One source: http://tnrbatteries.com/genesis.html
----- Original Message ----- From: "Chuck McCown - 3" <[EMAIL PROTECTED]> To: "WISPA General List" <wireless@wispa.org> Sent: Thursday, November 20, 2008 10:12 PM Subject: Re: [WISPA] Remote Powered Access Pont > http://www.enersysreservepower.com/documents/US-GPL-AM-003_0906.pdf > > Genesis pure lead EP or XE version will work down to -40. > They are rated for 100% depth of discharge. Repeatedly. 400 times. > And can come back from 100% discharge at -40 to be fully charged. > They are good for 2 years sitting on the shelf totally unused. > I don't know of any other battery that can do that. > > They also have most of their energy available at super cold temperatures, > where flooded cells lose most of their energy when cold. > But you will pay 2 to 3 times more than for a Trojan. > > I figure everything by watt hour first. So you need 5 watts * 24 hours * > 30 > days = 3600 watt hours. > At 30 cents per watt hour, you will end up paying more than $1000 for that > battery. Hopefully you can shop around and find them for less. I used to > pay 20 cents. I don't know why they went up so much. > > Watt hours / system voltage = amp hours > 3600/12=300 amp hours. > > One of our supervisors recently found a good price (if you can call it > good) > for the gates/hawker/enersys batteries. > If I can find the source I will post it. > > ----- Original Message ----- > From: "rabbtux rabbtux" <[EMAIL PROTECTED]> > To: "WISPA General List" <wireless@wispa.org> > Sent: Thursday, November 20, 2008 8:27 PM > Subject: Re: [WISPA] Remote Powered Access Pont > > >> Thanks for the great info Chuck! Almost made the trojan battery mistake. >> what exactly is the battery technology and brand you suggest? if I have >> a >> 5 >> watt system you suggest a 120W solar panel. Also 30 days or 360AH of >> usable capacity at 12V? >> >> Thanks for the clarification, and the pics that make your experience >> clear! >> >> On Wed, Nov 19, 2008 at 7:38 PM, Chuck McCown - 3 <[EMAIL PROTECTED]> >> wrote: >> >>> At 60% depth of discharge they freeze at 0F. Once frozen they are dead. >>> Liquid electrolyte batteries need to be liquid to work. >>> Not to mention the risk of a broken case. (You most likely mean you try >>> to >>> avoid taking them below 40% DOD, but 60% has a nice freezing point to >>> exploit for purposes of rhetoric). >>> >>> Trojans were designed for the cabin with the fireplace and the >>> intermittent >>> use of the residential solar application. (Really, they were designed >>> for >>> golf carts). >>> >>> Constant load, constant nightly cycling, periods of no charging and deep >>> discharge during the coldest days of the year is a different application >>> and >>> takes a different battery technology. >>> >>> Here is a good VLRA white paper on the temperature issue: >>> http://www.cdtechno.com/custserv/pdf/7953.pdf >>> >>> We use VLRAs inside central offices where there is HVAC. Not in the >>> field. >>> And they are much better than flooded cells like the T-105 >>> >>> AGMs go in the field. And for solar only a few types of AGMs can be >>> trusted. >>> >>> This app note is full of lots of good info. It is on the batts we use >>> that >>> will still deliver 40% of their power at -40 degrees. >>> http://www.enersysreservepower.com/documents/US-GPL-AM-003_0906.pdf >>> >>> But the only really important point is that in a solar situation, where >>> you >>> have weather and you have low temps, very few batteries will totally >>> recover >>> from an extreme deep discharge. And that happens all the time when >>> people >>> scrimp on their battery capacity and solar panel capacity. >>> >>> 20X watts 30 days autonomy = you will sleep all winter long. >>> ----- Original Message ----- >>> From: Blair Davis >>> To: WISPA General List >>> Sent: Wednesday, November 19, 2008 7:56 PM >>> Subject: Re: [WISPA] Remote Powered Access Pont >>> >>> >>> Ok. our answer to that problem has always been to double up on our >>> total >>> battery size so we never discharge them below 60% >>> >>> Sounds like you are in a much more inaccessible environment than we >>> are! >>> And in that kind of location, I'd likely be looking for the same thing. >>> >>> But, for us, inaccessibility won't last more than a week or so... >>> >>> Chuck McCown - 3 wrote: >>> We buy batts that are rated to give you the energy down to -20F. >>> Survive being at-20F while discharged to a stone cold state. >>> And recover when the next available bit of sunlight hits the panel >>> (perhaps >>> days later). >>> And last 2000 cycles. >>> For that you pay 30 cents per watt hour. And can sleep at night. >>> (we used to get these for 20 cents, I don't know why they are so much >>> more >>> now) >>> >>> I just found a website selling a T-105 for $160\each >>> 6 volts, 225 aH That comes to 11.8 cents per watt hour. >>> >>> The Trojan website says "avoid locations where freezing temperatures are >>> expected". >>> It also says the must be kept fully charged when freezing. Hard to do >>> with >>> solar on a mountain top. >>> >>> >>> http://www.trojan-battery.com/Tech-Support/documents/UsersGuide_0708_English_003.pdf >>> >>> So, if you have a nice warm place to keep the trojans then they are a >>> very >>> good value. >>> (assuming they are in an air conditioned place in the summer too, else >>> they >>> won't last too many summers) >>> >>> But most solar powered sites don't have a heater to keep them from >>> freezing >>> and splitting. >>> >>> >>> ----- Original Message ----- >>> From: Blair Davis >>> To: WISPA General List >>> Sent: Wednesday, November 19, 2008 7:25 PM >>> Subject: Re: [WISPA] Remote Powered Access Pont >>> >>> >>> What type of battery's are you using? That price sounds very high. >>> >>> 4x T-105 will provide 225Ah at 24V for a cost of about $500 >>> >>> Chuck McCoy's - 3 wrote: >>> I would use a 100 watt panel minimum. >>> And a one month battery. 5watts * 24hours * 30 days = 3600 watt hour >>> battery >>> If you are running a 24 volt system then you need 3600/24=150 aH >>> battery. >>> If you are running a 12 volt system, you need a 300 aH battery. >>> >>> You will pay about 30 cents per watt hour for a battery. So $1080 for >>> the >>> battery. >>> You will pay about $5/watt for the panel, so $500 for the panel. >>> Charge controllers are about $100 or less. >>> >>> If you build it this way it will always work. You can put in half the >>> battery for half the price. But then you have only two weeks of >>> insurance >>> against bad weather. >>> >>> Never ever go below 10X the load for the panel, that will just barely >>> cut >>> it >>> in the sunniest of climates. >>> Even then you will probably have to put in a back up generator and you >>> will >>> be cycling the crap out of your batts causing them to only last a couple >>> of >>> years. >>> >>> If you want 99.999% reliability you have to use a panel 24X the size of >>> the >>> load (unless you have a tracking mount, then you can reduce that). >>> I try to always use 20X panels and no less than a 2 week battery. But >>> even >>> then, a week or two of snow on the panels and gray skies every day can >>> cause >>> an outage. >>> >>> >>> ----- Original Message ----- >>> From: "Scott Parsons" <[EMAIL PROTECTED]> >>> To: "'WISPA General List'" <wireless@wispa.org> >>> Sent: Wednesday, November 19, 2008 5:33 PM >>> Subject: [WISPA] Remote Powered Access Pont >>> >>> >>> I'm looking into setting up a remote access point/repeater. >>> Power requirements are 5W. No access to grid power. >>> >>> I was curious what you guys use for this type of thing? >>> I figure I need a 30W solar panel, controller, battery and enclosure. >>> How much should I expect to pay for a setup? >>> Is there anything available off the shelf? >>> >>> Thanks for your help. >>> Scott >>> >>> >>> >>> >>> -------------------------------------------------------------------------------- >>> WISPA Wants You! 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