Custom 18650 & 21700 Battery Packs, Built to Your Spec
Any series-parallel configuration up to 12S — with custom terminals, custom BMS protection boards, and custom housings. Minimum order just 10 packs, produced in 7 days.
MOQ 10
Low minimum order — start with just 10 custom packs.
7 Days
Standard customization lead time from confirmed design to shipment.
1S–12S
Any series count up to 12S, any parallel count for the capacity you need.
18650 / 21700
Both cylindrical cell formats supported, pack layout designed to fit your device.
1S to 12S — Any Series-Parallel Combination
Series cells raise voltage; parallel cells raise capacity. We build any combination from a single-cell 1S pack up to 12S (44.4 V nominal) — 2S3P, 4S2P, 10S4P, whatever your application calls for.
1S · 3.7 V
2S · 7.4 V
3S · 11.1 V
4S · 14.8 V
5S · 18.5 V
6S · 22.2 V
7S · 25.9 V
8S · 29.6 V
9S · 33.3 V
10S · 37.0 V
11S · 40.7 V
12S · 44.4 V
Nominal voltages shown for 3.7 V li-ion cells. Need more runtime? Add parallel groups — capacity scales with every parallel cell while voltage stays the same.
Technical Reference: Voltage & Capacity
Use these tables to estimate your pack: series count sets the voltage, parallel count sets the capacity. Our engineers confirm the exact cell model and configuration during the quote.
Series Voltage (1S–12S)
| Series | Nominal (V) | Full Charge (V) |
|---|---|---|
| 1S | 3.7 | 4.2 |
| 2S | 7.4 | 8.4 |
| 3S | 11.1 | 12.6 |
| 4S | 14.8 | 16.8 |
| 5S | 18.5 | 21.0 |
| 6S | 22.2 | 25.2 |
| 7S | 25.9 | 29.4 |
| 8S | 29.6 | 33.6 |
| 9S | 33.3 | 37.8 |
| 10S | 37.0 | 42.0 |
| 11S | 40.7 | 46.2 |
| 12S | 44.4 | 50.4 |
Parallel Capacity (1P–6P)
| Parallel | 18650 (Ah) | 21700 (Ah) |
|---|---|---|
| 1P | 2.5–3.5 | 4.0–5.0 |
| 2P | 5.0–7.0 | 8.0–10.0 |
| 3P | 7.5–10.5 | 12–15 |
| 4P | 10–14 | 16–20 |
| 5P | 12.5–17.5 | 20–25 |
| 6P | 15–21 | 24–30 |
Formula reference: Voltage (V) = 3.7 × S · Capacity (Ah) = cell Ah × P · Energy (Wh) = V × Ah
Common Configurations & Typical Applications
| Configuration | Nominal Voltage | Typical Capacity (21700) | Typical Application |
|---|---|---|---|
| 2S1P | 7.4 V | 4–5 Ah | Handheld instruments, portable devices |
| 3S1P | 11.1 V | 4–5 Ah | Drones, RC models |
| 4S2P | 14.8 V | 8–10 Ah | Professional cameras, test equipment |
| 6S2P | 22.2 V | 8–10 Ah | Robotics, FPV, AGV modules |
| 7S3P | 25.9 V | 12–15 Ah | Cordless power tools, garden tools |
| 10S3P | 37 V | 12–15 Ah | E-bikes, e-scooters |
| 12S4P | 44.4 V | 16–20 Ah | Industrial equipment, AGVs, backup power |
Customize Every Part of the Pack
Terminals & Connectors
JST, XT, Molex, ring lugs, bare leads — or fully custom terminals engineered to match your device connector.
Protection Board (BMS)
Custom PCM/BMS matched to your voltage and current requirements — over-charge, over-discharge and short-circuit protection.
Housing & Casing
Heat-shrink wrap, ABS plastic cases, or fully custom enclosures with your branding and mounting points.
Cells & Pack Layout
Choose 18650 or 21700 cells. We design the cell arrangement to fit your space envelope and weight budget.
18650 vs 21700 — Which Cell Should You Choose?
