Monday, January 20, 2025

Unburdened by what has been: How LiFePO4 chemistry obsoleted my 12V shack PS

Before moving to Florida 2-1/2 years ago, my shack power supply was two Trojan golf cart batteries. Big, heavy mofos, full of acid and lead. They needed periodic maintenance charges which I sometimes neglected.

They were kept charged by a 200-watt solar panel on my roof and offered significant advantages to other 12V sources of power: no RF noise and no power outages due to storms.

Reliability to the max.

Then came LiFePO4 - a game-changer, a 120VAC-to12VDC power supply obsoleter. Goodbye, big ol clunky Astron.

My current (pun intended) shack supply for the past two years has been a 50AH LiFePO4 battery that runs my Hermes Lite 2 (and other radios), Neptune 100W amp, LDG autotuner, GPS clock and my keyer. Sometimes the FT-891 is online, but either way, I'm using 100 watts from the home QTH.

The battery is good for a 7 hours of non-stop, contest style activity; or, all day the way I use it, and that's if it's not attached to a trickle charger...which it always is.

Pure DC, no ripple.

I rarely operate for more than two hours a day and when I do, it's not non-stop transmitting and receiving. It's mostly just receiving. The battery doesn't break a sweat, even with the whole 100W shebang powered up. Step away for a meal and a bit of TV and the battery is fully charged by the time I can get back in front of the radio.

Same advantages of the old solar set-up but with a lighter, much smaller battery that has a better discharge curve and no special maintenance charges needed.

Less expensive as well - that wasn't the case at first, but it is now. LiFePO4 is cheaper than old-school lead-acid.

I still have the Astron but it is now the back-up for the batteries (I've never needed it) rather than batteries being the back-up for the PS. 

I know someone out there is thinking: "That's not the way to care for LiFePO4 batteries - you won't get maximum life out of them if they're often on a trickle charge".

Yes, that may be true. Rather than 2000 charge/discharge cycles, I may now only get the equivalent of 1800. I'm okay with that, given the advantages of the set-up.

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