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⚡ Power up your diagnostics with pro-grade precision and fast charge mastery!
The FNIRSI FNB58 is a compact, multi-interface USB tester featuring a bright 2.0-inch TFT LCD display and advanced 16-bit ADC technology. It supports a wide range of fast charging protocols including QC2.0/3.0, PD2.0/3.0, VOOC, and more, enabling precise voltage, current, power, and resistance measurements. Designed for tech-savvy professionals, it offers detailed cable chip reading, ripple analysis, and smart data logging, all housed in a durable metal case. Ideal for engineers and enthusiasts who demand accurate, real-time USB power diagnostics.















| ASIN | B0BS2ZS813 |
| Best Sellers Rank | #178,596 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #134 in Voltage Testers |
| Brand | FNIRSI |
| Brand Name | FNIRSI |
| Color | multi-color |
| Customer Reviews | 4.4 out of 5 stars 177 Reviews |
| Included Components | USB Tester |
| Item Dimensions | 3.23 x 1.65 x 0.47 inches |
| Item Weight | 1.6 ounces |
| Item dimensions L x W x H | 3.23 x 1.65 x 0.47 inches |
| Manufacturer | FNIRSI |
| Measurement Type | Multimeter |
| Minimum Operating Voltage | 4 |
| Model | FNIRSI-FNB58-bp |
| Part Number | FNIRSI-FNB58-bp |
| Power Source | Battery Powered |
| Specification Met | CE, FCC, RoHS, UL |
| Style | FNB58 |
| Style Name | FNB58 |
| Upper Temperature Rating | 125 Degrees Celsius |
T**O
Excellent USB-C cable and charger diagnostic
It's not perfect.. it has bugs, quirks, and inexplicable interactions, but --- once you figure out how to test the things that matter to you, it's very repeatable and clear. Specifically, it can read the Chip ID in USB-C cables, and show all the available power modes in USB-C PD, on a nice color built-in screen. That's nice. You can see the finer details of PD packet exchange as well, but this was less reliable. For testing batteries and other sources, it has a convenient "Trigger" function that can request any voltage or current from your supply, with a nice physical Switch that engages or disengages the "active" part. Switched off, the device is pass-through only and zero risk. Switched ON, you have a lot of direct control over voltage, and of course, risk. You want to put 20v on a USB-A socket? You can! I find the device is best to use when it's plugged into its own independent Micro-USB power source (5v, low current), because then it's not constantly turning off and on with your devices under test. It's easy to crash the device when messing with USB-PD packets, or even have it just beep nonstop until you pull power. The firmware could use some work. Some functions are duplicated or confusing (how many different trigger menus do you need?) but hey, it's affordable for DIY hobby work and comes in a nice well-made housing with an excellent screen for cheap. Unfortunately, the company web site is terrible, hosted on some Mediaflare thing that runs out of bandwidth, so downloading the firmware updates is way more hassle than it should be. They need to up their game, put up a professional site, and host their own files.
B**Y
High quality, capable and great display
Pros: 1) Nice metal case with easy to use controls 2) Excellent, bright and clear display, with auto-rotate 3) Loads of technical capabilities 4) Nice storage box to keep the unit protected 5) Companion Windows app (NOT macOS) is nicely done, and turns this into a capable testing and measurement device. The only con is the documentation, which is a bit lacking. I had to go to YouTube to learn how to upgrade the firmware (which was necessary because the unit displayed incorrect temperature readings). All in all though, if you're reasonably technically savvy, there won't be any significant issues. Recommended! The manual and firmware are available at the FNIRSI website.
B**9
There's something weird when charging iPhones
Overall this is a nice tester. Very accurate, lots of features (I like the realtime graph, very interesting to see how the current fluctuates over time). There's one weird problem though. My iPhone 15 Pro max is incapable of requesting 9V from a USB-PD charger when using the tester normally. It only gets 5V, which limits charging power to about 12W. In order to get 9V, you have to enter the PD trigger menu. Then, it can negotiate 9V. You can leave the PD trigger menu after that. The weird thing is, when I used this tester on my laptop, the laptop was able to get 20V without having to do anything special (which is a good thing because it can't charge on anything less). Not sure why the iPhone requires entering the PD trigger menu.
M**E
Works for me!
