This is caused by the squeegee being angled incorrectly forcing the water under the rubber blade out into the dry area of the glass or from solution being pushed up into the top edge of the window.
Although there is a slight difference between our original calculation and Teslaâs new oneâlast fall we built in a cost of $6,500, Teslaâs current cost for a Powerwall as part of a Solar Roof installation is $7,000.
Depends where you live. by Jose Pagliery @Jose_Pagliery May 1, 2015: 7:12 PM ET. The answer depends on where you live -- and how you use it. If you live in the South and already own solar panels, it could take you just under three years to make up the cost of the $3,000 Tesla Powerwall battery. But if you live in the Pacific Northwest and don't have solar panels, it could take you at least 16 years to make up the cost of buying Tesla's new home battery.