Looks like it was half written. But, step #1 is pull up it's spec sheet and replicate their capacity testing method. At least for single cells. For packs there

Looks like it was half written. But, step #1 is pull up it's spec sheet and replicate their capacity testing method. At least for single cells. For packs there's not much you can do but buy from trusted places- manufacturer, bhphoto (for cameras). 18650batterystore has always been good to me, at least for the 300 Samsung 25R's I bought.