Zenith coils | Values, wattage and Ohm's law

Zenith coils take seconds to change, which does little to encourage a close reading of what they state. Yet behind each value sits a small complete build, with its wire, its wick and a wattage range that listings do not all copy the same way. At the journal we look at a coil head the way we would look at a coil we had fitted ourselves. Ohms, watts, voltage and current, here is what each value really asks of your mod.

Zenith coils, the replacement heads behind the Zenith family

Zenith coils, sold by Innokin as Z-Coils, are the replacement heads designed for its Zenith and Zlide tanks and for the Kroma Z kit. Innokin states that the Zenith II takes every current Z-Coil and that the Kroma Z is compatible with the entire range.

They come in packs of five and cover every draw, from a very tight mouth-to-lung pull to restricted direct lung. The name can mislead, since Geekvape sells its own Z series for its Z Sub Ohm tanks. The two families share nothing beyond the letter.

Zenith coils values and their wattage ranges

Innokin does not publish every value on a single page. The table takes the ranges from the manufacturer’s product pages and, where those are silent, the figures on which two retailers agree.

Value	Build or draw	Range	Source
0.3 ohm	Restricted direct lung	30 to 40 W	Innokin
0.48 ohm	Plex3D, Kanthal mesh	13 to 16 W	Innokin
0.5 ohm	Plexus or dual wire, by retailer	14 to 19 W	Two retailers
0.6 ohm	DuoPrime	9 to 13 W	Two retailers
0.8 ohm	Kanthal	15 to 18 W	Innokin
1.0 ohm	Restricted direct lung	20 to 25 W	Innokin
1.2 ohm	Tight draw	10 to 14 W	Innokin
1.6 ohm	Kanthal, very tight draw	10 to 12 W	Retailer overlap

The 1.6 ohm is the least well documented. One retailer gives 8 to 12 W, another 9 to 12 W in its description and 10 to 14 W in its questions section. We keep the band on which they all overlap, 10 to 12 W.

Ohm’s law applied to each coil

A wattage range says nothing about the effort asked of the mod. Ohm’s law, covered in our piece on Ohm’s law and rebuildables, turns each power setting into a voltage and a current.

The working, value by value

Voltage is the square root of power multiplied by resistance, current the square root of power divided by resistance. The table applies both to the top of each range.

Coil	Top wattage	Voltage	Current
0.3 ohm	40 W	3.46 V	11.55 A
0.48 ohm	16 W	2.77 V	5.77 A
0.5 ohm	19 W	3.08 V	6.16 A
0.6 ohm	13 W	2.79 V	4.65 A
0.8 ohm	18 W	3.79 V	4.74 A
1.0 ohm	25 W	5.00 V	5.00 A
1.2 ohm	14 W	4.10 V	3.42 A
1.6 ohm	12 W	4.38 V	2.74 A

Low values pull current

The 0.3 ohm draws more than 11 A at 40 W, nearly twice any other value in the range. It is the coil that loads the cell and the mod’s circuit hardest. The Kroma Z, built around this range, is rated from 6 to 40 W, exactly the top of this coil’s range.

High values need voltage

The 1.6 and the 1.0 ohm work the other way round, with little current but a lot of voltage. A fully charged lithium cell delivers about 4.2 V. Beyond that, only a regulated mod able to step the voltage up holds the power on its screen.

What the 1.0 ohm Zenith coil reveals about your mod

The 1.0 ohm is the clearest case. At 25 W, the top of its range, it needs 5 V, a voltage no single cell supplies on its own. On an unregulated single-cell device, power tops out at around 17.6 W with a full cell, below the bottom of the range Innokin gives.

The same reasoning holds for the 1.6 ohm, capped at about 11 W at 4.2 V and losing more as the cell drains. A regulated mod makes up for that drop, but the point stands for an old tube or a mechanical device pressed into service under a tank.

The sum also works as a check. If the reading on your mod is well away from the value printed on the coil, the power actually delivered is no longer what you think you are setting, and reseating the coil before vaping is the sensible move.

On an unregulated device, the low values overshoot their range

The sum also works the other way round. Without regulation, power is no longer chosen, it follows from the cell’s voltage and equals that voltage squared divided by the resistance. The table gives it at 3.7 V, the nominal voltage of a lithium cell, and at 4.2 V, fully charged.

