
## Your Bikepacking Power Budget in Watt-Hours, Start to Finish

Build a bikepacking power budget in watt-hours like this. List every device. Convert each battery with `Wh = mAh / 1000 × V`. Estimate the fraction you spend per day, sum those, then divide by the share of a power bank's label you actually receive. The rule we derive below: **rated mAh is roughly 400 times your watt-hours per day times your days off-grid.**

The uncomfortable part first: the number printed on the side of a power bank is not the number you get. It describes energy in the cells at about 3.7 V, not energy leaving the USB port at 5 V, and the conversion takes a cut. Riders who size a bank off the label run out on day three and conclude the bank was faulty.

One conversion, one table, one division. It is the step that makes every other decision about [how a bikepacking charging system fits together](/posts/bikepacking-power-charging-guide) answerable with a number instead of a hunch.

<Highlight label="The short version">

- **One conversion only.** `Wh = mAh / 1000 × V`. A device cell quoted at 3.7 V and a USB port delivering 5 V are not the same currency.
- **Count watt-hours per day, not devices.** A phone navigating with the screen on is worth roughly ten satellite messengers.
- **Assume about 70 percent of a bank's printed energy reaches a battery.** Anker's own support pages put the boost circuit at about 82 percent and the receiving device at a further 15 percent loss.
- **Size for every day of the trip.** The credit for leaving the last socket full cancels almost exactly against the day of reserve you should carry.
- **The shortcut:** rated mAh is about 400 times watt-hours per day times days between sockets. An 18 Wh-per-day rider going five days needs roughly 36,000 mAh of label.
- **Check the 100 Wh line before you fly.** That 36,000 mAh works out at about 133 Wh, over the FAA's 100 Wh threshold for carry-on without airline approval — and individual carriers can be stricter.

</Highlight>

<SectionDivider variant="trail" />

## The One Conversion You Need: mAh to Watt-Hours

Milliamp-hours measure charge, not energy; charge becomes energy only when you multiply by a voltage. That is the whole trap — two batteries with the same mAh figure can hold very different amounts of electricity. The conversion is `Wh = mAh / 1000 × V`, and backwards, `mAh = Wh / V × 1000`.

Work one through. Apple leaves capacity out of its standard tech specs, but EU energy-label disclosures include it, and as reported by Notebookcheck those put the eSIM iPhone 17 Pro at 4,252 mAh. Macworld's comparison table converts that to 16.56 Wh — and lists the physical-SIM variant lower, at 3,988 mAh and 15.53 Wh, so check which version you own. Note that 16.56 divided by 4.252 implies a nominal voltage near 3.9 V, above the 3.7 V most capacity guides assume — the two conventions disagree by a few percent. We use published watt-hour figures where they exist and the 3.7 V convention where they do not.

Now the same arithmetic on a power bank. Anker's support pages work it explicitly: a 10,000 mAh bank holds about 37 Wh at 3.7 V, which at 5 V is only 7,400 mAh, and after roughly 82 percent circuit efficiency about 6,068 mAh. That is why banks advertising 10,000 mAh often carry a second, smaller rated figure near 6,000 mAh elsewhere on the label.

<PullQuote>A power bank's headline number is a statement about its cells. It is not a promise about your phone.</PullQuote>

## What Your Devices Actually Draw Per Day

The awkward reality of bikepacking electronics is that the devices you worry about are rarely the ones emptying your battery. A head unit recording a track is a small, steady load. A phone used for live navigation with the screen lit is the largest line in most budgets, by a wide margin.

Makers also publish inconsistent things: phone capacities in mAh because of EU labelling, head units and messengers as claimed runtime with no cell capacity at all, lights somewhere between.

| Device class | Published figure we could find | Realistic daily use | Watt-hours per day |
|---|---|---|---|
| Phone, live navigation, screen on | iPhone 17 Pro, eSIM, at 4,252 mAh per Apple's EU energy label, 16.56 Wh per Macworld | 60 percent of the battery | about 10 |
| Phone, offline maps, screen mostly off | the same 16.56 Wh | 25 percent of the battery | about 4 |
| Head unit recording all day | Wahoo claims up to 20 hours for the Elemnt Bolt 3; no cell capacity published | 7 hours, about a third of a charge | about 3.5, assuming 10 Wh per charge |
| Satellite messenger, 10-minute tracking | Garmin's inReach Mini 2 specification: up to 14 days at 10-minute tracking with a full sky view | one charge per week | under 1, assuming 5 Wh per charge |
| Front light, one hour at a mid setting | Lezyne Macro Drive 1400+ listed at 5,200 mAh and about 3 hours in 1400-lumen Overdrive | 1 hour, well below full output | about 3 |

Two of those rows contain an assumption rather than a specification, and we would rather flag it than hide it. **Neither Wahoo nor Garmin publishes a cell capacity for its head units** — Garmin lists the Edge 1050 at up to 20 hours in demanding use and up to 60 hours in battery-saver mode, which tells you hours and nothing about watt-hours. The 10 Wh per charge above is our estimate and the softest number in this article. Claimed runtimes are not a ceiling either: Cyclists Hub measured about 26.7 hours from a Bolt 3 against the 20-hour claim, and the5krunner roughly 25 hours with the backlight off. Our [cycling computer roundup](/posts/best-cycling-computers-bikepacking) collects the claimed figures across the field.

