Tim Wescott wrote: > 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 >> Tim Wescott Thank you for the clarification The APC documentation indicates stringing one or more "battery packs" to the BBU - if one were to try to duplicate this with just batteries and wire, I am assuming (pardon my ignorance here) that one would want to wire those extra batteries in parallel - is that true? IIRC parallel (+ to + and - to -) delivers the same current but for longer, and series (+ to - as in a flash light) delivers a higher voltage but not for longer? Thanks again Regards Fred James
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