Power Wall Pricing

[somber]

I don’t think EV batteries are under $300/kWh yet. Used 75 kWh Tesla batteries ask $12,500 on eBay and are not in a useful configuration for anything but transplant into another under-warranty Tesla.

Used 4.5 kWh modules from Tesla batteries ask $900 which includes a BCM designed to work in series or parallel with other like modules.

A Tesla Powerwall has 13.5 kWh of useful capacity in a complete integrated package with 100% duty cycle AC inverter/charger/controller. $7000.

Claims of $100/kWh are coming from wishful thinkers and not from a quality supplier who is capable of putting real product in your hands.

I'm not allowed to post a link on this board until I have at least 3 posts, but I got a current average price of $137/kWh, and with a low of just under $100/kWh from the latest Bloomberg NEF annual battery price survey dated December 16, 2020. Since I can't link it, others can google the title of the article: "Battery Pack Prices Cited Below $100/kWh for the First Time in 2020, While Market Average Sits at $137/kWh".

 

[dmccarty]

...

Seems to be avoiding grid tie dat sells back into grid to eliminate lot of red tape.

Somehow missed this discussion and am catching up.

I have always been interested in solar power but decades ago the price/performance ratio was not there. Today it is closer, but even with tax rebates, it is still not there for us. A few years ago, I went to a class at the community college about solar power, it was interesting to see people walk out of the first class when they realized that you had to have batteries to run the house when the grid went down. The guy teaching the class was an ex house builder who had built quite a few homes with solar power. The one big take away I had from the class was that in NC, at that time and I do not think it has changed for the better, one needed to avoid grid tie sell backs to the power company. In other words, size you solar installation to what you use each day, on average, and no more. Otherwise the red tape would drive you nuts and it was not worth the hassle to sell back to the power company nor worth the money.

Later,
Dan

 

[dmccarty]

I looked at Power Walls years ago, and I think this was mentioned earlier, but you can only charge the Power Wall from solar, the grid, and maybe wind generators. I think charging from a generator was possible, not sure how that could be prevented, but it voided the warranty.

The fire danger with the Power Wall is real. I would NOT have a Power Wall, or any other battery that was just labeled lithium, on my house. Away from the house, yes, but not on the house. Lithium batteries are a mix of chemicals. LiFePo batteries are a safe(r) lithium battery chemistry that is being used more and more in the boating world. There is at least one video out there showing someone trying to burn a LiFePo battery by shooting it and putting it in a fire.... The LiFePo battery did not burn. Having a lithium battery fire on a boat could be fatal and would almost certainly sink the boat.

A lithium battery that catches fire is going to be almost impossible for a fire department to put out. The bigger the lithium battery, the worse it will be. If that lithium battery pack is attached to your house, and it catches fire, one better have really good insurance. You will need it. This should NOT happen, it should be a low chance event, but if it does happen, your house is gone.

We might have a boat one day which would almost certainly use LiFePo batteries. No way in heck would I use anything just labeled "lithium."

The good news is that lithium batteries are sooooo much better than lead acid. Except for the initial price. :shocked: But that price has been falling and hopefully will keep falling. Solar and LiFePo batteries are a great mix. However, the price is not there to use on our house. We would have to take out a loan to install just solar panels... Just having a system that would run the lights, TV, networks, some outlets, fridge/freezer and the well pump for 4-6 hours would be wonderful. Not sure the price will be where we need though in the next few years.

Ironically, if we do sell everything and get a boat, we would likely have a generator(trying to avoid that though), engine alternators, solar panels and a wind generator dumping power into LiFePo batteries. We won't have to worry about the grid going down every again. :laughing:

Later,
Dan

 

[ponytug]

I hear you about not wanting combustible appliances on the house. We are installing ours a few feet away, attached to a concrete retaining wall.

Just for the record, the recommendation for Tesla batteries, and other large scale batteries is water. There seems to be quite a bit of misinformation out on the internet that seems to confuse lithium metal fires (class D fire extinguisher) with lithium ion battery fires (which have no lithium metal in them) and with electronics fires (class B extinguishers).

Here is a teaching video for firefighters, where they used a 400,000BTU torch for thirteen minutes to start a fire on a Tesla vehicle. Water is used as a cooling agent. The video points out that electric vehicle fires are much less common than petroleum fuel vehicles.

All the best, Peter