NO. 39,600 Watt/ Day
You are just trying to confuse the poor OP whose batteries will be drawing current to meet his objective over seconds, minutes, hours, days, etc. And he really needs to understand how much capacity his charged battery will be able to deliver over a certain period of time.
AND WHILE WE ARE ON THE TOPIC, ALMOST EVERY LITHOUM IRON PHOSPHASTE BATTERY HAS A C1 AND OR C2 RATING ON THE SPECS OR LABEL. C1 represents the maximum charging or discharging amps for a period of 1 hours. C2 represents the mazimum charging and discharging amps over a 2 hour period.
Older flooded batteries and glass mat usually have a C20 rate on them, the current output (discharge) over a 20 hour time frame for use of the battery.
Oh my goodness… you poor confused soul.
Wh is a unit of energy measurement…
Watt/hour is a random jumble of words. As is watt/day…
Stop.
Just stop.
When dealing with solar, thus trying to understand energy storage there are two measurements.
Ah, and Wh.
That is it.
In the case of lithium batteries, Ah is the combination derived from the nominal voltage of, for LFP cells, 3.2V per cell x the rated Ah of the bank.
A 48v 100 Ah bank is nominal voltage of 51.2V times 100… so 5120Wh
Now, the kiln in question is rated at 1000W.
He has stated it pulls max of 13.5A and depending on the voltage that amperage could be from 110v or 120V…
That would be approximately a max of 1620W… so 1620W is the absolute max the inverter NEEDS to be sized for.
We do not know what the duty cycle of the kiln is, and in all likelihood, if changes based on environment. Airflow, temp, etc.
The max hours the OP has stated they wish to operate the kiln for is 8.
So, the MAX the battery bank needs to be sized for is 12,960Wh
Odds are the 1620W is only for a few seconds as the cold kiln warms up to temp. Then it likely pulses anywhere from 250W if as mentioned they never run it on high… so it could have a 250-1000W setting. Knowing exactly what the Wh usage is over those 8 hours…