The light row is firmer because the capacity is published. A 5,200 mAh cell is about 19 Wh at 3.7 V, so if the listing gives roughly 3 hours at 1400 lumens, full output costs about 6.4 W. You will not ride on full output, and the same listing gives 950 lumens for 4 hours and 450 lumens for 12.5 hours — about 4.8 W and 1.5 W off that 19 Wh cell. That is why the hour at a usable setting in the table costs around 3 Wh rather than six. Bike Perfect's review of that light notes the quoted run times are optimistic — our guide to [lights for overnight bikepacking](/posts/best-bike-lights-overnight-bikepacking) goes through the modes that matter.

Sum the nav-heavy rider: 10 plus 3.5 plus 1 plus 3 is 17.5 Wh. **Call it 18 Wh a day.** Swap live navigation for offline maps and the same rider drops to about 11.5 Wh — a 36 percent cut from one behaviour change, worth more than any purchase. Our look at [bikepacking navigation apps](/posts/best-bikepacking-navigation-apps) covers which ones make it cheap.

<SectionDivider variant="rule" />

## Usable Versus Rated Capacity: Sizing a Power Bank for Bikepacking

Sizing a power bank for bikepacking means working backwards from watt-hours into cells, and paying two taxes on the way. The first is the boost circuit: cells sit near 3.7 V and USB needs 5 V, so something steps the voltage up, and Anker's support material puts that conversion at roughly 80 to 85 percent efficient, the rest lost as heat and to internal resistance. The second is your own device, which loses roughly a further 15 percent while charging, per the same source.

Multiply those and about 70 percent of the printed energy ends up in a battery. Anker's worked example for a 20,000 mAh bank is 74 Wh at the cell and about 60.7 Wh after conversion — and once the receiving device takes its share, something near 52 Wh of stored charge.

These are a vendor's own figures, not independent lab measurements, and Anker notes real efficiency varies by device. Treat 70 percent as a planning number rather than a constant; for a cold or cheap bank it is probably optimistic.

<Warning title="Sizing off the label is the classic error">

A rider who needs 90 Wh of delivered energy and buys a 20,000 mAh bank because "74 watt-hours is plenty" is about 38 Wh short — more than two days of budget. The bank is not faulty; it was never going to deliver its label, and nothing on the packaging says so. Convert to watt-hours, then divide by 0.7.

</Warning>

## The Worked Example: How Much Battery Capacity for a Week of Bikepacking

Here is the method on one rider — a worked example built from the published figures above, not a trip report. We have not metered these devices.

**The assumptions.** Seven-day gravel tour. Phone used for live navigation, head unit recording about 7 hours a day, satellite messenger tracking at 10-minute intervals, an hour of light most mornings. Daily total 18 Wh. The longest stretch without a wall socket is five days.

**The sum.** Five days at 18 Wh is 90 Wh that has to reach a cell. Two corrections apply, pulling opposite ways. You leave the last socket with every device full, worth roughly a day — true here, because each device holds at least one day of its own consumption. Then you add a day of reserve, worth the same.

<PullQuote>Subtract the day your devices start full, add a day of reserve, and the two cancel. Size the bank as if it must carry every day of the trip.</PullQuote>

**The conversion.** 90 Wh into cells, divided by 0.7, is about 129 Wh of printed capacity. At 3.7 V that is roughly 35,000 mAh. The shortcut — 400 times watt-hours per day times days off-grid — gives 18 times 5 times 400, or 36,000 mAh. Same answer.

**Therefore:** about 35,000 to 40,000 mAh of rated capacity, which in practice means two 20,000 mAh banks rather than one enormous one. That split is not only about redundancy. A 36,000 mAh bank is about 133 Wh, and the FAA's own PackSafe guidance puts the limit for carry-on without advance airline approval at 100 Wh per battery, with 101 to 160 Wh needing airline approval and a cap of two spare batteries. The FAA also notes airlines may set limits stricter than the federal baseline, so check your carrier before you book. Two 74 Wh banks each clear the line. One 133 Wh brick does not.

That total is also the moment to ask whether you should carry the energy at all. Thirty-five thousand mAh of lithium is a real weight penalty for five days of autonomy, and this is the crossover where [choosing between a dynamo hub and a power bank](/posts/dynamo-hub-vs-power-bank-bikepacking) stops being theoretical. Below three or four days off-grid the bank wins easily; above it, generating looks cheap. Once you have the number, our guide to [picking a portable charger for your phone and GPS](/posts/navigating-with-power-the-best-portable-charger-for-your-phone-and-gps) covers which bank to buy.

