Equipment need to test new Lithium ion battery?

[arvbnb]

I am new to this forum but have enjoyed Will's Youtube channel for some time and have learned quite a bit regarding solar systems, specifically for my vans.
I recently imported some 100a lithium ion batteries from a Chinese manufacturer and wanted to get a real world test of the actual capacity of the units.
As I mentioned they are rated at 12v - 100 amp hour
My question would be what instruments or devices would I need to get the true capacity in amps/watts?
I have seen some of the videos where Will has tested some batteries and would like to do the same...I am assuming I would need an inverter and some sort of digital battery monitor/shunt.
Thank you in advance for any useful information.

 

[Picasso]

Many options. I like this guy. https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole

 

[RogerD]

This is the unit Will uses when he tests capacity.

Amazon.com: DROK DC Voltmeter Ammeter, 0-90V 100A Digital Voltage Current Capacity AH WH Power Time Multimeter, 12V 24V 36V 48V 60V 80V LCD Battery Charge Discharge Monitor Volt Amp Watt Tester with Hall Sensor: Automotive

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