California schools $120M solar project
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From: Joel Koltner on 2 Jun 2010 18:02 "Michael" <mrdarrett(a)gmail.com> wrote in message news:73ea42e6-fd75-41b7-89c4-593b613accc1(a)a20g2000vbc.googlegroups.com... On Jun 2, 2:19 pm, "m...(a)sushi.com" <m...(a)sushi.com> wrote: > I bought a rechargeable drill from them awhile back, and the NiCd > battery charger doesn't even have a sensor telling when charging is > done. You have to guess when it's done charging. It's probably just a transformer->rectifier->resistor->battery, set to charge at a C/10 rate or thereabouts. So you just wait ~12 hours or so and you're guaranteed it's fully charged -- no guessing necessary. :-) There was a time, not that long ago, when most battery chargers were this, um, "featureless!" > Dad wanted to buy same drill (on sale for $15); I talked him out of > it. Sounds like it might be worth $15, actually... I think Harbor Freight is a good example of (1) you tend to get what you pay for and (2) advertising leads many people to believe they need a lot more than they really do. Their "value for the dollar" is actually pretty good -- unlike a well-known brand name where the "image" can sometimes be much flashier than what you're really getting (counting on many people never recognizing as much -- see #2), with Harbor Freight it's pretty clear exactly how rugged (or not) the item you're purchasing is. If you really want to impress your dad, get him one of these: http://www.amazon.com/Milwaukee-1676-6-2-Inch-Joist-Drill/dp/B00005OP5S ---Joel
From: vaughn on 2 Jun 2010 18:51 "Michael" <mrdarrett(a)gmail.com> wrote in message news:73ea42e6-fd75-41b7-89c4-593b613accc1(a)a20g2000vbc.googlegroups.com... >I bought a rechargeable drill from them awhile back, and the NiCd >battery charger doesn't even have a sensor telling when charging is >done. You have to guess when it's done charging. I have one; that is exactly true and is clearly mentioned in the manual! Forget and leave the battery in the charger for a couple days and you can kiss that battery goodbye. I bought 2 of those drill kits so I could have 2 batteries plus spare parts. Already, one of the chargers has died. Also the chuck tends to come unscrewed when you run the drill backwards, making it 50% usless as a screwdriver. Further, the batteries self-discharge after sitting about two weeks, so it will always be dead if you only use it occasionally. Other than all that stuff, it honestly is a strong, useful drill. >Dad wanted to buy same drill (on sale for $15); I talked him out of it. Same here. I bought him a new lithium Ryobi kit just yesterday. He will get if for his 92nd birthday next month! Vaughn
From: Michael on 2 Jun 2010 19:15 On Jun 2, 3:51 pm, "vaughn" <vaughnsi...(a)gmail.invalid> wrote: > "Michael" <mrdarr...(a)gmail.com> wrote in message > > news:73ea42e6-fd75-41b7-89c4-593b613accc1(a)a20g2000vbc.googlegroups.com... > > >I bought a rechargeable drill from them awhile back, and the NiCd > >battery charger doesn't even have a sensor telling when charging is > >done. You have to guess when it's done charging. > > I have one; that is exactly true and is clearly mentioned in the manual! Forget > and leave the battery in the charger for a couple days and you can kiss that > battery goodbye. I bought 2 of those drill kits so I could have 2 batteries > plus spare parts. Already, one of the chargers has died. Also the chuck tends > to come unscrewed when you run the drill backwards, making it 50% usless as a > screwdriver. Further, the batteries self-discharge after sitting about two > weeks, so it will always be dead if you only use it occasionally. Other than > all that stuff, it honestly is a strong, useful drill. Yep it's way strong. 18V. Battery is flat every time I want to use it though. 15 mins of charging gets it juiced up enough for most of my tasks. I'm sure I've hosed the battery with such short charges though. Thanks for the advisory re: drilling backwards. I was freaked out once when I unplugged the power brick (with the battery still attached) and the brick got warmer and warmer... that was strange. Tried to remember never to do that again... > >Dad wanted to buy same drill (on sale for $15); I talked him out of it. > > Same here. I bought him a new lithium Ryobi kit just yesterday. He will get if > for his 92nd birthday next month! That's a good idea for a Father's Day gift... thanks for the idea! > > Vaughn Michael
