Stop in for a cup of coffee

So, 2 weeks ago, buddy says his battery is a pos.
Grab new battery and install it.
I promptly bring old battery into shop and throw a 2 amp charge into it. Next morning, load test.
400 amps and climbing under load, holding 10 volts. Nope,nothing wrong with battery.
Deep discharge. And wont take a fast charge.
Your buddy probably didn't charge his battery and if he did he probably didn't test it. I did both twice so far. It only carries around 12.5 volts and fails a load test. It will only load to 150 amps. My charger does 12 volts only so on the wrong setting is not an issue.