Fred James wrote: > Keith Lofstrom wrote: > >> I fiddled a bit with the "Auxilliary Power Supply DC 12V" input to >> my FIOS BBU. >> >> The barrel connector seems to be a 0.15 inch barrel (approximately >> 6mm), center positive. I clipped the connector and cable off an >> obsolete wall wart, and proceeded. This is the same power connector >> as some of the older Nokia cell phones, IIRC. >> >> I set up a lab bench power supply with current and voltage limits, >> and connected it to the cable. When I increased the voltage above >> 12.5V , the "Auxilliary Power Source" light on the front panel lit >> up. The BBU drew less than 10mA. I dialed it up to 13.5V, about >> what a car battery puts out, and set the current limit to 5 amps. >> Since the unit draws 20W from the line in normal operation, I >> assumed that would be enough. >> >> I pulled the line power input to the BBU, the unit went on battery >> as intended. I pulled the internal battery connection, hoping it >> would use the auxiliary power instead of the internal battery, >> and the BBU shut down, without drawing current from the auxiliary >> jack and bench supply. It might have been a startup surge, so I >> tried again with 0.086 farads across the supply. Again, shut >> down, no current from the bench supply. I don't want to try a car >> battery directly, too much current if something shorts. >> >> So - a mystery. Perhaps there is some protocol on the wire to the >> approved external device. For extended life, use an external UPS >> on the line input, I guess. >> >> Keith >> >> > Keith Lofstrom > According to what I have read (online manual for the unit I have > (CPL28U12) - you didn't mention your model) ... you are/were almost > there ... there is (again, on my model) a button marked "Battery > Emergency Use" (next to the Alarm Silence button), which (although > Verizon fails to mention it in their documentation) is intended for > emergency use as follows ... > "Press the button once to use the reserve battery capacity and/or > the auxiliary battery capacity after low battery shutdown. The unit > will emit a confirmation beep." > ... as an additional note, the battery is a 12 V 7.2 AHr battery - I am > not sure what that would equal in amps from a bench power supply, Amp-hours vs. amps isn't entirely meaningless, but it's not terrifically meaningful in a battery vs. bench supply shoot-off. Battery capacity is rated in amp-hours, which along with the voltage tells you roughly how much energy is stored in the thing. A battery's ability to deliver current is measured in amps. All else being equal, a bigger amp-hour rating indicates a greater ability to deliver current, but there are potentially huge differences in construction from one battery to the next which drastically affects the capacity vs. current-delivering capability trade off.
(Having said that, most sealed gel-cell batteries for equipment power use are mostly designed for a minimum 10-hour discharge time, meaning you wouldn't want to pull more than 720mA out of that 7.2A-hr battery, and you could expect it to last 10 hours in that service). Putting a bigger battery on there will give you a longer discharge time, but may confuse the heck out of any charging circuit they may have built into the thing. > but I > don't think that was the cause of the NoGo in your test, as you didn't > mention pushing the Battery Emergency Use button. > Thanks for the input - that sounds (correct me if I am wrong) as if one > were to connect the free ends (say with alligator clips attached?) of a > cable of the description you gave above to a fully charged 12 V 7.2 AHr > battery (i.e., the same type as the one in the unit itself), and the > barrel end of that cable to the BBU auxiliary port provided, one could > be good to go? First making sure polarity on the cable was correct, of > course. > Regards > Fred James > > _______________________________________________ > PLUG mailing list > [email protected] > http://lists.pdxlinux.org/mailman/listinfo/plug > > -- Tim Wescott Wescott Design Services Voice: 503-631-7815 Cell: 503-349-8432 http://www.wescottdesign.com _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
