Customised Power Bank Singapore: Buy on Cells, Not on the Number

Custom Power Banks are a corporate gift with genuine compliance and safety obligations attached, which most buying guides skip entirely. If you are ordering these in volume, here is what to get in writing. ## Capacity: what you are actually buying Rated capacity is not delivered capacity. Conversion from the 3.7V cell to 5V output, plus heat, costs roughly 30-35%. | Labelled | Realistic delivered | Modern phone charges | |---|---|---| | 5,000 mAh | ~3,300 mAh | ~0.7 | | 10,000 mAh | ~6,500 mAh | ~1.5 | | 20,000 mAh | ~13,000 mAh | ~3 | A supplier quoting "charges your phone 4 times" from a 10,000mAh unit is measuring against a very old handset. Ask for cell capacity and rated output capacity as two separate numbers. ## The weight test Lithium cells have a physical energy density. A genuine 10,000mAh bank weighs roughly 180-220g. If a quoted 10,000mAh unit weighs 120g, the cells are not 10,000mAh. This is the fastest field check there is and it needs no equipment. ## Protection circuits — require all four - Over-charge - Over-discharge - Over-current - Short circuit Ask for the protection IC and the test report, not a bullet point on a brochure. ## Shipping and air travel Lithium batteries are dangerous goods. You will need a UN38.3 test report and an MSDS for air freight, and the supplier should provide both without being chased. Recipients should also be told these must go in cabin baggage, never checked — worth a line on the packaging if you are gifting to travellers. ## Output spec Two USB-A at a shared 2.1A is the old budget default. A 20W USB-C PD port is what people now expect, and it recharges the bank faster too. Include a short cable; it roughly doubles usage. ## Volumes - Stock models: 50-100 pcs, ~3 weeks - Custom shell, capacity or packaging: 500 pcs, 6-8 weeks Capacities and models are listed on the [customised power bank page](https://www.aquaholic.com.sg/gadgets/powerbank/). ## Also posted on - [Bluesky](https://bsky.app/profile/aquaholicgifts.bsky.social/post/3mujd7puirb2o) - [Pinterest](https://www.pinterest.com/pin/452541462580100028/)