In this review, we’ll try the Fnirsi HS-01 smart soldering iron. Eight years after the introduction of the famous TS100, many other competing irons have appeared. We can't wait to put this one to the test!

Overview

The HS-01, manufactured by Fnirsi, is a soldering iron designed for versatility in power sources. It features a USB-C input connector and can be powered using a USB charger, power bank, or any 9 to 24 Volts DC source equipped with a 5.5x2.1mm barrel plug, thanks to the included adapter. This soldering iron is equipped with temperature control, boasts a compact OLED display, and includes two buttons.

Soldering irons of this “smart” variety have seen significant success in recent years. Will the Fnirsi HS-01 live up to expectations?

HS-01 Specifications



Unboxing

The package contains :
  • A cardboard case containing the iron, a tip (HS01-BC2), a small user manual and a “Quality Check” card.
  • USB C to 5.5x2.1 mm barrel adapter
  • An assortment of additional tips: KR, K65, B2, ILS, BC3 (conical, knife, and hoof, in two sizes each)
  • A miniature stand with a tip-cleaning sponge
 
Package contents.
Package contents.
The iron in its case.
The iron in its case.

Description

The iron's outer casing is made of CNC machined aluminum and gives a good quality appearance. There is a rubber grip to prevent fingers from slipping towards the hot part. We'll see how well it works, and whether this part of the iron doesn't get too hot with prolonged use.

The cap protects the soldering tip when carrying the iron in a tool kit. It also prevents your belongings from being burnt when you put the iron away after use. Gas irons (Weller, Portasol, etc.) have exploited this principle for a very long time, so it's good news to see it appear on smart soldering irons!

The body of the iron is compact. The main dimensions are: length 184 mm with the closed cap, body length 120 mm, tip-to-grip distance about 70 mm. Depending on the size of your hands, you may need some time to adjust. Personally, I didn't experience any problems. It is slightly larger than most other similar products such as TS100, TS101, TS80 and Pinecil.
 
The HS-01 soldering iron.
The HS-01 soldering iron.

Design considerations

 
The iron is comfortable to handle.
The iron is comfortable to handle.
The tip is held in place by a locking collar. This seems a little less practical than on some other models (such as many T12 clones) where you simply push the tip in, but changing tips should still be possible without too much difficulty. If you're going to have such a locking system, the threaded locking collar is a rather elegant solution. In my opinion, it's better than having a side screw locking the tip, as on some other irons.

The buttons are positioned in the middle of the handle, which is ideal because they're easily accessible if you want to change a setting, but there's less risk of this happening accidentally.
 
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Power supply

The manufacturer has chosen to use a simple USB-C connector as the power connector. This may be seen as a disadvantage, but I personally don't mind. Most users will certainly have a suitable power source (Power Delivery compatible charger, Power Bank, PC charger...).

To use a non-PD compatible power supply (such as a battery or lab power supply), a USB-C to 5.5x2.1 mm barrel adapter is included in the package.

What's more, most users of this kind of products will be able to easily make a custom cable to suit their needs by cutting off the end of a USB-C cable salvaged from somewhere and installing the connector of their choice on the other side.

Using the Fnirsi HS-01

I didn’t have a USB-PD phone charger available to power on the iron for a first test, but I tried with a Dell laptop charger (20 V, USB-C) and it worked fine. But that was only a quick test, because I’ll need this charger for my laptop!

Then I found another laptop charger, an old Lenovo that I salvaged a while ago. I cut off the Lenovo connector and installed an appropriate connector.
 
Reusing a power supply.
Reusing a power supply.
When you switch on the iron by plugging it into a power supply, the iron boots up in sleep mode; the tip remains cold. You have to enter heating mode manually with a quick press on the lower button (the one towards the tip). I think this requirement is a good precaution to avoid burns. This type of iron is also intended for use “in the field”. You don’t want to burn yourself when you’re up the ladder and the iron gets hot before you’re ready!

Let’s turn it on

When the heating is switched on, a temperature of 360°C is reached in less than 10 seconds. This represents good performance compared to other irons on the market. By the way, the iron can be configured to use Fahrenheit scale, too.

As a side note, when the tip is brand new, the temperature will wander a bit for a few minutes. This is not a problem and is typical on these cartridge-type soldering irons. The tip just needs “running in”.

Using the menus

To change the temperature, when the iron is in heating mode, press either one of the buttons to activate the menu, then use the two buttons to change setpoint by 10°C (or 20°F) increments.

To quit the heating mode and enter sleep mode, make a long press on the upper button. Then a quick press on the lower button to wake up.

To enter the menu, press both button at the same time. Then quick press to navigate in the menus, long press to change parameters. The settings are Screen brightness, Temperature calibration, Temperature unit, Sleep time, Sleep temperature, Child lock, Language, Screen orientation and Voltage (negotiated with PD charger).

The HS-01 is suitable for most uses

I used the HS-01 iron for a few days of general use. I can say that for most soldering operations, I had no problems whatsoever. Handling the iron feels quite comfortable.
 
The HS-01 is fine for everyday soldering.
The HS-01 is fine for everyday soldering.
Only on some notoriously difficult solder joints (soldering the tab of a TO-220 to a ground plane or massive connectors) did I feel a lack of power compared with my Metcal PS-900. Having said that, the latter is 5 times more expensive!
 
Tasks requiring more heat such as making small shielded enclosures are also possible.
Tasks requiring more heat such as making small shielded enclosures are also possible.
In use, the part where you put your fingers to hold the iron has become a little hot, but not unbearably so.

There’s no provision for removing a hot soldering tip. Unscrewing the locking collar is easy, but the next part is trickier. Be very careful is you are using pliers; don't grip the tip too hard to remove it, or you'll crush it! Instead, use a rag folded over several times to briefly catch the hot tip. Other manufacturers supply a small silicone pad for this purpose, but Fnirsi doesn’t. Then simply put in the (cold) tip of your choice and screw the retaining collar back on. All in all, pretty easy.

The range of tips supplied is suitable for most applications. As with the vast majority of soldering irons, soldering tips are proprietary, i.e. they are not compatible with those of competing brands.

HS-01 Pros and Cons

Here are, in my view, the primary benefits of the HS-01, along with some areas where enhancements could be made.

Pros:
  • Actively controlled temperature
  • Cartridge system: the heating element, the iron tip and the temperature probe are combined in a single piece, for best thermal transfer and accuracy
  • Less expensive than a traditional soldering station of equivalent performance
  • Compact: no bulky base station required
  • Can be converted into a portable soldering iron with a PowerBank, model lithium battery or car battery
Cons:
  • To date, the Fnirsi HS-01 is not compatible with IronOS (formerly Ralim). It's a pity, because what's “smart” about these “smart irons” are the ingenious modifications made by users and developers! Let's hope that Fnirsi agrees to collaborate with IronOS developers in the future.
  • There doesn’t seem to be any chisel tip available from the manufacturer
  • No silicone pad is included for easy replacement of hot tips

Conclusion

If you're a beginner looking for a soldering iron with very good value for money, the Fnirsi HS-01 is a good investment. It's easy to handle and delivers excellent results. For more seasoned users (please don't ask me how many soldering irons I have) it can also make a worthy secondary soldering iron; for use outdoors, in an RV, on a boat, at the weekend... Its small size and versatility in terms of power supply will come in handy.

If you already have other smart soldering irons, this one's probably not much different, so you may not need to buy it. Ditto if you're more attracted by the prospect of tinkering with open source software.

In short, for most users, this is a good general-purpose soldering iron. Have fun with it!