Yes, the normal float voltage for flooded cell batts is 2.25 VPC. For a 48 Volt battery that is 24 cells x 2.25 = 54 volts. Some folks charge at 55 volts. Then during discharge, some consider 1.8 VPC to be the lower limit. 24 x 1. = 43.2 volts. I personally like 44 volts as the lower limit. So equipment designed to operate from a -48 volt supply is designed to span those limits at a minimum. Most would probably exceed that range by a volt or two on each end.
----- Original Message ----- From: "Cameron Kilton" <[EMAIL PROTECTED]> To: "'WISPA General List'" <[email protected]> Sent: Friday, October 10, 2008 6:50 AM Subject: Re: [WISPA] Alvarion VL Rackmount > There must be some sort of tolerance. Units work between 48 and 55v? > Something to that affect. > > -Cameron > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Gino Villarini > Sent: Thursday, October 09, 2008 4:08 PM > To: WISPA General List > Subject: Re: [WISPA] Alvarion VL Rackmount > > Iirc alvarion vl are 55 vdc > > Gino > > > -----Original Message----- > From: Tom DeReggi <[EMAIL PROTECTED]> > Sent: Thursday, October 09, 2008 3:42 PM > To: WISPA General List <[email protected]> > Subject: Re: [WISPA] Alvarion VL Rackmount > > Yes, the first place to start is to determine the Alvarion specs. 1) Max > > power or amperage draw from the Alvarion VLs, and 2) min and max Voltage > > tolerance. I don;t have that answer for you. But please share it, when > you > find out :-) > > The general rule is, you can make a combine POE system to serve > identical > distances as standalone POE systems. But you still ahve to do the math > for > stnadalone POE system. For example, You can take a 48V POE up 500 feet > easilly, to deliver JUST POWER. But data will never go that high. If > you > had to serve height beyond Ethernet POE specs, you'd then need to do the > > Power extraction up in a NEMA box on the tower. > > Again, we did not do it with Alvarion, but the way we did it was.... > > We took standard standalone POE injectors (ones without integrated PS). > Valemount Injectors that are black, square, one led, and sell for about > $5-$7. > This allowed us to have circuit board connecting both Ether jacks for > reliability. > These models allowed a wiretie to fit between the PS jack and the CAT5 > plug, > so it could be asilly secured and easilly individually untied in the > field. > We put one extra one inline for hot spare. > Now, we were doing 24v, so You need to confirm the injectors that you > selected allowed voltage level for Alvarion. > I know the little white half moons, can do 48V no problem. > If the standard 802.11 pin-out isn;t what Alvarion uses, then compensate > > with the pin-out of the Plug crimping on. > We then laid them side by side mounted flat to a plywood strip. > We actually just screwed the Strip to the rack, because we cut it to > reach > 19" rack. > It could also be glued to a Nema Box back, with construction plywood > roof > glue. > We cut the height of the strip about 6 inches, so we had 2 inched on top > and > bottom to Staple patch cable in place, with it still having room to > unplug. > IN one case we used screw in eye hooks, and then just strapped the cable > to > the eye hook for strain relief. > We then took standard two strand wire and soldered the round plugs to > them > (the kind that the standard POE required). > We then took two of those standard screw down DC bus bars (can be > ordered > from any electrician or electronic store) with like 8-12 screws on > thems, > and labeled them - and +. Then of course screwed down the wires to > them. > (Just as easilly we could have soldered the eight wires togeather, so > all > the cables were like a 8 cable bundled single unit.) > We then Used a thicker guage wire, I think it was 16-18 guage and ran > that > from the Bud Bar to our dedicated power supply. > (Many power supply types available). > > Whether it works is just doing the math of cable Voltage loss, and how > much > amperage the cable can take. See AWG chart attached. > Also see POE calculater at > http://www.demarctech.com/techsupport/poecalculate.htm > Its importnat to remember that the Voltage loss is different based on > the > amperage that is occuring at the time, so you don;t want to over power > voltage to compensate for the loss, to the extent that an inactive radio > > would be delviered voltage greater than the radio could accept. > > Tom DeReggi > RapidDSL & Wireless, Inc > IntAirNet- Fixed Wireless Broadband > > > ----- Original Message ----- > From: "Cameron Kilton" <[EMAIL