Confused beginner trying to spec for a kiln.

[NOKURSOXOV]

hi, I have a Kim that is 110 V. 1000 watts and draws 13 1/2 A.

I have a lot of low-voltage, hobby experience, but that doesn’t seem to be helping me.

i’m confused about the battery capacity that I would need to run the appliance.

I have nothing started, but was looking at a mobile set up to operate the kiln at shows.

The kiln cycles on and off like an oven range, and is never turned up over half.

I would like to be able to use it for 8 hours at a time.

 

[doing it different]

What battery voltage do you want to run? You kinda need to know how much it runs at a given temp inside a d outside.

 

[Supervstech]

Ok, you know the wattage, so now you need to know the accumulated runtime.

Best you can do is plug itninto a kWh log meter like a kill-a-watt meter and see what it uses.

You can estimate, but best is to measure.

1000W x 8 hours would be 8kWh
The machine doesnt run all the time, so there is a percentge of operation called duty cycle that would change based on conditions.

If you had 8kWh, it would likely handle the job.

4kWh might suffice.
2kWh with solar running might do it.


Do you have any equipment yet?

 

[doing it different]

Get something like this in 120v version
And figure out total watts used... that will give you a good idea how big a battery you need.

 

[NOKURSOXOV]

Ok, you know the wattage, so now you need to know the accumulated runtime.

Best you can do is plug itninto a kWh log meter like a kill-a-watt meter and see what it uses.

You can estimate, but best is to measure.

1000W x 8 hours would be 8kWh
The machine doesnt run all the time, so there is a percentge of operation called duty cycle that would change based on conditions.

If you had 8kWh, it would likely handle the job.

4kWh might suffice.
2kWh with solar running might do it.


Do you have any equipment yet?

None yet, I was trying to get ducks in a row

 

[glandpuck]

When your 120 volt kiln is heating, it is capable of drawing 1,620 watts at 120 volts. Generally, there is a thermostat that regulates the temperature, like on a dryer or oven that will turn on and off the heating element once the set temperature is reached to maintain the temperature desired. It is almost always a simple ON and OFF event, not a system with multiple stages of changing wattage to maintain heat. Those controls are expensive like in modern variable speed blowers and HVAC systems.

So 1,620 watts to heat, then maybe an average of 860 watts per hour for the remainder of the cycle.

See my comment below which corrects my original math error in this post, which I have deleted so my stupidity is not present for future readers to laugh at.

My bad. Sorry.

 

[400bird]

When your 120 volt kiln is heating, it is capable of drawing 13,500 watts at 120 volts.

What? The first post said 1,000 watts.
Or following the math (120v x 13.5 amps) maybe 1620 watts.
Where does 13,500 come from?

 

[Supervstech]

I certainly do not see the need for nearly that much capacity, or output...

The max usage the kiln would ever need is 13A, or 1100W... say you oversize it so the load doesnt stress the inverter, you get yourself a nie 2400W all in one inverter, pair it with 50% more battery than you calculate, somewhere between 3000 and 10000Wh

Thats a 5kwh server rack battery or two...

I dont understand why 7kw plus inverter would be needed.

 

[glandpuck]

What? The first post said 1,000 watts.
Or following the math (120v x 13.5 amps) maybe 1620 watts.
Where does 13,500 come from?

WELL I GOOFED ON MY MATH. I WILL EDIT THE POST.

SO THE KILN CAN DRAW 13.5 AMPS. THAT IS AT 120 VOLTS. THAT IS 120 X 13.5 = 1,620 WATTS in one hour. If it draws 7 amps to keep the temperature and we heat for 2 hours, then it would use 840 watts for 1 hour and 560 watts for 2/3rds of an hour. So total for 2 hours would be 1,620 + 840 + 560 = 3,020 watts or a little over 3 kW. So a 3kW inverter would do the job along with a single server rack battery.

 

[mikefitz]

,,

would like to be able to use it for 8 hours at a time.

110 volts and 13.5 amps is 1485 watts, if you are using an inverter you need at least a 2000 watt version, perhaps a 3000 watt model to give an operational margin. To power for 8 hourx at full power, that's 11900 watt hours. For some of the 8 hour period it will be duty cycled, let's guess on 9000 watt hours. A single 100Ah fully charged 12.8 volt lithium battery holds 1500 watt hours. Thus you need the equivalent of six 100Ah lithium batteries.
You can use a 12 volt or 24 volt or 48 volt system.
I suggest using a 12v system, 2000 to 3000 watt 12v inverter, and 3 off 200Ah batteries, ( connected in parallel).

It would be useful to measure the actual power used over a typical 8 hour demo.

 

[Supervstech]

WELL I GOOFED ON MY MATH. I WILL EDIT THE POST.

SO THE KILN CAN DRAW 13.5 AMPS. THAT IS AT 120 VOLTS. THAT IS 120 X 13.5 = 1,620 WATTS in one hour. If it draws 7 amps to keep the temperature and we heat for 2 hours, then it would use 840 watts for 1 hour and 560 watts for 2/3rds of an hour. So total for 2 hours would be 1,620 + 840 + 560 = 3,020 watts or a little over 3 kW. So a 3kW inverter would do the job along with a single server rack battery.

