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.

Works just fine for the money. I used it to build a new pack for my battery operated vacuum cleaner.Big advise....practice before building your pack, even if you have experience with other spot welders. What worked for me is about 70-75 for the batteries, 40-50 for strip to strip spots (I had to build a cross shaped jumper, welding a piece of strip to the existing strip between cells). Hold the welder at an angle, not straight down but at 45 degrees.What I've found is that after a few welds I needed to clean the tips. They get dirty pretty fast and won't solder correctly.

Good cheap welder with some caveats. Play around with angle and pressure on a junk battery to get your welds solid. Remember ohm's law: as voltage goes down amperage goes up. What might need gear 70 at 4 volts will need gear 50 at 3.2. I blew through a cell my first time not realizing this. Also this is a cheap welder with a small battery. My first pack was 20 cells, 8 welds per cell, so 160 welds and I had to charge it twice.

NO I did not do well on the first few attempts. Several did not stick and a few I melted a hole in the jumper. Well with a little practice it is great to have.

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.

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.

Works great. Don't believe the 1 star reviews. Works the way it is suppose to. Doesn't work well if you don't know what you are doing. Great buy!

Very nice friendly easy to use item