SEESII Battery Spot Welder - Compact Rechargeable Spot Welder

In this review the SEESII Battery Spot Welder is assessed as a compact, all-in-one tool for DIY battery pack builders and small repair work. The single biggest reason to buy is its integrated, handheld design with a built-in 5000mAh battery that removes the need for external cables while still delivering high current output for reliable nickel and steel sheet welds. For hobbyists who need portability and repeated spot welds without a bench power supply, this unit is a practical choice.

Key Features

• Compact Integrated Design: The welding pen and power unit are combined into one handheld tool so it can be used one-handed in tight spaces without extra cables.
• Versatile Battery Compatibility: Supports common cell sizes such as 18650, 26650 and 32650 and also works with NiMH and Ni-Cd cells for flexible DIY pack work.
• Material Support: Compatible with 0.1-0.2mm nickel-plated strips plus stainless steel and iron sheets to cover typical tab and strap materials used in battery assembly.
• Adjustable Power: Eighty selectable power levels with dual-pulse output allow fine tuning between automatic and manual welding modes for different sheet thicknesses.
• Built-in Rechargeable Battery: The internal 5000mAh battery supplies up to 800A output and is rated for over 800 welds per charge, reducing interruptions on the bench or field.
• OLED and Safety: An OLED display shows mode, power level and progress while built-in protections guard against overcurrent, overcharge and low voltage.

Who It's For

The SEESII spot welder is aimed at makers, technicians, and hobbyists assembling small battery packs or repairing cells where portability matters more than an industrial bench machine. Its one-handed form and Type-C charging make it convenient for field repairs or cramped workbenches where a heavy power supply would be inconvenient.

It is less suitable for high-volume industrial production where a dedicated bench spot welder with external power and cooling would be preferred. Users who need welds on thicker metals or very large pack builds should consider a higher-capacity stationary machine.

Pros & Cons

Pros

• Truly portable integrated design removes cables and simplifies setup for quick jobs.
• Broad cell and material compatibility supports 18650/26650/32650 and 0.1-0.2mm nickel and steel sheets for most DIY packs.
• Large selectable power range with OLED feedback helps dial in consistent welds.
• Rechargeable 5000mAh battery provides many welds per charge for off-grid work.

Cons

• Not intended for heavy industrial throughput; continuous high-volume welding may favor a bench unit instead.
• Built-in battery means runtime is finite and requires recharging between long sessions.

Specifications

Brand	SEESII
Battery Capacity	5000mAh internal rechargeable
Supported Cells	18650, 26650, 32650, NiMH, Ni-Cd
Welding Materials	0.1-0.2mm nickel-plated, stainless steel, iron sheets
Output Current	Up to 800A
Power Levels	80 adjustable levels with dual-pulse output
Charging	Fast Type-C charging

Our Verdict

The SEESII Battery Spot Welder is a strong value for makers and technicians who need a portable, cable-free spot welder for small to medium battery pack work. With broad cell compatibility, an OLED display for control, and an internal 5000mAh battery that supports many welds per charge, it balances convenience and capability for DIY and field repairs, while heavy production shops should opt for a bench system.

Frequently Asked Questions

Can this welder handle 18650 cell tabs?
Yes. It is designed to weld common lithium cells including 18650 and supports 0.1-0.2mm nickel strip commonly used for tabs.

How many welds per charge can you expect?
The unit ships with a 5000mAh internal battery and is rated for over 800 welds per full charge under typical conditions.

Does it use a separate power supply?
No. The pen and power unit are integrated and the welder charges via Type-C, so no external bench power supply is required for normal use.