Capacity Testing 5 Third Party Sony NP-FW50 Batteries

By Nathaniel Stephan
Last Updated: August 9, 2019
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Third Party Sony NP-FW50 Batteries Tested

If you're cheap like me, you don't want to pay the high-price for an OEM Sony NP-FW50 battery. The price isn't terrible if you only need 1 extra battery. Unfortunately, one of the problems with the Sony A7 is the short battery life.

You can get third party NP-FW50 batteries for much less than an OEM Sony battery.

This begs the question, is there a difference in quality? To find out I purchased and tested the capacity of batteries from RAVPower, Neewer, Powerextra, Wasabi Power, and the cheapest I could find on eBay.

Impossible Claims

Wasabi Power BTR-FW50-JWP
LiIon cell with an 880mAh rating, not the 1300mAh on the label.

Wasabi Power and PowerExtra overstate the capacity of their NP-FW50 batteries. Opening them up shows cells with 880mAh and 900mAh ratings, not the labeled 1300mAh and 1500mAh.

Powerextra FW50
LiIon cell with a 900mAh rating, not the 1500mAh on the label.

RAVPower and Neewer sell quality batteries. Opening them up did not reveal any information about the cells used. However, capacity testing showed that they were close to the 1100mAh listed on their labels. Keep in mind that an OEM Sony NP-FW50 is rated at 1020mAh.

eBay NP-FW50
Foam filling the void left by using smaller cells than the other batteries.

I also purchased the cheapest unbranded batteries I could find on eBay. What should come as a surprise to no one, they're garbage.

What's Inside a Camera Battery?

RAVPower RP-PB056 Savior Series
No identifying information can be seen on the cell.

RAVPower and Neewer likely came from the same factory. The tested capacity, weight, and case are all the same. They can even be purchased with the same charger.

Neewer NP-FW50

Opening the RAVPower and Neewer batteries did not reveal any information on the cells used. Internally, the battery protection boards appear to be the same. I would not be surprised if they were made at the same factory.

The Best Third-Party NP-FW50 Battery Is…

RAVPower or Neewer are the best batteries. While they don't meet their labeled capacity, they are close. What they do have is higher tested capacities than the labeled 1020mAh of a genuine Sony battery.

Differences in price mean you can get 4 RAVPower or Neewer batteries for the price of 1 Sony battery.

Check current battery prices at Amazon or eBay.

BrandWeightTested CapacityLabeled CapacityVoltage
RAVPower A45.48g1042mAh1100mAh8.41V
RAVPower B45.72g1026mAh1100mAh8.37V
Neewer A45.60g1018mAh1100mAh8.32V
Neewer B45.64g1059mAh1100mAh8.35V
Wasabi Power A43.34g916mAh1300mAh8.35V
Wasabi Power B43.65g892mAh1300mAh8.30V
PowerExtra A43.43g855mAh1500mAh8.35V
PowerExtra B43.54g872mAh1500mAh8.30V
Cheapest eBay A42.77g884mAh1500mAh8.38V
Cheapest eBay B36.80g453mAh1500mAh8.18V
  • Test Capacity is an average of 5 discharge cycles at a 500mAh draw rate.
  • The Voltage reading was taken 4 hours after batteries were fully charged in the Neewer charger.

TEC-06 Battery Capacity Tester

TEC-06 Battery Capacity Tester

The TEC-06 is a USB powered battery capacity tester. A test load can be placed on a battery. The measured capacity is displayed on the screen when the battery is fully drained.

Energy stored in the battery is turned in to heat. The heat sink and fan are there to dissipate that heat.

Testing Methodology

TEC-06 Contacts
Battery contacts I made to test the batteries.
  • Batteries were charged with the Neewer USB charger.
  • 6 volts was used as the cutoff voltage.
  • A 500mA load was placed on the batteries.
  • Nickle strips were soldered to wires to connect to the batteries.
  • The TEC-06 has firmware V6.06.

Two Li-Ion cells are wired in series to make the batteries. I do not have a data sheet for any of the batteries. I picked the most common cut off voltage, 3V, for Li-Ion cells with a nominal voltage of 3.7V.

Cells in a series have their voltages added together. 3.7V + 3.7V = 7.4V.

When the cell reaches 3V, it is considered fully drained. Discharging the cell past 3V can shorten the life of the cell. The cells are in series, so 6V was used as the cutoff for the batteries.

My Sony A7 gets about 2 hours of life out of a battery. A 500mA load was used because it would drain the cells in approximately 2 hours.

500mA x 2 hours = 1000mAh

Testing Self Discharge

Batteries will slowly discharge over time. This is an issue with high drain rechargeable Ni-MH batteries. There was almost no change in charge of the FW-NP50 batteries over the course of a week. Self-discharge is not a problem you have to worry about.

Here is the process I used to test the batteries:

  1. All batteries with fully charged on the Neewer charger.
  2. Batteries sat for ~4 hours before the initial voltage was taken with the TEC-06.
  3. A week later the battery voltages were checked again with the TEC-06.

At the end of the week, all of the batteries read 0.02V lower. This is a negligible amount. You would not notice the difference in charge from a battery that sat for a week. All of the batteries started as showing a 100% charge in my Sony A7.

Neewer & RAVPower USB Battery Charger

Neewer DU-FW50 USB Dual Battery Charger

The Neewer batteries I purchased from Amazon came with a USB charger. It looks identical to the charger that is bundled with RAVPower batteries.

A micro USB cable is required and not included. Charging requires 5V 2.1A USB power. USB chargers that powerful are not common. Most chargers will be 1A or less. Using a less powerful charger will still work, but charging will take longer than it would with a more powerful charger.

After seeing that it worked, I took it apart. There's not much inside. The case is either glued or plastic welded together. I would not recommend disassembling the charger.

If you need a USB NP-FW50 charger, this one charges batteries. I am going to continue to use it. If you want an adapter that plugs into an outlet, get a DigiPower TC-U450.

Sony Cameras That Use NP-FW50 Batteries

These are all the models of cameras that use NP-FW50 batteries.


8 comments on “Capacity Testing 5 Third Party Sony NP-FW50 Batteries”

  1. Hi. THe cyber shot rx10 mark 1v also uses this battery. excellent article. thank you. how many shots per charged use do these batteries last for?

    1. With my testing it was more an issue of how long the Sony A7 (the original) was on. Constantly reading the sensor and keeping the screen on ate through battery life. It ended up being about 2 hours. Less when shooting video.

  2. Very helpful information as we look to purchase an additional battery for our Sony a 6000. Thank you!

  3. Hi,
    Thank you for sharing your article. Very interesting to know the quality of hybrid batteries. We all know the capacity indicated on the label can’t be trusted,but no one know the real capacity. Good to know that Ravpower and Neewer are honest on theirs indication. Thanks again for your time.

  4. I was investgating Neewer Np-F batteries and found your article. Thank you for putting up such usefull information. There isn't much info about Neewer batts so your article is most valued - cheers

  5. Thank you for the article!

    We all knew what is advertised as 1500 mAh is not true, but I thought it would be more like around 1200-1300 mAh, but I can't believe PowerExtra was only almost half that!

    I had to return my PowerExtra because it was so weak compared to the native Sony battery.

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