No sciences were harmed during testing
I almost have to say this was a test jokingly. There is absolutely nothing scientific about this. I just plugged in a fully charged battery, noted the time, and than started playing radio with a POTA activation. However while no controls are in place, calculations made, or measurements taken; this method of "mess around and find" does give some tangible results as to what to expect in real field conditions. For they were real field conditions.
What and How
6Ah LiFePO4 battery from DenCo
POTA activation on multiple bands primarily calling CQ
Yaesu FT-891 HF & 6 meters transceiver using 100 watt transmit power
Yaesu ATAS-120 antenna
With an estimated 40-45% duty cycle, I got 1 hour and 12 minutes of battery life and 50+ contacts before I lost power and had to switch batteries. Clearly more than enough for a SOTA or POTA activation. If was using the radio in a less intense manor, like for checking into nets, etc. I would expect to have power for a acceptable amount of time for a more serious portable radio endeavor, like working a public event, etc.
Great size battery for my uses
I like this 6Ah size battery quite a bit. As shown here, it has enough power for a 100 watt POTA activation, yet is small and light enough to not be a hindrance to pack in a few miles down the trail for when I want to get out a ways from the crowds. Pair this battery with one of my QRP rigs and I may be able to get a few days worth of On The Air activations. Obviously I'll have to mess around and find out about that too!
First things first
While seeing what kind of life one could expect from a battery like this with QRP, I do have another QRO "test" to carry out sometime relatively soon. I'd like to see how long this 6Ah battery lasts if I dail back the transmit power to 50 watts.
Many portable operators who participate in the On The Air activities like to run there QRO rigs at a lower transmit power setting. Say 75 or 50 watts instead of the full 100 watts. I tend to go the full power the radio is made for. Figuring lets get as many contacts as I can in a short time, by doing what I can to make as many hunters or chasers can hear me. While using less power will only cost me a few S units, sometimes every S unit counts when trying to be heard.
With that said, it does make sense to lower the power if it extends the life of your battery. If there are lots of hunters or chasers that can hear you on 50 watts, you'll have more battery time to work more. Kind of a "slow and steady wins the race" way of looking at it.
I plan to do a few more POTAs with this battery and track the life I get out of it. Both more samples at 100 watt and also several times at 50 watts to average things out a bit. It will be interesting to see how what the delta is with battery life between 50 and 100 watts.