A power bank is a box of stored energy that you hand to someone and ask them to carry in their bag, next to their laptop, onto aeroplanes and into their children's bedrooms.

That is worth saying out loud, because in the corporate gift market the power bank is usually treated as a plastic shell with a logo on it. Buyers compare quotes on unit price and the capacity printed on the box, then choose the cheapest option that arrives in time for the conference. I understand why, but I think the way we buy them is backwards.

The cheap power bank does not fail because it is cheap. It fails because nobody asked the right questions before it was ordered.

The capacity number is the easiest thing to fake

Every power bank carries a headline figure in milliamp-hours. It is also the least reliable number on the device. Rated capacity describes the cells inside at their nominal voltage, not what actually reaches your phone after conversion losses, so even a well-built unit delivers noticeably less than the label suggests. That is normal. A label that bears no relation to the cells inside is not, and it is a familiar problem at the bottom end of the market.

For a buyer, the practical test is simple: ask the supplier for the cell specification and the expected usable output, not just the label figure. A reputable supplier will answer without fuss. If the answer is vague, so is the product.

The cell matters more than the casing

Lithium-ion cells vary enormously in quality. Good cells come from manufacturers with consistent chemistry and quality control, and they are matched so that they charge and discharge evenly. Poor cells may be recycled, mismatched or downgraded from rejected batches. They lose capacity quickly, they can swell, and in the worst cases they overheat.

The other half of the story is the protection circuit: the small board that stops the cells overcharging, over-discharging, short-circuiting or getting too hot. On a well-made unit it is invisible. On a cheap one it is often the first thing to be simplified, because nobody sees it in a product photo. You cannot judge either by looking at the outside of the device, which is exactly why the paperwork matters.

Certification is a document trail, not a sticker

Lithium cells and battery packs are covered by international safety standards, and electrical goods sold in South Africa fall under local regulatory requirements. Lithium batteries also have specific rules for how they may be transported. A responsible supplier should be able to show test reports from an accredited laboratory, tied to the exact model you are buying, along with the documentation needed to ship it legally.

The key word is exact. A report for a different model, a different factory or a lapsed date tells you very little. Logos on the casing tell you even less. Ask for the reports, check that the model numbers match, and keep them on file.

"It's just a giveaway"

The fair counter-argument is that a promotional power bank is a low-cost item, and that it is unreasonable to apply the same scrutiny to a conference gift as to a laptop.

I agree that not every gift needs to be expensive. But the risk in a battery does not scale with its price. A R100 power bank and a R1,000 power bank store energy in the same way, and when either one fails, your logo is on it. A mug that chips is a disappointment. A battery that swells in someone's bag becomes a story they tell about your brand. The extra diligence costs a few emails, not a bigger budget. And if the budget genuinely cannot stretch to a properly tested unit, the honest answer is often to choose a different gift altogether.

Buy it like the electrical product it is

The shift I would ask buyers to make is small but important. Stop thinking of a power bank as merchandise that happens to contain a battery, and start thinking of it as a battery that happens to carry your logo. Ask for cell specifications. Ask for model-specific test reports. Ask how the stock will be shipped and stored. Ask what happens if a batch fails.

The suppliers worth working with will welcome those questions. The rest will tell you everything you need to know by how they answer.

Nicholas Flemmer is the CTO of The SA Promo Group.