Battery coffee makers that heat their own water: coffee in a power cut (2026)
A battery espresso maker heats a small cup of water itself, from a battery you charge over USB-C, so you can make a real coffee in a power cut with no gas, no flame and no mains. This page compares the ones we list on what separates them: how many cups a charge makes from cold water, how they charge, what coffee they take and how tough they are. We have not used these ourselves; every heating time and cup count is the maker's own lab figure.
By Tom Calder · Updated 21 October 2026 · 2 products, all price-tracked
All 2 compared
| Coffee maker | Heats its own water (maker) | Cups per charge (maker) | 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 25°C to 93°C each time (OutIn's lab figure; 5,000mAh battery) · 45W USB-C PD, full in about 100 minutes · 85 ml tank; ground coffee (8 g basket) or Nespresso Original-compatible capsules A proper espresso in a power cut with no mains, 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 25°C to 93°C each time (OutIn's lab figure; 5,000mAh battery) | 45W USB-C PD, full in about 100 minutes | 85 ml tank; ground coffee (8 g basket) or Nespresso Original-compatible capsules | £159.99 at OutIn Checked 21 OctIn stockCheck price → |
Our verdictOur verdictResearched A hand-sized espresso maker that heats its own water from a battery, so a power cut 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 93°C, and it recharges over USB-C from a power bank or a power station. It makes one small cup at a time, so it is a comfort item, not a way to boil water for a household: a camping stove and kettle does that for far less. Ground coffee or Nespresso Original-compatible capsules both work. Best for A proper espresso in a power cut with no mains, 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 camping stove and kettle boils a litre at a time for much less. Read the full review → | |||||
 Yes: 50 ml from 25°C to 93°C in 149 seconds (OutIn's lab figure) · Up to 6 from room-temperature water; 500+ if you pour in water that is already hot (OutIn's lab figures; 3,000mAh battery) · USB-C, 30W input; 20% to 80% in 45 minutes, full in about 90 · Up to 70 ml; up to 12 g of ground coffee A tough, pocket-sized espresso maker for the car, the caravan or a grab bag | Yes: 50 ml from 25°C to 93°C in 149 seconds (OutIn's lab figure) | Up to 6 from room-temperature water; 500+ if you pour in water that is already hot (OutIn's lab figures; 3,000mAh battery) | USB-C, 30W input; 20% to 80% in 45 minutes, full in about 90 | Up to 70 ml; up to 12 g of ground coffee | £169.99 at OutIn Checked 21 OctIn stockCheck price → |
Our verdictOur verdictResearched The smaller, tougher OutIn: a 67 mm tube that heats its own water and is rated IP67 against dust and water, which suits a car, a caravan or a 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 flask. Like the Nano 2 it's one small cup at a time, and it takes ground coffee: a comfort item for a cold power cut, not a way to make hot water for a household. Best for A tough, pocket-sized espresso maker for the car, the caravan or a grab bag Good
Worth knowing
Who shouldn't buy it: Don't buy it if you want capsules or a bigger cup: the Nano 2 takes Nespresso Original-compatible capsules and holds 85 ml. Read the full review → | |||||
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Before you buy
Start with how you'd use it.
For a kitchen in a power cut, the bigger tank and capsule option of the OutIn Nano 2 suit a household that already drinks espresso. For a car, a caravan or a grab 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 cold water uses most of the battery: OutIn gives up to nine cups for the Nano 2 and up to six for the Mino from room-temperature water. Pour in water that's already hot, from a flask, and OutIn says the Mino manages 500-plus.
Both recharge over USB-C, so a power bank or a portable power station can top them up in a long cut.
Check your power bank's USB-C output: the Nano 2 charges fastest at 45W and the Mino takes up to 30W.
They take ground coffee, and the Nano 2 also takes Nespresso Original-compatible capsules.
Neither makes a mug of tea or instant soup: for those, a flask or a stove is the answer.
We verify every product's specifications against at least two independent sources, re-check its UK price and stock on a schedule where we can track it automatically, and cross-check safety-relevant claims against official guidance. Every review is labelled 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 93°C, by OutIn's figures), for one small cup. For tea, instant soup or a hot water bottle in a power cut, fill a vacuum flask while the power is on, or use a camping stove outdoors.
How many cups do they make on one charge?
By OutIn's own lab figures, up to nine for the Nano 2 and up to six for the Mino when they heat room-temperature water themselves. With water that's already hot, from a flask, the Mino's figure rises to 500-plus.
Can I charge one from a power bank?
Yes, both charge over USB-C. The Nano 2 takes up to 45W and the Mino up to 30W, so a power bank or power station with a USB-C PD port of that rating charges them fastest.
Will I pay import charges?
Possibly. OutIn ships from US, EU or China warehouses, and its shipping policy says import duties and taxes may be due on delivery and are the buyer's to pay.
