Your home battery can’t tell your fridge from your pool pump, so during a blackout it will feed both until it runs dry. That’s the problem sonnen smart breakers are built to solve. The fix is surprisingly simple.

Below, you’ll get a plain-English look at how smart breakers decide which circuits to switch off, why sonnen and SOLRITE Energy are using the same trick to support the grid, and what that means for your backup time on a bad night. You’ll also get my take on whether this belongs on your shortlist. Short version: shedding the right loads is one of the least glamorous and most useful upgrades a battery owner can make, but your experience will depend on how the program handles your home’s circuits.

Traditionally, this has been handled with a critical loads panel, a subpanel wired to the battery and fixed on install day. That decision rarely gets revisited. Smart breakers make it flexible: an electric water heater, dryer, or EV charger can be switched off temporarily, leaving more stored energy for lights, Wi-Fi, and the fridge. sonnen and SOLRITE are applying that logic beyond outages, cutting selected household loads while home batteries help meet electricity demand. The same hardware that stretches your backup could also make your battery more valuable to the grid.

How sonnen and SOLRITE’s smart breaker setup works

Switching off nonessential loads like HVAC, pool pumps, and water heaters

Your home battery isn’t drained by the lights or your phone charger. It’s drained by a handful of motor- and heat-driven appliances that would happily empty a full battery while you sleep through an outage. The idea behind load shedding is simple: when the grid goes down, the system cuts power to the energy hogs and keeps the circuits you actually need running. A typical residential electric water heater element is rated around 4,500 watts, which puts it in the same range as several refrigerators running at once. Letting that reheat a tank of water during a blackout is a bad trade for most households.

The usual suspects on the shed list look like this:

• Central HVAC: compressors draw heavily on startup and run in long cycles, especially in summer heat.
• Pool pumps: they run for hours and contribute nothing to keeping you safe or fed during an outage.
• Electric water heaters: big resistive loads that can wait until the grid or the sun comes back.
• EV chargers: a Level 2 charger will happily move your battery’s energy into your car’s battery, which isn’t the point of backup.

Shedding these loads automatically, instead of relying on someone to run to the breaker panel with a flashlight, is the real upgrade. Manual load management works great in theory and fails at 2 a.m. My take: if you’re spending real money on a home battery, skipping smart load control is like buying a big gas tank and leaving the engine idling in the driveway.

How smart breakers pair with sonnen home batteries

The appeal of sonnen smart breakers is that selected circuits can be switched off temporarily rather than being fixed by a wiring diagram. Traditional backup setups solve this with a separate “critical loads” subpanel, where an electrician physically moves your essential circuits so the battery only sees those. That works, but it locks you into whatever you chose on install day. If you later decide the garage freezer matters more than the guest room outlets, you’re calling the electrician again. Smart breakers make that choice changeable without rewiring.

In principle, smart load control can do something a conventional panel can’t: temporarily switch off selected circuits when that energy is better used elsewhere. It reflects the idea that the breaker box should be part of the energy system rather than a gray metal afterthought. An integrated setup avoids piecing together a battery from one company and load control from another. Integration matters here. Mismatched hardware from different vendors is where finger-pointing support calls are born.

The honest caveat: smart breakers don’t create energy, they just stop you from wasting it. If your battery is undersized for your home or you live somewhere with multi-day outages and little winter sun, load shedding stretches your runtime but won’t fix the underlying math. Still, for most homeowners weighing a second battery against smarter control of the one they have, the breakers are the more sensible first move. Making a battery last longer by using it wisely beats buying more battery to feed a pool pump during a blackout.

Why load control matters for home battery backup

Stretching runtime during blackouts

A home battery’s runtime has less to do with how many kilowatt-hours you bought and more to do with what you leave plugged in. Take a hypothetical 10 kWh battery. A refrigerator, a few LED lights, the Wi-Fi router, and phone chargers might draw a few hundred watts combined, which works out to more than a day of backup. Add a central air conditioner pulling several kilowatts every time the compressor kicks on, and that same battery could be drained before you’ve finished complaining about the outage on social media.

