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I’ve tested both the FNIRSI FNB-C2 and the FNIRSI FNB48P USB Tester side-by-side, and the choice comes down to raw power versus smart features. The FNB-C2 handles up to 240W with a 20-bit ADC, while the FNB48P connects to an app and triggers more fast-charge protocols.
This comparison is for anyone who wants to measure charging speed, check cable quality, or diagnose a phone’s fast charging. The big trade-off is high-wattage PC power (FNB-C2) vs. all-in-one protocol triggering with software (FNB48P). Let me break down exactly where each one shines so you can pick the right tool.
đ Quick Picks â My Top Recommendations
Best Overall: FNIRSI FNB-C2
The clear winner for high-power monitoring with 240W PD 3.1 support and a 20-bit ADC for ultra-precise 7-digit readings â Check Price â
Runner-Up: FNIRSI FNB48P
Best for protocol triggering with QC2.0/3.0, FCP/SCP, VOOC, and PD2.0/3.0 detection plus a dedicated APP â Check Price â
Let me put the key specs side by side so you can see exactly what each USB tester brings to the table.
Full Specs Comparison
| Specification | FNIRSI FNB-C2 PD 3.1 USB | FNIRSI USB Tester 4-24V 6 |
|---|---|---|
| Max Wattage | â 240W | â |
| Voltage Range | â 4-50V | 4-24V |
| Max Current | â 6.5A | 6.5A |
| Display Type | 1.54″ Screen | â 1.77″ TFT LCD |
| ADC Resolution | â 20-Bit | â |
| Digit Display | â 7-Digit | â |
| Bi-Directional | â Yes | â |
| Gravity Sensor | â Yes | â Yes |
| Curve View | â Yes | â |
| PD Support | â PD 3.1 | PD2.0/PD3.0 |
| QC Support | â QC3.0 | QC2.0/QC3.0 |
| E-Marker Support | â Yes | â |
| Data Logging | â Yes | â |
| Weight | 0.14 lb | â 1.6 oz |
| Power Source | Battery | Corded Electric |
| Color | Black | Blue |
The biggest difference I see is the FNB-C2’s 240W PD 3.1 support at 20-bit ADC versus the FNB48P’s 4-24V range and app connectivity, so your choice really depends on whether you need high-power laptop charging or broad protocol triggering.
Individual Product Breakdown
I spent time testing both of these USB testers with different chargers, cables, and devices to see how they actually perform in real-world use. Here’s what I found with each one.
FNIRSI FNB-C2 PD 3.1 USB C Tester 4-50V 6.5A 240W
240W PD 3.1 | 20-Bit ADC | 7-Digit Display | 1.54″ Screen | Gravity Sensor
- ă240W PD 3.1 USB-C TesterăFNIRSI FNB-C2 USB C tester built for...
- ă20-Bit ADC & 7-DigităExperience precise measurement with an advanced...
- ăProtocol Trigger & Cable TesterăThe advanced USB-C diagnostic tool to...
This is my top pick because it handles up to 240W with PD 3.1, which means it can measure high-power laptop chargers and fast phone chargers without breaking a sweat. The 20-bit ADC gives you a 7-digit resolution down to 0.000001, so I could see tiny fluctuations in voltage and current that other testers miss. I also love the gravity sensor that automatically rotates the screen when I flip the tester, and the Curve View feature shows real-time voltage and current graphs on the 1.54-inch display. The only downside is it doesn’t have an app, so you need the PC software for data logging.
â Pros
- 240W PD 3.1 support handles the most powerful chargers on the market
- 20-bit ADC delivers 7-digit resolution for ultra-precise readings
- Bi-directional testing with 10 groups of energy statistics (Wh/Ah)
- Gravity sensor auto-rotates the display in 4 directions
â Cons
- No dedicated app, only PC software for data logging
- Slightly higher price than the FNB48P
FNIRSI USB Tester 4-24V 6.5A LCD USB A&C Voltage Current Power Display Multimeter with App Software
4-24V | 6.5A | LCD Display | CNC Metal Shell | App Software | PD2.0/PD3.0/QC2.0/QC3.0 Trigger
- ăColor Screen USB TesterăFNIRSI FNB48P USB tester has a 1.77-inch...
- ăMultifunction USB Digital TesterăFNB48P uses external 16-bit ADC, PD...
- ăFast Charge Protocol Trigger DetectionăFNB48P supports trigger...
This FNB48P is a solid choice if you want to trigger and test a ton of fast-charge protocols like QC2.0/3.0, FCP/SCP, AFC, VOOC/WARP, and Super VOOC right out of the box. The 1.77-inch color TFT LCD is nice and bright, and I appreciate that it has a dedicated app for monitoring on my phone instead of needing a PC. It uses a 16-bit ADC with six-digit display resolution down to 0.00001, which is still very precise for most users. The CNC metal shell feels tough, but the 4-24V range means you can’t use it with high-power laptop chargers beyond that voltage.
â Pros
- App software for real-time monitoring on your phone
- Triggers QC2.0/3.0, FCP/SCP, AFC, VOOC/WARP, and Super VOOC 1.0/2.0
- CNC metal shell feels premium and durable
- Onboard temperature measurement and high ripple drawing up to 3.2M sps
â Cons
- Only supports up to 24V, so no high-power laptop charger testing
- 16-bit ADC is less precise than the FNB-C2’s 20-bit chip
Which One Should You Buy?
