What's with these Li-Ions?

Nearly all of my torches are designed to work with 3.7v lithium ion (Li-Ion) rechargeable batteries, which are found in almost every cellphone, laptop and digital camera today because they are much more powerful and durable than the batteries sold in supermarkets.

Li-Ions can be recharged hundreds of times, hold their charge for months, are resistant to high and low temperatures, weigh less, are more friendly to the environment, and have no "memory effect". To learn more about the difference between lithium ion (Li-Ion) batteries and other chemistries, go to my FAQ, here, and scroll down to the section on batteries.

I sell top-quality Li-Ions made by companies like Sanyo, Samsung, LG and Lishen which are "re-wrapped" with covers carrying names like Keeppower, Trustfire and Sofirn. I don't sell "cheap" batteries which almost never live up to their specifications and can be downright dangerous. You can compare many of the Li-Ions on the market for yourself here.

These days I keep a variety of different sizes and capacities of Li-Ion, some of which are designed for regular powered torches (under 1,500 lumens per battery) and others for very high powered torches, which are increasingly common. My own preference is to have two sets of batteries, which not only give you longer run-time overall but allow you to charge one set while using the other.

Protected Li-Ions?

Note that some of my batteries are "protected", which means they turn themselves off if they are over-charged, over-discharged, overloaded or short-circuited. When you put them in the charger they are re-set and carry on as if nothing happened. This means you can't run the battery "flat" – it will turn itself off long before it reaches that point.

I also sell high-drain batteries (only needed by a few ultra-high performance torches), some of which are "unprotected". In theory you can run these flat, but if you discharge them below about 2.5v they will be irreparably damaged. In practice this is unlikely to happen because all my torches will warn you (by flashing their beams) when the battery is getting low, but if you ignore the flashing or leave the torch on standby mode you may drain the batteries past the point of no return over a period of days (so, to be on the safe side, take unprotected batteries out of your torch after the beam has flashed).

However, if your torch is flashing its beam and you turn it off and leave it for a while, it may work again for a bit without flashing. This is because lithium ion batteries "recover" some of their voltage after the load is removed. This recovery is more noticeable if you've been using your torch on maximum power – if you were using it on moonlight mode there won't be much recovery.

If the protection circuit (PC) on a protected battery has tripped, it won't work at all until it's been put back in the charger. It takes just a few seconds in a charger to re-set the PC but it will take a few hours to charge the battery if it's fully discharged. Li-Ions don't like to be rapid-charged, so it can take up to 10 hours to re-charge them. Topping up batteries – which I'll discuss shortly – is much quicker.

Li-Ion cubs

Lithium ion batteries have a longer shelf-life if they are stored with a partial "storage charge", which is how they come from the factory. So when you first get your battery you need to charge it before use.

Note that I don't pre-charge batteries, partly because I don't have the time but mostly because, in your shoes, I'd wonder whether a fully charged cell is actually new, and how long it's been stored with a full charge? I know it can be tantalising to get a new torch and then wait half a day for the batteries to charge, but isn't it nice to know your cells are in the best possible condition when you get them? (If you want me to pre-charge yours, please let me know when you order your torch).

Note, too, that it can take a few charge/discharge cycles before your batteries settle down into a predictable runtime, so don't be too quick to take out your stopwatch.

Getting the longest life from your Li-Ions

I'm VERY aware that lithium ion batteries are expensive – together with a charger, they can cost more than the torch itself. The upside is that all of my torches use industry-standard batteries that are easy to replace (unlike the bespoke battery packs in some brands) and most use the same chargers, so you don't need a new charger with each torch. If you use a torch regularly, you will definitely save money using Li-Ions.

That said, at R200 or more, it's important to know how to squeeze the most life out of each Li-Ion. You'll find the detailed answer to this question here at the Battery University. However, there's a difference between theory and practice. For example, if you keep a Li-Ion in a fridge with a 40% charge for maximum shelf life, it's going to take half a day to get it ready for use, which isn't very useful in an emergency. While storing a battery this way may extend its life a bit, it will last almost as long – and be much more useful – if you follow these tips:

  • if you have two sets of batteries, keep both sets charged, and rotate them so they all get used (Li-Ions don't like being stored for long periods with a full charge);
  • top up your Li-Ions after each use, rather than running them down (I know this is counter-intuitive, but a shallower depth-of-discharge dramatically improves their lifespan);
  • avoid keeping your Li-Ions in hot places for extended periods – especially in the glove compartment of a car parked in the sun;
  • avoid rapid-charging, over-charging and trickle-charging your Li-Ions (you don't need to worry about any of these things if you're using one of my chargers);
  • if you really want to extend the life of your Li-Ions, remove them from the charger just before they are fully charged. This will result in shorter run-times for your torch, but a much longer lifespan for your batteries.

Li-Ions degrade over time, so it makes more sense to buy new Li-Ions after four or five years than to attempt to store them for that long. If anything, they are likely to come down in price during that time.

Having two sets of batteries is great – it means that if you forget to charge your cells after an outing, you can simply swap the depleted batteries for the freshly charged set. Better yet, you can charge your depleted batteries while you're using the fully charged set. Best of all, if you need maximum run-time (like a neighbourhood watch patrol, a night at the game reserve's waterhole or an overnight race) you can carry spare batteries with you.

Oddly enough, the biggest problem for old timers (like me) is that we don't use our torches very often, and lithium ion batteries don't like to be left for long periods (i.e. many weeks) with a full charge. We still think of torches as expensive to run, not very durable, and only useful for a few things. However youngsters have no such hang-ups – I have young customers who use their torches as bedside lamps and who walk around their home at night with headlights on – even when there's no load-shedding (truly!)

Li-Ions like to roar – so use your torches (and batteries) all the time and don't worry!

With great power comes great responsibility!!

You need to be aware that the energy contained in all lithium ion batteries (even those in your cellphone or laptop) can be destructive, so it is important that you:

  • make sure your batteries are inserted into your torch and charger the right way around. Note that the warranty does not cover damage if you insert the battery the wrong way around. Take a few moments to check which way they should go in – it's time well spent!
  • charge and top up your Li-Ion batteries as often as you like, but don't leave them charging if you leave the house and please remove them from the charger when they're fully charged. BTW, this also applies to the batteries in cellphones, laptops and other devices.
  • the best place to keep your battery is in your torch. If it's not in a torch, make sure it can't make contact with metallic objects (like keys, or other batteries).
  • do not use Li-Ion batteries in place of regular batteries. Li-Ions deliver three times the voltage of rechargeable AA batteries, and will destroy any device that isn't designed to work with them. This is especially important with the 14500 Li-Ion which is the same size as a regular AA battery. Some torches are designed to accept both 14500 and AA batteries, but most are not.

You can use lithium primary (i.e. disposable) batteries in place of Li-Ion secondary (rechargeable) batteries in some torches (check the specifications). One CR123A primary can usually replace a 16340 secondary (as long as the torch uses only one), and two CR123A may be compatible with torches that normally use a single 18650 Li-Ion (not always – be careful!)

CR123A batteries are available from Clicks and Dischem, have an exceptionally long shelf-life (typically ten years) and have roughly twice the energy of a rechargeable battery of similar size, so keeping a few handy for emergencies is a great idea. Unfortunately they are too expensive to be practical for everyday use.

But what if. . .

I provide a one-year warranty on my protected batteries. If your battery gives trouble within 12 months of purchase, send it back to me and I will repair or replace it – as long as you haven't abused it. Signs of abuse from rough handling, modification or overheating are pretty clear. Note that this doesn't apply to unprotected batteries, since they can't defend themselves against mistreatment and the effects are not detectable.