Recent content by mikesm

I think it's going to be very difficult for Tesla to compete in the small car segment with the Chinese. The cheaper and less luxurious the car, the smaller the margins will be, even if he can hold market share with the Chinese. That may not happen in the US but definitely will be the case...

Given the decision today to lay off the whole supercharger team, it sure sounds like he's not interested in building (or supporting existing) cars for individual users. This kinds of makes sense if your bet is all on robotaxis to go after Uber and Lyft. That kind of fleet could not user...

There will never be a significant impact on greenhouse gas emission if the ROI for battery systems isn't positive. Some like you may make financial compromises as part of your economic calculation, but that is not going to be a significant number of households, not just in the US, but across...

I disagree. If reliability is the number one goal, it's very hard to beat a quality diesel or natural gas/propane generator. They work when it's cold and overcast, and they work in the dead of winter when you have fewer hours of charging time available, and they work when you have a large...

PS I was wrong about 1 item: 1) The bi-directional inverter does 400V and 800V DC fast changing, not 200V and 400V

The Solaredge bi-directional V2H charger seems a much better design. It charges the vehicle with 200V or 400V DC from the inverters DC bus input. When pulling power from the vehicle, it puts that on the DC bus and uses the solar inverter to power the house. For Solar to vehicle charging that...

I think it might cut into Powerwall sales. I assume in CA they are selling a lot less of those as the number of solar installs have come down thanks to NEM 3.0. I think the margin on the PW's is not insigificant. It also will increase the number of cycles on the battery, driving more service...

I am looking forward to the Solaredge bidirectional EV charger that is supposed to ship this year. It DC charges the car battery direct from solar, and powers the house through the solar inverter from the DC bus if Solar is inadequate. This seems like an easy way to do load shifting through a...

Kohler makes a number on industrial 400A transfer switches. Very programmable too. I got one on Ebay that had never been installed for about $1200 and mated it with my 30 KW diesel generator. A great pair, and have modbus interfaces to a remote control and display panel in my house. Tesla...

I am a big generator fan (as opposed to Powerwall$), but these small gensets are not made to run for extended run times without maintenance. That's fine for a few hours here and there, but if you need multiday continuous operation, these may not survive that sort of use.

Interesting, Are they still going to produce Powerwall 2's? If not it definitely signals a move into a completely vertical environment - you can't have Powerwalls with Enphase or Solaredge systems, and no retrofit markets will work. I guess if you had Sunnyboy or Fronius string inverters you...

I think he is asking if there is any reason he needs a Powerwall when he has an amazing net metering agreement that has no TOU charging. If that's the case, I think is answer is a resounding no! If there is no TOU, then you don't need load shifting. For backup power in an outage, a...

That sounds about right for NEM 2.0. What would happen if you plugged in the NEM 3.0 rates into your model and actual experience in terms of ROI?

What is the cost of capital you are using? The money you are spending on the solar+ESS could be earning money in a money market account, or investment in the stock market. So there is an opportunity cost that has to be considered in the calcs - a lot of people use 7% for these sorts of calcs...

If backup power is the goal, a generator is a far cheaper and more reliable solution. Agreed that ROI on NEM3 is non-existent. You should forget about deploying solar - it doesn't pencil out anymore, and that's why the installer is giving you these crazy numbers.