so we have a county-level ARES exercise coming up in about 5 weeks and im trying to nail down the power side of things before i start stressing about the antenna situation. our served agency wants us to run for a minimum of 12 hours without resupply which is totally doable but the question is whether we go with a generator setup or just stack up enough battery capacity and call it good.

for context we're running an IC-7300 as the primary HF station, probably pulling somewhere around 20-22 amps at full power but we rarely actually transmit at 100 watts during net operations so average current draw is probably more like 8-10 amps if i had to guess. also have a VHF/UHF station for local coordination thats a lot less of a concern power wise.

the generator option is a 2000 watt honda eu2200i that one of our members has, quiet enough that it wont drive everyone crazy, but fuel logistics over 12 hours is a thing and honestly i hate dealing with generators at exercises because something always goes wrong. the battery side im thinking two 100ah lithium (lifepo4) batteries giving us around 200ah usable which at 10 amp average draw should be more than enough with headroom. but then i also want to run laptops and logging software and maybe a small fan if its hot out which eats into that.

antenna wise we're planning a simple linked dipole for 40/80 and maybe 20, hung between two spiderpoles. has anyone done the math on running an extended field op like this purely on lifepo4? curious if there are thermal issues with the batteries in direct sun that i should be worried about

the lifepo4 route sounds solid to me honestly. i did a similar thing last summer for a 24 hour public service event and ran two 100ah battleborn batteries in parallel feeding everything through a west mountain epic pwrgate. the IC-7300 was our main rig too and we barely touched 60% state of charge over the whole event running a mix of digital and voice. your math on the average current draw sounds about right, maybe a little conservative depending on how much receive time vs transmit you have.

the thermal thing is real though. lifepo4 doesn't like sitting in direct sun baking all day, not because it'll catch fire like some of the older lithium chemistries but the BMS in most of those batteries will start derate or even shut things down if the cells get too hot. we threw a cheap moving blanket over ours and it made a noticeable difference. just dont seal it up completely obviously you still want some airflow.

personally id bring the honda anyway as a backup even if you dont plan to use it. fuel logistics for 12 hours on a 2200 is like, what, 2 gallons? thats nothing. but yeah try to run on batteries first, generators at exercises always seem to bring drama, spilled fuel, noise complaints from the served agency, someone flooding the carb, you know how it goes.

yeah the linked dipole on spiderpoles works great for that kind of thing. we use the same setup. one thing i'll mention is if you're doing 40 and 80 make sure you account for how much real estate you need for 80m legs, at a field site sometimes the footprint sneaks up on you especially if theyre sharing a space with other agencies or the command post is weirdly positioned relative to trees or whatever anchor points you have.

on the power question i dont have strong feelings either way but 200ah lifepo4 for a 12 hour op with an IC-7300 and some aux gear should be totally fine. the laptop draw is worth metering if you havent, some of those older panasonic toughbooks people use for logging can pull 3-4 amps on their own. just do a shakedown run at home for a couple hours with everything on and watch your coulomb counter if you have one, takes the guesswork out of it