So, this is what the DTSE NP-FV100 aftermarket battery does at indicated 20% in the X70 viewfinder...embarrassing. Should also let you know that when put on the charger, the reading still indicates 20%. Early use, the battery would display END at 40% as indicated on the charger. :-)

https://youtu.be/dOLwL8H-bX4

"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey. It's unwise to pay too much, but it's worse to pay too little. When you pay too much, you lose a little money - that's all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do. The common law of business balance prohibits paying a little and getting a lot - it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that you will have enough to pay for something better."
-- John Ruskin

Heh Doug...in this brave new world, we have integrated handicapping mechanisms, in the form of "chips". I have had amazing luck with DTSE batteries, in the NP-F series, such as the 570 and 970, but the chipping of their X70 batteries seems to not be fully compatible. I had their BP-U60 batteries for my X180, and except for the % remaining discrepancy, they worked much longer than the OEM batteries of the exact same size.

Paul