How to choose a custom lithium ion battery pack
Choosing a custom pack is a sequence of decisions, and the sequence matters more than any single decision. This guide walks through it in the order a buyer should actually decide.
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 device, and write its requirements down before looking at any model. What does the device do, how much power does it draw on average and at peak, how long must it run between charges, and what space — length, width and maximum thickness — does its enclosure allow? Those five facts are the specification. A buyer who has them can be quoted accurately; a buyer who has only a target price cannot, because price follows specification and never precedes it.
Next choose the chemistry. LiFePO4 suits storage, solar, backup and any use where long cycle life and stability matter more than the smallest size. Li-ion suits tools, garden equipment, light electric vehicles and general industrial devices where energy density matters. Li-polymer suits thin, shaped and wearable devices where the outline is the constraint. NiMH suits toys, home devices and legacy equipment built around NiMH voltages. Sodium-ion models exist in this range as a secondary line, and this guide does not present them as a general replacement for lithium: where a sodium-ion model fits, it fits for a specific device, and the comparison should be made for that device, not in the abstract.
Then fix voltage and capacity together. Voltage follows from the device's electronics and from the series count — 12V-class for small systems, 24V and 48V for larger ones — and capacity follows from energy: multiply voltage by capacity to get watt-hours, and compare that with the load's energy need over the required runtime. A pack with the right voltage but half the needed capacity runs half as long; a pack with the right capacity but the wrong voltage does not run at all. Check both, in that order, against the device's real requirements rather than against a neighbouring product's label.
Then settle protection, connector and charger as a system. Ask what protection the pack carries, what connector it uses, and which charger matches its chemistry and voltage. Those three answers must agree with each other and with the device; a pack, a protection board and a charger chosen independently often disagree on at least one of them. Finally, agree the sample step: a listed sample, an engineering sample for a custom design, or a small trial order, and the test you will run on arrival. Order quantities, in general industry terms, are discussed as bands — samples, trial orders and volume orders — rather than as a single figure, because the right band depends on the design's maturity and the buyer's market, and this site does not present a general quantity figure as this company's policy for any particular model.
A final caution: do not let a single attractive figure decide the pack. A high cycle-life figure, a low price or a large capacity each describe one dimension, and a pack is a system of dimensions. Compare listings on the same basis — same voltage, same discharge conditions, same protection — and confirm the chosen listing's full specification in writing before you pay.
Questions to ask before you order
- What are the device's average and peak power draws, and its required runtime?
- What space does the enclosure allow, including maximum thickness?
- Which chemistry suits the application, and why — not just which is newest?
- What protection does the exact pack carry, and which charger matches it?
- What sample step comes before bulk, and what test will you run on arrival?
Related pages
Custom packs · LiFePO4 vs Li-ion · Choosing a manufacturer · Contact
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.