**The weekend pass.** Same rider, two days without a socket. 18 times 2 times 400 is 14,400 mAh, rounding up to a 20,000 mAh bank. But the formula over-buys on short trips, because the day your devices start full is half of a two-day window instead of a fifth of a five-day one. A 10,000 mAh bank delivers about 26 Wh into cells against 18 Wh of real need, covering the weekend with half a day spare. We would take the 10,000 and accept the thinner margin — and on offline maps at 11.5 Wh a day, it becomes genuinely comfortable.

<SectionDivider variant="ornamental" />

## The Reserve, and What Eats Your Budget Without Warning

Three things reliably spend power you never budgeted.

**Cold.** Capacity falls as temperature does, and the published numbers are chemistry-specific. A 2025 study in *Batteries* of a commercial LiFePO4 module measured capacity down about 15 percent near -10 °C and about 35 percent near -20 °C relative to room temperature. That is a different chemistry from the pouch cells in your phone, so read it as a direction rather than a figure for your kit. Battery University's own page on discharging at high and low temperatures is consistent in shape: cold temperature increases internal resistance and lowers capacity, and that reduced capacity applies only while the cell is cold. Battery University does not prescribe a bigger pack for cold riding — sizing up is our inference from the loss figures, not its advice. Our [cold-weather bikepacking guide](/posts/winter-bikepacking-cold-weather-guide) covers keeping a bank warm, which is cheaper than carrying a bigger one.

**Losses you pay twice.** Topping a power bank up from a dynamo and then charging a phone from the bank pays the conversion tax twice, so the delivered figure is lower than a single-stage estimate suggests.

**A device hunting for signal.** The same Garmin specification that gives 14 days of 10-minute tracking with a full sky view gives about 4 days under moderate tree cover, which is the default setting — a cut of more than two-thirds from sky view alone, with no change in how you used the device.

<Tip title="The reserve rule we use">

Carry one extra day of your daily watt-hour figure and never spend it on navigation. The reserve is for the detour, the unplanned bivvy and the hour spent with the phone out working out where the track went. If you ride in the cold, make it a day and a half. Our separate articles on [charging your devices on route](/posts/charging-devices-on-route-bikepacking) and device power management on tour cover recovering a budget that has already gone wrong.

</Tip>

## Check Your Real Consumption on a Shakedown Ride

The table above is a starting point, and the head-unit row is an estimate. Replace it with your own numbers on a ride you can bail out of. Charge everything to full, ride a normal day with your real settings, and write down the percentage left on each device that evening. Percentages are enough: 40 percent of a 16.56 Wh phone battery is 6.6 Wh, and that is a measurement rather than a guess.

Then test the bank. Run a full power bank down charging your actual kit and count the device-charges before it dies. That figure is your real usable capacity, and it either validates or demolishes the 70 percent assumption.

Change one thing at a time afterwards — recording interval, backlight, screen timeout and radio settings all move the number, and three changes at once tell you nothing.

<SectionDivider variant="trail" />

## What To Do Next

List your devices tonight. Convert each to watt-hours with `Wh = mAh / 1000 × V`, using published figures where you can find them and flagging your estimates. Sum your daily total, multiply by 400 and by your days between sockets, and you have a rated capacity to shop against.

Then take the tradeoff seriously. The arithmetic usually says carry more lithium than you expected, and the honest alternative is to need less electricity — offline maps, a dimmer screen, a longer recording interval. We would do that work first and buy the smaller bank second. To turn the number into a system, start with [the full bikepacking power and charging guide](/posts/bikepacking-power-charging-guide).


How Much Battery Do You Actually Need? Bikepacking Power Budgeting

Bikepacking Power and Charging: The Complete Guide to Staying Charged Off-Grid


## Dynamo Hub vs Power Bank for Bikepacking: The Short Answer

Ride long days, for many days, away from sockets, and the dynamo hub wins. Ride short days or short trips, and the power bank wins. The crossover sits at roughly **six to seven hours of riding a day** and **about a week between mains outlets**. Below those numbers a dynamo cannot earn back its weight, cost or drag.

That is the whole decision, and it is not about money. It is about how many hours a day you actually turn the cranks. A dynamo is a generator with a fixed cost per hour of riding and effectively infinite range. A power bank is a fuel tank with zero drag and a hard bottom. Everything else in your [bikepacking power and charging setup](/posts/bikepacking-power-charging-guide) follows from which of those two things your route needs.

The uncomfortable version: a dynamo bought for a weekend trip is almost always the wrong purchase, and a dynamo bought for a month-long remote route is almost always the right one. Riders arrive asking which is better. Below a certain daily mileage the honest answer is that a dynamo cannot cover its own charging overhead, and above a certain trip length a power bank big enough to do the job weighs more than the hub.

