Smart Lock Backup Power Options

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Opening

You’re standing in your hallway. It’s 11 PM. The power just went out.

Your phone’s flashlight is on. You’re holding your keys in one hand. Groceries in the other. And you reach for your front door.

You pull down the handle. Nothing. You press the keypad. The lights are dead. You try the app. No Wi-Fi.

You’re locked out. Of your own house. Because your smart lock just became a very expensive brick.

This is After the Install . I’m Nick. And today we’re talking about something nobody thinks about until they’re standing in the dark with a dead lock.

Smart lock backup power options.

Here’s the thing. Most smart locks run on batteries. Four AAs. Maybe eight. And when those batteries die, or when your home network goes down, that hundred-and-fifty-dollar deadbolt becomes a decorative paperweight.

I’ve seen it happen. I’ve had it happen. And I’m going to show you exactly how to make sure it never happens to you.

We’re going to cover three backup power strategies. The basic. The better. And the “you probably don’t need this but here it is anyway.”

Let’s start with the obvious question.

The Problem Nobody Talks About

According to the U.S. Energy Information Administration, the average American home experienced over seven hours of power interruptions in 2023. That’s up from about four hours in 2020.

Seven hours. That’s a full workday. That’s a dinner shift. That’s a night’s sleep.

Now, if you’re running a dumb lock, you don’t care. You turn the key. You’re inside. Problem solved.

But smart locks are different. They need power to operate the motor. They need a network connection to authenticate your code. They need both to be useful.

Here’s the thing. Most smart lock manufacturers have thought about this. But their solutions range from “adequate” to “why did you even bother?”

Take the August Smart Lock Pro. It runs on four CR123 batteries. Those are the lithium ones that look like fat AAs. And when they die, the lock has a 9-volt backup terminal on the bottom.

You press a 9-volt battery against those contacts. The lock powers up just long enough for you to enter your code. Then it dies again.

That works. But it requires you to own a 9-volt battery. Which, if you’re like most people, you don’t. Not until you’re standing in the rain at midnight.

The Schlage Encode has a different approach. It uses four AA batteries. And when those die, the lock still works as a mechanical deadbolt. You turn the thumb turn from the inside. You use the physical key from the outside.

That’s better. But it assumes you carry your house key. Which, if you bought a smart lock, you probably stopped doing six months ago.

The Yale Assure Lock takes it a step further. It has a physical key override built in. But here’s the catch. Some models don’t include the key cylinder by default. You have to buy the version with the key. Or add it later.

So you’ve got three different approaches. Battery backup terminals. Mechanical overrides. Key cylinders. All from the same category of product.

And none of them solve the problem of network failure.

Backup Power Strategy One – The Battery Basics

Let’s start with the simplest option. And the one I recommend for everyone.

Keep spare batteries. Specifically, keep the exact batteries your lock uses. In a place you can access them.

I keep four Energizer CR123s in a small plastic case. That case sits in my car’s glove compartment. And there’s another set in my emergency kit in the basement.

For about sixty bucks, this changes everything.

Here’s the thing. Most smart locks give you a low battery warning. The app will tell you when you’ve got about two weeks of charge left. But that warning only works if your Wi-Fi is working.

If the power goes out and your router dies, you don’t get that warning. You get a dead lock.

So the first rule of smart lock backup power is this. Check your batteries on a schedule. First of the month. Every month. Replace them at 50% charge. Not at 10%.

I use a battery tester. It costs twelve dollars on Amazon. It tells me exactly how much juice is left. And I replace anything below 60%.

That might sound wasteful. But a four-pack of CR123s costs about fifteen dollars. Replacing them twice a year costs thirty dollars. Compare that to the cost of a locksmith at 11 PM on a Saturday.

You do the math.

But batteries are just the first layer. Let’s talk about what happens when the whole house goes dark.

Backup Power Strategy Two – The Network Problem

Here’s a scenario that catches a lot of people.

Your smart lock has fresh batteries. It’s at 85%. You’re good, right?

Not necessarily.

Most smart locks use Bluetooth or Wi-Fi to communicate with your phone. Some use Zigbee — that’s the low-power mesh protocol that lets devices talk to each other without going through your router.

But here’s the problem. Even if your lock has Zigbee, it still needs a hub. And that hub needs power. And if the power is out, the hub is down.

So your lock might have battery power. But it can’t talk to anything. You can’t unlock it from your phone. You can’t check its status. You can’t grant access to a guest.

You’re back to the physical key. If you have one.

The solution is a backup power source for your network equipment.

I use a UPS — that’s an Uninterruptible Power Supply — for my router and my smart home hub. It’s a box about the size of a shoebox. It has a battery inside. When the power goes out, it keeps my equipment running for about four hours.

For about a hundred and twenty bucks, this keeps my entire smart home online during a blackout.

Now, you don’t need a UPS for every device. Just your router. Your smart home hub. And maybe your modem.

That’s three devices. They probably draw less than 50 watts total. A small UPS can handle that for hours.

But here’s the thing. Most people plug their router into a power strip. And that power strip goes into the wall. When the power goes out, the router dies. The smart lock goes silent.

Move your router to a UPS. It’s a five-minute change. And it solves the network problem.

The Mid-Roll Pivot

Before we go deeper, I want to make sure you’re set up for success.

I’ve put together a guide called “Smart Lock Backup Power Options.” It covers exactly what we’re talking about today. Plus a checklist you can print out and stick on your breaker panel.

You can get it at aftersmartinstall.com/backup. That’s aftersmartinstall.com/backup.

No email required. No upsell. Just the guide.

Now, let’s talk about the option most people don’t consider.

Backup Power Strategy Three – The Smart Plug Approach

Here’s a trick I’ve been using for about a year now.

