"EVs are much better at the high power levels required for stabilization (though I do not see anything preventing the solution, other than that the spec is for a low power from the battery, I mean 8 Amps at around 400V is not an EV power level, it is actually rather underwhelming - I wonder why Tesla with a profile of high-power application is releasing such a low power spec. ​"
With smart grid and many nodes you can have a bunch of smaller inputs for the grid stabilization​. I suspect this is the more forward thinking approach that Tesla is nudging us towards. SOrt of like using 7000 small cells to run a car. On Mon, May 4, 2015 at 4:07 PM, Cor van de Water via EV <[email protected]> wrote: > The best (but probably also most complex = expensive) hardware > would be to make this pack act as grid energy storage and stabilization, > though that would not be ideal with this pack - EVs are much better at the > high > power levels required for stabilization (though I do not see anything > preventing > the solution, other than that the spec is for a low power from the battery, > I mean 8 Amps at around 400V is not an EV power level, it is actually > rather > underwhelming - I wonder why Tesla with a profile of high-power application > is releasing such a low power spec. > > What I think though is that it will be promoted especially as a backup > solution > for "when the grid goes down" and by recharging it only from your solar, > you > will always have power even if the grid goes out for longer periods. > Of course you can also charge it from the grid (at night, when power cost > may be down to ~6 cents per kWh) to replace some of the power that you > consume > at the highest tariff, but this will be questionable if this has a good > business case. > However, sometimes it is more about the feeling than the pocket book, so > that may > also be why they are making such a big deal out of a smallish pack of > batteries > not too different from what you can buy online everywhere. > Indeed it looks like it is optimized for direct DC input from a solar > array at a > typical string voltage under 600V, probably the built-in DC/DC converter > can take > this, do MPPT (although the PowerWall specs are short on details) for > charging > from the sun in an optimal way - you'd only need to connect the inverter > to get > your humongous UPS system, which is something that I did to my EV: add a > 3kW inverter > and if the grid goes down, I have power for a while... > > Cor van de Water > Chief Scientist > Proxim Wireless > > office +1 408 383 7626 Skype: cor_van_de_water > XoIP +31 87 784 1130 private: cvandewater.info > www.proxim.com > > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received > this message in error, please delete it and notify the sender. Any > unauthorized use, disclosure, distribution, or copying of any part of this > message is prohibited. > > > -----Original Message----- > From: EV [mailto:[email protected]] On Behalf Of Mark Abramowitz > via EV > Sent: Monday, May 04, 2015 10:34 AM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] virtual power plant > > Not very efficient at that scale, I'm told. > > At you move to larger scale and longer periods of storage, other solutions > surpass batteries. > > Sent from my iPhone > > > On May 4, 2015, at 10:20 AM, robert winfield via EV <[email protected]> > wrote: > > > > > > dont forget aggregating, say, 1,000 of these 10kW Powerwalls into a 10 > > megawatt virtual power plant VPP, (or any multiplier) for microgrids > > of distributated generation > > -------------------------------------------- > > On Fri, 5/1/15, Robert Bruninga via EV <[email protected]> wrote: > > > > Subject: Re: [EVDL] Tesla plugs into new market with home battery > > system (backup foolishness) > > To: "Electric Vehicle Discussion List" <[email protected]> > > Date: Friday, May 1, 2015, 9:39 PM > > > > Huh? Plenty wrong with > > your assumptions. > > > >> $6k > > of golf cart batteries is about 60 of them; that's around 80 KWH of > > storage! Who on earth needs that much for a home. > > > > My > > solar panels produce typically 60 to 70 kWH every sunny day. If I do > > not use every bit of it every day, then I am wasting my solar > > investment right? Hence, I sell it to the grid every day and buy it > > back when I need it at no net cost.. > > > > If I had to store it > > in batteries (at your proposed 10% daily depth of > > discharge) then I would need 600 kWh of batteries or $60K investment > > (and replace it every 10 years). Again, batteries MAKE NO ECONOMICAL > > SENSE WHATSOEVER compared to grid-tie. > > BUT... > > > > BUT, if utilities > > began paying the homeowner the same TEN-TIMES PEAK rates they have to > > pay for power during summer peaks, then of course, batteries coiuld > > make some economical sense. They don't have to handle the full > > working load of my solar array, but only enough to meet those > > instantaneoud peak value periods... > > > > Bob > > > > > > > > -----Original Message----- > > From: EV [mailto:[email protected]] > > On Behalf Of Lee Hart via EV > > Sent: Friday, > > May 01, 2015 7:02 PM > > To: Electric Vehicle > > Discussion List > > Subject: Re: [EVDL] Tesla > > plugs into new market with home battery system > > (backup foolishness) > > > > Robert Bruninga via EV wrote: > >>> A quality GC2 golf cart battery > > (Trojan, US Battery, etc.) is 220-240 > >>> amphours at the 20-hour rate, and > > costs $75-$150. They are good for > > 5-10 years, and 600-1200 discharges to 50% or so state of > > charge. > >> > >> No, not > > BOTH. One or the other. 5-10 years just sitting there > > doing > >> nothing but waiting for the grid > > to go out (4 hours a year around > > here)... > > > > Correct. They are "used > > up" once they have accumulated 600-1200 cycles, > > *or* are 5-10 years old. > > > >> OR they barely will last 2 years in daily > > solar-off-grid use (and > >> note, you are > > only getting 50% of their capacity just to last that > > long)... > > > > That > > would be the case if you discharge them 50% or so every day. > > But 50% > > is an excessively deep discharge if > > you're going to use them every day. > > > > For daily use, you would limit your depth of > > discharge to just 10% or so. > > Then they would > > still last for their calendary life; 5-10 years. > > > > Note that life is a function > > of depth of discharge for *all* types of > > batteries. If you expect them to last, the > > shallower the discharge, the > > better. > > You'd also murder a lithium pack in a few years, if you > > deeply > > discharged it every day. > > > > If you really have a situation > > that requires daily deep discharges, you > > probably have to use the old Edison nickel-iron > > cells. Aside from quality > > or abuse, they are > > the only type with an indefinite cycle life. > > (There are 100-year-old Edison cells still in > > use). > > > >> Yes, may as well > > just throw $6k in the trash every few years since you > >> never use them. The cost of the > > electricity for the 4 hours average > > outage per year is only about 80 cents. (1 kW for 4 > > hours). Amazing > >> how many people will > > spend $6k for that 80 cent problem. > > > > I see a pretty heavy thumb on the scale here, > > Bob. :-) $6k of golf cart > > batteries is about > > 60 of them; that's around 80 KWH of storage! Who on > > earth needs that much for a home. > > > > You have to select the size > > and type of battery according to the > > application. Some will be best served with > > lead-acid, some nickel-iron, > > others lithium > > etc. Some applications aren't appropriate for batteries > > of > > any type. > > > > If all you have to cover is 4 hours of outage > > per year, then dumb old > > lead-acids are going > > to be the cheapest by far. Like I said, they will die > > of old age before you wear them out. > > > > -- > > Don't > > worry about people stealing your ideas. If your ideas are > > any good, > > you'll have to ram them down > > people's throats. -- Howard Aiken > > -- > > Lee Hart, 814 8th Ave N, Sartell MN 56377, > > www.sunrise-ev.com > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use > > NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > > > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- To invent, you need a good imagination and a pile of junk. 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