formulas and calculations

/rant on/ ok, i had to ask this question because i could not search for it in a way that would not drive me any crazier than i have been so far. I am building a calculator for windows and android, and I have plans for various features not found in any other app, and i want to offer it here, eventually. But i'm having so much trouble wrapping my brain around all the formulas, the calculations, the battery chemistry, the rules, the limits, and so on. its all driving me crazy. /rant over/

In Will's videos (his last and recent others) he is using a heat gun to run a test on a battery he is building (or talking about).
And, he also goes on to say that it will take 5 to 6 hours before the battery (or system) shuts down because he is measuring performance, etc.
The amp-hour he states (typically) is "100 Amp-Hour".

The question: what is the constant wattage that he is using in that test?

1500w usually

He often shows the Wh meter screen... it will have the ampdraw, and the voltage showing. A 6 hour test would be a pretty low draw on 100Ah

in his latest video (Renogy "Smart" 100Ah LiFePO4 Battery Tear Down --> ) at 6:07 he shows the monitor, and it says (13.5V, 21.9A, 295W) and after coming back about 5 hours later, the monitor showed (10.2V, 26.2A, 268W) before finally shutting off. I did not see 1000w or 1500w.

So, I must have misunderstood, that he is using a 1500W heat gun, but that he is using a low setting of 300 watts and running that for 5 to 6 hours. Because, for 6 hours at 1500 watts, that's a good heater for my minivan at night, though I would use two small 250 watt heaters (called, "my heat") for much longer hours. But, I don't know. I'm confused with trying to do the math for calculating load or run times for a given device like a 250 watts heater.

JohnLM said:

in his latest video (Renogy "Smart" 100Ah LiFePO4 Battery Tear Down -->

) at 6:07 he shows the monitor, and it says (13.5V, 21.9A, 295W) and after coming back about 5 hours later, the monitor showed (10.2V, 26.2A, 268W) before finally shutting off. I did not see 1000w or 1500w.

So, I must have misunderstood, that he is using a 1500W heat gun, but that he is using a low setting of 300 watts and running that for 5 to 6 hours. Because, for 6 hours at 1500 watts, that's a good heater for my minivan at night, though I would use two small 250 watt heaters (called, "my heat") for much longer hours. But, I don't know. I'm confused with trying to do the math for calculating load or run times for a given device like a 250 watts heater.

Click to expand...

250 watts used for 1 hour is 250 watt-hour.
250 watts used for 2 hours is 500 watt-hour.
Number of watts multiplied how many hours equals watt-hours.

250 Watts times 2 heaters equal to 500 watts.
500 watts for 6 hours equal 3000 watt-hours, or 3 kilowatts-hours, 3kWh

(https://www.techwalla.com/articles/how-to-calculate-amp-hours-by-watt-usage)
Amp-Hours to Watts Equation
There isn't an equation for amp-hours to watts directly, but with watt-hours, you can make use of the simple relation:

Amp-hours × Volts = Watt-hours

RESOLVED

Okay. I got it now. I finally figured it out.. how to calculate the load/run times.. at least for this example.

Will was using a low heat setting (300 watts) on his 1500 watt heat gun. Thus, (1200 div 300 = 4 hours of run time).

The reason he says 5 to 6 hours is simple. His heat gun's low-wattage setting is fluctuating during the test process: You see, as warmer air increases in his work-space lab area, the heat gun compensate by decreasing the wattage, and as cold/cooler air increases in his workspace, the heat gun compensates by increasing the wattage, thus a low wattage setting (ie, 300 watts) will fluctuate between 250 to 300 watts during that 5 to 6 hours test process. And, that does also explains the "amp" changes as well.

So, the reason the 4 hour run time is not met (and is more 5 to 6 hours) in the above test process is because the heat gun is constantly adjusting the wattage output of the heat. Thus, the more the lower wattage of the heat gun during that time period, the longer it will run. So, if the gun is mostly under 300 watts (ie, 268 watts) the run-time will be longer, or roughly 5 to 6 hours. That makes a whole lot more sense now!

An additional follow-up to Resolved

Remember, Will posted his final findings of 1370 Wh's.. so roughly 5.4 hours of run time.