Talk Morgan Forums Community The Malvern Arms Off grid and power walls etc

Hopefully one day the maths for both EV cars and off grid batteries will make sense but I can't make any sense of it yet.

I keep seeing headlines like New Battery tech will make EV's as cheap to buy as a petrol car, but the only thing I have seen is the Tesla 3 go up in price significantly this year. Take a Toyota Corolla in Australia, one of the best selling cars. Brand new ranges from $23,000 to $39,000 for a Hybrid with all the bells and whistles. The cheapest Tesla is the 3 at $70,000 without the long range battery or any other features. The battery is supposed to be worth either $7000USD or $16,000USD depending on what I read, basically $10,000 to $20,000 AUD. Using the highest cost of $20,000 a Tesla 3 would be over $50,000AUD for the car without batteries, making it more expensive that the most expensive Toyota Corolla and double the price of the cheapest. That doesn't make sense to me when they both look like pretty bland 4 door cars and the Tesla doesn't even have a dash in front of the driver, just a cheap looking iPAD stuck in the middle.

For my sons house back to grid is 8cents, to buy is 23cents and the 6KW system generates about 40KW a day in summer and 25KW in winter. His bills were nearly $4,000 a year before and with solar have now dropped to about $1,000 a year, I am not sure how much due to less usage and how much due to back to the grid credit. The solar panels cost me $13,000 and save him $2,500 to $3000 a year so pay itself off in about 5 years and have a 25 year warranty. No problem with that part of the maths.

But a 13KWh battery costs $16,000. Unless I am mistaken to charge a 13KWbattery from flat to full is meaning 13KW less going to the grid so he will get 13 * 8 is 104 cents or basically $1.00 less credit during the day. If he uses all 13KW during the evening would save 23cents by 13 = 299cents or pretty close to $3.00 so an overall saving of $2.00 by keeping the power rather than exporting it. If the full capacity of the battery can be used every day that is 365 days by $2 or $730, at $16,000 for the battery it will itself in about 22 years and has an 8 year warranty. So while the panels are very much likely to pay for themselves before needing replacement the battery is likely to need replacing well before it has paid for itself. So again Batteries have to get to get a lot cheaper before they make sense.

I read an article about the duck curve at electricity substations. The issue is there is many houses (including mine and my sons) with solar panels but no battery storage meaning that during the day they send power to the grid but at night take power and that causes the power usage to spike at the same time the excess power is not being sent to the grid. This is an issue for the power companies trying to keep the supply constant. This so called power expert said it made perfect sense for everyone to put on a 20kw battery on their house to charge during the day and use in the evening flatten this curve. He said it went from a duck curve to a flat line and fixed all the issues. Sorry but batteries have to get a lot cheaper, or electricity a lot more expensive before a 20KW battery for off grid storage will make sense.