[Coco] Off-topic question for electronics wizards

Christopher Barnett Fox cbfox01 at syr.edu
Sun Mar 1 15:36:12 EST 2015


Thanks, Gene! This SLA gel battery shows a "top charge" date of 2009, so
it's lived a long, full life. Instead of pursuing my "work around" to
avoid buying a new battery, I managed to find a compatible replacement on
Amazon for $16 shipped.

I appreciate the advice from folks on the list who responded.

Christopher


On 2015/02/28/, 7:46 PM, "Gene Heskett" <gheskett at wdtv.com> wrote:

>On Saturday 28 February 2015 15:02:00 Christopher Barnett Fox wrote:
>> 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.
>
>How old is this battery?  Nicads have about a 200-500 recharge cycles in
>them, but will grow metal whiskers and short out internally in 6 months
>or less if left on a trickle charge.  Lithiums hold a charge much
>better, and I personally have not yet had a failure in my power tools.
>
>But if its a gel-cel, a lead acid IOW, they'll typically have a working
>life of 2 to 4 years depending on how smart the charger is.
>> 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?
>
>Generally a bad idea IMO.  If the battery is sulfated, the voltage will
>rise  to 16 to 18 volts, and that wouldn't be healthy for the rest of
>the device.  If its got a shorted cell, then the voltage will for a
>short period of time, be held to under 11 volts, probably overloading
>the wall wart to the point its internal thermal fuse will clear, usually
>before it starts a fire..
>
>If its 2+ years old, in lead acid terms it doesn't owe you a thing,
>replace it. I have a couple 12 volt LA batteries sitting on the floor,
>to go into my UPS yet tonight as the nearly 5 yo batteries in it signed
>off a while back.  At a tad over $40 in the front door, those new
>batteries will replace the dead ones, and I owe the old ones a decent
>recycling.
>
>The key word here is TANSTAAFL.  As said by a C.E.T. ;-)  Plagerized from
>E. Hemingway by way of R. A. Heinlein. :)
>
>> Thanks for your time and expertise!
>>
>> Christopher
>
>Cheers, Gene Heskett
>-- 
>"There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
>-Ed Howdershelt (Author)
>Genes Web page <http://geneslinuxbox.net:6309/gene>
>
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