Short answer: it depends mostly on the heat level. Our SnapWarm jacket is rated for up to 8 to 12 hours on low with a 10,000mAh power bank, and expect far less on high. How long you really get also depends on the power bank and how cold it is.
The quick version
- Battery life depends mostly on the heat level you use.
- Low lasts longest. High drains the battery much faster.
- 10,000mAh is a sensible size for most people. It is also small enough for a pocket.
- Any standard 5V USB power bank works with a USB jacket, including one you already own.
- Cold weather reduces the charge you can get from any lithium battery.
What decides how long the battery lasts?
The heat level
This is the biggest factor. The higher the setting, the more power the panels draw. If you use low most of the time and only turn it up when you stop moving, the battery lasts much longer.
The size of the power bank
Capacity is measured in mAh. All else being equal, a 20,000mAh power bank lasts about twice as long as a 10,000mAh one, but it is also heavier and bulkier in your pocket.
The real capacity of the power bank
The figure on the box is not all available to your jacket, because some energy is lost when the battery converts to USB power. An older power bank also holds less charge than it did when new.
The temperature outside
Lithium batteries give less in the cold. Keeping the power bank in the inside pocket, close to your body, helps.
Which power bank size should you choose?
| Capacity | Good for | Keep in mind |
|---|---|---|
| 5,000mAh | Short trips, the school run, a dog walk | Light, but you may need to charge it often |
| 10,000mAh | Most people, commuting, a day out | A good balance of size and run time |
| 20,000mAh | Long shifts, full days outside on higher heat | Heavier, and you will feel it in the pocket |
How to make the battery last longer
- Preheat, then turn it down. Start on high for a few minutes, then drop to low.
- Keep your coat closed. Zip up so the heat stays with you. Wear a shell on top if it is windy.
- Turn it off when you go indoors. Hold the button to switch off, because it is easy to forget.
- Charge the power bank fully the night before.
- Carry a spare for long days. It is cheaper than buying a much bigger one.
Do you need a special battery?
Not with a USB jacket. Any standard 5V USB power bank works, so the one you use for your phone may already do the job. Some brands use their own battery, which can cost more to replace. Check for a USB-A output, because that is what the jacket's cable plugs into.
Whichever jacket you choose, check whether a battery is included before you buy. Ours does not include a power bank.
Where SnapWarm fits
The SnapWarm Heated Jacket runs on any standard 5V USB power bank and has 3 heat levels on one button. If you do not have one, our 10,000mAh Power Pack fits in the pocket and also charges your phone. It ships separately from the jacket and usually takes 2 to 3 weeks to arrive, so if you need the jacket sooner, you can use a power bank you already have.
New to heated clothing? Read do heated jackets actually work?
FAQ
How long does a heated jacket battery last?
It varies by jacket and heat level. Ours is rated for up to 8 to 12 hours on low with a 10,000mAh power bank, and much less on high.
What size power bank do I need for a heated jacket?
10,000mAh suits most people. Choose 20,000mAh for long shifts or if you mostly use high heat.
Can I use my phone power bank?
Yes, if it has a standard 5V USB output. Check it has a USB-A port for the jacket's cable.
Can I charge the power bank while wearing the jacket?
Check the instructions for your power bank, because not every model can charge and output power at the same time.
Does cold weather drain the battery faster?
Yes, lithium batteries give less in the cold. Keep the power bank in an inside pocket.