My experience with scopes is pretty limited, so take this as the opinion of a FW/SW dev. I love this little guy. Power consumption measurement of MCUs has been elusive until now. The sampling resolution doesn't blow me away, but it is good enough for my needs. Very easy to read and use. I found the menu system on the intuitive side, which surprised me. A like its size as well. At first I was wishing for a bigger screen. After using it for a while, I found that the smallish size is great because now I can leave it connected all the time without hogging up desk space. Excellent. And for the record, I've seen no evidence of interference with MCU D+/D- signals. Wish I'd picked this up a long time ago.
S**C
Test your usb stuff.
Very good tester, its nice to use the auto detect though its not 100%. Pd pass thru is amazingly helpful and pd trigger is good when using a USB c charger that requires a load device to provide power. Jitter reading isn't sure useful but the other readout and charts are good for load testing.
C**G
Works great
Works great
B**T
In Constant Use. Love It!
I bought this to test the e-marker (max voltage, amps, watts) on my forest of cables. I did find one high-dara-speed gem I didn't know I had! It took some sorting out to learn exactly when to hook up the micro-usb input, but it's not needed often. I've tested 4 power banks, 10 charging bricks, and solar power hub to see what standards (and thus how fast) they can charge. It's a hobby now. I've become Sheldon, putting stickers on the good stuff, tossing the junk cables. It's a great unit. Zero regrets!
D**.
Doesn't do any of the advanced fast charging features that it says it will in the manual. Pointless!
I have a OnePlus 9 Pro. It uses their unusual 10.5V , 6.5A protocol to charge, which on reading is also called VOOC. Reading the manual this device claims to be able to transcode between protocols, and I wanted something that I could plug into any PSS charger and at least be able to charge by phone at 10V 5A with it. The long and the short of it is, after spending about 3 hours updating the firmware, downloading the PC software and reading the manual several times, this thing straight up doesn't work. It doesn't detect the protocol used to fast charge on my factory charger, saying it is only QC2.0 and 3.0 compatible, and when I'm eventually by luck in the right screen that when I plug in the phone it starts fast charging it says it's using QC2.0 but when I go into that specific page in the fast charge menu it jumps out of warp charge and charges at 5V saying it doesn't find the handshake. The PC software is horrible, beyond being basic it disconnects randomly and stops logging. It's basically only good for updating the firmware. This thing was a total waste of time, and I regret being seduced into thinking this would do what it said it would in the manual.
W**N
não tem bluetooth
Produto de excelente qualidade, ótimo acabamento e muito preciso
E**E
Excelente , cumple con lo publicado,
Excelente , cumple con lo publicado,
B**P
Top in the market
Excellent product
S**N
Massively versatile, does everything!
I bought the FNB58 as I'm into small electronics and wanted a tester to test cables, chargers, etc. This thing does it all. From simple voltage/current/wattage readings to battery capacity measurement and fast charge protocol control, there's not much else you could possibly need. The feature set is incredible, and the UI is easy to use, although the manual isn't really much help: I looked to YouTube reviews and tutorials to learn how to use it: Pros: Small form factor, large display Physical buttons have great tactile feeling Measures and tests just about everything Cons: Manual is pretty much useless. More expensive than others (but with better features so that's expected) No internal battery (some functions will require a seperate cable and brick to power the device). There is a different variation of the FNB58 with Bluetooth and an app for your phone. The casing on the Bluetooth model is a lighter blue/grey, as opposed to the black casing this one has. I have not tested any PC connection features, as I don't really have the need to. 2 warnings: 1. If you are using any fast charge feature, make sure you know what you're doing, as it is possible to send high voltage to a device and fry it. There is a warning when entering the menu reminding you to unplug anything connected to the output. 2. Flicking the PD COM switch to on will connect the power from all the ports except the PC micro-USB on the top. When using a feature like PD listener, you should power the device with the PC micro USB port, as it's isolated from the rest of the circuitry. One review I saw didn't do this and sent 20v from a laptop charger into a 5V battery pack. Fortunately the battery pack had over voltage protection, but it's not a risk worth taking. Overall, for the hobbyist with the budget, or the professional repair technician, the Fnirsi FNB58 is a great package that you won't be disappointed with.
C**N
Muy útil acoplado a una generador de carga
Lo utilizo para comprobar la calidad de los cables y las prestaciones de los puertos USB. Acoplado a un generador de carga de USB es una herramienta excelente. Inclusive puedes medir la resistencia interna de los cables, o la corriente máxima que puede entregarte un puerto USB. Recomendado.
Trustpilot
1 month ago
2 months ago