I get that by going for the additional charging device can double my charge rate. What does the extra weight of the device do to performance or is it very light?
Don't know the actual weight, but by analogy to similar hardware my guess would be 10-20 pounds. No material effect on range.
The twin charger appears to be a waste of money. The only time you can utilize the twin charger is if you have the High Power Wall Connector and another 240 outlet to plug your car into. When will you have the opportunity to do that? Only when you're home. When you're home, you most likely have the luxury of several hours to charge your car. The only time you would ever need to speed up the charge at home is if you drove 150 miles that day and you have to run out again for another 150 miles. Something to think about before spending the money.
twin charger can be also utilized on the road(trip) if you can find public charging with high-amp supply (J1772 with 70A in US or 20kW Mennekes in EU). I don't know how common it is in the US, but in my country (EU) it is quite common, much more common than CHAdeMO or other level 3.
but back to your question, I don't know exact weight, but it's not enough to affect ride quality or range...
hademarco in the near future Level 3 public J1772 (i think i got the numbers right) will be more common and they will need dual chargers to take advantage of the extra power.
However, From what I hear you can add the second charger after the car is made from a service center if you need it. Though I have no idea how much more this route would go.
The second charger is $3,600 plus tax, installed, when you add it after delivery. I believe it is $1,500 when you order it with the car. Hademarco is not correct. There are lots of 70+ amp public stations that make road trips much easier with the twin chargers, depending on where you live. You can find them from Vancouver, B.C. down to San Diego on the west coast (https://maps.google.com/maps/ms?ie=UTF8&oe=UTF8&msa=0&msid=2133590501081...), and from Vancouver to Nova Scotia across the southern tier of Canada (https://suncountryhighway.ca/ev-trip-planner/#.UbpWjflvPoJ). There are also a handful scattered elsewhere around the country.
The only time I've regretted not getting the twin chargers was when planning a road trip where there are 70 amp chargers but no Superchargers
Made a huge difference in my trip from Seattle to the SF Bay Area this past February. By next year, hopefully they will have superchargers.
Hademarco, you're mistaken. Twin chargers does not mean two cords. It means being able to take more than 40 amps from a single cord.
If you only care about the mobile charging cable, or 40 amps or less from public stations, then a single charger is fine. If you want to get more than that (other than a supercharger) you need (a) twin chargers so they can divide the increased current over the two, and (b) a high power wall connector and/or public stations that go over 40 amps.
Does anyone really think that spending $3600+tax is worth mitigating the extremely rare case on a road trip when it would make a significant difference? How many "hours per year" would the HPWC save? (For me, zero)
After reviewing the Tesla SC rollout plan, if you knew you absolutely needed this capability 1-2 times a month indefinitely, yep - go for it! But I wouldn't expect this feature to add a single dime to the resale value.