<Highlight label="The short version">

- A dynamo is regulated to about **3 W at 6 V** on most modern hubs, and Schmidt quotes **65 percent efficiency, but only at 15 km/h**, according to Wikipedia's hub dynamo entry.
- CyclingAbout's lab rig measured a Shimano UR700 producing **4.2 W at 15 km/h** at its maximum power point, but only **2.8 W at the same speed** through a real Forumslader V6 charger.
- The same test found a phone's **2.5 W charging threshold** needs about **13 km/h** with the best hub and charger pairing, and up to **18 km/h** with a worse one.
- Busch+Müller's own USB-Werk documentation says a dynamo supplies about **3 W at 15 km/h** while some phones draw **up to 5 W**, which is why a cache battery is not optional.
- Anker's own arithmetic turns a **10,000 mAh** bank into **37 Wh** and then into about **6,068 mAh at 5 V** once conversion losses are counted. Call it **30 Wh usable**, not 37.
- At a modest **20 Wh a day**, one month off-grid needs roughly **3.8 kg** of power banks. That is the point where the hub stops being a luxury.

</Highlight>

<SectionDivider variant="rule" />

## What Each System Actually Is, and What Each One Costs

A hub dynamo is a small alternator built into your front hub. Most modern hubs are regulated to about 3 W at 6 V, with some reaching 6 W at 12 V, according to [Wikipedia's hub dynamo entry](https://en.wikipedia.org/wiki/Hub_dynamo). On its own it produces wild AC, so a dynamo-to-USB regulator converts and smooths it into something a device will accept.

Its costs are three, and only one is obvious. First, capital: hub, regulator, and usually a cache battery. Second, a wheel rebuild or a new front wheel, because the hub is the wheel. Third, drag — a real, permanent tax on every hour you ride.

That drag has been measured. CyclingAbout's lab test, which spins a dynamo wheel against a motor on a steel plate and subtracts a non-dynamo baseline, found drag with lights and chargers off running from **1.4 W to 1.9 W for a SON 28** across 10 to 30 km/h, against 1.9 W to 5.2 W for an SP PD-8 and 1.4 W to 4.5 W for a Shimano UR700, with the figures accurate to within about 1 W ([CyclingAbout](https://www.cyclingabout.com/dynamo-hub-power-drag-testing-schmidt-son-shutter-precision-shimano/)). Switch a bright light on and the load climbs steeply — the same rig reported 14.5 W at 15 km/h for a UR700 driving a Busch+Müller IQ-X.

A power bank is a sealed lithium cell with a converter on the front. Its costs are simpler: carried weight, a hard capacity limit, and the logistics of finding a socket. Its great virtue is that it adds exactly zero drag. Nothing it does slows you down.

<PullQuote>A dynamo charges you by the hour. A power bank charges you once, in grams.</PullQuote>

<SectionDivider variant="trail" />

## The Dynamo Case: Output at Realistic Touring Speeds

Dynamo output is a function of wheel speed, and the numbers at touring speed are smaller than most riders expect. CyclingAbout's rig measured a Shimano UR700 at its maximum power point producing 1.5 W at 5 km/h, 2.6 W at 10 km/h, **4.2 W at 15 km/h**, 6.0 W at 20 km/h, 7.7 W at 25 km/h and 9.1 W at 30 km/h.

That is the theoretical ceiling. Through an actual charger you get less. The same test put a Forumslader V6 on that hub and measured 2.0 W at 10 km/h, **2.8 W at 15 km/h** and 4.7 W at 20 km/h. The honest planning figure for a loaded bike at a genuine 15 km/h is therefore under 3 W, nowhere near the 9 W you see on a fast descent.

Output also plateaus. Hubs are regulated, so once you are above their rated speed you are not harvesting proportionally more. Retailer listings for the SON 28 state it reaches rated output at about 16 km/h in a 700c wheel, against about 19 km/h for the lighter SONdelux ([SJS Cycles](https://www.sjscycles.co.uk/hubs-front/son-28-centre-lock-disc-dynamo-front-hub-polished-36-hole)). The practical consequence is that a dynamo rewards *duration*, not speed. Eight slow hours beats two fast ones.

<Tip title="Without a cache battery, riders conclude the dynamo does not work">

A dynamo does not charge a phone well directly, and this is the single most common disappointment. Busch+Müller's documentation for the USB-Werk explains the mechanism plainly: the dynamo supplies only about 3 W at around 15 km/h while some phones draw up to 5 W, so a buffer battery charges first and the USB output stays off until it reaches a set level. When the phone pulls the buffer down to its minimum, the output switches off again and the buffer refills, which "leads to interruptions, which some USB devices indicate with the charge start sound" ([bike-components product documentation](https://www.bike-components.de/en/busch-mueller/USB-Werk-Mobile-Charging-Device-p35972/)). The same source notes the buffer needs roughly 20 minutes above 17 km/h with nothing plugged in and the lights off to fill completely. Buy the hub and the regulator and skip the cache battery, and every stop sign undoes your charging.

