3.7V 350mAh LiPo Batteries: Compare Compact Sizes
Gain more nominal energy than a 300mAh design while keeping a compact pouch-cell envelope for a keychain sensor or badge.
When a 300mAh cell does not provide enough runtime but a 500mAh pack demands too much space, 350mAh can provide a useful intermediate design point. Compare the listed 350mAh pouch-cell models across thin, narrow and compact-footprint geometries, screen potential matches by estimated finished dimensions, and confirm the complete PCM, wiring and connector envelope before prototyping.
3mm to 8mm Bare-Cell Thickness
Custom PCM & Connector Options
Engineering Fit Review
Technical Overview
When a 300mAh cell does not provide enough runtime but a 500mAh pack demands too much space, 350mAh is a useful intermediate design point. At 350mAh, geometry can matter as much as nominal capacity: the same rating can be built in very different thickness, width and length combinations. In devices such as a keychain air-quality monitor or a smart ID badge, the load is a low sensor duty cycle with periodic BLE, Thread or display events, so the finished-pack envelope and thin geometry drive the choice. Select by the finished-pack envelope and actual load profile, not by capacity alone.
Find a 350mAh LiPo Battery for Your Available Space
Enter the maximum battery space available in your device to screen the listed 350mAh models. Results are potential matches based on estimated finished dimensions; final fit requires review of PCM, insulation, wiring, connector position, manufacturing tolerance and mechanical clearance.
13 listed 350mAh models
Finished dimensions depend on PCM, insulation, connector and wire-harness configuration and are confirmed on the engineering drawing for the selected model.
Increase Runtime Without Jumping to a 500mAh Pack
At the same nominal voltage, 350mAh represents approximately 17% more nominal capacity than 300mAh. This can provide useful runtime margin for devices with periodic wireless transmission, sensing or display activity, while avoiding the larger capacity step to 500mAh. Actual runtime improvement depends on the load profile, cutoff voltage, temperature, cell resistance and protection design, so it must be verified in the device.
A 350mAh model is most useful when the project needs more margin than 300mAh but still has a tightly controlled mechanical envelope.
Same 350mAh capacity, very different geometry. The listed models below all store 350mAh, yet each one asks for completely different space inside a device:
THOR-303442
3 × 34 × 42 mm — the thinnest listed 350mAh cell. Thin and flat; suits a badge or slim keychain body.
THOR-501646
5 × 16 × 46 mm — a narrow, elongated strip. Suits a pen-style sensor or thin edge channel.
THOR-802025
8 × 20 × 25 mm — thicker with the smallest footprint. Trades thickness for a tiny sensor or tag module.
Choosing between them is primarily a question of which enclosure axis has usable space: if thickness is the limit, start from the thin, flat models; if the device is a narrow strip or a tiny module, a thicker geometry can shrink the footprint.
Validate 350mAh Current Capability for Compact Portable Loads
The 350mAh rating describes charge capacity, not maximum continuous or peak current. In a compact wearable or sensing device such as a keychain air-quality monitor, smart ID badge or Matter/Thread sensor, most operating time is a low sensor duty cycle with short BLE, Thread or display peaks. Whether the cell sustains those peaks depends on the specific cell model, C-rate, internal resistance, PCM and temperature. Use the battery runtime and capacity guide for energy planning, then validate loaded voltage, pulse duration and low-state behavior with the actual electronics. A custom LiPo battery configuration should be reviewed when the standard assembly does not satisfy these constraints.
Bare Cell Size vs Finished Battery Size
The model code and nominal dimensions describe the bare 350mAh pouch cell. The usable battery assembly may be larger after the protection circuit, insulation, lead wires and connector are added.
For a compact wearable or sensor, the PCM, insulation and wire bend may consume the same limited thickness or edge space that the product enclosure needs for clips, sensors or antennas.
Bare Cell Size
Raw pouch-cell dimensions
(T × W × L)
→
+ PCM, Insulation, Wires, Connector
Protection circuitry, insulation wrap, lead wires, connector & wire exit
→
Estimated Finished Size
Approximate assembled dimensions for initial screening
Use the estimated finished size for initial screening, then approve the device cavity against the final drawing for the selected configuration and agreed manufacturing tolerances.
How to Choose a 350mAh LiPo Battery
Measure the Space
Record the maximum usable thickness, width and length after internal components are installed.
Allow Clearance
Reserve space for tolerance, insulation, assembly access and expected long-term cell expansion.
Confirm the Load
Provide average, continuous and peak current requirements. Capacity alone does not define current capability.
Define the Assembly
Confirm PCM, connector, polarity, wire gauge, wire length, exit direction and labeling.
Test the Prototype
Verify mechanical fit, runtime and electrical behavior with the final sample configuration.
Custom 350mAh LiPo Battery Configuration
THOR Power can review a 350mAh project for pouch geometry, PCM, connector and polarity, wire gauge, lead length and exit direction, labeling and packaging. Finished dimensions and electrical limits are confirmed for the selected configuration.
Need a 350mAh LiPo Battery for Your Project?
Tell us your available battery space, application, working current, peak current, connector requirement and quantity. Our engineering team will review the suitable 350mAh model and finished battery configuration.
- Bare Cell Size
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- Approx. Finished Size
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350mAh LiPo Battery FAQ
What size is a 350mAh LiPo battery?
There is no single standard 350mAh size. The listed models range from 3mm to 8mm in nominal bare-cell thickness and use different width and length combinations. Compare the complete dimensions rather than capacity alone.
How is a 350mAh battery different from a 300mAh battery?
At the same nominal voltage, 350mAh provides approximately 17% more nominal capacity. Actual device runtime does not increase by a guaranteed percentage because it also depends on load behavior, cutoff voltage, temperature, resistance and the final protection design.
Should I choose 350mAh or 500mAh?
Choose based on verified runtime and available finished-pack space. A 350mAh model can be useful when 300mAh has insufficient margin but a 500mAh pack is difficult to integrate. A 500mAh option may be preferable when the enclosure permits a larger battery and the project needs a larger capacity increase.
Is bare-cell size the same as finished battery size?
No. Bare-cell dimensions do not represent the complete protected assembly. PCM, insulation, wires, connector position and bend radius can increase the required envelope.
What current can a 350mAh battery deliver?
Do not determine allowable current from the 350mAh rating alone. Continuous load, peak current, pulse duration, temperature and cutoff requirements must be checked against the exact cell and PCM specification.
Is a 350mAh LiPo suitable for a keychain air-quality monitor?
It can be considered when the finished-pack envelope fits and the selected cell supports the measured sensor duty cycle with BLE or display events. Confirm PCM behavior, connector routing, charging, temperature and project-specific validation with the actual monitor electronics.
What should I check for a smart ID badge or Matter/Thread sensor?
For a smart ID badge or a Matter/Thread sensor, verify that the cell and PCM handle the short radio-transmit peaks without excessive voltage sag, and confirm self-discharge over long standby, the charging strategy and the temperature range with the actual electronics.
Related Pages
Why compare nearby capacities: A 300mAh option can preserve more mechanical margin in a very small wearable or sensor. A 500mAh option may extend runtime when the device can accept a larger finished pack.