Yes, I'm thinking they sorted that out after the whole Roadster bricking fiasco.
On Wednesday, March 23, 2016, Eric Kuhnke <eric.kuh...@gmail.com> wrote: > I'm assuming for a moment that Tesla are not complete idiots and aren't > allowing the lithium ion 18650 cells in the powerwall to drain to 0%, and > that it actually has a low voltage disconnect cutoff around 25%. > > Saying all batteries are the same, whether lead acid of li-ion, isn't > really accurate... A large pack of 18650s will last 2000 to 5000 cycles if > never drained below 25% voltage. That's a lot longer than a set of lead > acid batteries will last even if you only cycle them to 40% capacity daily. > > > http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries > > On Wed, Mar 23, 2016 at 8:51 PM, Chuck McCown <ch...@wbmfg.com > <javascript:_e(%7B%7D,'cvml','ch...@wbmfg.com');>> wrote: > >> It won’t. It has batts. All batts die with cycles and die quicker if >> they are deeply cycled. >> It is a nice package and much easier for folks to purchase and install. >> But it isn’t good for much IMHO. >> >> *From:* Eric Kuhnke >> <javascript:_e(%7B%7D,'cvml','eric.kuh...@gmail.com');> >> *Sent:* Wednesday, March 23, 2016 9:48 PM >> *To:* af@afmug.com <javascript:_e(%7B%7D,'cvml','af@afmug.com');> >> *Subject:* Re: [AFMUG] Tesla 7kWh powerwall as UPS? >> >> The thing is... Calculating lead acid batteries as 30 or 15 cents per >> kWh to purchase doesn't take into account lifecycle cost. If the lead acid >> batteries are only good for 800 to 1000 cycles, absolute maximum, and the >> competing battery option is twice as expensive but lasts for 4000 or 5000 >> cycles, the more expensive option actually costs a great deal less. >> >> It remains to be seen whether the powerwall will really hold up to >> thousands of cycles. >> >> On Wed, Mar 23, 2016 at 8:45 PM, Chuck McCown <ch...@wbmfg.com >> <javascript:_e(%7B%7D,'cvml','ch...@wbmfg.com');>> wrote: >> >>> 7/5=1.4 hours at full load. >>> >>> Batts are about 30 cents per watt hour for AGM, half that for flooded >>> cells. >>> Inverters are about 25 cents per watt. >>> >>> 7kWh battery == $1125 –$2250 >>> 5 kW inverter == $1250 >>> Put it on your critical loads. Charge the batts with a rectifier that >>> is fed from commercial power. >>> You can run the inverter all the time, or use a smaller charger and put >>> in a transfer switch. >>> Transfer switches/contactors are not very expensive. One single relay >>> will do the job. >>> >>> *From:* Eric Kuhnke >>> <javascript:_e(%7B%7D,'cvml','eric.kuh...@gmail.com');> >>> *Sent:* Wednesday, March 23, 2016 7:45 PM >>> *To:* af@afmug.com <javascript:_e(%7B%7D,'cvml','af@afmug.com');> >>> *Subject:* [AFMUG] Tesla 7kWh powerwall as UPS? >>> >>> $3000 is not so bad for something that can deliver up to 5kW for >>> multiple hours... >>> >>> >>> http://arstechnica.com/business/2015/09/tesla-powerwall-home-installations-are-starting-for-pilot-customers/ >>> >>> I am interested to see the results of integrating two of these in >>> parallel with an off grid solar array. At first glance it appears a great >>> deal less expensive than buying a dozen 12V 200Ah lead acid AGM batteries >>> to make a string. And should last a lot longer in 60% cycle depth daily >>> cyclic use. >>> >>> >>> Interesting they've cancelled the 10kWh model ($3500) which had a much >>> shorter lifespan, the 7kW model is rated at 5000 cycles. >>> >>> >> > >
