Tesla Powerwall, The Specs, Numbers, and Implementation Absolutely Brilliant

[Sunking]

Glad to hear you admit it.

I like it.

[tehan]

Tesla Owners are not off-grid. have internet, and more money then they have common sense. They drank the Kool-Aid

I know that is what you meant, I just said it for you.

I was pretty sure that's what he meant, but thank you for the translation!

[tehan]

The battery pack is about 300VDC There is no base of installed off-grid systems based on 300VDC. So it's all new vaporware.
And I don't have 24/7 internet (needed for Tesla to control the pack) No reason for off-grid to need internet connection.

I understand there is a very small base of off-grid users who are upset that Powerwall does nothing for them. There's a guy on the Tesla forum who rants about this daily. But the on-grid manufacturers (i.e. 99% of the PV industry) have been using high voltage DC for some time. And as storage is added to the on-grid mix I suspect that 48V DC is just going to go away.

[tehan]

So I gather you are going forward and getting one of the Tesla batteries for your home. That is your choice to make and money to spend. I wish you luck.

I'm thinking about it. I enjoy hearing other people's opinions, especially those critical of the product, and they are very much contributing to my decision making process.

I'm looking at installing a PV system for about $3.50 per watt. But I live in Texas where electricity is cheap and net metering not very favorable (I can net energy cost, but not distribution cost). So even with local and federal incentives the economic case is marginal. Adding Powerwall to the system will increase cost by about $1 per watt, but it provides an important secondary benefit as a grid backup system. It's hard for me to place a value on this, but it isn't small given that I can't run a generator here so I have no other backup options.

[SunEagle]

I'm thinking about it. I enjoy hearing other people's opinions, especially those critical of the product, and they are very much contributing to my decision making process.

I'm looking at installing a PV system for about $3.50 per watt. But I live in Texas where electricity is cheap and net metering not very favorable (I can net energy cost, but not distribution cost). So even with local and federal incentives the economic case is marginal. Adding Powerwall to the system will increase cost by about $1 per watt, but it provides an important secondary benefit as a grid backup system. It's hard for me to place a value on this, but it isn't small given that I can't run a generator here so I have no other backup options.

I believe I understand your needs for a secure backup power source where generators are not an option.

One of the reasons I have both generators and batteries is to provide a power source for my mother in law's oxygen machine. That needs to work at night even if the grid is down.

You have limited choices and none are cheap. I hope energy storage prices come down and you find a way to feel safe and secure with your choices.

[Sunking]

I understand there is a very small base of off-grid users who are upset that Powerwall does nothing for them. There's a guy on the Tesla forum who rants about this daily. But the on-grid manufacturers (i.e. 99% of the PV industry) have been using high voltage DC for some time. And as storage is added to the on-grid mix I suspect that 48V DC is just going to go away.

It will not go away. All the electrical codes and rules change when you go higher than 50 volts. Lot mo money involved.

[tehan]

It will not go away. All the electrical codes and rules change when you go higher than 50 volts. Lot mo money involved.

Actually NEC code doesn't allow residential batteries over 50V at all. So it's not completely clear how Tesla plans do get UL approval for Powerwall, but I presume they have a plan. It seems Powerwall works the same way the battery in the Tesla car works: it won't deliver any current unless a normally-open relay is closed by some external controller (i.e. the inverter). This is a significant fail-safe improvement over existing batteries and I suspect overcomes any objections on safety grounds. Oh and it costs virtually nothing - it's just smart engineering.

[inetdog]

Actually NEC code doesn't allow residential batteries over 50V at all. .

Can you quote a Code section supporting this?
Would that mean that I could not use a commercial high voltage UPS in my home?

[Mike90250]

I understand there is a very small base of off-grid users who are upset that Powerwall does nothing for them. .....

So wrong. sigh....

I do not know what your background in solar is, but it's apparent, that you have none.
There is a large base of educated users whom are upset that the powerwall is a poor product with a lot of hype behind it.

Some Grid Tie systems use high voltage DC but the powerwall does not have an integral charger, so that would have to be purchased separately. It may pass NEC by the fact it's a sealed "box" with no accessible parts.

[tehan]

Can you quote a Code section supporting this?
Would that mean that I could not use a commercial high voltage UPS in my home?

690.71B. There are exceptions listed there too which I guess Tesla (and your UPS) may fall under.

[tehan]

So wrong. sigh....

I do not know what your background in solar is, but it's apparent, that you have none.
There is a large base of educated users whom are upset that the powerwall is a poor product with a lot of hype behind it.

Some Grid Tie systems use high voltage DC but the powerwall does not have an integral charger, so that would have to be purchased separately. It may pass NEC by the fact it's a sealed "box" with no accessible parts.

I guess when you have no more points to make then you resort to the ad hominem attacks. Sad.

No need to purchase a separate charger: all you need is a SolarEdge inverter and the Powerwall battery. Watch for the SolarEdge demonstration and press release next week. Wish I could tell you more but I don't want to spoil the surprise!

[Sunking]

Can you quote a Code section supporting this?

Ditto been doing this professionally for 35 years. Have installed hundreds of systems with 200 plus battery volts on UPS systems with FLA open cells. Passed every inspection even in NEW YORK CITY AND CHICAGO.

So please enlighten us on your expertise. Warning I sat on the NEC code panels for 2 cycles, and a moderator on MH NEC code forum. Even taught a few classes for MH.

[Sunking]

So wrong. sigh....

I do not know what your background in solar is, but it's apparent, that you have none.

Can it be Willy Mike? You need to apologize to him , you might of hurt his feelings and have to tell on yourself.

[Sunking]

I guess when you have no more points to make then you resort to the ad hominem attacks. Sad.

Willy is that you?

Officer, did you get the IP number of that truck?

[tehan]

Ditto been doing this professionally for 35 years. Have installed hundreds of systems with 200 plus battery volts on UPS systems with FLA open cells. Passed every inspection even in NEW YORK CITY AND CHICAGO.

So please enlighten us on your expertise. Warning I sat on the NEC code panels for 2 cycles, and a moderator on MH NEC code forum. Even taught a few classes for MH.

To be clear, I haven't and don't claim subject matter expertise on NEC code. I was simply passing along information I had received from a reliable source. When asked, I researched and provided above the relevant reference. In part, this says:

"Storage batteries for dwellings shall have the cells connected so as to operate at less than 50 volts nominal. Lead-acid storage batteries for dwellings shall have no more than twenty-four 2-volt cells connected in series (48-volts nominal)."

I am not arguing that is the whole story. There are exceptions included in the above section, and I'm sure you need to read this section in conjunction with a million other sections/rules/policies whatever. But I didn't just make it up!