The term that got us cheap power was "unmetered CATV power supply". They allow connection of a fixed capacity power supply unit with no meter, just a small disconnect and drop a 120V 10AWG service and bill us based on half of the power supply's nameplate capacity.
On Tue, Aug 15, 2023 at 3:45 PM Chuck McCown via AF <[email protected]> wrote: > > Some places have what is called a “street light tariff” that is about as low > as you can get. > > > > From: [email protected] > Sent: Tuesday, August 15, 2023 10:38 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] battery nerd question > > > I can save you the suspense. If you have access to electric that’ll be > cheaper than solar. The problem is the need to run 24/7. You have to design > around the December-January months. I’m in NY State, and at our latitude we > only get a few hours of average production per day during those months. And > obviously if it’s snowing for a week you need to be able to ride through that > on mostly battery power. Even with a modest load it takes a silly amount of > panels and batteries to stay up 24/7 in the winter. More than you’d ever be > allowed to put on a utility pole. > > > > Talk to your electric co about the smallest service you can get. Explain > what you’re trying to do and that your max load is very low. > > NYSEG normally doesn’t do less than 100A, but they made an exception and let > us do 60A. You need a meter can, a service rated panel, a conduit up the > pole and a weatherhead. Then you either have an outdoor outlet, or have an > outlet inside your enclosure. You’ll want the smallest service they’ll let > you do because of the wire size on the service cable. A 20A (if they’d allow > it) would only need a 12/3 with ground, and that’s up to 4800 Watts (240x20) > so it’s still more than you’d ever need. A 12/3 is way cheaper than a 100A > service entrance cable. > > > > My figure is 8 years old, and obviously there’s been inflation since then, > but I went to the same contractor who does electric installs for the cable > company and they quoted me about $1000. Even if it’s 3x that for you today > you’d still never beat that with a solar installation even if they’d let you > do it. And I’m not some knee-jerk anti-solar lunatic, I’m just saying I’ve > run the numbers and it doesn’t add up. People do it when they’re off grid, > or when the electric service is unreliable in the area, or sometimes just for > the PR/marketing power of being “solar powered”. Those are all fine reasons, > but doing it for cost savings isn’t going to work out. > > > > -Adam > > > > > > From: AF <[email protected]> On Behalf Of Steve Jones > Sent: Tuesday, August 15, 2023 10:27 AM > To: AnimalFarm Microwave Users Group <[email protected]> > Subject: Re: [AFMUG] battery nerd question > > > > we have a dozen or so, but are looking at pole mount micropops (our own > poles). We are losing a grain elevator site because they decommissioned the > elevator and theres no real options for the customers in some of the areas. > Im just trying to get to something we can get solar power with enough battery > to last through overcast. So Im calculating per battery runtimes, then will > look at number of batteries we would need to survive vs paying for a ROW > meter vs losing the customers. Just have to get to the cost per customer to > retain them and the benefit gained per pole > > > > > > On Tue, Aug 15, 2023 at 8:53 AM Brian Webster <[email protected]> > wrote: > > How many of the batteries do you have? Do you need any voltages other than > the 48 volts? If you have 4 batteries and only need 48 volts then wire them > in series and not have to deal with the converter. > > > > Thank you, > > Brian Webster > > > > > > From: AF [mailto:[email protected]] On Behalf Of [email protected] > Sent: Tuesday, August 15, 2023 6:59 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] battery nerd question > > > > *You’re around C/30 which should be on the high end of capacity. > > Lower load usually means a little extra capacity out of the battery. I > realized that sentence might have been ambiguous. > > > > > > From: [email protected] <[email protected]> > Sent: Tuesday, August 15, 2023 6:56 AM > To: 'AnimalFarm Microwave Users Group' <[email protected]> > Subject: RE: [AFMUG] battery nerd question > > > > You can do the whole thing in Watts. > > > > 12V * 150ah = 1800 Watt-hours > > 1800Wh / 50W = 36 hours > > > > If they’re telling me 95% efficiency, I’d assume 50W out needs 53W in (50 / > 0.95). > > There’s usually an efficiency curve for the device based on load and > temperature so it wouldn’t be 95% in all circumstances. Your system should > be drawing less than 5A off the battery, and if your multimeter has a 10A > fuse like most do, then you could put the meter in line and actually measure > the amperage before and after the converter. Then you’d know for sure. > > > > And the battery’s total capacity will have a curve based on C-rate so there’s > some variability there too. Usually it lasts longer when you’re drawing > lower amperage. You’re around C/30 which should be on the high end. > > > > Age and maintenance of the battery affect runtime as well. If I want 6 hours > of runtime then I plan Ah for 12 hours runtime. When my batteries are halfway > toasted I’m still getting useful life out of them. > > > > > > From: AF <[email protected]> On Behalf Of Steve Jones > Sent: Monday, August 14, 2023 9:57 PM > To: AnimalFarm Microwave Users Group <[email protected]> > Subject: [AFMUG] battery nerd question > > > > Just trying to cipher runtimes > > I have on hand 150ah 12 volt batteries, so thats what id be looking to use. > > Excluding the conversion loss of a 12v to 48v step up converter is the math > correct here? > > 12v 150ah=1800 watt hours > 1800 watt hours at 48v = 37.5ah > 50 watts of radio running 48v = 1.04 amps > 37.5ah @ 1.04 amps = 32.77 hours runtime > > > > does a step up that claims 95% efficiency mean 95% of the watt hours? > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > ________________________________ > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com
