Salt silicate batteries continue charging at 100%

I have an offgrid Deye 8K inverter with 8x 12v 250AH salt silicate batteries in a 4S2P configuration (48V, 24kWh).

I have grid (gen) charge enabled to 99%, but the batteries have hit 100% and are still charging, albeit slowly (starts near 2kW and I took this screenshot about 1.25 hrs later at ~700W):



The system looks like this in Solar Assistant:



Is this normal and expected behavior? I have the battery voltages set as follows:

Battery float charge voltage: 55.2 V
Battery absorption charge voltage: 58.8 V
Battery equalization charge voltage: 55.2 V

When I reduce the charge target to 98% it reaches and holds 98% as specified. But when I set it to 99% or 100%, it seems to keep charging. I have not left it like this for more than a few hours (don't want to overcharge them, just in case that's a concern).

If still charging, the battery hasn't reached the target voltage. Not sure what is reporting 100%, but they aren't there yet.

Or it might have finished the main bulk/absorb charge and changed to the float balancing.

I should clarify, it was still charging at 58.8 V. I also would have expected it to switch to float charging (55.2 V) by now too.

Is the inverter monitoring the current the battery is absorbing and waiting for it to decline below a certain level? Or does it stop charging every so often so it can check the actual battery voltage? (The battery voltage reading in the inverter while charging simply shows 58.8 V, which does not seem particularly useful.)

Thanks for the earlier replies!

Another odd incident today; when a load was turned on that reduced the charging current to the silicate batteries, the battery SoC suddenly jumped from 85% to 100%, but the battery kept absorbing plenty of power after that point (up until PV input stopped for the day).



For me this again begs the question of how is SoC calculated and whether there's anything I need to do to adjust it?

@Watts247 - Ian Roux could you confirm if I have these settings correct and/or what other settings I might need to change on a Deye/Sol-Ark inverter for the silicate batteries?

Battery float charge voltage: 55.2 V
Battery absorption charge voltage: 58.8 V
Battery equalization charge voltage: 55.2 V

Many thanks.

Hi guys,

I have these batteries also have and struggled to identify the true max/min voltages.

The batteries say:

• 13.5-13.8v standby (does this mean storage voltage?)
• 14.4-15v cycle use (does this mean max?)

Mine are in 48v config and I was told to run them to 56.4 bulk, 54v float. That translates to 14.1v max charge which is lower than the "cycle use" printed on the battery.

I also have been unable to gather the true minimum safe voltage or what voltage = 0% SOC so I can stay away from there.

Ian from Watts 247 has been great to deal with and helpful; I've bought a lot of stuff from him but I do wish I had clarity on how to treat the batteries.

I do notice that if you charge to say 56.4v and it stops charging, any load quickly drops the voltage like a lead-acid battery. The Gro-watts I'm running don't seem to act like that have an absorption stage but maybe I'm not understanding. I just know as soon as you put any load on a fully charged battery, your voltage is way what you charged it to, within moments.

@solarfunnc we should put our heads together