[time-nuts] Backup DC power with current battery technology?

[John Ackermann N8UR]

I need to replace the batteries in my 28 VDC power distribution system 
in the clock room.  It's currently two series 12V AGM batteries with an 
IOTA Engineering float charger.

This system has two purposes: (a) primary power for some OCXOs and other 
gear; and (b) failover power for some AC/DC gear like HP standards. 
Under normal conditions, power draw is 2 or 3 amps.  During mains 
outage, it could reach 10 amps.  Now that I have a house generator, long 
run-time isn't a big issue so 25 Ah or so of capacity is plenty.

I haven't explored LiFePo4 batteries until now, and I'm having trouble 
finding a charger that can provide significant continuous load current 
while maintaining a battery floated across the line.  Does anyone have 
recommendations for something like this?

Thanks,
John