</Tip>

What the dynamo genuinely buys you is range that does not run out and lights that never die. On a route where resupply is food and water only, that is worth real weight. We will cover the hub choice itself in the best dynamo hubs for bikepacking, and the regulator choice in the best dynamo USB chargers, because the charger matters at least as much as the hub — the measured gap between pairings is the difference between charging a phone at 13 km/h and needing 18 km/h.

<SectionDivider variant="ornamental" />

## The Power Bank Case: Usable Capacity Is Not Rated Capacity

For most trips, the power bank is the correct answer, and it is not close. The tradeoff is that you are carrying every watt-hour you will use, and when it is gone it is gone.

Start by distrusting the number on the case. Anker's own support page works it through: a 10 Ah cell at 3.7 V is 37 Wh, which at 5 V is 7.4 Ah, and after conversion losses at "typically around 82 percent efficiency" the effective capacity a device can use is about 6,068 mAh ([Anker](https://service.anker.com/article-description/Why-Is-the-Rated-Capacity-Marked-on-a-Power-Bank-Lower-Than-Expected)). Converting that back to energy with `Wh = mAh / 1000 x V` gives 6.068 Ah at 5 V, or **about 30 Wh of usable energy from a 10,000 mAh bank** — roughly 60 percent of the headline 10,000 mAh.

Now weigh it. Retailer listings put Anker's PowerCore II 10000, a 37 Wh bank, at **195 g** ([Galaxus](https://galaxus.be/en/s1/product/anker-powercore-10000-mah-18-w-37-wh-powerbanks-10285520)). Against 30 Wh usable, that is about **6.4 g per usable watt-hour**. That single number is the one to carry around in your head, because it converts any power budget directly into grams.

The power bank also wins on every failure mode that matters. It works at 0 km/h, while you sleep, in a tent, on a bus. It has no spokes to true and nothing to short out in the rain. If you are choosing the bank itself, we go through capacities and ports in our guide to [picking a portable charger for your phone and GPS](/posts/navigating-with-power-the-best-portable-charger-for-your-phone-and-gps).

<SectionDivider variant="trail" />

## The Crossover: Show the Sums

Pick a daily draw. We will use **20 Wh a day** as a worked example — a phone topped up, a head unit kept alive, and a light or two. Your real figure may be half or double that, and getting it right is the whole exercise, so start with [how much battery you actually need](/posts/bikepacking-power-budget-watt-hours) and substitute your own number into the sums below. Head units vary enormously in appetite; our round-up of [cycling computers for bikepacking](/posts/best-cycling-computers-bikepacking) is a reasonable place to see the spread.

**Break-even in riding hours.** At the measured 2.8 W a Forumslader V6 delivered from a UR700 at 15 km/h, covering 20 Wh takes `20 / 2.8`, about **7.1 hours of riding a day**. Push to 20 km/h and the measured 4.7 W cuts that to about **4.3 hours**. Drop to 10 km/h and the measured 2.0 W pushes it out to **10 hours**. A three-hour evening ride at 15 km/h yields about 8.4 Wh — under half a day's budget. This is why a dynamo on a weekend trip is a net loss.

**Break-even in grams.** At 6.4 g per usable watt-hour, 20 Wh a day costs you about **128 g of power bank per day**. Schmidt lists the SON 28 hub itself at about 440 g, so on hub mass against bank mass the batteries overtake the hub at roughly `440 / 128`, about **3.4 days**. Be honest about that figure, though: the dynamo system also needs a regulator and a cache battery, and you only pay the *difference* between the dynamo hub and the plain front hub it replaces. Add those back and the real mass crossover lands closer to **a week of genuine off-grid riding**.

| Trip | Energy needed at 20 Wh/day | Power banks, approx. | Our call |
|---|---|---|---|
| Weekend, 2 days | 40 Wh | ~260 g | Power bank, no argument |
| One week, a socket mid-trip | ~60-80 Wh carried | ~400-500 g | Power bank |
| One week, no sockets at all | 140 Wh | ~900 g | Dynamo if you ride 6+ hours daily |
| One month off-grid | 600 Wh | ~3.8 kg | Dynamo |
| Remote and open-ended | unbounded | impossible | Dynamo, only answer |

The bottom row is the real case for a dynamo. It is not that the hub is lighter on a given trip — it is that a dynamo's capacity does not have a bottom, so a route with no known end does not have a battery calculation at all.