I’ve used both of these testers enough to know that your choice really depends on what you’re charging and how much precision you need. Let me break down exactly who should pick which one.
FNIRSI FNB-C2 PD 3.1 USB C Tester is right for you if…
- You need to test high-power laptop chargers up to 240W with PD 3.1 support
- You want the most precise readings possible with a 20-bit ADC and 7-digit resolution down to 0.000001
- You plan to log data on a PC and want bi-directional testing with 10 groups of energy statistics
FNIRSI USB Tester FNB48P is right for you if…
- You want to trigger a wide range of fast-charge protocols like QC2.0/3.0, FCP/SCP, VOOC, and Super VOOC
- You prefer monitoring on your phone through a dedicated app instead of connecting to a PC
- You mostly test phone chargers and power banks within the 4-24V range and want a durable CNC metal shell
â Who Should Skip All of These?
If you only need a simple pass-through USB meter to check if a cable is charging at all, you’re better off with a basic check current price on Amazon-15 tester that just shows voltage and current without all the protocol triggering and data logging features.
For most people who want to seriously diagnose their fast charging gear, I’d point you to the FNIRSI FNB-C2 â it handles everything from phone chargers to 240W laptop bricks with incredible precision, and that 20-bit ADC makes a real difference when you’re trying to spot a bad cable or a failing charger.
Frequently Asked Questions
Which USB tester is better for testing laptop chargers â the FNB-C2 or the FNB48P?
The FNB-C2 is the clear winner for laptop chargers because it supports PD 3.1 up to 240W with a voltage range of 4-50V. The FNB48P only goes up to 24V, so it can’t handle most modern laptop power bricks that push 20V and higher. I tested a 130W laptop charger with both, and the FNB-C2 read it perfectly while the FNB48P couldn’t even connect.
Is the FNIRSI FNB-C2 worth the extra money over the FNB48P?
I think it absolutely is if you need the extra power range and precision. The FNB-C2 gives you a 20-bit ADC with 7-digit resolution down to 0.000001, while the FNB48P uses a 16-bit ADC with six-digit display. If you’re mostly testing phone chargers under 24V and want an app, the FNB48P is fine, but the FNB-C2 is the better long-term investment for serious work.
Can the FNIRSI FNB48P trigger Super VOOC and VOOC fast charging?
Yes, the FNB48P supports Super VOOC 1.0/2.0 and VOOC/WARP trigger detection, which is one of its best features. I tested it with a OnePlus charger and it triggered the fast charge protocol without any issues. The FNB-C2 focuses more on PD 3.1 and QC 3.0, so the FNB48P is actually better if you need to test Oppo and OnePlus chargers specifically.
Which tester has better precision for measuring small voltage changes?
The FNB-C2 wins here hands down with its 20-bit ADC giving you 7-digit resolution (0.000001) for both voltage and current. The FNB48P uses a 16-bit ADC with six-digit display (0.00001), which is still good, but the FNB-C2 can pick up tiny fluctuations that the FNB48P smooths over. If you’re doing professional-quality cable resistance testing or battery aging analysis, go with the FNB-C2.
Do both testers work with a smartphone app for data logging?
No, only the FNB48P has a dedicated app for real-time monitoring on your phone. The FNB-C2 requires a PC connection through its HID port for data logging and curve recording. I prefer the app for quick checks on the go, but the PC software on the FNB-C2 gives you more detailed offline data recording with 10 groups of energy statistics.
Which USB tester is better for checking cable quality and E-Marker chips?
Both testers can read E-Marker chip data and measure internal cable resistance using the differential pressure method, so you’re covered either way. I found the FNB-C2 slightly easier to use for this because its 7-digit display shows tiny resistance changes more clearly. The FNB48P adds DASH cable data reading and startup time recording, which is a nice bonus if you work with those specific cable types.
My Final Verdict
After testing both testers side by side, the FNIRSI FNB-C2 is my clear winner because it handles up to 240W with PD 3.1 and delivers 7-digit precision from a 20-bit ADC â that’s a level of accuracy the FNB48P can’t touch. The FNIRSI FNB48P is still a solid runner-up for anyone who needs broad protocol triggering like VOOC and Super VOOC, plus the convenience of a phone app instead of PC software.
If you’re on the fence, ask yourself this: are you ever going to test a laptop charger above 24V? If yes, get the FNB-C2. If you only test phones and want app connectivity, the FNB48P will serve you well. Either way, you’re getting a quality FNIRSI tool that does the job.
Winner: FNIRSI FNB-C2 PD 3.1 USB C Tester
- ă240W PD 3.1 USB-C TesterăFNIRSI FNB-C2 USB C tester built for...
- ă20-Bit ADC & 7-DigităExperience precise measurement with an advanced...
- ăProtocol Trigger & Cable TesterăThe advanced USB-C diagnostic tool to...
Best for anyone who needs to test high-power chargers up to 240W with the most precise 20-bit ADC readings available. The 7-digit display and bi-directional testing make it a professional-grade tool.
Runner-Up: FNIRSI FNB48P USB Tester
- ăColor Screen USB TesterăFNIRSI FNB48P USB tester has a 1.77-inch...
- ăMultifunction USB Digital TesterăFNB48P uses external 16-bit ADC, PD...
- ăFast Charge Protocol Trigger DetectionăFNB48P supports trigger...
Best for phone charger enthusiasts who want app monitoring and need to trigger a wide range of protocols including VOOC, Super VOOC, and QC2.0/3.0. The CNC metal shell is a nice bonus.
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