... I found this brand on-line called - Big Crank ETX20L battery. Has anybody had used this brand?
Everyone needs a "Big Crank", or so I've been told
I bought an Interstate (brand) sealed AGM from my local Ace hardware store 4-5 years ago. I think it (I have two C-10's in the shed) just gave up the ghost. I do know I haven't bought a battery in four plus years, and both C-10's run the same battery.
It's not the cheapest, but is comparable in price to online battery dealers, and it supports my local store to boot.
FWIW, the defunct battery carries a "YTX20HL-BS" model number. And it's about 1/8" shorter in height to the OEM flooded lead-acid battery. A hunk of wide foam weatherstripping on the bottom of the tool tray solves that issue.
Rick