<SectionDivider variant="rule" />

## When the Answer Flips Regardless of the Maths

**Cold.** Battery capacity falls in the cold while a generator does not care.

<Warning title="Expect to lose roughly half your capacity in deep cold">

Battery University states that a battery delivering 100 percent capacity at 27 °C typically delivers about 50 percent at -18 °C, and that most batteries sit near 50 percent performance at -20 °C, though the shortfall is temporary and recovers at room temperature ([Battery University](https://batteryuniversity.com/article/bu-502-discharging-at-high-and-low-temperatures)). Plan a winter power budget on your bank's rated capacity and you can be short by a wide margin on the coldest morning of the trip. Sleeping the bank inside your quilt is the standard mitigation, and we go further into cold-weather behaviour in our [winter bikepacking guide](/posts/winter-bikepacking-cold-weather-guide).

</Warning>

**Very slow or technical riding.** Dynamo output tracks wheel speed, and CyclingAbout's test found the 2.5 W smartphone charging threshold requires about 13 km/h with a UR700 and an Igaro D1, rising to about 17 to 18 km/h with other hub and charger pairings. A route averaging 9 km/h on chunky doubletrack may spend most of the day below the threshold entirely.

**Hike-a-bike.** Pushing generates nothing. A route with hours of carrying per day is a power bank route no matter how many days it lasts.

**Electrically hungry setups.** If you are running a bright dynamo light *and* charging, you are splitting a very small budget. For most riders, a rechargeable light plus a bank is simpler than a dynamo trying to do both, and our [overnight bike light round-up](/posts/best-bike-lights-overnight-bikepacking) treats that choice directly.

**The device that must not go flat.** If a [satellite messenger](/posts/best-satellite-messengers-bikepacking) is your emergency plan, it gets its own reserve. Neither system changes that.

**Not wanting to rebuild a wheel.** This is a legitimate reason, not a failure of nerve. A dynamo means a wheel build or a new front wheel, plus a connector that has to survive weather and vibration. Some riders simply do not want another system to maintain, and that preference is worth more than a few grams.

<SectionDivider variant="ornamental" />

## What We Would Do

**Weekends and sub-week trips with any socket access.** A power bank, every time. At about 6.4 g per usable watt-hour, two or three days of autonomy costs a few hundred grams. The tradeoff is that you are rationing from day one, and on a long cold weekend you may ration harder than you expected.

**One to two weeks, mostly rural, occasional cafes.** Still a power bank — one larger bank, charged at every opportunity. The tradeoff is route dependence: your charging plan is now a list of places that have to exist and be open.

**One month or longer off-grid, 6 or more riding hours a day.** The dynamo, decisively. At 20 Wh a day, a month of carried battery is roughly 3.8 kg, and no hub weighs that. The tradeoff is 1.4 W to 1.9 W of permanent drag on a good hub, plus the capital cost and a wheel build — and you still carry a cache battery.

**Open-ended or expedition routes.** The dynamo, and it is not really a comparison. The tradeoff is complexity in a place where a failed connector is genuinely inconvenient, so carry a small bank as backup regardless.

**Short, slow, technical riding or heavy hike-a-bike.** A power bank, even on long trips. The dynamo simply will not spin fast enough to pay.

The useful reframe is that these are not competitors. A dynamo is a slow trickle that never stops; a bank is a fast reserve that does. Most riders who end up with a hub still carry a bank, which tells you what each thing is actually for. For the full system — budgets, device draw, cables and chargers — see [our complete guide to bikepacking power and charging](/posts/bikepacking-power-charging-guide).


Dynamo Hub vs Power Bank: Which Bikepacking Charging System Suits Your Trip


## Your Navigation Dies When Your Battery Does

Forty miles from the nearest road, your phone battery hits 5%. Your GPS track disappears. That planned resupply stop? Good luck finding it without navigation. As [REI's electronics guide](https://www.rei.com/learn/expert-advice/batteries-chargers-portable-power.html) notes, power management is one of the most overlooked aspects of modern adventure travel.

Modern bikepacking depends on electronics—phones for navigation and emergency contact, GPS units for route tracking, lights for night riding. Yet most cyclists pack power banks as an afterthought, grabbing whatever's cheapest at the airport.

The right power bank keeps your devices alive for days without weighing you down. The wrong one adds unnecessary grams, dies in cold weather, or fails when you need it most.

Here's what actually works for bikepacking in 2025.

For GPS device recommendations, see our [GPS Navigation Devices](/posts/gps-navigation-devices-bikepacking) and [Best Cycling Computers](/posts/best-cycling-computers-bikepacking) guides.

