Specifications

Part number: B420 YS1300-4S-XS-US

Discharge connector: XT60

Balance connector: 5-pin JST-XH

Rated parameters
Dimensions	31 x 34 x 72mm
Continuous Discharge	91A
Capacity	1300mAh
Nominal Voltage	14.8V
Charge	<2C
Weight	155g

Derived parameters
Energy Capacity	19.24Wh
Energy Density	446.9J/g

Observed parameters
Dimensions	32 x 34 x 76mm
DC Internal Resistance	3-8mΩ
Capacity	~1200mAh

Photos

From the manufacturer:

Test Results

Continuous discharge:

Vaping profiles:

Continuous discharge testing yield an average of 1200mAh per pack. Accordingly, I assert that these packs are roughly 8% over-rated with respect to capcity.

At MTL wattages, these packs were able to deliver 1290mAh - within the margin of error for my testing setup. However, at 75/150W they were closer to 1150mAh.

Observations

These packs handle 10A continuous discharge well, no observed swelling and only a 4-5°C temperature increase. Unfortunately, I will have to update this when I can test at >10A.