The POTV Guide To Batteries

The POTV guide to batteries aims to answer all of your questions regarding lithium-ion cells for vaping

by Dave Cross

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Should I buy bargain batteries?

No. We will start here because it is vital you buy quality lithium-ion cells from reputable vendors.

Many cheap knock offs come across from China where they slap on a shrink wrap label making all kinds of ridiculous claims. Some cells purport to be popular brands, others make wild claims as to performance – all of them are potentially very dangerous and a waste of money.

What is inside a lithium-ion battery?

The battery is actually a collection of cells and can be broadly represented as having a POSITIVE cathode and a NEGATIVE anode. You will see them marked on your battery’s wrapper. Inside the battery, an electrolyte is there to help ions move from the anode to the cathode.

The ions move across the separator – which is there to prevent the anode and cathode coming into contact.

This is important to remember when we talk about thermal runaway and batteries venting due to short circuits or overheating.

How does the battery work?

When ions arrive at the cathode they release electrons which travel around the circuit created when you press the fire button, returning to the anode and creating new ions.

What is the maximum current a battery can deliver?

This varies between models. The lower the ohms of your coil, the higher the amp rating your battery needs to be.

Batteries have two ratings: a constant fire maximum and a pulse fire maximum. Good advice is the err on the side of caution. Assume your battery is fully charged at 4.2 Volts.

The current rating your battery needs = 4.2 divided by the value of your coil’s resistance.

How do I calculate my coil’s resistance?

Steam Engine’s coil calculator is one of the first and still one of the best: https://www.steam-engine.org/coil

What is mAh?

mAh stands for milliamps per hour. This is the figure that tells you how long your battery will last in use. The higher the mAh, the longer you will use it before needing to recharge.

Ohm’s Law

What is a short circuit?

Instead of the atomiser coil offering resistance to the flow of electricity somewhere metal is touching metal to allow the electrons to skip that difficult path and allow them the fast easy route back to the battery.

Why is a short circuit bad?

This means the current flows much faster than the battery is built for, resulting in it heating up and, if left unchecked, triggering thermal runaway.

What is thermal runaway/venting?

When a battery gets too hot, as it will with a short circuit, the internal chemistry of the battery breaks down and the anode and cathode will come into contact.

Batteries are designed so that when things start going wrong gases will be thrown out of the positive end to prevent it exploding. This is called venting.

My battery got hot but didn’t vent, can I still use it?

When it got hot filaments called dendrites grew between the anode and cathode. This means it is more likely to vent in use in future. It is recommended to dispose of the battery and replace it – as you would if it had vented.

Is a venting battery dangerous?

A venting battery is only dangerous if the gases being released have nowhere to go. Check that the mod you use has holes in the battery compartment to allow a safe vent. Some mech mods have insufficient vent holes and this can lead to the build-up of pressure then an accident.

How long does a battery last?

Battery performance deteriorates over time and the number of times they’ve been recharged. Some keep them going for a couple of years or more, but the more safety conscious vapers tend to replace them annually.

Where should I buy batteries from?

A reputable vape shop or a specialist battery supplier.

Never buy lithium-ion batteries from eBay or Amazon.

Are there different qualities of batteries?

Yes. A rule of thumb is that you get exactly what you pay for. Buying cheap is a false economy. Cheap batteries do not perform as well, for as long, or as reliably as more expensive ones. Buy the best you can afford for performance and safety.

How do I charge a battery?

Use a quality charging unit from a reputable vape shop or a specialist battery supplier.

Only use a lead supplied with the mod if you are charging within the device.

Never leave a charging battery unattended.

Never leave a battery charging while you go to sleep.

You might want to consider investing in a charging bag.

Can I overcharge a lithium-ion battery?

Not if you use a quality charger from a reputable vape shop or a specialist battery supplier.

How do I recycle a lithium-ion battery?

Many stores now offer a battery recycling point or take it/them to your local recycling centre.

What about mods that have a contained battery?

The same applies as above. Just because you can’t remove it for recharging, only use the supplied lead and follow our recharging advice.

If you drop you mod, this might have damaged the internal battery and you should consider replacing it. Likewise, if the mod gets wet, even if the device dries and operates normally, the battery contacts or circuitry could slowly corrode and pose a safety hazard.

How do I carry batteries?

Never carry batteries loose in your pocket or bag.

It may come into contact with metal objects, such as coins, keys, or jewellery. Metal objects can cross the electrical connections and cause the battery to vent which may lead to injury.

Use a plastic battery case, they are cheap and widely available.

My battery is bulging/leaking, what should I do?

Recycle it – do not use it.

The plastic wrapper on my battery is damaged, what should I do?

Do not use it. Replace the plastic wrapping with a new wrap from a vape store or battery supplier. They are easy to apply with a hair dryer.

Who is The Battery Mooch?

Mooch runs a YouTube channel. His videos look at battery manufacturer claims and tests their products.

Dave Cross

Writer at POTV

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Dave is a freelance writer; with articles on music, motorbikes, football, pop-science, vaping and tobacco harm reduction in Sounds, Melody Maker, UBG, AWoL, Bike, When Saturday Comes, Vape News Magazine, and syndicated across the Johnston Press group. He was published in an anthology of “Greatest Football Writing”, but still believes this was a mistake. Dave contributes sketches to comedy shows and used to co-host a radio sketch show. He’s worked with numerous vape companies to develop content for their websites.

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