[vcf-midatlantic] OT: FIOS Voice Backup Battery Replacement for 12V 7.2Ah

Herb Johnson hjohnson at retrotechnology.info
Tue Jul 19 12:12:45 EDT 2016

> How do I know that the battery needs recharging vs. failing?

Look for a date code, stamped or printed on the battery. But frankly, 
given the application - your phone and networking! - I'd say replace it 
every three-four years with a fresh battery. And keep one around 
on-charge for backup.

You can trickle charge old batteries with a few-dollar 12V trickle 
charger - anything that puts out 10% of rated current at voltage (720mA 
at 14 volts max) will not cook your battery.

Safety compels me to say: don't charge batteries unattended. There's a 
small chance of overcharge or shorting and excessive current, to lead to 
a fire.

As to where to get these batteries. Many places that sell electroniics 
and car batteries locally sell them, at higher prices. Alarm companies 
use them, emergency lighting uses them, so those vendors may source 
them. Or you can mail-order them, and pay several dollars shipping. 
Jeff, without further comment - this is a once every three-four year 
purchase, so you decide how much shopping you want to do. This is a 
$15-$30 purchase.

check the date of any battery you buy off the shelf. If it's more than a 
year old, I'd not buy it at retail prices.

The size and placement of the terminals matters, as noted previously. So 
carry the old one to compare, or measure and photograph it, so you don't 
"ooops, the terminals are backwards, the wires won't reach, the 
connectors won't fit".

Rule of thumb for lead type batteries: the heavier the battery for the 
same "ratings", the more capacity you'll actually have. The lead carries 
and produces the current; more lead means more current. battery makers 
won't waste lead but a more expensive brand won't cut lead.


PS: this is vaguely on-topic, for the robot builders. Gel batteries are 
often used in hobby robots, they are common and cheap as used/discards.

Herbert R. Johnson,  New Jersey USA
http://www.retrotechnology.com OR .net

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