NP-FZ100 Teardowns

Neewer NP-FZ100

Product Image:

Amazon.com and other online retailers carry an NP-FZ100 type battery from the Neewer brand. They claim to have a “large capacity” 2280mAh battery. This means that each cell within the battery would equate to 2280mAh of capacity x 2 cells = 16.2Wh. Battery manufacturer’s always claim some outlandish number, however, my job is to actually test these batteries and see if they live up to their claim. Below you will find information pertaining to the Neewer NP-FZ100 battery as well as a full teardown with pictures and a detailed result of my tests.

From the Amazon.com listing:

LARGE CAPACITY: 7.2v 2280mAh rechargeable Li-ion with premium cell for longer battery life without memory effect; Long-lasting power and durability

The teardown reveals that the battery is comprised of (2) 18500 Lithium Ion battery cells in series connected to a BMS in the center. This cell type is very interesting. I think most people will be familiar with the 18650 cells that are found in most older laptop batteries, the Tesla first edition of the Tesla Roadsters and many other electronics we use today. 18650 cells are great for high current while obtaining modest capacity ratings while keeping their side relatively small. Due to the size constraints, Sony had to opt for a shorter battery to fit inside the grip of the Alpha cameras. the 18650 cell is 65mm long and the 18500 cell is 50mm long, 15mm shorter.

This is a very interesting design because the older NP-FZ50 battery uses a flat pouch type cell that fills almost the entire inside of the battery compartment. I understand Sony’s decision to use cylindrical cells in their batteries since these batteries are typically mass produced and readily available in the masses. The only downside to having small batteries use small cylindrical cells is there is a lot of “dead” space between each cell since they’re round. A pouch type cell might actually fair better in using the all available space within the battery compartment, however, pouch type cells typically have slightly lower energy densities due to their construction and production process.

Testing Methods & Results:

Each cell was individually charged up to 4.20V and confirmed with a digital multimeter. A hobby charger/discharger was used to calculate the energy capacity of the cell during discharge and voltage was monitored at the same time using the digital multimeter. The test ended when the cell reached 3.00V, although typical Li-Ion cells can be safely discharged to ~2.80V.

You will see a graph to the right that outlines the measured voltage at a given capacity rating across the test span. The cell of the Neewer NP-FZ100 battery came in just shy of 2000mAh,

Rated Capacity: 2280mAh (16.2Wh)

Tested Capacity: 1995mAh (14.4Wh) (88% of rated capacity)

Variance: -283mAh (-1.8Wh)

Pros:

+ Very high capacity 18500 cells. From my research, some of the highest rated cells available

+ Plastic casing seems well made and two piece shell firmly secured together with glue

+ It was good to see positive terminal insulator and additional tape insulation on the positive end of the battery

Cons:

- Absolutely no balancing circuit which means each cell could potentially become unbalanced as they age and reduce overall battery performance

- Cutoff high end voltage seems to be around 4.22V which is slightly over the maximum voltage for a li-ion cell of 4.20V. This shouldn’t pose major safety issues.

- Spot welds of the nickel strip material seem very poor and sometimes just 1 spot weld per cell connection

Neewer NP-FZ100 battery with 18500 cells (I added the hot glue between the cells to prevent them from separating)