charger won't go below 9 amps?

2001 ds 48 volt. 4 year old batteries. Charger won't shut off, stays at 5 amps .

So today, i started out by measuring battery voltage. Voltage was 48.9 volts.

I plugged a charger in, and let it run for about 6 hours ( it is still plugged in now).

When i originally plug the charger in, it started out at 12 amps, for a few minutes, then went to 10, and hasn't dropped more than 1 amp since.

So i unplugged that charger and plugged in a second charger. The second charger started out at 9 amps also,. My understanding from Sergio, was when you plug a charger in, it should immediately go to about 15 amps, then drop, if batteries are charged.

I have tried 3 different chargers, all start out at 9 amps. I also bypassed the obc, and used a obc bypassed charger, and that charger also starts out at 9 amps.

Also tried a obc reset, just to make sure. So my thinking is since i bypassed the obc, and still got the 9 amp starting point, that should eliminate the obc from this equation. So although the batteries still seem strong, and when charging, they all range between 8.8 and 9.1 volts at 9 amps,
I'm thinking the batteries must be the problem??

Any input?