FiOS SFH ONT 612A SLA battery replacement with Lifepo4

[Xringer]

I was going to buy another SLA battery for my Fios optical fiber box.
When I saw my order history, I realized that I've spent over $100 since 2013 on these SLA batteries. Last month we took a pile of them to be recycled.
I've heard the 612A ONT runs periodic load tests on it's back-up battery before deciding to start that annoying Warning Beeper.
That's when I remove the SLA battery, stick in another used SLA battery.
It's typically a few months to a year before the used SLA batteries give up.
The other day, my last (used) spare would only charge to 9V..
So, when I saw a cool Ampere-Time "drop in", on sale for about the same price as the SLA batteries I had been buying.
I decided to try one! At first the FIOS charger warmed up(90F), but cooled off(72F) within a few hours. It's fully charged.
Yesterday, during charging, I unplugged the 120vac for about an hour to see if there was any failure because of the 6 amp limit on battery output. No problems seen.
The charger & Lifepo4 terminal connectors readings:
2-24-22 13.96 Vdc
2-25-22 13.98 Vdc
2-26-22 14.00 Vdc

Since that's lower than the recommended Charge Voltage: 14.6±0.2V
I think this new battery will only charge up to 80 or 90 percent of capacity.
Which means the life span will be longer.?.

I plan to monitor the voltage to see if there's any variation, perform random 'grid-down' test and post about any problems.

So far, I'm liking this experiment. Since I'm 76, this might be the last FIOS battery I ever change! If it fails in some non-self-destucting way, I'll use the battery in my old hardwired home alarm system.. It's SLA is about aged out.



FiOS SFH ONT 612A SLA battery replacement with Lifepo4 from Amazon.
WAS On sale for $25.49" Ampere Time-LiFePO4 12V 6Ah"
Nominal Voltage: 12.8V
Nominal Capacity: 6Ah 0.2C
Energy: 76.8Wh
Charge Voltage: 14.6±0.2V
Charger Current: 1.2A
Max. Charge Current: 3A
Discharge Current: 1.2A
Max. Continuous Current: 6A
Max. Pulse Current: 20A(＜3S)
Discharge Cut-off Voltage: 10.0V
Cell & Method: IFR32700 N60, 4S1P
*** Did not find Over-Voltage Cut-Off.!. (to prevent over-charge)
https://youtu.be/DYfS2ydD-1Y
Charge & discharge setup video 30 seconds.