Thing I made: Ryobi-compatible cordless TS100 soldering iron power adapter

I'm super excited about a new tool I made.  It's a cordless power adapter that connects Ryobi One+ batteries to my favorite soldering iron, the TS100.

The backstory on this is kind of funny.  I turned my ad-blocker off to test a site for work. While it was off, I saw an ad for a generic Ryobi battery adapter. I was immediately hooked and bought it, even skipping the customary two-week procrastination delay. I had thought about these back when I got this iron, but they didn't exist.  I was too lazy to design and 3-D print one. Now they do exist, and this may be the only time I've ever been excited to see an ad on the internet.  Wonders will never cease.

When I bought this iron, I also got an adapter to connect it to a RC Car Li-Po batteries with an XT-60 connector.  This worked, but Li-Po batteries are scary.  My Ryobi batteries are far more durable (and less explodey!). When the parts came, I soldered on an XT-60 connector, cursed a little, put a quarter in the forgot-to-put-on-the-heatshrink-jar, desoldered it, added heatshrink, re-soldered it, and viola, my favorite soldering iron is now cordless and even more favorite-er.  No more extension cord!  This is 10/10 awesome.

Nerd stuff: This particular adapter includes an in-line fuse holder and some 30-amp fuses.  The soldering iron is rated for 12-24 Volts and 17-65 Watts.  At the Ryobi One+ battery's ~20 volts, the math comes out to about 3 amps, so I'll be changing the the 30 amp fuse for a 5-amp fuse from the auto-parts store.  I tested the current draw with an ammeter and the startup current was right at the specified 3 amps, dropping down to about half an amp after the iron is hot.

Battery life:  This specific P105 battery is rated at 48 watt-hours.  According to the tin, the maximum power draw of this iron is 65 watts.  That would put the battery life at 45 minutes maximum.  In real-world testing, the power draw of the iron in use after initial heat-up is under an amp.  That means, for this battery specifically, I can work for a couple of hours and still have plenty of juice left.  If I were planning to use this a lot, I'd add a battery beeper to warn me when it gets low.  We'll put that on the list of future projects. Given that list contains other long-term goals like "cure for cancer" and "solve world hunger", it may be on there a while.

Here's some links if you want to replicate it.  I specifically ordered the battery adapter from Temu, but you can get them from Amazon too. The amazon links are affiliate links, the Temu one is not.

The battery adapter I bought:

Battery Adapter 18v Power Upgrade Adapter Li Ion Battery Adapter Upgraded Power Wheel Adapter Battery Adapter With Wire Terminals (

Alternates, if you want to build it all with parts from Amazon:

Bonus tips.
  1. Be smarter than me. Remember to put the heat shrink on before soldering.
  2.  If you have extra tips for this soldering iron, you can put them in test tubes to keep them from banging around in your soldering box.
  3. A rubber band or hair tie plus a pair of pliers makes a handy holder for soldering connectors.  It's more stable than holding it in a little "third hand" thing.