I need a solar inverter that charges a backup battery during a grid outage.

To keep your essential appliances running and your batteries charged during a blackout, you need a hybrid solar inverter (sometimes called an all-in-one solar inverter-charger). Unlike standard grid-tied inverters that shut down for safety when the power grid goes down, a hybrid inverter isolates your home (via an automatic transfer switch/UPS function) and uses your solar panels to actively juice up your battery bank while feeding your home loads.

Top-performing options on the market depend on your power scale and budget:

• Sol-Ark 12K-2P / 18K-2P Go to product viewer dialog for this item.: Widely considered the gold standard for whole-home resilience. It's an all-in-one heavy-hitter featuring lightning-fast switching, massive surge capacity, generator integration, and seamless compatibility with a wide range of 48V lithium batteries. You can view specs or options via Home Depot's Sol-Ark 12kW Listing.
• EG4 12kPV Hybrid Inverter Go to product viewer dialog for this item.: An extremely popular, cost-effective choice for robust residential backup. It provides split-phase 120/240V power, rapid <10ms transfer time during grid failures, closed-loop communication with prominent lithium batteries, and high scalability. Check retailer availability on ShopSolar.com's EG4 12K PV Page.
• ECO-WORTHY 5kW / 10kW All-In-One Inverter Go to product viewer dialog for this item.: A budget-friendly, highly integrated option ideal for smaller setups, cabins, or essential-circuit backups. It features dual MPPT controllers and built-in UPS switching to jump into battery mode the moment the grid drops. Explore details on the Eco-Worthy Official Store.

To help narrow down which inverter fits your setup, tell me:

• Do you want to back up just essential circuits (fridge, lights, Wi-Fi) or your entire home?
• What is your approximate solar array size (in kW) or planned battery voltage/capacity?

Yes — what you want is a hybrid solar inverter/charger, not a standard grid-tied solar inverter.

It should:

• Use solar panels to power the house and charge the battery.
• Keep the battery charged from the grid when appropriate.
• Automatically disconnect from the grid during an outage and run your backup loads from battery + solar.
• Ideally provide 120/240V split-phase output for a U.S. home.
• Support a lithium/LiFePO₄ battery with BMS communication.

Good options

• EG4 FlexBOSS18 13kW Hybrid Inverter - $2,999.00 (Renewable Outdoors)

• Solis S6 12K 48V Hybrid Inverter - $5,140.00 (self2solar)

• Sol-Ark 15K-2P Hybrid Inverter - $5,199.00 (Walmart - Premier Goods Trading Co)

• EG4 6000XP 48V Inverter Charger - $1,549.00 (US Solar Supplier)

• EG4 FlexBOSS18 — a strong choice for whole-home backup; 48V split-phase and UL1741 certified.

• Solis S6 12K — particularly interesting if you want a modern hybrid system; the S6 family supports 9.6–16 kW, 200A pass-through, and battery storage.

• Sol-Ark 15K-2P — premium option if you want a powerful, expandable system.

• EG4 6000XP — better suited to essential-load backup rather than a large whole-house system.

For example, the EG4 12kPV is a 48V split-phase hybrid inverter with up to 12 kW of solar input, 8 kW continuous output, generator support, and UL1741/SA/SB certifications.

The battery is just as important

The inverter's kW rating determines how much you can run simultaneously; the battery's kWh capacity determines how long you can run it.

For example, a 10 kWh battery theoretically provides about:

• 1 kW load → ~10 hours
• 2 kW → ~5 hours
• 5 kW → ~2 hours

Real-world runtime will be somewhat lower because of inverter losses, battery reserve, temperature, etc.

If you tell me (1) your solar-panel wattage, (2) which appliances you want running during an outage, and (3) roughly how many hours/days of backup you want, I can size the inverter and battery and recommend a specific setup.

Yes — what you’re looking for is a hybrid solar inverter / battery inverter that can operate in backup (islanding) mode. A normal grid-tied inverter will shut down when the utility fails; a properly designed hybrid system can keep selected circuits—or the whole house—powered from the battery and solar.

Good options

• Sol-Ark 15K Hybrid Inverter - $5,299.00 (Renewable Outdoors)

• Solis S6 10kW Hybrid Inverter - $2,059.00 (self2solar)

• Solis S6 7.6kW Hybrid Inverter - $1,469.00 (self2solar)

• Solis S5 5kW Hybrid Inverter - $942.11 (VoltaconSolar)

• Sol-Ark 15K — a strong choice if you want whole-home 120/240V backup, substantial surge capability, and flexibility with batteries. The current listing shows 12 kW battery output and 200A pass-through.

• Solis S6 — worth considering for a new solar + battery installation; it comes in several power levels and is designed around energy-storage applications.

