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 Sent: Wednesday, March 23, 2016 7:45 PM To: [email protected] 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.
