Comparison of Sony NP-FZ100 Batteries and Third-Party Alternatives

I use the Sony A7R V as my main camera for various purposes, including photography, 8K video recording, and high-speed continuous shooting.

The camera comes with a single genuine Sony battery: NP-FZ100, but one battery often proves insufficient for power users. To address this, I purchased several third-party batteries from AliExpress. However, most of them have been disappointing in terms of runtime.

Recently, I purchased a new charger for Sony batteries—the ISDT NP2 Air—which can measure battery capacity during charging. Using this charger, I measured the capacity of all my batteries I have, both genuine Sony and third-party ones.

The measurement process was as follows:

1. I discharged each battery to 0%, until the internal protection cut-off was triggered. On most third-party batteries, the BMS cuts off output near 6.2 V (approximately 3.1 V per cell). However, the genuine Sony battery does not cut off even at 6.0 V, making a perfect in-camera discharge impossible. (The camera avoids to boot up with ‘Battery Exhausted’ popup.) Since most lithium-ion batteries show almost zero capacity below about 3.4 V per cell, this discrepancy may not be critical. Note, though, that discharging below 3.0 V can damage lithium-ion cells.

2. Due to their high internal resistance, some batteries never reached 100 percent even after the charger displayed the “Charge Completed” message. I tested both quick charge mode on and off but observed no significant difference. FYI: the ISDT NP2 Air’s quick charge mode for NP-FZ100 batteries supplies 1.5A, whilst normal mode supplies 1.0A; both rate remain well below the 1C charging limit, typical of most Li-Ion batteries. I charged each battery until the charger shut off automatically.

Batteries tested

1. Sony NP-FZ100
2. Batmax NP-FZ100 (from AliExpress)
3. Probty NP-FZ100 (beige model with USB-C charging port; from AliExpress)
4. SmallRig 4265 NP-FZ100 (blue model)

Rated Capacities

1. Sony NP-FZ100: 2280 mAh
2. Batmax NP-FZ100: 2280 mAh
3. Probty NP-FZ100: 2800 mAh
4. SmallRig 4265 NP-FZ100: 2400 mAh (cell capacity; battery nominal capacity is 2250mAh)

Prices

1. Sony NP-FZ100: ~₩75,000
2. Batmax NP-FZ100 (two batteries + dual charger): USD 39.69
3. Probty NP-FZ100: USD 20.97
4. SmallRig 4265 NP-FZ100: USD 34.05

Measured Weights

1. Sony NP-FZ100: battery #1 0 82.53 g; battery #2 – 82.44 g
2. Batmax NP-FZ100: not measured yet
3. Probty NP-FZ100: 79.02 g
4. SmallRig 4265 NP-FZ100: 78.30 g

Manufacture Dates

1. Sony NP-FZ100: battery #1 – 2022; battery #2 – 2024
2. Batmax NP-FZ100: 2022
3. Probty NP-FZ100: 2023
4. SmallRig 4265 NP-FZ100: 2025

Note: Capacity measurements were performed in June 2025.

Results

1. Sony batteries
   1. Battery #1 (manufactured 2022): 2381 mAh
   2. Battery #2 (manufactured 2024): 2422 mAh

   

2. Batmax batteries
   1. Battery #1: 1756 mAh
      
   2. Battery #2: 1726 mAh
      
3. Probty battery: 1863 mAh
   
4. SmallRig battery: 2250 mAh
   

Disclaimer: One Sony battery, as well as the Batmax and Probty batteries, were purchased several years ago and may have undergone significant degradation.

Conclusions

The genuine Sony NP-FZ100 batteries demonstrated exceptional capacity retention after three years of use. In contrast, most third-party NP-FZ100 batteries exhibited significantly lower capacities. Only one third-party model, the SmallRig 4265, exceeded its rated capacity. Although some third-party batteries offer additional features—such as USB-C charging—these come at the expense of usable capacity.

Despite both genuine and aftermarket batteries using the same 18500 (or 18490) standard cells, I remain surprised that no third-party manufacturer offers capacities comparable to Sony’s genuine units.

Limitations

1. Accurate capacity measurement requires a dedicated load tester. These measurements were performed by the charger itself, so actual discharge performance and stored energy may differ, especially due to variations in internal resistance. Note: these measurements reflect charge capacity, not energy capacity.
2. Only a single sample of each battery model was tested; these samples may be defective or unrepresentative.

I have begun a natural discharge test for all units today (June 29). I will provide updates later.