## The Power Budget: Know Your Numbers Before You Leave

Most bikepackers guess at power needs—and run out of battery three days into a five-day trip. Calculate your actual power budget before departure:

**Step 1: Audit Your Devices (15 minutes at home)**

| Device | Battery (mAh) | Usage Pattern | Est. Daily Drain |
|--------|---------------|---------------|------------------|
| Phone | 4,000 | Airplane mode, 2hrs navigation | ~30% = 1,200mAh |
| GPS | 2,000 | 8hrs navigation | ~80% = 1,600mAh |
| Headlight | 2,500 | 2hrs medium | ~40% = 1,000mAh |
| Taillight | 500 | 4hrs flash | ~30% = 150mAh |
| **Total** | | | **~4,000mAh/day** |

**Step 2: Calculate Required Capacity**

Daily consumption × trip days × 1.4 (efficiency loss + margin) = required power bank capacity

*Example:* 4,000mAh/day × 4 days × 1.4 = 22,400mAh needed

**Step 3: Match to Reality**
- Two 10,000mAh banks = ~14,000mAh usable
- Gap = 8,400mAh short
- Solution: Plan one town recharge on day 2

**Common Discoveries:**
- **Phone GPS kills batteries**—switch to dedicated GPS if possible
- **Screen brightness is the killer**—minimum brightness saves 30-40%
- **Cold weather cuts everything by 20-30%**—budget extra for alpine/shoulder seasons
- **You charge more than expected**—devices rarely reach 100%, reducing efficiency

**The Pre-Trip Test:**
One week before your trip, use your devices as you plan to use them on the trail:
1. Put phone in airplane mode with GPS navigation only
2. Run your cycling computer through a full day
3. Use your lights for planned duration
4. Note exact battery consumption

Multiply by trip length. Add 40% margin. Now you have a real power budget—not a guess.

---

## How to Size Your Power Bank

**The Math:**
- Modern smartphones: ~3,500mAh battery
- GPS units: ~1,500-2,500mAh battery
- Real-world efficiency: ~65-70% (you lose capacity to heat and voltage conversion)

A 10,000mAh power bank delivers roughly 6,500mAh of usable power—enough for about 1.5 full phone charges or 2-3 GPS charges. For most bikepackers, that covers 2-3 days of moderate use.

**Sizing Guidelines:**
- **Weekend trips (2-3 days):** 10,000mAh
- **Week-long adventures:** 20,000mAh or two 10,000mAh units
- **Extended expeditions:** Consider solar charging to supplement batteries

## What Makes a Power Bank Bikepacking-Worthy

**Weight-to-capacity ratio matters most.** Premium ultralight banks hit 180-200mAh per gram. Budget options often deliver 120-150mAh per gram—meaning you carry 30%+ more weight for the same power.

**Water resistance is essential.** Look for IPX4 (splash-proof) minimum. IPX5+ handles genuine rain. Fully sealed construction survives stream crossings.

**Cold weather performance varies wildly.** Lithium-ion batteries lose capacity in cold. Carbon fiber cases and insulated designs maintain output when temperatures drop.

**Fast charging saves time.** USB-C Power Delivery (PD) and Quick Charge (QC) protocols charge devices 3-4x faster than standard USB-A. Worth it when you're racing daylight.

## Featured Products

<ProductCard
  name="Nitecore NB10000 Gen 3"
  pickLabel="Our Pick"
  description="The NB10000 Gen 3 sets the standard for ultralight power banks. At just 5.3 ounces for 10,000mAh, it delivers the best weight-to-capacity ratio in the industry. The carbon fiber shell resists cold weather better than plastic, maintaining output when temperatures drop—critical for alpine and shoulder-season riding. Dual USB-C ports enable fast charging in both directions, and IPX5 water resistance handles genuine rain. Rubberized corner bumpers protect against drops. This is the power bank serious ultralight bikepackers reach for."
  amazonLink="https://www.amazon.com/dp/B0D5CLSMFB?linkCode=ll1&tag=besamadea0bd-20"
  highlights={["Ultra-light at 5.3 oz (150g)", "Carbon fiber cold-weather performance", "IPX5 water resistance", "Dual USB-C fast charging", "257mWh/g energy density"]}
  specs="10,000mAh, 5.3 oz, IPX5"
  rating={5}
/>

<ProductCard
  name="Anker PowerCore 10000"
  pickLabel="Also Good"
  description="Anker built its reputation on reliable, affordable power banks—and the PowerCore 10000 shows why. At roughly half the price of premium ultralight options, it delivers consistent performance trip after trip. PowerIQ and VoltageBoost technologies automatically detect connected devices and optimize charging speed. The compact design fits in jersey pockets. No, it's not as light as the Nitecore, and it lacks water resistance, but for bikepackers who want proven reliability without premium pricing, this is the go-to choice."
  amazonLink="https://www.amazon.com/dp/B0D5CLSMFB?linkCode=ll1&tag=besamadea0bd-20"
  highlights={["Proven Anker reliability", "PowerIQ device detection", "Compact pocket-friendly size", "30W fast charging", "Budget-friendly price point"]}
  specs="10,000mAh, ~6.4 oz, 30W output"
  rating={5}
/>