PROTECTED]> > To: "'WISPA General List'" <[email protected]> > Sent: Thursday, October 09, 2008 1:18 PM > Subject: Re: [WISPA] Alvarion VL Rackmount > > >> All of your questions Tom are important and have taken those into >> consideration. >> >> Right now, I just want to figure out if anybody has done it and how. >> >> We have made a POE system that puts out 48volt and it works on the > bench >> with VL units, but when there is a significant cable run it stops >> working, I guess the important thing to find out is what is the > minimum >> and maximum voltage that can be sent to a Alvarion VL or B radio? >> >> -Cameron >> >> -----Original Message----- >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On >> Behalf Of Randy Cosby >> Sent: Thursday, October 09, 2008 1:07 PM >> To: WISPA General List >> Subject: Re: [WISPA] Alvarion VL Rackmount >> >> I have got to put a plug in for the "SuperRMS". We just installed our >> second unit. Just a great box for doing DC power control (or AC if > you >> want). Pricey, but very flexibile and powerful. Also has > temperature, >> voltage measurent, alarm contact monitoring, USB port with camera >> drivers, alert and relay scripting, linux shell and on and on.... >> >> http://www.remotemonitoringsystems.ca/rms2/ >> >> >> >> Tom DeReggi wrote: >>> There are three questions that come up... >>> >>> 1) Redundancy >>> 2) minimizing impact of failure >>> 3) Ability to remote reboot. >>> >>> We had chosen to stay with individual AC Adapter POE systems, for the >> above >>> reasons. >>> The individual AC PS adapter plugged into the AC style Digital Logger >> reboot >>> device. >>> If a PS fails, only one radio dies, and quick to replace the one PS >> for $15. >>> And if a radio locks up, we can reboot the port via Digital logger. >>> Whether or not our device is located in the Closet, mid-way on tower, >> or way >>> up the tower, its one standard method to remote access the devices, >> and >>> power them. >>> >>> So to run one cetnral power supply to power all radios.... How will >> you >>> remote reboot them? And what will you do if the main Power supply >> fails? >>> I'd only recommend doing a shared power supply if it was redundant >> with a >>> ready to go spare (two units onsite). As well, you then need to >> convert to >>> a DC based reboot device, and put the relays (or it) inline with the >> power >>> to the POE. >>> >>> Digital logger also makes a DC based model, with screw down panels. >> This >>> device could be your method to combine the DC power. However not >> positive >>> but this model might be 24V. >>> http://www.digital-loggers.com/din.html >>> . >>> I think Alvarions are 54-56V. Side note some of the old MEtrocom >> installs >>> had used 54V powersupply power plants. You might be able to find them >> used >>> cheap. I know we had picked up a few. (but didn;t have 54V gear) >>> >>> >>> >>> Tom DeReggi >>> RapidDSL & Wireless, Inc >>> IntAirNet- Fixed Wireless Broadband >>> >>> >>> ----- Original Message ----- >>> From: "Cameron Kilton" <[EMAIL PROTECTED]> >>> To: <[email protected]> >>> Sent: Thursday, October 09, 2008 8:29 AM >>> Subject: [WISPA] Alvarion VL Rackmount >>> >>> >>>> I have a bunch of Stand Alone 5.8 VL AU gear, I want to make a 12 >> port >>>> rack mount power supply for it. Has anybody tried this? >>>> >>>> Thank You, >>>> Cameron Kilton >>>> >>>> >>>> >>>> >>>> >> > ------------------------------------------------------------------------ >> -------- >>>> WISPA Wants You! Join today! >>>> http://signup.wispa.org/ >>>> >> > ------------------------------------------------------------------------ >> -------- >>>> >>>> WISPA Wireless List: [email protected] >>>> >>>> Subscribe/Unsubscribe: >>>> http://lists.wispa.org/mailman/listinfo/wireless >>>> >>>> Archives: http://lists.wispa.org/pipermail/wireless/ >>> >>> >>> >>> >> > ------------------------------------------------------------------------ >> -------- >>> WISPA Wants You! Join today! >>> http://signup.wispa.org/ >>> >> > ------------------------------------------------------------------------ >> -------- >>> >>> WISPA Wireless List: [email protected] >>> >>> Subscribe/Unsubscribe: >>> http://lists.wispa.org/mailman/listinfo/wireless >>> >>> Archives: http://lists.wispa.org/pipermail/wireless/ >> >> -- >> Randy Cosby >> Vice President >> InfoWest, Inc >> >> office: 435-773-6071 >> >> >> >> > ------------------------------------------------------------------------ >> -------- >> WISPA Wants You! 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