From: wmbjkREMOVE on 2 Jun 2010 19:20 On Wed, 02 Jun 2010 17:01:29 +0100, Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote: >On 02/06/2010 16:35, wmbjkREMOVE(a)citlink.net wrote: >> On Wed, 2 Jun 2010 09:38:28 +0100, Ahem A Rivet's Shot >> <steveo(a)eircom.net> wrote: >> >>> On Tue, 01 Jun 2010 17:18:57 -0700 >>> wmbjkREMOVE(a)citlink.net wrote: >>> >>>> On Tue, 1 Jun 2010 23:56:08 +0000 (UTC), don(a)manx.misty.com (Don >>>> Klipstein) wrote: >>>> >>>> >>>>> Compare that to the 1 KW >>>>> per square meter that I have some impression that solar cell arrays are >>>>> rated at... >>>> >>>> Where'd you get that impression? Here's a typical module. >>> >>> Probably from reading the specs and knowing about the typical >>> efficiency of PV cells. The output rating of PV cells is usually quoted >>> under "full sun" conditions of around 1000 W per sq. metre. >>> >>>> http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=807. >>>> ~135W per sq. meter. >>> >>> That's the electrical output of that panel, >> >> No kidding? >> >>> which given the normal >>> efficiency of panels like that (10-15%) means an insolation of around 1000 W >>> per sq. meter. Actually the specs for that panel claim 13.1% efficiency so >>> slightly over 1000 W per sq. metre is required to achieve that output. >>> >>>>> That sounds to me like 34-47 dollars per watt in Philadelphia, if the >>>>> panels are laid horizontally. >>>> >>>> GIGO >>> >>> Not so - those were pretty accurate calculations. >> >> If Klipstein mounts one of the modules I referenced above in full sun >> in Philly on a cool day and measures the output, he'll conclude that >> it costs out at ~$2 per Watt, not the $30-$40 he managed to arrive at. > >That is their price per peak output per watt installed and seems >unusually low. I picked a module that I know several of my neighbors have purchased. Occasionally the same site I mentioned has modules for even less. The downward trend for PV is likely to continue, same as the upward trend for grid energy. Which makes long-term estimates silly if they don't include some allowances. >$4/W is still about the going rate A better argument is that PV generally requires other hardware that increases the basic cost. > and some are closer to >$8/W where you paying a premium for higher efficiency. Some might be selling for $100 per W. If you were buying, which would you seek out? Here's the thing - the people who are buying find the low prices, and the people who seek to discourage others from buying find higher prices. >But unless you can arrange continuous sunlight the average output over >the year allowing for clouds and including diffuse light is something >like 1/8 to 1/10 of peak installed capacity. So his $30-40/W delivered >for use is basically in the right ballpark in the long term. Nonsense. I've lived off-grid for ~15 years. My costs for the solar portion (including batteries, inverters, trackers, etc, but not counting sweat equity), were ~ $13 per watt. PV was ~$5 back then. Inverters were similar to current prices, but batteries were less. >Operating at peak efficiency with a clear sky and normal incidence >sunlight then the array can achieve peak performance, but the rest of >the time it does not by a long way. And obviously at night it is idle. Again, no kidding? >> motor, but>20% plus overall. PV economics aren't great, especially if >> one is willing to ignore the unbilled-cost of grid energy and the >> unsustainability of the billed cost. So those who seek to be negative >> about the economics really don't need to exaggerate. > >I think you just have to be clear about what measure you are using. Sure. Most people use Wh and specify location, application, and everything that's required to make it all work. Dollar per W is a strange measure. >The PV array link you pointed at is the cheapest I have seen on offer - >has anyone here obtained one? Or are they vapourware? Yes, several posters here (AEH), including me, have used that outfit, and many have purchased at ~$2 per watt. Choices at the low end of the price scale are sometimes limited though. A friend had to pay a little over $3 a few months ago to get modules with a voltage that fit his application. And some of the best deals are on stuff that isn't UL rated, which can be an issue. Wayne
From: Jamie on 2 Jun 2010 20:36
vaughn wrote: > "Michael" <mrdarrett(a)gmail.com> wrote in message > news:73ea42e6-fd75-41b7-89c4-593b613accc1(a)a20g2000vbc.googlegroups.com... > >>I bought a rechargeable drill from them awhile back, and the NiCd >>battery charger doesn't even have a sensor telling when charging is >>done. You have to guess when it's done charging. > > > I have one; that is exactly true and is clearly mentioned in the manual! Forget > and leave the battery in the charger for a couple days and you can kiss that > battery goodbye. I bought 2 of those drill kits so I could have 2 batteries > plus spare parts. Already, one of the chargers has died. Also the chuck tends > to come unscrewed when you run the drill backwards, making it 50% usless as a > screwdriver. Further, the batteries self-discharge after sitting about two > weeks, so it will always be dead if you only use it occasionally. Other than > all that stuff, it honestly is a strong, useful drill. > > >>Dad wanted to buy same drill (on sale for $15); I talked him out of it. > > > Same here. I bought him a new lithium Ryobi kit just yesterday. He will get if > for his 92nd birthday next month! > > > Vaughn > > Next time that chuck comes unscrewed, put RED thread lock in there before screwing it back in.. You'll have no more issues after that.. P.S. That problem happens to well known brands also along with chargers going dead. |