EV owners have the biggest version of this problem. A Level 2 charger on a 40-amp circuit pulls 32 amps at 240 volts, which is roughly 7.7 kW. That’s enough to empty a mid-sized home battery in about an hour if nothing stops it. This is the core case for load control. Instead of rationing power by running to the breaker box with a flashlight, the system decides which circuits get power, and it can change those decisions as the battery’s state of charge drops. Here are the loads that usually get cut first:

• Level 2 EV chargers: the largest single load in most garages, and you rarely need one during a short outage
• Central AC and heat pumps: worth running in short bursts, wasteful to leave on all the time
• Electric water heaters and dryers: large loads that can wait until the grid returns
• Pool pumps and hot tubs: no one has ever needed a hot tub to survive a blackout

Smart breakers vs. a traditional critical loads panel

The traditional fix, a critical loads panel, is a commitment you make on installation day and then live with for the next decade. An electrician moves your chosen circuits (fridge, a few outlets, maybe the furnace blower) into a separate subpanel that the battery backs up. Everything else goes dark when the grid fails. It works, and it’s cheap and simple. It’s also rigid. If you decide two years later that the home office matters more than the guest bedroom, that means another call to the electrician and another invoice.

Smart breakers reverse that logic. With smart breakers, a battery can in principle back up more of the panel and switch off selected circuits as conditions change. On a short outage with a full battery, you might keep almost everything running. If the outage drags into a second day, nonessential circuits can drop off so the fridge and router keep going. The decision moves from a one-time wiring choice to an ongoing, adjustable one, which suits how power outages actually behave: you don’t know how long one will last when it starts.

My take is that smart breakers aren’t automatically the right choice for everyone. If your backup priorities are simple and won’t change, a basic critical loads panel is honest, inexpensive engineering, and there’s nothing wrong with that. But if you own an EV, run a heat pump, or live somewhere with multi-day outages, a fixed subpanel forces you to guess your future needs ahead of time. Smart load control lets you change your mind later. A home battery is an expensive purchase, and the hardware that decides where its energy goes matters nearly as much as the battery itself.

Smart breakers and the virtual power plant model

How shedding household load helps batteries support grid demand

A home battery can only send power to the grid if your house isn’t eating it first. That’s the problem smart breakers solve in a virtual power plant (VPP), where a utility or aggregator links thousands of home batteries and dispatches them together during peak demand. When the grid is strained on a 100-degree August evening, the battery’s stored energy is split between your house and the grid. Every kilowatt your air conditioner, pool pump, or EV charger draws is a kilowatt that never reaches the grid.

Here’s a quick example with round numbers. Say your battery can discharge at 5 kW and you’re enrolled in a VPP event lasting two hours. If your home is pulling 4 kW at the time, only about 1 kW goes to the grid, and the battery runs down supporting your thermostat instead of the neighborhood. Now say smart breakers cut the nonessential circuits and your load falls to 1 kW. You’ve quadrupled your grid contribution without adding battery capacity. That’s what load shedding buys you: the same hardware does more useful work.

The loads worth shedding during a grid event tend to be large, flexible, and easy to defer:

• Level 2 EV charging: a 32-amp charger on a 240-volt circuit draws about 7.7 kW, more than many home batteries can output. Pausing it for two hours costs you some range, which you can usually recover by charging later.
• Electric water heaters: a tank of hot water stays hot for hours, so there’s no reason to reheat it during a peak event.
• Pool pumps and hot tub heaters: nobody’s pool chemistry has ever collapsed because the pump took an evening off.
• Dryers and secondary HVAC zones: the guest room doesn’t need to be 70 degrees if no one’s sleeping in it.

This is where sonnen smart breakers get interesting, and where I’d raise one caution. Circuit-level control makes the VPP model work at household scale because it lets the system make small, specific cuts instead of asking you to suffer through a blanket “reduce usage” text message. But someone has to decide which circuits are expendable, and the default settings won’t know about the medical device in the back bedroom or that your teenager’s gaming PC is apparently essential infrastructure. Spend twenty minutes setting circuit priorities properly before you enroll in any grid program. The default assumptions are a starting point, not a decision made for you.

My take: smart breakers are what make VPP participation tolerable over the long run. Asking people to voluntarily turn things off works about as well as you’d expect on a hot day. Automated, circuit-by-circuit shedding takes the willpower out of it. If you own an EV, you’re already the ideal candidate, because your car’s charging is the biggest flexible load in the house and also the easiest one to move. Letting your charger pause during peak events, so the battery can earn credits or lower grid strain instead, is about the least painful way to support the grid there is. You won’t notice the difference in your morning commute.

Real-world applications and examples

The biggest win shows up at 2 a.m. during a storm outage, when your home battery stops wasting energy on things nobody needs. Without load control, a backup battery powers whatever is plugged in and switched on: the electric water heater reheating a tank nobody will use until morning, the pool pump, the garage fridge holding three cans of seltzer. With smart load control, those circuits can be shed automatically so stored energy goes to the loads that matter. The result is the same battery lasting much further into an outage, simply because it carries less dead weight.