I have a TP-Link Kasa Kasa smart plug on my router. That smart plug is connected to my Wi-Fi. And I have it set to send me an alert if the power goes out.

When the plug loses power, it goes offline. My home automation system detects that. And it sends me a notification.

“Your router has lost power. Your smart lock may be affected.”

That notification gives me time to react. I can grab my spare batteries. I can check my mechanical key. I can make sure I’m not locked out when I get home.

But here’s the advanced part.

I have that same smart plug connected to a small battery backup. Not a full UPS. Just a portable power station. About the size of a lunchbox. It’s got enough capacity to run my router for about eight hours.

When the power goes out, the smart plug detects the loss. It triggers an automation that switches the router to the backup battery. And I get a notification telling me everything is fine.

Cost breakdown. Smart plug, twenty bucks. Portable power station, eighty bucks. Total, a hundred bucks.

For that hundred bucks, I get eight hours of network uptime. Which means my smart lock stays online. My cameras keep recording. My thermostat keeps running.

Here’s the thing. Most people don’t need a full UPS. They just need enough power to get through a typical outage. And in most areas, that’s under four hours.

A portable power station with a smart plug is cheaper. It’s easier to set up. And it’s portable. You can take it camping. You can use it for tools. It’s not a dedicated piece of equipment that sits in a closet collecting dust.

But there’s a catch. And it’s a big one.

The Common Mistake

Most people set up their backup power once. And then they forget about it.

Three months later, the power goes out. And the backup battery is dead. Because it’s been sitting in a drawer, uncharged, since they bought it.

Or the smart plug is on a different network. And the automation doesn’t trigger. Because the firmware updated and broke the integration.

Or the portable power station is at 20% because you used it last weekend to charge your phone at the park.

Backup power systems need maintenance. Just like your smoke detectors. Just like your HVAC filter. Just like your smart lock batteries.

I test my backup power system every three months. First of the quarter. Same day I change my air filters.

I unplug my router. I watch the smart plug notification come through. I verify that the portable power station kicks on. I check the battery level. I make sure everything works.

It takes ten minutes. And it’s saved me twice in the last year.

Once was a planned outage. The utility company notified us. I knew it was coming. But without the test, I wouldn’t have known that my portable power station was at 30%.

The second time was a tree branch taking out a power line. No warning. But the system worked. Because I’d tested it the week before.

Test your backup power. Put it on your calendar. Do it now.

The Contrarian Take

Here’s something you don’t hear very often.

You might not need backup power for your smart lock.

Let me explain.

If your smart lock has a mechanical key override, and you carry that key with you, and you have a way to get into your house that doesn’t depend on power or network…

Then you’re already covered.

A smart lock is a convenience device. It’s not a security device. It’s not a life safety device. It’s a deadbolt that you can control from your phone.

And if you have a backup plan that doesn’t involve your phone, you’re fine.

The people who need backup power are the ones who have completely eliminated their mechanical keys. The ones who use keyless entry for everything. The ones who have smart locks on every door, and no physical keys anywhere.

That’s a choice. And it’s a valid one. But it comes with a responsibility.

If you’ve gone fully keyless, you need a backup power strategy. Because when the power goes out, you have no other option.

But if you still carry a house key, and you’re comfortable using it, you can skip the UPS. You can skip the portable power station. You just need fresh batteries in your lock.

That’s the contrarian take. Backup power is important. But only if you’ve designed your system to depend on it.

How To Choose Your Strategy

Let’s make this practical.

Here’s how to decide which backup power option is right for you.

**Option One. The Battery Kit.**

You need this if. Your lock uses non-standard batteries. You don’t have a mechanical key. You travel frequently and need to access your home remotely.

Cost. About thirty dollars for two sets of batteries and a tester.

Time to set up. Five minutes.

**Option Two. The Network UPS.**

You need this if. You have multiple smart devices. You work from home and need internet during outages. You have a smart lock that requires network access to operate.

Cost. About a hundred and twenty dollars for a UPS that can run your router for four hours.

Time to set up. Fifteen minutes.

**Option Three. The Smart Plug Plus Portable Power Station.**

You need this if. You want notifications about power loss. You want a portable solution. You have a smart home automation system that can trigger actions.

Cost. About a hundred dollars total.

Time to set up. Thirty minutes, including automation configuration.

**Option Four. Do Nothing.**

You can choose this if. You have a mechanical key. You carry it with you. You’re okay using it during an outage.

Cost. Zero dollars.

Time to set up. Zero minutes.

Here’s the thing. There’s no wrong answer. There’s only the answer that matches your situation.

I use Option Three. Because I like the notifications. And I like having a portable power station for camping.

But if I lost my keys every week, I’d use Option One. Because the most important thing is having a backup that actually works when you need it.

The Final Verdict

Let me leave you with this.

A smart lock is not a replacement for a key. It’s an addition to a key.

And the best backup power option is the one you actually maintain.

Batteries die. Networks fail. Power goes out.

But if you plan for it, you never get locked out.

Check your batteries. Test your backup. Keep a key somewhere safe.

That’s the whole strategy. It’s not complicated. It just requires thinking about it before you need it.

Cross-Promo and Outro

If you want to go deeper on home security, check out the Smart Home Security Podcast. It’s a sister show that covers exactly what the name says. Cameras. Sensors. Alarms. The stuff that actually protects your home.

And if you’re still shopping for a smart lock, I’ve got a buyer’s guide at aftersmartinstall.com/locks. It covers the models I recommend, the ones I don’t, and the ones that are fine but not great.

That’s aftersmartinstall.com/locks.

This has been After the Install . I’m Nick.

Thanks for tuning in. Stay smart. Stay secure. And keep a spare battery in your car.

Until next time.