Two multiplications and one division separate a marketing claim from a runtime you can plan around. Nobody in this category publishes them, so we do.
Skip the reading and put your own numbers in: the runtime calculator does the arithmetic on this page in one screen.
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Our top pick in battery & power
ororo PD 10K Battery for Heated Apparel
The only route to genuinely long runtime is a bigger pack, and this is the largest one in the category with a published capacity — roughly double the energy of the pack most jackets ship with.
Watt-hours are the only honest measure of a heated garment's battery: Wh = (mAh ÷ 1000) × volts. Runtime is Wh ÷ watts drawn. Makers publish mAh and voltage but not draw, then advertise the lowest setting's hours — so the conversion has to be done by the buyer, and this hub does it.
The two lines of arithmetic this whole site rests on
Capacity in milliamp-hours tells you almost nothing on its own, because it is only half of an energy figure. Two packs can both say 5,000 mAh and hold wildly different amounts of energy if they run at different voltages. The energy figure is watt-hours:
Work a real one. A 7.4 V, 5,200 mAh pack — the most common configuration in heated apparel — holds 38.5 watt-hours. The same maker publishes a 2.5 A output rating for that pack, so the most it can deliver is 7.4 × 2.5 = 18.5 watts. Divide: 38.5 ÷ 18.5 is a little over two hours. That is the shortest runtime physically available from that pack, derived entirely from figures the maker chose to publish.
Running the claim backwards
Because draw is the unpublished input, the useful move is to invert the advertised runtime. If a maker says a 37.6 Wh pack gives "up to 10 hours", then the claim assumes a draw of 37.6 ÷ 10 = 3.8 watts. If Milwaukee says its jacket runs up to 8 hours on a 2.0 Ah M12 pack, that is 21.6 watt-hours at the platform's 10.8 V nominal, so the claim assumes 2.7 watts.
Those are small numbers, and they are the point. The advertised hours are not describing the setting you will use. They describe a trickle. Everything on this site follows from putting that figure next to the setting people actually run.
Verdict first
Quick picks
Tap any row to jump to the full write-up below. The energy column is the pack’s capacity times its voltage — the number this category does not print.
#
Product
Best for
Energy
Price
1
ororoNo photo
ororo Men's Soft Shell Heated JacketThe clearest power story in the category: ororo publishes capacity and voltage for every pack it sells, so you can wor…
Milwaukee M12 Heated TOUGHSHELL Jacket (204B-20)Built like site clothing rather than outerwear, and the only jacket here whose battery you can swap in seconds because…
ororo PD 10K Battery for Heated ApparelThe only route to genuinely long runtime is a bigger pack, and this is the largest one in the category with a publishe…
Third-Party 7.4V 16,000mAh Heated Apparel BatteryThe largest capacity on this page by a wide margin, and the one we are most careful about: a third-party pack with a b…
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ororoNo photo
#1 · A first heated jacket
ororo Men's Soft Shell Heated Jacket
The clearest power story in the category: ororo publishes capacity and voltage for every pack it sells, so you can work out what you are getting instead of taking a marketing number on faith.
On wattage: ororo publishes no wattage for the garment. It does publish hours for each of the three settings, which states the draw whether it meant to or not.
What we like
ororo publishes capacity AND voltage for every pack, which almost nobody else in this category does
Per-setting runtime claims rather than one 'up to' number, so the low-to-high spread is visible before you buy
Soft-shell cut layers under a work coat without bulk
What we do not
No published wattage for the garment itself
Three zones only — nothing at the arms or the kidneys
The headline runtime figure is the low setting, as it is everywhere
Who this suits
Someone standing still outdoors for two to four hours at a stretch who wants the power figures on the table before buying.
Who should skip it
You need heat for a full eight-hour shift on high. No 38 Wh pack does that, and this one does not claim to.
On wattage: Milwaukee publishes run-time, not watts. Its own 'up to 8 hours on the REDLITHIUM 2.0' figure plus the pack's published capacity are enough to derive the draw that claim assumes.
What we like
Hot-swappable packs — the only real answer to a short runtime is a second battery, and you already have one
Genuinely durable shell fabric, built for work rather than for a catalog photo
The pack doubles as a tool battery, so nothing in the van is single-purpose
What we do not
The 2.0 Ah pack is small by heated-apparel standards once you convert it honestly
Jacket-only SKUs ship without a battery, which is easy to miss at checkout
Heavier than a soft-shell layer
Who this suits
A trades worker with an M12 kit already in the van, for whom a spare pack costs nothing extra to carry.
Who should skip it
You own no M12 tools. Buying into a tool platform for one jacket is the most expensive route into heated clothing.
The only route to genuinely long runtime is a bigger pack, and this is the largest one in the category with a published capacity — roughly double the energy of the pack most jackets ship with.
Not washable — remove before laundering the garment
On wattage: The 17-hour claim is a pack-level figure. Divide the pack's energy by 17 and you get the draw that claim assumes, which is far below what the pack can deliver at full output.
