If you've had an e-cigarette battery that suddenly stopped charging, or a charger lead where the LED stays blue no matter what you do, your first thought is probably the obvious one: it's broken, time for a replacement.

It's almost always wrong.

After nearly two decades of selling and replacing e-cigarette batteries, we can tell you with some confidence that roughly nine out of ten batteries and charger leads that come back to us as "faulty" aren't faulty at all. They're dirty. A few minutes with a knife, a pin and a wipe brings them straight back to life.

It sounds like a small thing. It isn't. Hopefully this post saves you some frustration, and possibly a replacement order you never needed to place.

What's actually going on

The contact points on both the battery and the charger lead are small, exposed, and constantly in and out of pockets, bags, wallets and drawers. Over time they collect what pockets collect: lint, dust, fragments of tobacco from old packets, sticky residue, fluff, all of it.

That debris doesn't just sit on top of the contact looking ugly. It does two specific things:

On the battery, the debris settles in the small well around the central contact, and works its way into the tiny airflow pinhole on the thread. The battery needs that airflow to sense when you're inhaling — that's how it knows to activate. Block the airflow and the battery feels completely dead. It isn't. It just can't sense the draw.

On the charger lead, even a thin film of grime creates a barrier between the lead's contact and the battery's contact. You plug a battery in, the LED stays blue, and you assume the lead has packed up. It hasn't. It just can't detect the battery underneath the dirt.

In both cases the hardware is fine. The connection isn't.

The pattern we see again and again

We see this every week. Batteries come back to us, customers entirely reasonably assuming they're faulty after months of good service. We test them, give the contact a quick clean, and they work perfectly. Same story with charger leads — sent back as not detecting the battery, working again four minutes later.

This isn't a complaint about customers. The whole point of our lifetime battery replacement guarantee is that you shouldn't have to think about hardware failure. If you think something's broken, send it to us and we'll replace it — no debate.

But if you'd rather not be without your kit for a few days, or you just like the satisfaction of a five-minute fix, knowing what's actually happening can save you time and hassle.

The simplest thing you can do

If we had to give one piece of advice for keeping a battery working as it should, it would be this:

Keep an old cartomiser attached to your battery whenever it's not in use.

It sounds trivial. It's by far the most effective single habit. The cartomiser caps the contact and the well, and stops debris from settling there in the first place. If your battery is going to spend the day in a coat pocket, a handbag, or rattling around in a drawer with a few coins and a packet of mints, the cartomiser is the difference between a clean contact and one you'll be cleaning out in two weeks' time.

A few other small things that make a difference:

• Store everything dry and at room temperature. Damp environments damage the electronics.
• Keep your charger lead in a drawer or pouch rather than loose on a kitchen counter where it'll pick up whatever's around.
• If you spot debris on a contact, deal with it before it builds up.
• Use the carry cases we supply, they are not expensive.  Great for on the go and they protect batteries and cartomisers

When cleaning fixes it (and when it doesn't)

We've written up the cleaning technique in detail on our maintenance page — three simple tools, two short procedures, one video showing exactly what we do here when we receive returned items.

How to clean your battery and USB charger contact points →

If you've followed that and your battery or lead still won't work, then it really might be the hardware. That's what the lifetime guarantee is for. Get in touch and we'll sort it out.

The point of all this

We sell batteries. We could quite happily let every "faulty" battery be a replacement order. We don't, partly because that wouldn't be honest, and partly because customers who understand how their kit works tend to be customers who stick around.

Most of the e-cigarette batteries that get thrown away in the UK every week are working batteries that haven't been looked after. Five minutes once every few months is all it takes to keep yours going.

Miniciggy has supplied UK adult smokers with cigalike e-cigarettes since 2006. Every battery we sell is covered by our lifetime replacement guarantee. Browse our batteries and chargers, or read more in our FAQs.