• 5–7.6 kW class — appropriate if you're backing up essential loads rather than trying to run the entire house.

For a California home, I'd generally favor a UL-listed, grid-interactive hybrid system from an established manufacturer over the very inexpensive generic 48V inverters. A professionally installed system also needs the appropriate transfer/islanding equipment and battery compatibility; the inverter, battery BMS, solar array, and electrical panel all have to work together.

The battery size is just as important as the inverter. For example, a 10 kWh battery can theoretically supply a 5 kW load for about two hours, before accounting for conversion losses and reserve capacity.

If you tell me (1) whether you already have solar, (2) your existing inverter model, (3) what you want to keep running during an outage—AC, refrigerator, well pump, etc.—and (4) roughly how many hours/days of backup you want, I can narrow this down to the right inverter + battery combination and current prices.

To keep your home powered and your batteries charging via solar panels during a grid outage, you need a hybrid solar inverter (sometimes called a multi-mode or all-in-one inverter charger). Standard grid-tied inverters automatically shut down during a blackout for safety reasons (anti-islanding), whereas hybrid inverters can isolate from the grid, power your home, and actively pull energy from your solar array to recharge your backup battery bank.

Top-tier options available on the market range from whole-home industrial systems to modular all-in-one units:

Add to list Sol-Ark 15K-2P or 12K-2P Hybrid Inverter – Widely considered the gold standard for robust, whole-home residential backup. It features lightning-fast switchover times (~ 5 ms), massive surge capacity, high-voltage PV inputs, and seamless integration with a wide variety of 48V lithium battery banks.

Add to list Tesla Powerwall 3 – An integrated all-in-one unit combining the battery and a high-efficiency solar inverter into a single sleek package designed specifically for seamless backup.

Add to listEG4 FlexBOSS21 – A next-generation split-phase hybrid inverter engineered for heavy-duty whole-home backup and flexible solar harvesting, offering high PV capacity and native 48V battery compatibility.

Add to list EcoFlow DELTA Pro Ultra X – A modular, highly scalable plug-and-play style whole-home backup solution that pairs high-output inverter capabilities with expandable LFP battery stacks and rapid auto-switchover.

Add to list Sungrow Hybrid Inverters – Excellent all-around grid-interactive hybrid units providing flexible battery pairing and reliable dedicated emergency backup outputs.

To help narrow down the best choice, let me know:

• Do you need whole-home backup (running heavy loads like central AC) or just critical loads (refrigerator, lights, internet)?
• What is your budget range or preferred battery size?
• Do you already have existing solar panels , or is this a completely new build?

Yes — what you want is a hybrid solar inverter / inverter-charger. It can:

• Run your house from the grid normally.
• Charge the battery from solar and/or the grid.
• Automatically switch to the battery when the grid fails.
• Continue using solar to charge the battery during an outage, depending on the system design.
• Provide 120/240V split-phase power for typical U.S. homes.

Good options I found

EG4 FlexBOSS18 13kW Hybrid Inverter

$2,999.00

Solis S6 12K 48V Hybrid Inverter

$5,010.00

BigBattery APEX 6.5K Hybrid Inverter

$1,490.00

EG4 6000XP 48V 6kW Inverter/Charger

$1,549.00

My picks:

1. EG4 FlexBOSS18 — strong choice if you want substantial whole-home backup. It's a 48V split-phase hybrid inverter with UL 1741 certification.
2. Solis S6 — a more conventional residential hybrid system; its U.S. model provides native 120/240V backup and can supply up to 11.4 kW continuously.
3. BigBattery APEX 6.5K — less expensive option if you're primarily backing up essential circuits rather than the entire house.
4. EG4 6000XP — another 6 kW-class option worth considering for a 48V battery bank.

For a higher-end system, the Sol-Ark 18K is another excellent candidate. It supports 48V batteries, 120/240V split phase, solar, battery, generator and grid integration, with UL 1741 SA certification. Home Depot currently lists it around $6,699 for the inverter alone.

One important distinction

If by "charges a backup battery during a grid outage" you mean the solar panels should continue charging the battery while the utility grid is completely down, make sure you buy a true hybrid/off-grid-capable inverter, not merely a grid-tie inverter with a battery.

Also, don't size the inverter just by your home's service size. For example, a 6 kW inverter can handle roughly 6,000 W of continuous load, while an 18 kW unit can handle substantially more. Your battery's kWh capacity determines how long you can run those loads.

If you tell me (1) your solar-panel wattage, (2) whether you want whole-house or just essentials, (3) your desired backup time, and (4) your approximate budget, I can narrow this down to 2–3 specific inverter + battery combinations.

