Home vs. Electric Car Battery Capacity and Cost

[mikedunkel]

I have to be missing something, but for the life of me I can't figure out why batteries for the home solar system have so little capacity and cost so much when you can get far more powerful and inexpensive batteries in your electric car. For example, my LG RESU-16H is going to cost me $9800 installed, for $612.50 per Kwh of storage capacity. A Model 3 battery can be between 50 and 82 kwh and can cost up to $16k installed (this is the HIGHEST price I saw online, I saw other quotes for as low as $12k) for about $250 per Kwh of storage capacity. I was very generous with my math, the ratio is probably closer to 4:1 when you just look at the cost of the battery (installation more difficult in a car than a home).

So what am I missing? Home batteries don't have many of the constraints or trade offs of a car battery but cost a LOT more. Why?

[SunEagle]

I guess the answer is a solar company that includes batteries can get more for them because people just really don't understand or care what the cost is as long as they think they are going GREEN.

[solardreamer]

I have to be missing something, but for the life of me I can't figure out why batteries for the home solar system have so little capacity and cost so much when you can get far more powerful and inexpensive batteries in your electric car. For example, my LG RESU-16H is going to cost me $9800 installed, for $612.50 per Kwh of storage capacity. A Model 3 battery can be between 50 and 82 kwh and can cost up to $16k installed (this is the HIGHEST price I saw online, I saw other quotes for as low as $12k) for about $250 per Kwh of storage capacity. I was very generous with my math, the ratio is probably closer to 4:1 when you just look at the cost of the battery (installation more difficult in a car than a home).

So what am I missing? Home batteries don't have many of the constraints or trade offs of a car battery but cost a LOT more. Why?

Installation in EV is much lower cost since it's standardized and highly automated compared to home installation which is fully custom involving multiple parties and approvals. It's not unusual for a home battery system installation to require major electrical upgrade or some construction project with additional complexity and cost. So, home battery installers add buffer to cover such costs. That said, scale of economy is probably a much bigger factor for the cost difference at this point. Given all the media, vendor sales push and government subsidies over the years I had thought large portion of solar owners have bought home battery systems. So, I was surprised to find actually < 5% of solar homes have home battery systems. The EV market is much much bigger than home battery market and will likely remain so.

[J.P.M.]

I guess the answer is a solar company that includes batteries can get more for them because people just really don't understand or care what the cost is as long as they think they are going GREEN.

+1 *10.

[foo1bar]

I. For example, my LG RESU-16H is going to cost me $9800 installed
...
A Model 3 battery can be between 50 and 82 kwh and can cost up to $16k installed
...
Home batteries don't have many of the constraints or trade offs of a car battery but cost a LOT more. Why?

Your LG RESU-16H will include 16kwh battery, and the electronics to charge the battery and the inverter to get the power back out again.
As well as handling anything that the inspector sees when they inspect the installation as part of your permit process.

A model 3 battery is only the battery. it doesn't include the electronics for the power going into the battery or for the power coming out.
What I've seen is ~$13k for the battery and ~$3k for the labor.
So 50kwh for $13k = $.26/wh

If we assume $1k is cost of the charger, $1k is cost of the inverter, and $3k for labor, your RESU-16H is $4800 for 16kwh. $4.8k / 16kwh = $0.3/kwh

So we're talking about 15% more per kwh for the batteries.

15% sounds reasonable to me given the overall smaller market, smaller units (16 vs. 50), and IMO a market that will bear a higher markup.

[solardreamer]

Your LG RESU-16H will include 16kwh battery, and the electronics to charge the battery and the inverter to get the power back out again.

Last time I checked, LG RESU units don't include charger or inverter but they have built-in BMS. You need to pair appropriate inverter/charger (e.g. StorEdge) with them.