Both formats use the same 3.7 V li-ion chemistry and support identical series-parallel configurations — the difference is size and energy per cell. Not sure which fits? Send us your space envelope and runtime target and we'll recommend the better option.
| 18650 | 21700 | |
|---|---|---|
| Cell dimensions | 18 × 65 mm | 21 × 70 mm |
| Typical capacity | 2,500–3,500 mAh | 4,000–5,000 mAh |
| Energy per cell | Lower — more cells for the same Wh | ~40% higher — fewer cells, fewer welds |
| Pack size | Slimmer packs, finer shape control | Slightly larger, better Wh per liter |
| Best for | Compact, space-constrained designs | Maximum runtime and capacity per cell |
Looking for off-the-shelf options instead? Browse our standard battery packs or join the wholesale program for volume pricing.
Custom Battery Packs for Your Industry
Drones & UAVs
High discharge rate packs (3S–6S) with lightweight layouts for maximum flight time.
E-Bikes & Scooters
10S–12S high-capacity packs (36–44 V) with smart BMS for long-range mobility.
Power & Garden Tools
High-drain 5S–7S packs built for repeated heavy loads and tough duty cycles.
Medical & Instruments
Stable, consistent power for portable diagnostic and measurement equipment.
Energy Storage
Modular packs for backup power and small-scale storage, scalable in parallel.
Robotics, AGV & Industrial
Rugged 6S–12S packs with custom housings, connectors and communication-ready BMS.
From Spec to Shipment in 7 Days
01
Share Your Requirements
Voltage, capacity, dimensions, terminal type, BMS specs and housing needs.
02
Engineering Proposal & Quote
We confirm the cell configuration, BMS and mechanical design, and send your quote.
03
Confirm the Design
Approve the final spec — production starts immediately after confirmation.
04
Production & QC in 7 Days
Packs are assembled, tested and shipped within the 7-day standard lead time.
Safety, Testing & BMS Protection
Every Pack Ships With BMS Protection
- Over-charge protection
- Over-discharge protection
- Short-circuit protection
- Over-current protection
- Temperature monitoring
- Cell balancing
- Optional smart BMS with communication (UART / I2C / SMBus / CAN)
Tested Before It Ships
- Electrical: capacity, internal resistance, discharge rate verification
- Safety: over-charge, over-discharge and short-circuit response
- Mechanical: weld strength and structural integrity checks
- Aging & consistency screening of every cell before assembly
- UN38.3-compliant packaging and documentation for air & sea freight
Custom Battery Pack FAQ
What is the minimum order quantity?
MOQ is just 10 packs for custom 18650 / 21700 configurations — ideal for prototypes, pilot runs and small-batch production.
How long does customization take?
Standard lead time is 7 days from design confirmation to shipment, including assembly and quality testing.
Which configurations can you build?
Any series-parallel combination up to 12S (3.7–44.4 V nominal), with the parallel count sized to your capacity target.
Can you customize the BMS, terminals and housing?
Yes — protection boards, terminals/connectors and housings are all built to your specification, including branded enclosures.
Should I choose 18650 or 21700 cells?
Choose 18650 for compact, space-constrained designs; choose 21700 when you want maximum capacity per cell and fewer cells per pack. Send us your size and runtime targets and we'll recommend the best fit.
Can I order samples before bulk production?
Yes — with an MOQ of just 10 packs, a pilot order doubles as your sample run. Contact us to arrange sample units for validation before scaling up.
How are lithium battery packs shipped internationally?
Packs are shipped with UN38.3-compliant packaging and transport documentation by air or sea freight, following lithium battery shipping regulations.
Can you replicate or replace an existing battery pack?
Yes — send us the specifications, photos or a sample of your current pack (including discontinued models) and we'll match the configuration, terminals and housing.
What information should I include in my quote request?
Voltage (or series count), capacity (or runtime target), maximum dimensions, discharge current, terminal/connector type, BMS requirements, housing preference and order quantity. Partial specs are fine — our engineers will fill the gaps with you.
Configure Your Custom Pack & Get a Quote
Set your size, pick terminals, wiring and discharge rate — see an instant fit estimate and send it to our engineers in one step.
1 Cell Type
2 Max Pack Dimensions & Voltage
3 Terminal / Connector
4 Wiring / Pinout
5 Continuous Discharge Rate
1C — standard energy cells, the most cost-effective choice for most devices.