Li-polymer battery packs: how to choose
Li-polymer packs are chosen by outline first and by capacity second, because the pouch format exists to fit spaces that rigid cells cannot. This guide explains that order and the checks that follow it.
Layered pack cross-section — the site's recurring diagram motif. It is a schematic, not a photograph of a product, factory or customer project, and it is not presented as a photograph of this company's factory.
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Start with the outline. Measure the cavity — length, width and maximum thickness — and allow room for the protection board, the wiring and the connector, because a pouch pack is a system, not just a cell. The detail pack on this site is 26 x 67 x 90 mm at 288 g, and other Li-polymer packs in the range differ in every dimension. A buyer who states only capacity has not described a purchasable pouch pack, because the same capacity can be built in many outlines, and only one of them fits the cavity.
Next fix voltage and capacity together. A single pouch cell is about 3.7V nominal; series counts give higher voltages — the detail pack is three cells in series at 11.1V nominal, 5600mAh, with a 12.6V maximum charge voltage and a 9.0V discharge cut-off. Capacity follows from runtime: the device's average power draw multiplied by the required runtime, divided by the nominal voltage, gives the amp-hours. A pack with the right outline but half the needed capacity runs half as long, and a pack with the right capacity but the wrong outline does not fit at all.
Then settle protection and connector as part of the pack. The detail pack carries a built-in PCM supporting 0.5C charge and 1C continuous current, a 10K ohm NTC for temperature protection, and a Molex 51146-5P connector, with red, black and white external cables 50 mm long. Those are that listing's values, and they illustrate what a complete Li-polymer specification contains: protection, temperature sensing, connector type and cable details, not just voltage and capacity. A buyer should ask for the same completeness for any Li-polymer pack, and should confirm it in writing.
Finally, consider the charger's match and the pack's handling. A Li-polymer pack needs a charger matched to its chemistry, series count and charge rate, and it needs handling that respects the pouch: no puncture, no sharp folding, no pressure on the sealed edges. The charger category page on this site covers chargers for Li-polymer packs among others, and the charger must be confirmed against the exact pack, not chosen on voltage alone. For a new device, the custom route covers custom dimensions and shapes; send the cavity drawing with the inquiry, because a pouch pack designed from a drawing fits, while one designed from a capacity figure may not.
Questions to ask before you order
- What are the cavity's length, width and maximum thickness, with room for wiring?
- What series count gives the required voltage, and what capacity gives the runtime?
- What protection, temperature sensing and connector does the exact pack carry?
- Does the charger match the pack's chemistry, series count and charge rate?
- Is a listed outline sufficient, or does the cavity need a custom shape?
Related pages
3S Li-polymer pack · Li-polymer range · Chargers · Drone use
How to place an inquiry, step by step
- Send the device facts. Tell us the device type, the available space (length, width and maximum thickness), the nominal voltage you need, the capacity or runtime you target, and the peak current if your device has motors, radios or heaters.
- Name the model or the chemistry. If a page on this site matches, quote its model description and listing details. If nothing matches, say so and describe the chemistry and voltage you need, so the conversation starts on the custom route.
- Confirm documents and terms in writing. Ask for the certificate set for that exact model, confirm the minimum order, the price basis and the lead time for that listing, and confirm payment and warranty terms before you pay. Terms stated for one model listing do not transfer to another model.
- Agree the sample step. Confirm whether the next step is a listed sample, an engineering sample for a custom design, or a small trial order, and what test you will run on arrival — fit in the enclosure, runtime, or peak-current behaviour.
Send all of this in one message through the contact page: device type, space, voltage, capacity, peak current, model description if you have one, and the documents you need. That is the whole inquiry — no separate form, no account, no extra step.
What to send us now
Send one message with your device type, the space the pack must fit, the voltage and capacity you need, the peak current if it matters, and the model description if a page on this site already matches. Add the documents you need — certificates are available upon request — and whether you need a listed model or a custom design. Use the contact page or write to [email protected], or call +86-755-25629920. A specific message like that is what turns a range of hundreds of models into a short, answerable question.