[Coco] Off-topic question for electronics wizards

[Dave Philipsen]

I've seen these units before (Verizon FiOS ONT).  The battery is a standard lead-acid gel type.  These types of batteries almost always use a charger which checks battery voltage and applies a charge if the voltage falls below a preset level.  In my opinion, you have a couple of options here.  But these easiest one to try might simply be a small electrolytic capacitor.  You could probably get by with something like 100 microfarads rated at 25 volts.  Disconnect the battery completely and connect the electrolytic capacitor in its place being sure to observe polarity (electrolytics have a nasty way of acting like a firecracker if they're hooked up backwards).  The unit will initially see the electrolytic as a dead battery, try to charge it up, which it will do in a matter of a fraction of a second, and then believe it is always charged.  If the capacitor leaks down in charge a bit the charger will just continue to keep it "topped up".  The capacitor should last for years; much longer than a lead-acid battery.  And, it shouldn't cost you but a buck or two.

Dave Philipsen




Date: Sat, 28 Feb 2015 20:02:00 +0000
From: Christopher Barnett Fox<cbfox01 at syr.edu>
To: CoCoList for Color Computer Enthusiasts<coco at maltedmedia.com>
Subject: [Coco] Off-topic question for electronics wizards
Message-ID:<D11788E6.1C83A%cbfox01 at syr.edu>
Content-Type: text/plain; charset="utf-8"

Hey folks,

Sorry to send out an off-topic message, but it does relate to electronics,
so perhaps not entirely off the mark. I have a pretty basic question that
could probably be answered very quickly by someone with enough background,
and this list seems to have ample supply. I confess while I'm very
interested and willing to learn, I'm an electronics amateur.

My Verizon FiOS ONT backup battery, a GS Portalac PX12072 SLA, needs to be
replaced. This is a 12V 7.2Ah battery, used only to maintain voice
services in the event of a power outage. I do not have Verizon land-line
service (or any land-line service, for that matter), and only use
Verizon's FiOS broadband internet. The BBU doesn't provide any backup
supply for data services.

So, I don't want to spend the ~$20 to replace the battery, but the darn
ONT won't stop complaining about the missing/presumed dead battery, with
an obnoxious BEEP every five minutes or so.

Here's my line of thinking... could I "trick" the ONT's battery backup
unit into*thinking*  it has a fully-charged battery by just using a 120V
AC to 12V DC transformer? I have loads of spare "wall wart" supplies
around, and I'm sure I could scrounge one up that provides 12V DC. Does
the output amperage matter?

Thanks for your time and expertise!

Christopher