To keep your backup battery charged via solar panels during a grid outage, you need what is known as a hybrid solar inverter (or a multi-mode inverter/charger). Unlike standard grid-tied inverters that automatically shut down during a blackout for safety reasons, a hybrid inverter isolates your home from the grid, keeps powering your loads, and routes surplus solar energy straight into your battery bank.

Top Hybrid Inverter Recommendations

Sol-Ark 15K / 8K — Widely considered the gold standard "workhorse" for residential backup. It has a massive surge capacity, handles whole-home backup easily (including heavy loads like well pumps or AC units), switches instantly during an outage, and integrates seamlessly with various 48V battery brands.

Tesla Powerwall 3 — An all-in-one unit featuring an integrated solar inverter and massive energy storage capacity. It's sleek, highly efficient, and automates whole-home or critical load backup smartly.

EG4 (18kPV or FlexBOSS21) — A very popular, cost-effective 48V split-phase hybrid choice for robust residential backup and high PV input capacity, well-supported by the DIY and professional solar community alike.

Enphase IQ8 Series with IQ Battery — Instead of a single central box, Enphase uses microinverters at the panel level coupled with an Enphase storage system. It offers unique grid-forming capabilities and modular expansion.

SolarEdge Energy Hub — A great DC-optimized string inverter choice if your roof layout has partial shading issues and you want streamlined battery management in a single unit.

Key Factors to Keep in Mind Before Buying

• Battery Compatibility: Hybrid inverters are often picky about communication protocols. Always check if the inverter officially supports the specific brand and voltage (e.g., 48V vs. high-voltage proprietary batteries) of the battery you plan to use.
• Whole-Home vs. Critical Loads Backup: Ensure the continuous wattage output of the inverter can handle what you intend to run. Backing up an entire home requires a 9kW to 15kW+ unit, whereas a smaller 5kW–6kW inverter may require a dedicated sub-panel for critical loads (fridge, lights, Wi-Fi).
• Split-Phase Output: If you live in North America and use standard US household power, make sure the inverter explicitly states it outputs 120V/240V split-phase so it can drive your large 240V appliances.
• Code and Certifications: Look for UL1741 (or UL1741SB) certification, which is universally required by US utility companies and inspectors for grid-interactive backup systems.

To help narrow down the exact model you need, could you share:

• Do you want to back up your entire house or just critical appliances?
• Do you already own or have a specific battery brand in mind?

You’re looking for a hybrid solar inverter with battery backup capability. A normal grid-tied solar inverter will shut down during an outage; a backup-capable hybrid inverter can isolate from the grid, charge a battery from solar, and supply your home (or selected circuits) when the utility is down.

A few options to consider:

Sol-Ark 15K Hybrid Inverter

$5,299.00

EG4 FlexBOSS18 Hybrid Inverter

$2,999.00

Growatt MIN 11.4kW Hybrid Inverter

$1,698.00

Solis S6 3.8kW Hybrid Inverter

$998.00

For a typical home:

• Small backup (lights, fridge, internet, a few circuits): ~3–6 kW inverter + 5–15 kWh battery.
• Partial-home backup (well pump, appliances, selected HVAC loads): ~6–10 kW inverter + larger battery bank.
• Whole-home backup: usually 10 kW+ split-phase equipment with enough battery capacity to handle large startup loads.

Key specs to check:

• Battery voltage compatibility (many modern systems use 48V or high-voltage lithium batteries).
• Backup output rating (continuous watts and surge watts for motors/compressors).
• Transfer time if you need seamless backup for sensitive electronics.
• Whole-home vs critical-load backup — many systems require a backup loads panel or transfer equipment.

If you tell me:

1. your solar panel size (kW) or whether you have panels already,
2. your battery capacity target (hours of backup),
3. whether you want whole house or just essentials, and
4. your voltage/service (for example, 120/240V U.S. home),

I can narrow it to the right inverter size and battery pairing.

What you are looking for is called a hybrid solar inverter . Unlike standard grid-tied inverters that shut down during a blackout for safety reasons, a hybrid inverter isolates itself from the grid during an outage (called "islanding") and uses your solar panels to actively charge your backup battery while simultaneously powering your home.

Top-performing hybrid inverter options range from heavy-duty whole-home solutions to modular all-in-one systems:

Widely considered the gold standard for robust residential backup. It features a 200A pass-through, lightning-fast switchover time (~5 ms), massive surge capacity to start heavy appliances like central air or well pumps, and broad compatibility with 48V lithium batteries.

An exceptional value-to-performance choice heavily favored in the residential and DIY/pro-sumer market. The EG4 systems pair high PV input capacities with seamless split-phase output and closed-loop communication with server-rack or wall-mount lithium-iron-phosphate (LiFePO4) batteries.

