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FNIRSI SWM-20 is a portable spot welder with up to 1200 A current, dual-pulse mode, and a 5000 mAh battery
FNIRSI SWM-20 is a portable spot welder primarily designed for joining thin metal strips in the manufacture and repair of battery packs. Compared to simple, cheap spot welders, it offers dual-pulse welding, a maximum declared current of 1200 A, a 2.4-inch TFT display, detailed pulse settings, and a built-in 5000 mAh battery.
pandealia.euThe best coupons from Chinese stores, prices and price history in one place.FNIRSI SWM-20 is a portable spot welder primarily designed for joining thin metal strips in the manufacture and repair of battery packs. Compared to simple, cheap spot welders, it offers dual-pulse welding, a maximum declared current of 1200 A, a 2.4-inch TFT display, detailed pulse setting, and a built-in 5000 mAh battery.
The biggest advantage is that the user does not have to work with only a few preset power levels. The SWM-20 allows you to adjust preheat, main pulse, interval, and number of spots, enabling better adaptation to different materials and thicknesses.
Dual-pulse welding has practical significance
FNIRSI uses a dual-pulse system. The first pulse prepares the contact surface and limits the influence of oxidation, and the second then creates the actual joint.
When spot welding battery strips, consistency is very important. A spot that is too weak may loosen over time, while a pulse that is too strong can burn through the strip or unnecessarily overheat the cell.
That is why the ability to fine-tune the settings is more useful than the marketing figure of maximum current alone.
Maximum current of 1200 A
The manufacturer states a peak welding current of up to 1200 A.
For a similar device, this is not a continuous current but a very short pulse. The actual result depends on the thickness of the strip, material, cleanliness of contacts, electrode pressure, and the time set.
Thus, the SWM-20 is suitable for thin strips, not as a replacement for classic welders used on steel constructions.
What materials can it handle?
The official technical specifications differentiate maximum thickness by material:
| Material | Maximum declared thickness |
|---|---|
| Steel | 0.5 mm |
| Nickel-plated steel | 0.4 mm |
| Iron | 0.3 mm |
| Pure nickel | 0.25 mm |
| Copper | 0.1 mm |
| Nickel-plated copper | 0.1 mm |
These values should be understood as the manufacturer's upper limits. When working with batteries, it is better first to make test joints on the same material and only then weld directly onto cells.
Very wide setting options
The SWM-20 offers more than a simple "low / medium / high" power choice.
Settings include:
- preheat approximately 1 to 10 ms,
- main pulse approximately 1 to 99 ms,
- interval between pulses,
- number of repeated spots,
- activation delay,
- spacing between repeated welds.
The manufacturer mentions more than 10,000 combinations of settings. Practically, the important thing is that the user can change parameters according to the specific strip.
2.4-inch TFT display
The front is formed by a 2.4" color TFT display with a resolution of 320 × 240 px.
It displays set parameters, voltage, temperature, and operational status. Control is by a rotary encoder along with physical buttons.
This is a pleasant difference compared to simple spot welders with a few LEDs where users often do not know exactly what is set.
5000 mAh battery and approx. 1500 spots
The SWM-20 has a built-in battery with a capacity of 5000 mAh. The manufacturer states approximately 1500 welding cycles on one charge, although the actual number will depend on the pulse intensity.
Charging is via USB-C at 5 V / 2.1 A.
Practically, the device can also be used as a 5 V / 2.1 A power bank.
Copper welding pens
The welding pens use 99.9% copper contact parts, which helps reduce electrical resistance and dissipate heat.
The manufacturer states pens approximately 32 cm long, and spare tips are included in the package.
Eight safety protections
FNIRSI states protection against:
- overheating,
- undervoltage,
- overcharge,
- excessive discharge,
- short circuit,
- low temperature,
- impact,
- voltage stabilization issues.
Caution is still necessary when working with Li-ion cells. Spot welding operates with very high pulse current, and incorrectly applied electrodes can cause a short circuit.
What do users say?
Experience of SWM-20 owners is mostly positive, especially when welding nickel strips.
One practical note is repeated: at the beginning, time must be spent finding the right setting for the specific material. For example, one user said that with 0.15 mm pure nickel he had to adjust the combination of preheat and main pulse several times before achieving a strong joint.
This is not a drawback of the device but a natural characteristic of an adjustable spot welder.
Main parameters of the FNIRSI SWM-20
| Parameter | Value |
|---|---|
| Type | portable spot welder |
| Technology | dual-pulse welding |
| Maximum declared current | 1200 A |
| Battery | 5000 mAh |
| Display | 2.4" TFT, 320 × 240 px |
| Charging | USB-C, 5 V / 2.1 A |
| Power bank | 5 V / 2.1 A |
| Max steel thickness | 0.5 mm |
| Max pure nickel thickness | 0.25 mm |
| Max copper thickness | 0.1 mm |
| Welding cycles | up to approx. 1500 (manufacturer stated) |
Who is the SWM-20 suitable for?
It makes the most sense for users who repair or assemble battery packs, work with nickel strips, or need small, precise spot welding.
For complete beginners, the display and preset modes are an advantage, but before working with Li-ion cells it is advisable to rehearse the settings on safe test material.
Is the FNIRSI SWM-20 worth it?
The SWM-20 is interesting mainly because it combines very fine setting, dual-pulse welding, and portable battery design.
If you mainly need to weld nickel strips onto cells, it offers more control than simple cheap spot welders. The 1200 A power should not be considered the only deciding factor – the ability to precisely set timing and repeat the same quality joint is of greater value.
