Batteries not charging fully?

[JohnRichard]

After following the "Milk Crate" build videos, last year I assembled my own system which consists of the following:

1x DROK 48V Power Supply
1x RICH SOLAR 20 Amp 12V/24V DC Input MPPT Solar Charge Controller
2x 12v 100ah lithium batteries (I'll have to look up the brand) wired parallel.

Anyhow, charging from solar works fine with two Renogy panels in series.
Charging from the 48v power supply from a house 110v supply doesn't seem to charge the batteries beyond 13.8v.

I set the power supply to 14.4 or sometimes 14.9 (whatever the charger feels like putting out on the day), and leave it. I've left it overnight. I've left it 24 hours.
As soon as I unplug the charger, the battery voltage drops to 13.8.

Originally I had the charger supply power to the PV input on the MPPT, but then I wired it directly to the battery through a fuse block, bypassing the MPPT.
Nothing changed. Its possible the BMS inside the batteries is limiting the charge, but I thought I would ask if anyone else has seen these types of issues?

Thanks for any advice.

 

[Culchee]

After following the "Milk Crate" build videos, last year I assembled my own system which consists of the following:

1x DROK 48V Power Supply
1x RICH SOLAR 20 Amp 12V/24V DC Input MPPT Solar Charge Controller
2x 12v 100ah lithium batteries (I'll have to look up the brand) wired parallel.

Anyhow, charging from solar works fine with two Renogy panels in series.
Charging from the 48v power supply from a house 110v supply doesn't seem to charge the batteries beyond 13.8v.

I set the power supply to 14.4 or sometimes 14.9 (whatever the charger feels like putting out on the day), and leave it. I've left it overnight. I've left it 24 hours.
As soon as I unplug the charger, the battery voltage drops to 13.8.

Originally I had the charger supply power to the PV input on the MPPT, but then I wired it directly to the battery through a fuse block, bypassing the MPPT.
Nothing changed. Its possible the BMS inside the batteries is limiting the charge, but I thought I would ask if anyone else has seen these types of issues?

Thanks for any advice.

If you divide the 13.8v between what I imagine is a 12v battery made up of 4 cells... then the cells are resting at 3.45v ... this seems to be quite normal... it’s possible to push each cell to a higher voltage.. as you said... possibly the bms limiting the charge... so I think this is acceptable...

 

[Culchee]

After following the "Milk Crate" build videos, last year I assembled my own system which consists of the following:

1x DROK 48V Power Supply
1x RICH SOLAR 20 Amp 12V/24V DC Input MPPT Solar Charge Controller
2x 12v 100ah lithium batteries (I'll have to look up the brand) wired parallel.

Anyhow, charging from solar works fine with two Renogy panels in series.
Charging from the 48v power supply from a house 110v supply doesn't seem to charge the batteries beyond 13.8v.

I set the power supply to 14.4 or sometimes 14.9 (whatever the charger feels like putting out on the day), and leave it. I've left it overnight. I've left it 24 hours.
As soon as I unplug the charger, the battery voltage drops to 13.8.

Originally I had the charger supply power to the PV input on the MPPT, but then I wired it directly to the battery through a fuse block, bypassing the MPPT.
Nothing changed. Its possible the BMS inside the batteries is limiting the charge, but I thought I would ask if anyone else has seen these types of issues?

Thanks for any advice.

Forgot to add that pushing each cell past 3.45v is ok to a degree... but won’t help battery longevity..so it seems the bms is doing a good job...