Battery coffee makers that heat their own water: coffee in a power outage (2026)
A battery espresso maker heats a small cup of water itself, from a battery you charge over USB, so you can make a real coffee in a power outage with no gas, no flame and no outlet. This page compares the ones we list on what separates them: how many cups a charge makes from room-temperature water, how they charge, what coffee they take and how tough they are. We haven't used these ourselves; every heating time and cup count is the maker's own lab figure.
By Tom Calder · Updated October 24, 2026 · 3 products, all price-tracked
All 3 compared
| Coffee maker | Heats its own water (maker's figure) | Cups per charge (maker's figure) | Charging | Water per cup | Price |
|---|---|---|---|---|---|
 Yes: 120W heater, room-temperature water hot in as little as 159 seconds (OutIn's lab figure) · Up to 9, heating 50 ml from 77°F to 199°F each time; over 600 with water that's already hot (OutIn's lab figures; 5,000mAh, 54Wh battery) · 45W USB-C PD, full in about 100 minutes · 85 ml (about 2.9 fl oz) tank; ground coffee (8 g basket) or Nespresso Original Line-compatible capsules A real espresso in a power outage with no outlet, no gas and no flame | Yes: 120W heater, room-temperature water hot in as little as 159 seconds (OutIn's lab figure) | Up to 9, heating 50 ml from 77°F to 199°F each time; over 600 with water that's already hot (OutIn's lab figures; 5,000mAh, 54Wh battery) | 45W USB-C PD, full in about 100 minutes | 85 ml (about 2.9 fl oz) tank; ground coffee (8 g basket) or Nespresso Original Line-compatible capsules | $159.99 at OutIn Checked Oct 24In stockCheck price → |
Our verdictOur verdictResearched A hand-sized espresso maker that heats its own water from a battery, so a power outage doesn't stop your morning coffee and there's no gas or flame involved. OutIn's own lab figures give up to nine cups per charge from room-temperature water, each 50 ml heated to 199°F, and it recharges over USB-C from a power bank or a power station. It makes one small cup at a time, so it's a comfort item, not a way to boil water for a household: a camp stove used outdoors does that for far less. Ground coffee or Nespresso Original Line-compatible capsules both work. Best for A real espresso in a power outage with no outlet, no gas and no flame Good
Worth knowing
Who shouldn't buy it: Don't buy it if you need hot water for the whole household: a camp stove and kettle, used outdoors, boils a quart at a time for much less. | |||||
 Yes: 50 ml from 77°F to 199.9°F in 149 seconds (OutIn's lab figure) · Up to 6 from room-temperature water; 500+ with water that's already hot (OutIn's lab figures; 3,000mAh battery) · USB-C, 30W input; 20% to 80% in 45 minutes, full in about 90 · 50 to 70 ml (up to about 2.4 fl oz); up to 12 g of ground coffee A tough, pocket-sized espresso maker for the car, the RV or a go-bag | Yes: 50 ml from 77°F to 199.9°F in 149 seconds (OutIn's lab figure) | Up to 6 from room-temperature water; 500+ with water that's already hot (OutIn's lab figures; 3,000mAh battery) | USB-C, 30W input; 20% to 80% in 45 minutes, full in about 90 | 50 to 70 ml (up to about 2.4 fl oz); up to 12 g of ground coffee | $169.99 at OutIn Checked Oct 24In stockCheck price → |
Our verdictOur verdictResearched The smaller, tougher OutIn: a 2.6-inch-wide tube that heats its own water and is rated IP67 against dust and water, which suits a car, an RV or a go-bag. By OutIn's own lab figures it makes up to six cups per charge from room-temperature water, or 500-plus if you pour in water that's already hot, say from a vacuum bottle. OutIn rates it to work from 5°F to 113°F. Like the Nano 2 it's one small cup at a time: a comfort item for a cold power outage, not a way to make hot water for a household. Best for A tough, pocket-sized espresso maker for the car, the RV or a go-bag Good
Worth knowing
Who shouldn't buy it: Don't buy it if you want a bigger cup: the Nano 2 holds 85 ml and makes up to nine cups per charge by OutIn's figures. | |||||