Here is the kind of triage a typical owner might set up, ranked from “keep at all costs” to “it can wait”:

• Critical: refrigerator, internet router, a few lighting circuits, medical devices such as a CPAP machine
• Conditional: furnace blower or a single mini-split, enabled only while the battery stays above a set charge level
• Non-essential: electric water heater, pool pump, dryer, and the Level 2 EV charger

That last item deserves its own paragraph, because it is the one EV owners get wrong.

A Level 2 charger drawing 48 amps (on a 60-amp circuit) pulls roughly 11.5 kW, which is more than a lot of home batteries can deliver continuously and enough to drain a pack in a few hours. Plug your car in during an outage without load management and you have essentially poured your house’s stored energy into your car’s much larger battery, where it barely moves the range needle. The smarter play is to treat the EV charger as a sheddable load during grid-down events and let it resume once the grid returns or solar production is strong. If you really need range during a multi-day outage, a scheduled midday charging window off excess solar is far kinder to your home battery than an overnight session. Your car is the bigger battery. Act like it.

Smart breakers also earn their keep when the grid is up, especially for owners on time-of-use rates. During the expensive evening peak, the system can hold off power-hungry appliances such as the water heater or pool pump and let the battery cover only essentials, stretching stored solar energy across more of the high-rate hours. In practice, that looks like your water heater heating at 1 p.m. off rooftop solar instead of at 6 p.m. off a battery you would rather save for dinner and lights. None of this requires you to remember anything, which is the point, because nobody wants to flip breakers by hand after a long day.

sonnen is not alone here. Other smart panels and smart breakers chase the same idea: make every circuit controllable instead of all-or-nothing. My take is that the hardware brand matters less than how well it talks to your battery and inverter, because a smart breaker that cannot read battery state of charge is just an expensive remote switch. If you already own a sonnen system, keeping control inside one ecosystem is the obvious move and spares you the integration headaches. If you are shopping fresh, ask every installer the same question: which circuits shed automatically, at what battery level, and can I change that from my phone without calling you?

Frequently Asked Questions

What are sonnen smart breakers and how do they actually work?

Think of them as circuit breakers that also take orders from your battery. Instead of only tripping on overloads, smart breakers can temporarily switch off selected household circuits. In principle, the same approach during an outage would shed big, non-essential loads like a pool pump, a second HVAC unit, or an EV charger so the stored energy goes to your fridge, lights, internet, and medical devices. The point isn’t more capacity. It’s spending the capacity you already have more wisely.

Do sonnen smart breakers work with my existing sonnen battery?

Possibly, but don’t assume it. Compatibility can depend on your specific system and electrical panel. The honest answer is to ask your sonnen-certified installer before you buy anything. They can confirm whether your unit supports smart load control and whether your panel has the space and rating for the swap. If someone quotes you without looking at your panel, that’s a red flag. Get a site assessment first.

Are sonnen smart breakers worth it compared to a full smart panel?

It depends on what you’re starting with. A full smart panel typically replaces your entire load center and gives you circuit-level monitoring and control, but it’s generally a bigger install. Smart breakers are the more targeted fix: you control the handful of heavy loads that actually drain a battery during an outage. If you already own a sonnen system and mostly want longer backup runtime, breakers are probably the smarter spend. If you’re redoing your panel anyway, or you want detailed whole-home energy data, a smart panel makes more sense.

Can sonnen smart breakers manage my EV charger during a power outage?

This is where they earn their keep for EV owners. A 48-amp Level 2 charger pulls about 11.5 kW, which is more than many home batteries can deliver continuously and can empty one in an hour or two. Put the charger on a smart breaker and the system can cut it during an outage so your car doesn’t quietly drain the backup meant for your fridge and furnace. My take: unless you truly need to charge during a blackout, your EV should be the first load shed. Most cars have plenty of range to wait out a typical outage.

The Bottom Line

A home battery’s real capacity during an outage depends on what you let it power. Raw kilowatt-hours matter less than discipline, and most of us don’t have much of that at 2 a.m. when the grid goes down and the AC is still set to 70. That’s the appeal of sonnen smart breakers. They make load decisions automatically, so a well-sized battery doesn’t get drained by a well-meaning household.

For EV owners, this matters more. A Level 2 charger drawing 48 amps pulls about 11.5 kW, enough to drain a typical residential battery in an hour or two. Without circuit-level control, your car and your house compete for the same stored energy, and the car usually wins. Smart breakers let you decide which one comes first.

Before you spend more on extra battery modules, figure out which circuits you’d actually keep running if the power were out for three days. If you can’t answer that, you don’t have a capacity problem. You have a control problem.