Electric Unicycle Battery Voltage Explained: 84V to 151V, Wh and Ah

An electric unicycle's voltage is its battery's voltage at full charge, and it tells you how many lithium-ion cells are wired in series. Each cell charges to 4.2V, so an 84V wheel has 20 cells in series, 100.8V has 24, 134.4V has 32 and 151.2V has 36. Voltage sets how much power headroom the motor has; watt-hours, not volts, set how far the wheel goes. More of either means more cells, and more cells mean a heavier wheel.

Where the numbers come from

The makers' own spec sheets show the arithmetic. InMotion lists the V9's pack as 20S2P (20 cells in series, 2 in parallel) with an 84V charger: 84 divided by 20 is 4.2V per cell at full charge. Its V14 Pro is 32S4P at 134.4V, again 4.2V per cell. King Song's F18 has 144 cells and a 151.2V maximum charging voltage, which is 36 cells in series (151.2 divided by 4.2) and, by our arithmetic, four in parallel.

A cell's nominal voltage, its average over a discharge, is lower. Molicel rates its 21700-size P45B cell at 3.6V nominal. Makers round this differently: King Song lists the 84V 18XL Pro at 72V nominal (3.6V per cell for 20 cells) but the 151.2V F18 at 133.2V nominal (3.7V per cell for 36). Either way, the full-charge figure is the one in the name.

The voltage classes

Class (full charge)	Cells in series	Nominal at 3.6V per cell	Examples
54.6V	13	46.8V	InMotion E20 (13S2P, 54.8V charger listed)
67.2V	16	57.6V	King Song 16S Pro (67.2V charger)
84V	20	72V	InMotion V9, King Song 18XL Pro (72V nominal)
100.8V	24	86.4V	InMotion V12 Pro (24S2P, sold out when we checked)
126V	30	108V	No current InMotion or King Song page we read states this class (King Song lists no voltage for the S18 Pro+ or S19 Pro)
134.4V	32	115.2V	InMotion V14 Pro (32S4P)
151.2V	36	129.6V (King Song states 133.2V)	King Song F18
168V	40	144V	Begode Blitz Pro 168v and X-Way 168v (named on Begode's store)

Two notes on the table. The cell counts for the 54.6V to 151.2V rows follow from 4.2V per cell; where a maker states the series count (the V9, V12 Pro, V14 Pro and E20), it matches. The 168V row is our arithmetic from Begode's product names; Begode's store page did not give cell counts. InMotion's E20 page also lists a "26V" battery voltage, which does not fit a 13-cell pack charged at 54.8V, so we go by the cell layout and charger.

Watt-hours vs amp-hours

Watt-hours measure energy, and energy is what sets range. Amp-hours measure charge at a given voltage, so they only compare fairly between packs of the same voltage. To convert, multiply amp-hours by nominal voltage:

• Watt-hours = amp-hours x nominal volts.
• Amp-hours = watt-hours / nominal volts.

Worked example: the V9's 750 Wh at 72V nominal is about 10.4 Ah. A wheel listed as 20 Ah at 72V would be 1,440 Wh, while 20 Ah at 129.6V would be about 2,592 Wh, nearly double the energy for the same amp-hour figure. That is why spec sheets in Ah can mislead across voltage classes, and why our range calculator takes watt-hours.

Cell-level arithmetic works the same way. A Molicel P45B cell is rated 4.5 Ah at 3.6V nominal, or 16.2 Wh. A hypothetical 20S4P pack of those cells (80 cells) would hold 80 x 16.2 = 1,296 Wh.

Why higher voltage gives more headroom

Electrical power is volts times amps. A controller can only push so much current (InMotion quotes 180A for the V9's controller), so at the same current, more voltage means more power: 151.2V is 1.8 times 84V. That is why high-voltage packs sit on the most powerful wheels in each line-up: King Song's 151.2V F18 is rated at 5,000W, InMotion's 84V V9 at 1,000W.

Voltage also falls as a battery drains, from 4.2V per cell at full toward and below the 3.6V nominal. Less voltage means less headroom, which is why wheels get more cautious on a low battery. King Song's 16S Pro FAQ lists "low-battery alerts, current limiting, forced deceleration, and pedal tilt-back" among its protections and warns that low battery "does not mean the wheel should be pushed harder."

Why a bigger pack means a heavier wheel

Every extra volt or watt-hour is more cells. The makers' own figures show weight rising with cell count:

Wheel	Pack layout	Cells	Battery	Weight
InMotion E20	13S2P	26	240 Wh	30 lb
InMotion V9	20S2P	40	750 Wh	50.7 lb (spec table)
InMotion V14 Pro	32S4P	128	2,400 Wh	86 lb
King Song F18	144 cells (36 in series)	144	2,664 Wh	90 lb

Motors, suspension and shells add to these totals, so cells are not the whole story, but no wheel gets a big pack without the weight that comes with it. Choose the smallest pack that covers your riding with a margin.

Voltage and charging

A charger must match the pack: an 84V wheel needs a charger whose output is 84V, a 151.2V wheel one that outputs 151.2V. King Song's 16S Pro uses a 67.2V charger; InMotion's V9 an 84V one. Never use a charger made for a different voltage class. The CPSC tells consumers to use only the charger provided with a micromobility device and not to use "universal" chargers unless they have been tested and approved for that device.

Voltage also converts watt-hours to the amp-hours a charger works in. Our charging time calculator does that step for each pack class, and our guide to battery safety and UL 2272 covers charging and storage habits.

How to read the battery line on a spec sheet

1. Find the watt-hours. If only amp-hours are given, multiply by the nominal voltage.
2. Find the full-charge voltage or the charger's output voltage, and divide by 4.2 to get the cells in series.
3. Before comparing amp-hours between makers, check whether the nominal figure assumes 3.6V or 3.7V per cell.
4. Note the cell maker and layout where given (InMotion lists layouts such as 20S2P; King Song names the cell model, such as Samsung 50S on the F18).
5. Note the charger's output current; with watt-hours and voltage, it sets the charging time.

Which voltage should you buy?

• Learning and short trips: the 13S to 16S packs on trainers and small wheels are plenty.
• Commuting: 84V wheels such as the V9 and 18XL Pro cover most commutes.
• Trails and experienced riders: 134.4V and 151.2V wheels like the V14 Pro and F18 add headroom and weight in equal measure.

Our buying guide puts voltage alongside the other specs that matter.