How Long Does The SteriPEN Charge Last?

SteriPEN Ultra Battery Life

UV Light Water Purifers like the Steripen work really well, but they rely on a battery to work. You’re basically screwed once the battery dies, so hopefully you brought a portable charger or extra batteries. Don’t Worry! The SteriPEN has a surprisingly long battery life so you shouldn’t have any problems using it on a backpacking trip.

How Long Does The SteriPen Charge Last? There are Multiple Steripen models with varying battery lives. Steripen Ultra, Aqua, and Adventurer at 50 liters on a charge and the classic 3 which runs on AA batteries is rated up to 150 Liters. I’ve found that you can only get 35-40 liters and about 120 liters with the classic 3. A 40 Liter battery life gives me about 4-5 days water supply or 3 days with my wife. You can always recharge the Ultra with portable power bank or replace the batteries in the rest of the lineup.

It took way too long for me to finally pull the trigger on a Steripen when it first came out. I couldn’t believe that a UV light would be powerful enough to purify water and boy was I wrong. It’s so much easier to use with my Nalgene water bottle. I still use a prefilter (this one) attached to my Nalgene to remove sediment, but the made purifying water so much easier. Plus there’s no risk of food poisoning from contaminated water sources.

The SteriPEN was great on short trips, but I was always worried that it wouldn’t work. I’ve used multiple models over the last 5 years and I can safely say that the SteriPEN is a game changer. I’ve settled on the SteriPEN Ultra, but they all work just as well. So how long does the SteriPEN work and will it need to be recharged (or replace batteries) on a backpacking trip?

Steripen Battery Life: Keeping It Charged

CR123 and AA Batteries for steripen

I’ve grown to love the SteriPEN over the past couple of years. I prefer the Steripen Ultra since it has rechargeable batteries and I already carry portable power banks for my cell phone. The vast majority of people use the SteriPEN with 32oz Wide Mouth Nalgene water bottles.

They even sell a prefilter (On Amazon) that screws onto the lid of a Nalgene bottle to filter out sediment. It’s designed to work with a liter of water so a 32oz Nalgene is just about perfect. Just make sure you buy the wide mouth bottle so it’s easy to drop in.

I can get through a 3 day weekend trip with my wife on a single charge, but I usually toss it on the power bank every morning and it’s fully in an hour or so. I can get about 5 days on a single charge when I’m backpacking alone. It can take 3-4 hours to charge if you let the batteries drain completely or about an hour if you charge up every morning.

You should definitely pack replacement batteries with models that rely on batteries. The Steripen Aqua (50 Liter) and Classic 3 (150 Liter) both run off of standard AA batteries. The Classic 3 is only about 10-15 dollars more so it’s worth upgrading to the better model.

The SteriPEN adventurer takes CR123 batteries and has a 50 liter battery life. It’s about 2oz lighter than the SteriPEN ultra so you can save pack weight, but it’s not that big of a difference. Early Adventurer models had sensor issues (that have been fixed) so avoid buying a used model.

There’s no real advantage to CR123s except for a slight weight reduction. The only reason you might want to consider the Adventurer model is if you have carry other items (like headlamps) that use the same batteries. You can find CR123s at Walmart and most hardware stores, but they can be hard to find in most remote locations. Definitely pick up a couple packs of replacement batteries before you head out.

SteriPEN Battery Life Is Overstated

I have never been able to get close the 50 Liter rated battery life with any of the Steripen models. It doesn’t matter how new the batteries are or what kind I use. I’ve never been able to purify more than 40 liters of water (usually about 35 liters). The SteriPen Classic is rated at 150 liters and you can get about 120 liters on a charge.

That’s more than enough to get 2 people through a weekend backpacking trip, but you should still carry backup batteries. I also carry water purification tablets (Aquatab Packets) in my first-aid kit just in case the SteriPen quits working.

I’ve been using the SteriPEN without any problems for over 5 years, but who knows what can happen with an electronic item. The only time I ran into a problem was when I forgot to charge my portable power bank. I was on a 10 day backpacking trip with my wife and it died on day 5. Luckily, I had a Sawyer Squeeze filter tucked away in my pack so it wasn’t a huge issue.

Why Is My SteriPEN Blinking Red?

The Steripen has an LED indicator light that lets you know the current status of your SteriPEN. After turning it on, the light will flash green when it’s ready to use. Dip it in the water and the UV light should turn on once the sensor detects water. Once the purification process is over the LED indicator should start blinking again with a green light.

A green light means the SteriPEN is functioning normally and red indicates there’s a problem. When the light blinks with an alternating red, green, red, green pattern, that the means the battery level is getting low (still safe to drink). A blinking red light (without green) means the purification process failed and you need to recharge/replace the batteries. Do not consume the water, because it didn’t complete the purification process.

A solid red light indicates that there’s a problem with the sensor and no water was detected. Try again and see if it will detect the water. If that doesn’t work the unit might need to be replaced. I’ve heard stories about high mineral content water affecting the sensor, but I’ve never experienced that personally.