Running a Tankless Water Heater on Battery Power: Is It Possible?
When you have to take a cold shower because the power went out, you realize how much you depend on energy. Then the question comes up: can a battery power a portable water heater? Having a backup hot water system that you can count on is a nice thought. It gives you a little more independence when the power goes out. To help you decide if connecting your tankless heater to a battery is right for your home, we'll discuss the real-world possibilities.
How Much Power Does a Tankless Heater Really Need?
Tankless water heaters, sometimes called on-demand heaters, work very differently than the big old tank heaters. Instead of keeping a huge tank of water hot 24/7, they flash-heat water the second you turn on the faucet. This instant heating process takes a serious jolt of power for a short time.
The power consumption of a heater that does not require a tank is measured in kilowatts (kW). Electric models are the ones that consume the most electricity, drawing anywhere from three kilowatts to more than twenty kilowatts, depending on the amount of hot water that is being run simultaneously. Gas-powered tankless heaters still need some electricity for their digital controls, fans, and electronic ignition, but they sip power by comparison—usually less than a few hundred watts.
You need to have a thorough understanding of the unique power requirements of your device before you can even begin to consider a battery solution. Simply consult the label or the handbook; the number in question is the essential element in determining what comes next.
What Can Modern Batteries Handle?
Power stations that use batteries have come a long way. Advanced lithium-ion batteries in these portable power packs, like the ones from EcoFlow, can hold a lot of power and put it out in a big way. The two main numbers you'll see are capacity (in watt-hours, or Wh) and power output (in watts, or W). Capacity tells you how much energy it can store and power output tells you how much electricity it can send out at once.
To run a tankless water heater, a battery station needs to check two boxes:
It must have enough juice (capacity) to power the heater for as long as you need hot water during an outage.
It must have enough muscle (power output) to handle the heater’s intense power surge the moment it kicks on.
Most portable battery stations will run out of power pretty fast for those electric tankless heaters that are in high demand. But for a gas tankless type that doesn't need much electricity, it makes more sense to use a battery for hot water in an emergency.
The Reality of Powering an Electric Tankless Heater
To be honest, most people can't run a big electric portable water heater on battery power for any length of time that is useful.
Most of the trouble is with how much power they use. In minutes, not hours, an electric heater can drain even a large battery station. Even though battery technology is getting better all the time, a small unit can't hold as much power as an electric heater needed to run a shower. The quick, high demand for power may also be too much for the battery to handle, so it will shut down to protect itself.
Still, it's not always completely impossible. A strong battery station might give you a few short bursts of hot water from a small, low-power electric heater at a single sink. For sure, you'd have to do the math to know if it's worth it.
A Much Brighter Outlook for Gas Heaters
Things look much better if you have a gas tankless water heater. Since the gas does all the heavy lifting for heating, the electricity is just for the brains of the operation—the control panel, fan, and ignition. This usually adds up to a modest 50 to 200 watts.
A battery power station with a decent capacity can easily handle that kind of load, often for hours. How long it lasts depends on:
Battery Capacity (Wh): The bigger the battery, the longer it runs.(2)
Heater’s Power Draw (W): A more efficient unit uses less power and extends battery life.
How Often You Use Hot Water: Every time you turn on the tap, you use up a little more of the battery.
A robust power station, like the EcoFlow DELTA Pro Ultra, could easily keep a gas tankless heater running through an extended outage, thanks to its substantial capacity and high power output.
Setting It All Up
There are a few things you need to do before you can set up a battery backup for your portable plant.
You need to think about how to hook up the battery to the heater. If you need a quick fix, a heavy-duty extension cord might do, but an electrician is the only way to get a safer, more permanent answer. When you're on battery power, this gadget safely disconnects your heater from the grid. This is very important to keep utility workers safe.
You should also make sure that the power output of your battery station can handle the heater's electricity load. Also, don't forget to think about how you'll charge the battery. When the power comes back on, you can plug it into the wall, connect it to solar panels, or even use a gas engine.
Always make sure to follow the safety rules for both your heater and the power station. Even if the gas comes from a battery, the room still needs to have enough air flow for the device.
A Quick Way to Estimate Your Runtime
Do you want a general estimate of how long your battery will provide power? Here is a straightforward formula:
Runtime (in hours) = Battery Capacity (in Wh) / Heater's Power Draw (in W)
So, if your gas heater uses 100 watts and your power station is rated for 1000 Wh:
1000 Wh / 100 W = 10 hours of runtime
This is merely a rough estimate. It is possible that the real duration will be somewhat shorter due to factors such as the effectiveness of the power conversion, but it will get you close to the target.
Go a Step Further with Solar
Solar panels can be used with your battery station to create a backup system that is both fully off-grid and environmentally friendly. In the event that there is a prolonged power outage, the panels have the ability to recharge the battery during the day, providing you with an almost limitless supply of electricity for your gas tankless heater. A solar and battery system that is well-designed can completely transform the resiliency of a home. Creating a genuinely self-sufficient hot water backup that recharges with the sun can be accomplished by constructing your system around a powerhouse unit like as the EcoFlow DELTA Pro Ultra, which is intended for easy integration with solar energy.
Hot Water When You Need It Most
Not having to worry about running out of hot water when the power goes out is more than just a relief. Electric tankless heaters use a lot of power, so batteries might not be ready for them yet. However, they are a great and useful way to keep a gas tankless system running. Be ready for a power outage and avoid being cold by making sure you have the right battery for your heater.