 Yes: up to 198°F, heated in about 200 seconds (OutIn's lab figure) · Up to 5 from room-temperature water; 200+ with water that's already hot (OutIn's lab figures; 2,500mAh battery) · USB charger or 12V or 24V car charger (OutIn says a 5W phone charger won't charge it) · 50 to 80 ml; ground coffee or coffee capsules The lowest-priced self-heating OutIn, for an occasional cup | Yes: up to 198°F, heated in about 200 seconds (OutIn's lab figure) | Up to 5 from room-temperature water; 200+ with water that's already hot (OutIn's lab figures; 2,500mAh battery) | USB charger or 12V or 24V car charger (OutIn says a 5W phone charger won't charge it) | 50 to 80 ml; ground coffee or coffee capsules | $139.99 at OutIn Checked Oct 24In stockCheck price → |
Our verdictOur verdictResearched The original Nano, still sold alongside the Nano 2: it heats its own water from a battery, but more slowly and for fewer cups. OutIn's lab figures give up to five cups per charge from room-temperature water, or more than 200 with water that's already hot, and it charges from a USB charger or a 12V car outlet. For most people the Nano 2's nine cups per charge and faster USB-C charging are worth the extra; this one makes sense if the occasional cup in an outage is all you want. Best for The lowest-priced self-heating OutIn, for an occasional cup Good
Worth knowing
Who shouldn't buy it: Don't buy it if you'd use it every day of a long outage: the Nano 2 makes nearly twice the cups per charge. | |||||
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Before you buy
Start with how you'd use it.
For the kitchen in a power outage, the bigger tank and capsule option of the OutIn Nano 2 suit a household that already drinks espresso. For a car, an RV or a go-bag, the smaller Mino is rated IP67 against dust and water and fits in a door pocket.
Cups per charge depend on the water you start with.
Heating room-temperature water uses most of the battery: OutIn gives up to nine cups for the Nano 2, six for the Mino and five for the original Nano. Pour in water that's already hot, from a vacuum bottle, and OutIn's figures run into the hundreds.
The Nano 2 and Mino recharge over USB-C, so a power bank or a portable power station can top them up in a long outage.
Check your power bank's USB-C output: the Nano 2 charges fastest at 45W and the Mino takes up to 30W. The original Nano also charges from a 12V car outlet.
They take ground coffee, and the Nano models also take capsules.
None of them makes a mug of tea or instant soup: for those, a vacuum bottle or a camp stove is the answer.
We verify every product's specifications against at least two independent sources, re-check its US price and stock on a schedule where we can track it automatically, and cross-check safety-relevant claims against official guidance. Every review is labeled Researched or Used and reviewed by us: where we've bought a product, or been sent it free, and used it ourselves, its review says which; where we haven't, our verdict is a considered spec-and-evidence comparison, not a hands-on test — and commissions never change a ranking either way. Read our full methodology →
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Common questions
Can a battery coffee maker boil water for tea?
No. They heat about 50 to 85 ml at a time to espresso temperature, around 199°F by OutIn's figures, for one small cup. For tea, instant soup or a hot water bottle in a power outage, fill a vacuum bottle while the power is on, or use a camp stove outdoors.
How many cups do they make on one charge?
By OutIn's own lab figures, up to nine for the Nano 2, six for the Mino and five for the original Nano when they heat room-temperature water themselves. With water that's already hot, the figures rise to 600-plus for the Nano 2, 500-plus for the Mino and 200-plus for the Nano.
Can I charge one from a power bank or power station?
Yes. The Nano 2 and Mino charge over USB-C, at up to 45W and 30W, so a power bank or power station with a USB-C PD port of that rating charges them fastest. OutIn says a 5W phone charger won't charge the original Nano.
Are these a substitute for a camp stove?
No. They make one small cup of coffee at a time. A camp stove, used outdoors only, heats water and food for a household; never use one indoors.