New battery, but won’t start unless on a jumper box

[sellersrodshop]

Help me out here guys. Truck barely turns over like battery is low so since the battery was actually 10 yrs old, I replaced it, figuring that was the issue. As early thing with the brand new battery. Turns over very slowly but if I hook up my jumper box, it starts right up. Checked battery with a multimeter & it shows good, alternator is putting out/ charging fine & I have cleaned/ tightened/ checked the terminals & ground connection on the cables.

Truck was stored at a friends house for 6 months while I was moving & after jumping it off initially, did fine on the 275 mi trip over a couple weeks ago.

Any ideas on what to check/ test next? Thanks!