One of the major problems with 'battery powered' large devices, like cars, is one of math.
Take lead acid, one of the most economical rechargeable batteries on the market.
A typical lead acid 'car battery' that starts gasoline engines can be recharged about 1,000 times (about 3-5 years). It costs $100 and holds 1,000 watts per charge.
The math... I know, math is boring and sad, but needed here.
1,000 watts (max storage per charge) multiplied by 1,000 (max number of recharges) is 1,000,000 watts that a typical battery can store over its lifespan.
1,000,000 watts, if bought from the local coal power plant, cost $150 (at 15 cents per Kilowatt (1,000,000 / 1,000 * .15))
What this means is that you wear out $100 worth of rechargeable batteries for every $150 worth of electricity you manage to store.
Even if Elon Musk cuts the price in half and triples the lifespan (unlikely in our lifetime), the cost of replacing the batteries every 50,000 miles or so will still amount to a hefty 'battery tax' that will add 8% to 55% to the cost of electricity you stored.
Now, if electricity was free, like a penny per KWH, then batteries make sense... but it'll still be painful. Most replacement Prius batteries cost $3-5,000 and need replacing every 7 years. A Tesla battery costs $10-20,000 and needs replacing about as often. This means a Tesla costs $1,000 per year in batteries ON TOP OF the thousands it jacks up your electric bill. Basic math says that for every dollar an electric car increases your electric bill, you should put 50 cents in a jar for future replacement batteries.
But it gets worse. Musk wants to build batteries for homes... again, it costs (by wearing out rechargeable batteries) around $100 in batteries to store $150 worth of electricity. That is a scam to sell batteries, not save energy. Of course, like with cars, Musk stands to make a fortune in 'kickbacks' from politically connected democrat friends in office... technically called 'rebates' and 'credits'.
But it gets worse. Most 'charge cycles' are only %80 efficient. This means it costs $120 worth of electricity to store $100 worth of power in batteries. No big deal for laptops and phones, but you're talking real money for electric cars.
Look, it makes sense to build batteries into phones, laptops, tablets, drills, etc., because mobility is a premium and the amount of power is ridiculously tiny (a phone uses 5-15 watts per day, so a few dollars worth of batteries gives you a day of cord free surfing per charge and 3-5 years worth of recharges, more than enough for most planned obsolete electronics) but the math goes sideways fast for cars and house power.
Put another way, off the grid solar, even if you got the panels free, you would cut you 'electric bill' to zero, but your battery bill would be around %50 what your electric bill used to be, and instead of arriving monthly, you would get your multi-thousand-dollar battery bill all at once every 5 years or so.
This is the rude slap in the face waiting for every fool that bought an electric car.