A newer high-capacity hybrid option boasting massive solar input flexibility (up to 40kW), high split-phase output, NEMA 3R outdoor rating, and modular expandability for heavy inductive loads.

Great choices if you prefer a streamlined, heavily integrated ecosystem . The Powerwall 3 embeds the inverter directly into the battery unit itself, while SolarEdge handles DC-optimized string layouts exceptionally well if your roof has partial shading.

When shopping, keep these core specs in mind:

1. Continuous AC Output (kW) : Determines how many appliances you can run simultaneously during an outage. A 6kW to 8kW inverter handles essentials; 12kW to 15kW+ can typically back up an entire home.
2. Battery Voltage & Ecosystem : Make sure the inverter's DC voltage matches your battery bank (commonly 48V or high-voltage proprietary setups). Using "closed-loop" communication ensures the inverter accurately commands the battery's BMS for safe charging.
3. Transfer Time : Look for automatic switchover times measured in milliseconds so your computers and clocks don't reset when the grid drops.

To help narrow down the ideal unit, let me know:

• Do you want whole-home backup (running heavy loads like HVAC and well pumps) or critical-load backup (just refrigerators, lights, and Wi-Fi)?
• Are you planning to pair it with a specific battery brand or starting from scratch?

To keep your home powered and your backup battery charged using solar panels during a grid outage, you need a hybrid solar inverter (or a multi-mode inverter/charger) with grid-forming/islanding capability . Standard grid-tied inverters automatically shut down during a blackout for safety reasons (to prevent backfeeding electricity into downed utility lines).

Top-performing hybrid inverters capable of handling solar generation, charging batteries, and seamlessly transitioning to backup power during an outage include:

Sol-Ark 15K / 12K Hybrid Inverter – Widely considered a premier heavy-duty, all-in-one choice for whole-home backup. It features a massive surge capacity, rapid automatic transfer times, and built-in charge controllers that seamlessly manage solar input, batteries, and even backup generators.

EG4 FlexBOSS21 – A flexible, high-capacity split-phase hybrid inverter engineered for whole-home and off-grid configurations, capable of handling heavy startup loads like central air conditioners while continuously charging from extensive PV arrays.

Tesla Powerwall 3 – An all-in-one unit featuring an integrated solar inverter built directly into the high-capacity storage battery, offering clean design and automated blackout transition.

Enphase IQ8 Series Microinverters + IQ Battery – A decentralized approach that uses panel-level microinverters capable of forming a local micro-grid, which can power critical loads and recharge batteries safely even during shifting daylight conditions.

Sungrow Hybrid (SH Series) – A reliable, highly efficient global favorite for residential energy storage that supports high-voltage batteries and flexible backup configurations.

To help narrow down the best specific model for your setup, let me know:

• Are you looking for partial backup (just essentials like a fridge and lights) or whole-home backup (including heavy loads like AC units or an EV charger)?
• Do you already have existing solar panels , or is this a brand-new installation?

Yes — what you want is a hybrid solar inverter / inverter-charger with battery backup. It should be able to:

1. Take power from your solar panels.
2. Charge a battery.
3. Power your house from the grid normally.
4. Automatically switch to battery + solar when the grid goes down.
5. Continue charging the battery from solar during the outage.

A normal grid-tied solar inverter will not do this by itself because it normally shuts down during an outage.

Good options

Sol-Ark 12K Hybrid Inverter

$5,299.00

EG4 FlexBOSS18 Hybrid Inverter

$2,999.00

EG4 12kPV Hybrid Inverter

$14,070.00

BigBattery APEX 6.5K Hybrid Inverter

$1,490.00

Sol-Ark 5K Hybrid Inverter

$2,998.00

My first choice for a typical U.S. house: a 48V, 120/240V split-phase hybrid inverter. That gives you compatibility with normal American residential service and allows 240V loads such as HVAC, well pumps, and electric appliances where the inverter has sufficient output.

For example, the Sol-Ark 12K is a higher-end choice if you want substantial whole-house backup. The EG4 FlexBOSS18 is another high-capacity 48V split-phase option. For a smaller critical-load system, something around 6 kW can be considerably less expensive.

The important part: size the battery separately

For example, a 10 kWh battery doesn't mean you'll get 10 hours of backup. Roughly:

• 500 W average load → ~20 hours
• 1,000 W → ~10 hours
• 2,000 W → ~5 hours
• 5,000 W → ~2 hours

Actual runtime is lower after inverter/battery losses and depends on how much usable battery capacity you have.

If you tell me (a) your solar-panel wattage, (b) the appliances you want running during an outage, (c) whether you want whole-house or just essential circuits, and (d) your desired backup time, I can recommend the appropriate inverter and battery size rather than having you overspend.