What we like
By far the largest published capacity in heated apparel, and the capacity IS published
USB-C in means one cable for the pack and the phone
Still comfortably inside the FAA's 100 Wh carry-on threshold once you convert it
What we do not
Heavy and bulky in a chest pocket next to a 2,200 mAh accessory pack
Only worth buying if your garment's connector matches
The 17-hour claim, like all of them, describes the lowest setting
Who this suits
Someone whose actual complaint is that the jacket dies before the shift does, and who would rather fix it with energy than with a warmer setting.
Who should skip it
Your problem is peak warmth rather than duration. A bigger pack runs the same elements for longer; it does not make them hotter.
The largest capacity on this page by a wide margin, and the one we are most careful about: a third-party pack with a big number on it deserves more skepticism than a brand pack with a small one.
On wattage: No published wattage and no published output current, which means we cannot even state the pack's own delivery ceiling.
On the pack: Third-party capacity claims are not independently verified by anyone, including us. The watt-hour figure below is arithmetic on the seller's own numbers — it is not a measurement of the pack.
What we like
If the claim holds, roughly three times the energy of the pack most jackets ship with
An LED display means you know where you stand before you go out
Adapter cables cover the common garment connectors
What we do not
Third-party capacity claims are unverified by definition
No published output current, so the delivery ceiling is unknown
A pack this large deserves a certification you can look up, and this one's is not clearly stated
Who this suits
Someone whose jacket genuinely dies mid-shift and who has already weighed the trade-off.
Who should skip it
You are not comfortable buying an unverified capacity claim from a third party. That is the right instinct and we share it.
Tool-platform garments introduce a wrinkle worth knowing. In the US, lithium packs are commonly labeled with their peak charge voltage rather than their working voltage. DEWALT prints the distinction on its own packaging: "Maximum initial battery voltage (measured without a workload) is 20 volts. Nominal voltage is 18."
So a "20V MAX" 2.0 Ah pack is 18 × 2.0 = 36 watt-hours, not 40. An M12 2.0 Ah pack is 10.8 × 2.0 = 21.6 watt-hours, not 24. Using the label voltage overstates the energy by about 11% every time. It is a small error that compounds across every comparison you make, and it is why the figures on this site use nominal voltage throughout. Wattage explained works through it in full.
The arithmetic
Watt-hours, and what they buy
Energy is capacity times nominal voltage. The ceiling draw is the pack’s own published output current times its voltage. The implied draw runs the maker’s advertised hours backwards. Nothing here is measured — check our working.
Product
Capacity
Volts
Energy
Ceiling draw
Shortest runtime
Implied draw at the claim
ororo Men's Soft Shell Heated Jacket
5,200 mAh
7.4 V
38.5 Wh
18.5 W
2h 05m
15.4 Wat 2.5 h high
Milwaukee M12 Heated TOUGHSHELL Jacket (204B-20)
2,000 mAh
10.8 V
21.6 Wh
Not published
Not derivable
2.7 Wat 8 h maker's headline claim
ororo PD 10K Battery for Heated Apparel
10,150 mAh
7.4 V
75.1 Wh
18.5 W
4h 04m
4.4 Wat 17 h maker's headline claim
Third-Party 7.4V 16,000mAh Heated Apparel Battery
16,000 mAh
7.4 V
118.4 Wh
Not published
Not derivable
No claim published
“Not derivable” means the manufacturer does not publish the figure the sum needs. We leave it blank rather than estimating it, borrowing a number from a similar model, or rounding one into existence. These are ceilings, not promises: cold, wind, movement and pack age all push real runtime below them. Run your own numbers.
Watt-hours are also how the FAA thinks
There is a practical reason to learn this conversion that has nothing to do with shopping. The FAA writes its baggage limits in watt-hours: packs at or below 100 Wh travel freely in carry-on, 101 to 160 Wh need airline approval, and above 160 Wh is forbidden. Manufacturers publish milliamp-hours. Which means a traveler literally cannot check whether their pack is compliant without doing the conversion first.
The good news is that every heated apparel pack we have converted sits comfortably under the 100 Wh line — the largest published capacity in the category works out to about 75 Wh. Flying with heated clothing batteries has the full table and the rules.
Divide the milliamp-hours by 1,000 to get amp-hours, then multiply by the pack's nominal voltage. A 5,200 mAh pack at 7.4 V is 5.2 × 7.4 = 38.5 watt-hours. Use nominal voltage, not the number on the label, if the two differ.
Why don't heated clothing makers publish wattage?
We cannot tell you their reasoning, only what the effect is: without a draw figure, the buyer cannot convert a battery into hours and has to accept the maker's chosen runtime number instead. Nine competitors were fetched while researching this site and not one of them publishes the draw either.
Is a higher mAh battery always better?
Only at the same voltage. Milliamp-hours are half of an energy figure, so a 5,000 mAh pack at 7.4 V holds more energy than a 5,000 mAh pack at 3.7 V — nearly twice as much. Compare watt-hours, never milliamp-hours.
Why is my heated jacket's real runtime shorter than the box says?
Three reasons stack up. The advertised figure is the lowest setting. Cold reduces usable lithium capacity. And the pack ages, losing capacity with every charge cycle. The arithmetic on this page gives you a ceiling, not a promise — real runtime lands below it.
Can I use a bigger battery to get longer runtime?
Yes, provided the voltage and connector match. More watt-hours at the same voltage runs the same elements for longer. It does not make them hotter — that is set by the garment's draw, not by the pack.
