They might do it how other UPS units do it, they switch the device over to the battery to run off it and watch the voltage drop. If it drops too fast the battery is bad.
-Jerry > On May 23, 2015, at 5:55 PM, Dawes, Andrew M. <[email protected]> wrote: > > Now my curiosity is piqued beyond just stopping the beep… how would a circuit > tell between a battery and a voltage source like a large capacitor? Perhaps > measure a few points of the discharge curve or something clever like that? > >> On May 23, 2015, at 4:53 PM, Jerry Biehler <[email protected]> wrote: >> >> Not sure, it seems on mine it could actually detect a battery that was not >> so hot even though it had a full charge. After a few days it would start >> beeping at me again. And for $10 you really cant mess around with tricking >> the system. >> >> -Jerry >> >>> On May 23, 2015, at 4:35 PM, Jason Barnett <[email protected]> >>> wrote: >>> >>> You could try throwing a capacitor in place of the battery. It won't help >>> in case of a power outage, but neither will a bad battery... >>> >>> >>> On Sat, May 23, 2015, 12:19 PM Jerry Biehler <[email protected]> >>> wrote: >>> No, assuming the battery charger is even a remotely recent design it is >>> measuring the voltage of the battery so you would have to have something >>> there for it to measure. And I am pretty sure these chargers are actually >>> pretty smart. I have one of these fios boxes too. >>> >>>> On Saturday, May 23, 2015, Dawes, Andrew M. <[email protected]> wrote: >>>> You would have to fake out the battery charger into thinking it is at >>>> voltage. >>> Yes, so I guess my question was: would a zener diode rated at the battery >>> voltage do that, or does it depend on the implementation of the charger? >>> >>>> They have tested good used batteries that will fit at surplusgizmos for >>>> $10. >>> Good to know, thanks! >>> >>> -Andy >>> >>>> >>>> >>>> On May 23, 2015, at 11:29 AM, Dawes, Andrew M. <[email protected]> wrote: >>>> >>>>> I have a battery backup system as part of my Fiber-to-the-home service >>>>> from a certain regional telecom provider. The battery for this system is >>>>> a 12V sealed lead-acid battery (not unlike a golf cart or scooter >>>>> battery). The trouble is that there is a system alarm when the battery >>>>> “wears out” and needs to be replaced ― it’s been beeping every 8-9 >>>>> minutes for the past few months. I’m not really interested in consuming >>>>> another battery for no real reason (I don’t need backup because if the >>>>> power is out at my house I have no need for internet access). That said, >>>>> I’m thinking of a non-destructive way to trick the charger/alarm circuit >>>>> into thinking it has a fully-charged, new & happy 12V battery. >>>>> >>>>> I don’t know much about lead-acid charger circuits but I suspect some >>>>> sort of current-limited voltage-regulated supply that alarms when the >>>>> battery no longer holds 11V or some other specified threshold. >>>>> >>>>> Would a simple 12V zener diode work, or would a charge circuit just dump >>>>> a wasteful amount of current into the diode? Perhaps a 13V zener so that >>>>> no current even flows? I have easy access to the battery terminals, and >>>>> medium access to the rest of the circuit. >>>>> >>>>> I’m ok with mangling the alarm itself, but I’d prefer a nice >>>>> “plug-n-play” solution since I know at least three friends in a similar >>>>> situation who aren’t as destructive. >>>>> >>>>> -Andy >>>>> >>>>> >>>>> >>>>> -- >>>>> Andrew M.C. Dawes >>>>> Associate Professor of Physics >>>>> Pacific University >>>>> amcdawes.com >>>>> >>>>> _______________________________________________ >>>>> dorkbotpdx-blabber mailing list >>>>> [email protected] >>>>> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber >>>> _______________________________________________ >>>> dorkbotpdx-blabber mailing list >>>> [email protected] >>>> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber >>> >>> -- >>> Andrew M.C. Dawes >>> Associate Professor of Physics >>> Pacific University >>> amcdawes.com >>> >>> _______________________________________________ >>> dorkbotpdx-blabber mailing list >>> [email protected] >>> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber >>> _______________________________________________ >>> dorkbotpdx-blabber mailing list >>> [email protected] >>> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber >> >> _______________________________________________ >> dorkbotpdx-blabber mailing list >> [email protected] >> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber > > -- > Andrew M.C. Dawes > Associate Professor of Physics > Pacific University > amcdawes.com > > _______________________________________________ > dorkbotpdx-blabber mailing list > [email protected] > http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
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