Battery Backup for Grid-Tied Solar
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Battery Backup for Grid-Tied Solar: Why Your Panels Go Dark During a Power Outage (and How to Fix It)
If you’ve ever stood in a dark house during a grid outage while your solar panels sat outside soaking up perfectly good sunlight, you’ve run into one of the most common — and least understood — limitations of on-grid solar.
Most residential and small commercial solar installations are grid-tied, meaning they lack battery backup by design and need utility power present to operate at all. It’s a safety requirement, not a design flaw: when the grid goes down, your inverter is designed to shut off too, so it doesn’t send power back down the lines and endanger utility workers repairing the outage. The result is that your solar investment goes idle at exactly the moment you need power most.
Until now, fixing this meant a full system overhaul — ripping out your existing setup and replacing it with a hybrid inverter and battery bank from scratch. That’s expensive, disruptive, and often overkill for what most homes and small businesses actually need: power for the essentials during an outage, not a complete energy independence system.
iSUN: Retrofit Battery Backup for Existing Solar Systems
Energy24by7’s iSUN is built specifically to solve this problem — by retrofitting your *existing* grid-tied solar system with battery backup, instead of replacing it.
Here’s the idea in plain terms: iSUN charges a battery bank using your solar system’s output, and that battery bank powers a backup inverter/UPS you already have in place. When the grid goes down, your critical loads — lights, refrigerator, routers, medical equipment, whatever matters most — switch over to battery power automatically. Meanwhile, your original solar system keeps running exactly as it always has, uninterrupted, once grid power returns or if the outage doesn’t affect its normal operation.
Why this approach works
No compromise on solar efficiency. iSUN doesn’t touch the way your existing solar array feeds the grid. It adds backup capability alongside your system rather than reworking it, so you don’t lose any of the performance you’ve already paid for.
Minimal wiring, minimal disruption. Because iSUN is designed as a retrofit, installation doesn’t require rewiring your entire system or replacing your existing backup inverter/UPS. That keeps installation time down and keeps costs predictable.
Instant switchover. When an outage hits, backup power turns on immediately — no manual switching, no gap where your critical loads sit unpowered while someone flips a breaker.
Fits the battery system you already have. iSUN is available in 12V, 24V, 36V, and 48V configurations, matching it to your existing backup inverter/battery voltage rather than forcing you into a new one.
Clean and scalable. Whether you’re protecting a few household circuits or a small commercial load panel, iSUN scales to the backup capacity you actually need, without over-building the system.
Who Needs a Grid-Tied Solar Battery Backup Solution?
If any of the following sounds like you, iSUN is worth a look:
– You have a grid-tied solar system and it goes dark every time the power does.
– You already own a backup inverter/UPS and battery bank, but they aren’t currently tied into your solar output.
– You want outage protection for critical loads without the cost and disruption of a full hybrid system replacement.
– You want a solution that’s simple to install and doesn’t touch the efficiency of your existing solar setup.
The Bottom Line
Grid outages shouldn’t mean your solar system becomes useless. With iSUN, Energy24by7 gives existing solar owners a straightforward, economical way to add real backup power — using the battery system they already have, with minimal wiring, instant switchover, and zero compromise to solar performance.
Your panels don’t stop making power when the grid goes down. With iSUN, neither should you.
Want to know if iSUN is the right fit for your existing solar setup? Get in touch with the Energy24by7 team to find the right voltage configuration for your system.