Tesla Wants to Build a Battery for Your House

[SunEagle]

Here $7,000 will get you about $90 a year in a CD at current Interest rates, not even worth the effort to drive to the bank. Over 10 years no one knows.

True. What use to be a good way to invest, CD's have a pretty poor ROI.

There are other ways to invest where you can get more return but as you know the higher the rate the higher the risk. The trick is finding one that is good.

Funny how back in the 60's I had a savings account that got me 5.5% and I also got a set of glassware with only a $100 deposit.

[Willy T]

Something I think people fail to factor in, in battery storage cost, is expected ROI is the income earning potential off the capital investment of all the components.

If this battery cost $7000 and last for 10 years,

then in business terms you would want a minimum 10% per annum ROI. so that 7K could earn you 11K,

Even at 5% term deposit it would earn you $4400,

Obviously there are some variables with tax etc,

But still something that a lot of people over look

Here $7,000 will get you about $90 a year in a CD at current Interest rates, not even worth the effort to drive to the bank. Over 10 years no one knows.

[Bala]

Something I think people fail to factor in, in battery storage cost, is expected ROI is the income earning potential off the capital investment of all the components.

If this battery cost $7000 and last for 10 years,

then in business terms you would want a minimum 10% per annum ROI. so that 7K could earn you 11K,

Even at 5% term deposit it would earn you $4400,

Obviously there are some variables with tax etc,

But still something that a lot of people over look

[Willy T]

I am kinda slow sometimes so help me out.

You are estimating that the battery system will cost you $1.90/day (for 10 years).

You are using 40kWh at $0.36/kWh rate a day at a cost of $14.40 but want to offset that cost by using your export kWh at $0.04/kWh to charge that battery.

So how much kWh do you normally export at the $0.04/kWh rate a day?

It depends, one I am using it to re-charge the batteries and running A/C and other things I time shift. Weather is always a factor. I have two sub panels and one I can cut if necessary during low production. There many days I generate 50 + KWH on the panels alone.

[SunEagle]

The $.04 is the reimbursement rate for any excess, that is the power you store for later use.

My Typical TOU used to be about 40 KWH per day @ $.36 = $14.40. Anything I can off set above the $1.90 + 40 x .04 = $1.60 so $3.50 cost, or $10.90 saved if I could replace it all. Realistically I have about 20 kw storage and the panels supply the rest ( 8.2 kw ) and use grid support for some of the big stuff.

I am kinda slow sometimes so help me out.

You are estimating that the battery system will cost you $1.90/day (for 10 years).

You are using 40kWh at $0.36/kWh rate a day at a cost of $14.40 but want to offset that cost by using your export kWh at $0.04/kWh to charge that battery.

So how much kWh do you normally export at the $0.04/kWh rate a day?

[Willy T]

Someone just got caught in a big fat lie and is making things up. From another thread you stated and I quote directly.



Your busted.

Do you know how many systems I have ?? I thought not. The LiFep04 is a system I am playing with to see if I want to switch from FLA in the future. If you took the time to read you'd have seen it's connected to a outback GFX 1312 Inverter, hardly a house sized system. You know what you can do with the name calling.

[Sunking]

I have about 20 kw storage and the panels supply the rest ( 8.2 kw ) and use grid support for some of the big stuff.

Someone just got caught in a big fat lie and is making things up. From another thread you stated and I quote directly.

I have 8, 260 amp hr Winston cells, 520 amp hr @ 12 ( 2p4s) .

Your busted.

[Willy T]

If anyone stores energy in batteries it will be the utility. They will have the first right.

For individuals to store energy in batteries and expect to sell it back at TOU high rates only happens due to politics - it makes no business sense. It only works at all due to the small penetration of solar PV as of today.

+1 Totally Agree

[Willy T]

I agree that the grid tie is definitely worth it and will pay for itself quickly in high Tier locations.

I just don't see that battery being an economical solution even if your credit for excess power is only $0.04/kWh.

The $.04 is the reimbursement rate for any excess, that is the power you store for later use.

My Typical TOU used to be about 40 KWH per day @ $.36 = $14.40. Anything I can off set above the $1.90 + 40 x .04 = $1.60 so $3.50 cost, or $10.90 saved if I could replace it all. Realistically I have about 20 kw storage and the panels supply the rest ( 8.2 kw ) and use grid support for some of the big stuff.

[russ]

The $1.90 is to break even, I am off setting $.15 Per KWH + my TOU - the $1.90. My motivation is to NOT have a electric bill, why have a grid tie in the first place ?? For most people just buying more panels makes sense, but TOU is hard to over come without storage.

If anyone stores energy in batteries it will be the utility. They will have the first right.

For individuals to store energy in batteries and expect to sell it back at TOU high rates only happens due to politics - it makes no business sense. It only works at all due to the small penetration of solar PV as of today.

[SunEagle]

The $1.90 is to break even, I am off setting $.15 Per KWH + my TOU - the $1.90. My motivation is to NOT have a electric bill, why have a grid tie in the first place ??

I agree that the grid tie is definitely worth it and will pay for itself quickly in high Tier locations.

I just don't see that battery being an economical solution even if your credit for excess power is only $0.04/kWh..

[Willy T]

I still don't understand your math and motivation. It will take 10 years (minimum) at $1.90/day to get back that $7000 you spent for that battery. But you can make over $1000 in those 10 years selling your excess at $0.04/kWh without spending another dime.

The $1.90 is to break even, I am off setting $.15 Per KWH + my TOU - the $1.90. My motivation is to NOT have a electric bill, why have a grid tie in the first place ?? For most people just buying more panels makes sense, but TOU is hard to over come without storage.

[SunEagle]

I'll take $.11 cents a KWH from anyone that wants to give it to me. All I need is $1.90 a day @ $7,000 to pay for my powerwall. My Solar is free, I'll charge batteries all day before I give it away for $.04 cents a KWH. I know the math, my bill has been zero for the last 4 years except for the $10 service fee. We havn't even started on the $.36 - $.41 per KWH TOU cost.

I still don't understand your math and motivation. It will take 10 years (minimum) at $1.90/day to get back that $7000 you spent for that battery. But you can make over $1000 in those 10 years selling your excess at $0.04/kWh without spending another dime.

[Willy T]

Geez are you kidding? Where did you go to school and learn math?

Two Jewish tailors are standing in front of their shops named Adam and David. Adam's biz is slow and Davids is booming. Conversation goes like this:

Adam: It cost me $400 to make a suit.

David: Yeah, same here $400

Adam: What do you ell your suits for?

David: $300

Adam: How do you stay in biz and make a profit?

David: Volume makes up for the loss.

I'll take $.11 cents a KWH from anyone that wants to give it to me. All I need is $1.90 a day @ $7,000 to pay for my powerwall. My Solar is free, I'll charge batteries all day before I give it away for $.04 cents a KWH. I know the math, my bill has been zero for the last 4 years except for the $10 service fee. We havn't even started on the $.36 - $.41 per KWH TOU cost.

[russ]

Fronius hasn't announced a US version AFAIK. Whoever makes solarcity inverters (solar edge?) will make the U.S. version, I think.

The point of the home battery is not to put power out on the grid. It's to save self self-produced solar for later, or as back up.

I find it strange to question whether Tesla can make the powerwall work as spec'd. The issue is the full cost, and the value proposition.

When the concept is viable you can bet the utilities will be the first in line to use it.

The Musk bull is just him trying to make good PR about his name and therefore projects. For example, whenever I read about Space X another rocket has blown up.