Battery technology in consumer markets and products is evolving, and that has made possible new applications that benefit homeowners and renters. A large battery-backup system, for example, doesn’t make practical or economic sense for some people. Small portable power stations can provide energy at a much lower cost during outages or where electricity isn’t available, and are a good choice for those who rent.
Appliance manufacturers are starting to build batteries into their products. This provides backup electricity in the event of a power outage, and it can save money in some unexpected ways. I’ll cover two of the most interesting appliance battery examples — heat pump water heaters and induction stoves — but first I’ll talk about portable power stations and how you can best take advantage of them.
What are portable power stations?
Portable power stations are battery packs ranging from around 100 watts to 6,000 watts in power output and weighing between two and more than 100 pounds. They come with a variety of connectors depending on the model, including USB ports, standard three-prong outlets, car ports, and DC ports. The more ports, the more devices you can connect at a time.
The two most common uses for portable power stations are for backup during outages and providing electricity sources away from the grid. Although some come close, none take the place of a dedicated home battery-backup system, as they are capable of powering only a few critical items. They might keep your refrigerator cold, your internet connection live, or medical equipment running. Don’t expect them to run too many things at once or anything with a heavy electricity demand, such as an oven, clothes dryer, or heat pump.
Most small portable power stations use lithium-ion batteries, but most larger models have newer lithium-iron phosphate (LiFePO₄) batteries that have better longevity and are safer. Some manufacturers sell optional small solar panels that can charge the battery when grid power is not available.
Portable power station performance
Performance is measured in watt-hours, or how many watts a unit can deliver in an hour. This is not the same as the watt power output numbers I mentioned above, which describe the total power they can deliver at any given moment. A 2,400-watt portable power station, for example, might provide a little more than 2,000 watt-hours, which is enough to run a full-size refrigerator for up to 14 hours.
You also need to consider two types of power output. The watt numbers are for running power output, which refers to the portable power station’s ability to maintain operation of something like a refrigerator. Surge watts refer to a unit’s ability to handle a sudden large load demand, such as a well’s water pump starting up.
So, you need to know what appliances and systems you want the portable power station to run, as well as what their running and surge demands are. Matching that information against the model specifications will then give you a short list of which ones to consider. You want a model that can handle the initial surge demands of the systems, devices, and appliances you want to back up. Then consider the length of time it can operate those items during an outage.
Portable power stations are quite capable of providing electricity away from the grid where you might otherwise use a gas-powered generator. You can power lighting and small appliances, or keep devices charged during camping trips, for example. For outdoor DIY projects, you can charge or provide electricity to power tools when an electrical outlet is not nearby. Some people use small portable power stations routinely for medical devices, such as CPAP machines, to provide continuous operation in case of an outage.
What does a portable power station cost?
Size and features of portable power stations vary widely, and that determines the cost. Prices start at under $300 for small units best suited for outdoor use. Models capable of providing some home backup capability start at around $500 and can run as high as $5,000 or more depending on what options you buy. Options include additional batteries or increased battery size, solar panels for off-grid charging, and components that automatically switch connected items to battery power during an outage.
Stationary battery backup systems and whole-house backup generators will keep more things running longer during an outage, but they can cost twice as much as a high-end portable power station or more. They also require professional help to install. If limited capabilities are enough for you, then a portable power station can be a bargain. Here’s a review that identifies best-in-class portable power station models: https://www.bobvila.com/reviews/best-portable-power-stations/.
Why the heck would you put a battery in a water heater?
That was my first thought when I learned of heat pump water heaters and induction stoves with batteries. Once I learned more, it made perfect sense. Most models require a 240-volt connection. Adding a battery to either appliance means you can plug it into a standard 120V outlet. Here’s why.
You need a 240V connection to handle peak load electricity demands. Because those peak demand times are short, a battery can supplement the 120V connection without overloading your home’s electrical system. It does lower the efficiency of the heat pump water heater a bit, but units with the battery still outperform most fossil fuel and standard resistance electric-powered units.
Using a 120V connection eliminates the need for an electrician to install a 240V connector or upgrade your electrical panel. This reduces the cost of installing a heat pump water heater significantly. LiFePO₄ batteries are commonly used in both induction stoves and heat pump water heaters, so you don’t have to worry about the fire risks associated with lithium-ion batteries.
Some manufacturers provide two-way chargers with their battery-equipped appliances. This means that you can use their stored power during an outage to run some lights or small devices.
Electrical work associated with 240V connections is often a significant barrier to installing energy-efficient appliances such as a heat pump water heater or induction stove as well as heat pump water heaters. Now you can benefit from them without the cost and hassle of hiring a contractor.
Michael Nadeau is a member of the Community Power Committee.