeps itself “awake” and ready for use. While often not discussed in sales presentations, understanding this small but steady energy use is crucial for accurate solar system sizing and long-term energy planning.
Key points about tare loss:
Powers essential electronics, including inverters, safety monitoring, and communication systems.
Exists in all modern battery systems — it’s not a flaw, but a necessary feature.
Over weeks and months, even a low daily consumption can add up to noticeable energy usage.
The Enphase IQ Battery 10C: Extremely Low Standby Draw
Among residential batteries, the Enphase IQ Battery 10C stands out for its extremely low tare loss compared to competitors.
Typical daily consumption: approximately 1.4–1.5 kWh per day to remain fully operational and ready for backup.
Efficiency advantage: minimal standby draw means more of your stored energy is available for actual home use.
Why it matters: lower tare loss reduces the need to oversize your solar array, keeping upfront costs efficient.
How We Address Tare Loss with a PV System
Ignoring tare loss can lead to under- or over-sized solar arrays, reduced energy efficiency, and surprises for homeowners. At Spectrum Energy, we account for this in our designs to maximize system performance.
Practical strategies we use:
Upsizing the solar array: Adding one extra panel (or more, if necessary) to offset daily standby consumption.
Smart dispatch: Configuring the battery to optimize charge/discharge cycles and minimize unnecessary cycling.
Monitoring: Tracking actual standby consumption over time to ensure energy efficiency targets are met.
Education: Making sure clients understand that while small, tare loss is real and accounted for in system design.
Real-World Example
For a 10 kWh Enphase 10C battery, a daily standby draw of 1.4–1.5 kWh adds up to roughly 42–45 kWh per month. By upsizing the solar array slightly, this energy is fully offset, allowing the system to deliver the expected savings without noticeable impact on your electric bill.
Conclusion
Tare loss is an inherent part of all modern battery systems, but with proper design and planning, it has minimal impact on overall performance. The Enphase IQ Battery 10C offers one of the lowest standby consumption rates on the market, making it an excellent choice for homeowners looking to maximize solar self-consumption and energy efficiency.
If you’re considering a home battery system, reach out to Spectrum Energy to learn how we design PV + storage systems that account for tare loss, optimize performance, and deliver dependable energy savings for years to come.
