Seesii Battery Spot Welder with 5.0Ah Battery: Upgraded Handheld Mini Portable Spot Welder for 18650 Battery, Welding Nickel Sheets 0.1-0.2mm, Iron,Stainless Steel Sheets, 80 Gear,Auto and Manual Mode

Purchased to repair battery packs. Works well with the nickel plated steel provided. I only used on auto which works with an on-delay once you contact metal. 40 gears seems to work well with the 0.100" material provided, I did however, double each series connection with one plate then another on top-welding each one. Hold at a 45 ° angle while applying a decent amount of down pressure will assure a good weld. This tool is adjustable up to 80 gears. It did not produce any penetration on the brass plates that came standard in my Bosch battery pack. I had intended on using those for this repair but this tool did not have enough power to weld those. I added a picture of my welds and the settings along with the brass plates that my tool would not penetrate. Good for occasional welds but would purchase a more powerful model if spot welding was needed more frequently. 5 stars due to price and ease of use.

Makes great welds! Has more power than I need, but allows the user to increase or decrease depending on the project. Easy to use! Had never used one of these, but the learning curve was quick! The battery life is ridiculously long considering the power this welder puts out. I was amazed at the extras that were provided in order to make this a very functional device. This welder is very sophisticated electronically, yet easy to figure out. I use this to weld batteries together to make inexpensive battery packs, and save a lot of money rather than buying OEM packs. Ie. 6 lithium CR123 3v batteries for about $15, makes 3 6v battery packs that would otherwise cost around $50 a piece. I definitely recommend this item!

I like that the machine is automatic and fairly intuitive to operate. You will have to experiment a bit to get the speed of the welding given the thickness of the material. It is powerful enough to pop through the battery top so be aware that you should start with a low gear (faster weld) and work your way up if you are not getting results. It will spit sparks at you occasionally so just work on an appropriate workspace where you can't burn the rug or put a tiny burn hole in something you care about. Overall it will repair batteries and I replaced a couple of bade cells in an expensive 4 hour tool battery saving me $75 for a new one. The spot welder and the new battery cells was less than half that cost and that is only one use so the value is there.

Picked up this unit due to the price. Finally got around to making a custom battery after purchasing this a couple months ago. Initially charged it when it arrived and it held a decent charge months after. As for the functionality, the buttons, albeit tiny, work fine. After reading the manual, I found it didn’t really help much so trial and error was the way to go. I used the included nickel strips and settled on 65 power. I was able to get about 60 spot welds before the end of the battery or it got too hot. It seems to work well once I got the right settings and angle.

Some of the reviews of this welder talk about it having a decent battery life, but if you read all the reviews a significant portion mentioning having to recharge the welder after just a few welds. In my experience with mine, it can do about four welds and then needs to go back on the charger for about 20 minutes to do four more. I was upgrading all 5 cells in a 20v Max drill battery, meaning I had ten welds to make, requiring me to recharge the unit twice. Pretty frustrating. On the upside, when charged the unit makes quick strong welds with no sparks or splatter, and was up to the task. It came with a nice selection of nickel straps and replacement tips.

After charging the unit and welding my first 15 or so batteries I was about to leave a 5 star review. However, after getting to battery 30ish, it blew a hole through one of my batteries causing it to leak. I had turned the power down to 25ms for most of the welds on .15 strips. I had tried on .2 strips but had issues getting solid welds, but it was working well on .15. If anyone welds battery packs, you know the issues with a blown out battery and trying to get it out when its in the middle of a half welded pack. Anyhow I continued on being cautious of the varying weld power. Long story short, you never know what power you are getting on each weld no matter what setting you choose. It can be turned up high and barely weld a battery, or you can have it turned down to 20 and blow a hole in a battery. I welded a total of 3 13s8p packs and 1 13s6p pack. I had a total of 5 random blow outs causing leaks, and 3 that blew the wire strip completely off with tons of sparks, but didnt appear to penetrate the battery. This item does work, but you have to be careful and maybe not use it for large projects. The battery lasts about 60 welds at 20-30ms. Takes hours to charge though.

Affordable, simple to use, li.ion battery welder. I welded a new battery pack together of 18650 li ion batteries for electronics products. This came with nickel weld.strip, extra tips, instructions. Charged unit first thing. Used somw of the nickel metal strip to weld batteries. If you are not sure on initial settings then cut some strips and practice first, off of the battery. Once you have welder set then weld to battery. Welds were strong held well

Welder came quickly and is way better than I was expecting. I have put together several battery packs since getting it and once the power and time is dialed in it makes perfect welds every time. The rechargeable battery lasts way longer than I expected. Easy to use and well made.