<ProductCard
  name="INIU 45W Slim Power Bank with Built-in Cable"
  pickLabel="Also Good"
  description="Forgetting your charging cable three days into a bikepacking trip is a special kind of frustrating. The INIU 45W solves this with a built-in USB-C cable that doubles as a lanyard. At 45W, it's one of the fastest-charging 10,000mAh banks available—your iPhone hits 60% in 25 minutes. The TinyCell technology packs 27% smaller than standard cells, keeping the package slim. Pass-through charging lets you charge both the bank and your phone simultaneously when you find an outlet. Not quite as rugged as dedicated outdoor banks, but the convenience factor is hard to beat."
  amazonLink="https://www.amazon.com/dp/B0CB1FW5FC?linkCode=ll1&tag=besamadea0bd-20"
  highlights={["Built-in USB-C cable/lanyard", "45W ultra-fast charging", "27% smaller than standard 10K banks", "Pass-through charging supported", "Phone to 60% in 25 minutes"]}
  specs="10,000mAh, 45W, built-in cable"
  rating={4}
/>

<ProductCard
  name="INIU Portable Charger 22.5W"
  pickLabel="Budget Pick"
  description="Need reliable power without breaking the bank? The INIU 22.5W delivers 10,000mAh capacity at a price point that's hard to argue with. PD 3.0 and QC 4+ support means it charges modern devices at near-maximum speeds. The built-in phone holder stands your device upright while charging—surprisingly useful for checking maps at camp. Three outputs let you charge multiple devices simultaneously. It's slightly heavier than premium options and lacks water resistance, but for occasional bikepackers or as a backup unit, the value is exceptional."
  amazonLink="https://www.amazon.com/dp/B09176JCKZ?linkCode=ll1&tag=besamadea0bd-20"
  highlights={["Outstanding value pricing", "22.5W PD 3.0 + QC 4+ fast charging", "Built-in phone stand", "Three simultaneous outputs", "TSA-approved capacity"]}
  specs="10,000mAh, 22.5W, 3 outputs"
  rating={4}
/>

## One 20K or Two 10K?

Here's a counterintuitive finding from our testing: two 10,000mAh power banks often weigh the same or less than a single 20,000mAh unit. Beyond weight, carrying two provides redundancy—lose one, and you still have backup power.

The two-bank strategy also lets you keep one in your frame bag (for daily charging) and one in your [saddle pack](/posts/best-saddle-bags-bikepacking) (as reserve). No digging through bags when you need a quick top-up.

## Extending Battery Life in the Field

**Airplane mode is your friend.** Disable cellular and Bluetooth when not needed. Your phone searching for signal drains battery faster than anything else.

**Lower screen brightness.** GPS apps with the screen on constantly murder batteries. Many GPS units offer always-on displays that sip power.

**Charge opportunistically.** Top off devices whenever you pass a cafe or campsite with power. Partial charges don't harm modern lithium batteries.

**Consider offline maps.** Downloaded maps reduce data usage and battery drain. Load your route before leaving cell coverage. See our [first bikepacking trip guide](/posts/your-first-bikepacking-trip-planning) for complete pre-trip planning.

## FAQ

**Can I bring power banks on flights?**

Yes, but with limits. TSA allows power banks up to 100Wh (~27,000mAh) in carry-on luggage only—not checked bags. All the power banks in this article are TSA-approved. Larger capacity banks (100-160Wh) require airline approval.

**How many charges will I actually get?**

Take the power bank capacity, multiply by 0.65-0.70 (accounting for conversion losses), then divide by your device's battery size. A 10,000mAh bank provides roughly 6,500mAh of usable power—about 1.8 charges for a 3,500mAh phone.

**Should I get a solar charger instead?**

Solar works as a supplement, not a replacement. Panels need direct sunlight and time—challenging when you're riding all day. Pack a power bank for reliable base power; add a compact solar panel for extended expeditions where you can charge during breaks.

**Does fast charging damage batteries?**

Modern devices manage charging speed automatically based on battery temperature and health. Fast charging is safe for occasional use. If you're concerned, use standard charging overnight and save fast charging for when you need quick top-ups.

**What about wireless charging power banks?**

Avoid them for bikepacking. Wireless charging adds weight, reduces efficiency (more power lost to heat), and requires precise positioning—impractical on a vibrating bicycle. Stick with wired charging.

---

For more on electronics and bikepacking, see our [bike lights guide](/posts/best-bike-lights-overnight-bikepacking) and [night riding safety gear](/posts/night-riding-safety-gear-bikepacking). Pack your power bank in a [frame bag](/posts/best-frame-bags-bikepacking) where weight is centered and protected.


electronics

How Much Battery Do You Actually Need? Bikepacking Power Budgeting

Bikepacking Power and Charging: The Complete Guide to Staying Charged Off-Grid

Dynamo Hub vs Power Bank: Which Bikepacking Charging System Suits Your Trip

Navigating with Power: The Best Portable Charger for Your Phone and GPS