Coil	Range	Power at 3.7 V	Power at 4.2 V
0.3 ohm	30 to 40 W	45.6 W	58.8 W
0.48 ohm	13 to 16 W	28.5 W	36.8 W
0.5 ohm	14 to 19 W	27.4 W	35.3 W
0.6 ohm	9 to 13 W	22.8 W	29.4 W
0.8 ohm	15 to 18 W	17.1 W	22.1 W
1.0 ohm	20 to 25 W	13.7 W	17.6 W
1.2 ohm	10 to 14 W	11.4 W	14.7 W
1.6 ohm	10 to 12 W	8.6 W	11.0 W

The 0.48 ohm Plex3D, the 0.5 ohm and the 0.6 ohm DuoPrime then receive from nearly one and a half to more than twice the top of their range, and the 0.3 ohm also overshoots its 40 W. These heads are built to heat at low power despite a low value, with Innokin describing the Plex3D as a three-dimensional Kanthal mesh. The ohm value alone therefore does not tell you the power they need, and only a regulated mod keeps them inside their range.

The 1.0 ohm, by contrast, stays below its range and the 1.6 ohm only reaches its own on a full cell, as seen above. The 0.8 and 1.2 ohm stay close to theirs until the cell is fully charged. The safety margins that apply to unregulated devices are set out in our piece on Ohm’s law mentioned earlier.

The 0.3 ohm, a compatibility exception

Innokin presents the range as interchangeable, yet two retailers warn that the 0.3 ohm does not fit every model. One rules it out for the Zlide Tube, the other for the original Zenith and the Zlide D22 and D24.

Their lists do not fully overlap, so check your tank’s manual before ordering this value. Innokin ships the Zenith II with 0.3 and 0.8 ohm coils in its standard box, which settles the question for that model, although the manufacturer notes that the kit sold in France comes with 0.8 and 1.6 ohm coils instead.

2 ml tanks and coil changes in the UK

Under the Tobacco and Related Products Regulations 2016, a refillable tank sold in the UK holds no more than 2 ml, and nicotine refills are capped at 10 ml and 20 mg/ml. Innokin lists the Zenith II at 5.5 ml or 2 ml and the Zlide at 2 ml, so the 2 ml version is the one to look for. A smaller tank means more frequent refills, not a different coil.

Changing the coil varies by tank. On the Zlide, Innokin says to unscrew the bottom cap, and on the Zenith Pro it highlights a coil swap without draining the tank. Either way, let the cotton soak before the first draw and start at the bottom of the range. Spitting or a burnt taste early on calls for the same diagnosis as on a rebuildable, covered in our guide to a spitting coil and burnt taste.

FAQ

Five answers on points that product listings leave out.

Can a Zenith coil be rewicked?

Innokin sells it as a replacement part, in packs of five. To fit your own wire and cotton, a rebuildable atomiser is the route designed for that.

Why does the 0.8 ohm range vary between listings?

Innokin gives 15 to 18 W on its Zenith II and Kroma Z pages, and that is the range we keep. A different figure on a retailer’s page is worth checking against the manufacturer’s.

Which coil suits a restricted direct-lung draw?

Innokin places the 0.3 ohm, at 30 to 40 W, and the 1.0 ohm, at 20 to 25 W, in that draw. The second needs less current but a regulated mod to reach the top of its range.

Does the Kroma Z accept coils outside the range?

Innokin gives a resistance range of 0.2 to 3.5 ohms for the device. The kit is still designed around these coils, and a 510 adaptor sold separately lets you fit another Zenith or Zlide tank.

Which value for a tight draw?

The 1.2 and the 1.6 ohm are the tightest in the range. The 1.6 ohm asks for less power, while the 1.2 ohm sets a little higher, up to 14 W.

Reading Zenith coils like a build

A shop-bought coil head follows the same rules as a coil fitted by hand. Value, range, voltage and current take one line to work out, and the sum tells you whether your mod will hold the power it displays.

Keep three markers in mind. The 0.3 ohm leans on current, the 1.0 and 1.6 ohm on voltage, and the manufacturer’s page outranks the retailer’s listing. Read that way, Zenith coils become builds like any other, and the approach works for every coil you fit, from a clearomiser to a rebuildable.

Editorial content for adult readers only. Vaping products can contain nicotine, a substance that causes addiction. Nicotine vaping products are not for sale to anyone under 18 in the UK. This article is not a buying recommendation.