Im not sure wht you keep adding wh to show W usage...

1650W is 1650W... running 24/7 it will only be 1650W...

The inverter need only be sized to output 1650W.
I would install cushion for cooler operation, and additional loads if desired, but the KILN will only ever draw the 1650W...
Period.
You do have to size the battery bank to provide voltage for the Wh duration needed.

So, a 5kWh or two is wise.

 

[glandpuck]

Im not sure wht you keep adding wh to show W usage...

1650W is 1650W... running 24/7 it will only be 1650W...

The inverter need only be sized to output 1650W.
I would install cushion for cooler operation, and additional loads if desired, but the KILN will only ever draw the 1650W...
Period.
You do have to size the battery bank to provide voltage for the Wh duration needed.

So, a 5kWh or two is wise.

Nope. Running 24x7 it will consume 1650 watts x 24 hours = 39,600 watts. If you have 2 5.1kW batteries, they will not supply the needed power.

 

[niktak11]

Nope. Running 24x7 it will consume 1650 watts x 24 hours = 39,600 watts. If you have 2 5.1kW batteries, they will not supply the needed power.

1650W for 24 hours is 39600 Wh (watt-hours)

 

[Supervstech]

Nope. Running 24x7 it will consume 1650 watts x 24 hours = 39,600 watts. If you have 2 5.1kW batteries, they will not supply the needed power.

Wh are not the same as Watts...

1650 watts, running for 24 hours is still 1650 watts from the inverter.

Please re read my posts, try to understand the wording and the difference between Watts of demand, and Wh of storage.


OP states they only have a need for 8 hour runtime, so his 1000W kiln that only draws 1650W at startup and likely settles during the 8 hour run will likely not need 5kWh of battery, but having 2 gives better cushion.

 

[Supervstech]

1650W for 24 hours is 39600 Wh (watt-hours)

Yup, and always 1650W (or less due to heater draw drop at temp)

 

[50ShadesOfDirt]

I think OP's options are:
- store-bought solar generator (with appropriate number of battery packs from that vendor)
- diy solar generator hand-truck (plenty of vids out there) ... should save lots of money
- (somewhat) inexpensive (very small, but correctly sized) fuel generator w/ noise cover (plenty of vids out there)

Depending on what shows, what accommodations, etc., you'll sometimes find shows with power, shows without but allowing gens, and perhaps something where you want absolute quiet (a pure solar gen, recharged at home or wherever when show is done).

Depending on additional requirements, like camping, backup power, etc., one or more of the options above will handle double- or triple-duty:
- use solar gen at show(s), then use for camping at/near same show
- use for emergency backup at home

Could even look into combining the solar gen with the fuel gen, and downsizing the solar-gen, as fuel-gen or shore power connections are there for recharge as the buffer drains from the kiln.

Hope this helps ...

 

[glandpuck]

1650W for 24 hours is 39600 Wh (watt-hours)

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.

 

[400bird]

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.

No
And you don't get to add in non-standard measurements and accuse someone else of confusing the OP. Plus you are wrong.
1650 watt hours is 1650 watts consumed for an hour straight. 1650 watts consumed for a full 24 hour day would be either 1650 watt days or 39,600 watt hours.
The conversation from days to hour is *24, so the math is simple enough for you to verify.

And with lithium batteries the C rate is not the same as lead.

 

[HRTKD]

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.

This is incorrect in that you have it backwards. The shorthand for LiFePO4 batteries puts the number to the left of the C. Rather than explain this, I found a random page on the Internet, of which there are thousands, that correctly explains the C rating for LiFePO4.

Battery C Rating Explanation And Calculation | ELB Energy Group

The battery C rating can be defined as the measure at which a battery is discharged relative to the maximum capacity of the batteries.

www.ecolithiumbattery.com

 

[Supervstech]

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…

 

[doing it different]

This is incorrect in that you have it backwards. The shorthand for LiFePO4 batteries puts the number to the left of the C. Rather than explain this, I found a random page on the Internet, of which there are thousands, that correctly explains the C rating for LiFePO4.

Battery C Rating Explanation And Calculation | ELB Energy Group

The battery C rating can be defined as the measure at which a battery is discharged relative to the maximum capacity of the batteries.

www.ecolithiumbattery.com

I have started seeing 1P in spec sheet.... does anyone know what P stands for? I assume it means the same as C ......

 

[Supervstech]

I have started seeing 1P in spec sheet.... does anyone know what P stands for? I assume it means the same as C ......

We would need to see the frame of reference for the 1P spec…

It could mean 1parallel… but that seems odd.

 

[doing it different]

I have seen it somewhere else the other day... it clearly means C from my understanding.

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[HRTKD]

I think their use of P is a typo.

 

[jgh]

1P is specifying a rate for constant power rather constant current - ie. taking account of the voltage changing with SOC.