AWithZ UF20B Capacitor Battery Spot Welder (3-in-1 Auto, Manual & Foot Pedal) for 18650 and LiFePO4 Packs
Product description
The essentials
If you’re building or repairing lithium battery packs, a capacitor battery spot welder is one of those tools that can save real time—when it’s matched to your workflow. The AWithZ UF20B is designed around three operating modes (automatic, manual, and foot pedal), so you can choose how involved you want to be during each weld. It also uses a wide 100–240V input approach and a quick-start setup, aiming to get you welding in minutes rather than doing a bunch of prep.
On paper, the biggest appeal is the combination of “fast to start” plus “responsive pulse power,” paired with the option to run it hands-free with a foot pedal. That said, capacitor-based setups have a catch: the unit’s design depends on what it stores, so you’ll want to plan around charging while you work.
Key takeaways (what matters before buying)
The UF20B positions itself as a practical spot welder for battery pack building and for spot-welding certain sheet materials. It’s compact, aluminum-alloy shelled, and uses a spot welding pen with a replaceable tip. For battery makers, the brand claims built-in super energy storage capacitors and up to 10KW maximum pulse welding power.
You’ll also see that it’s not limited to just one cell type. The included description specifically mentions cylindrical batteries like 18650/14500/21700, and it also references LiFePO4 batteries. For metal work, the same claims point to nickel plated sheet and stainless/iron sheet in a stated thickness pairing (nickel-plated 0.2mm butt-welded to reach 0.4mm total thickness). Those details can help you sanity-check whether your projects line up with its intended use.
Where it can feel less “plug-and-play,” depending on your experience, is the need to get the settings right. It lists 99 adjustable gears for different material requirements—useful, but it also means you may spend some time dialing in before every weld looks consistent.
What you’ll notice day to day
The three modes are the heart of this welder’s day-to-day feel.
In automatic mode, you adjust to what the device describes as the proper setting, insert the spot welder, and start quickly. In manual mode, the spot welding pen’s button outputs once per press, which can be helpful if you prefer control and repeatable timing. In foot pedal mode, the description focuses on easier positioning—step on the pedal and the welder outputs a signal once, which can free up your hands for holding tabs, aligning nickel strips, or keeping pressure steady.
There’s also a practical “tool length” note: the spot welding pen is 40cm long, and the brand says this length is best for spot welding effect. If you stretch the working distance much further than intended, the output current may be affected and the results can suffer.
Tech summary
Tech specs
- Name: Capacitor Battery Spot Welder (UF20B)
- Power input: 100–240V wide voltage input
- Modes: 3-in-1 automatic, manual, foot pedal
- Display behavior: shows “OK for spot welding” within a quick-start window
- Claimed maximum pulse welding power: up to 10KW
- Adjustable settings: 99 adjustable gears
- Use cases mentioned: battery pack building (18650/14500/21700, LiFePO4) and spot welding sheet materials
- Spot welding pen: removable, replaceable tip, 40cm length
- Foot pedal cable length: 2m
- Power storage note: built-in super energy storage capacitors (ultracapacitors)
- Battery/charging guidance: connect to wall power and charge while using, capacitors store very little electricity and will be consumed within a minute or two
Pros
- Multiple control styles (auto, manual button, and foot pedal), so you can match the tool to your building habits.
- Quick-start approach: the description emphasizes reaching the spot welding mark within about 5 minutes with the included setup.
- Built-in super energy storage capacitors with claimed up to 10KW maximum pulse welding power.
- Compact, rounded design and aluminum-alloy shell, the description also claims flame-retardant nature.
- Replaceable spot welding pen tip and a pen length designed to support effective output.
Limitations / who should be cautious
- Capacitor storage means you can’t treat it like a battery-powered welder. The description is direct: you must connect to wall power and keep charging while using, because the capacitor energy will be consumed within a minute or two.
- With 99 adjustable gears, it’s not “set-and-forget.” If you’re new to spot welding, results may vary until you find the right setting for your exact nickel strip and cell/tab thickness.
- The sheet-metal thickness guidance given is specific, so if your material stack is different, you’ll likely need to test and tune rather than assume the same outcome.
Is it worth it?
This is a solid pick if you’re trying to spot weld battery pack materials (especially cylindrical cells like 18650/14500/21700 and LiFePO4 packs) and you want flexibility between automatic and manual control—plus the option to use a foot pedal for steadier positioning.
You may want to skip it if you need a welder that can run longer without being plugged in and actively charging. Also, if your projects require very specific metal stacks outside the thickness pairing mentioned in the description, you should expect to do some dialing-in.
Mini FAQ
How do the three welding modes work in practice?
Automatic mode is described as adjusting to a proper setting and then welding immediately once you insert the spot welder. Manual mode uses the pen button for a single output per press. Foot pedal mode is meant to make alignment easier by letting you trigger the weld with your foot.
Does it work for battery pack building?
The description explicitly targets battery pack work for cylindrical batteries (18650/14500/21700) and also references LiFePO4 batteries.
Do I need to keep it plugged in?
Yes—according to the description, the capacitors store very little electricity and will be consumed within a minute or two, so you must connect to wall power and charge while using it.
What’s included so you can start right away?
The package description lists the UF20 spot welding machine, a charger cable, a foot pedal, a pair of spot welder pen components, a roll of 2-meter nickel plated sheet, a file, and a manual.
Is the spot welding pen replaceable?
It is. The description says the pen can be removed to replace the tip, with a specific output button for manual mode.