Tesla Motors Announces a New Home Battery • Hacker News Board

Re: Tesla Motors Announces a New Home Battery

#91

Post by lsaferite » Tue, Feb 17, 2015, 2:30 PM UTC

skrause wrote: post #38

oloboWd wrote: post #33

Earlier quoted context omitted.

There are many possible reasons. You might enjoy the feeling of independence or self reliance that supplying your own power brings. You might be a weed grower and not want to be found out because of your energy bills. You may feel that it's more responsible to produce your own electricity and have a clear understanding of its environmental costs. Grid power may be unreliable in your area, or expensive. Maybe you thin…

All those are good reasons to also have your own power. You'll get your independence and might even save some money. But even then it's still good to be connected to the grid. It will serve as a backup line and if you produce more enery than you can consume, you might be able to sell something back to the grid.

And THAT is a primary reason utility companies are fighting grid-connected consumer solar right now. If you are grid attached you are part of the cost of maintaining the grid that is normally offset by your revenue to the utility. If you are just using it as a glorified battery backup by feeding in excess during the day and pulling during the night and you are a net zero to then company then your per-customer revenue is much much lower. If only a small percentage of customers do this then you can level it out. If that percentage starts to grow then something has to give. Either you lower your maintenance budget, lower your operating costs, or lower your net profits. No one directly involved wants any of those to actually happen. This is obviously greatly simplified (e.g. The extra cost of handling customer generated power), but you get the idea.

Re: Tesla Motors Announces a New Home Battery

#92

Post by lsaferite » Tue, Feb 17, 2015, 2:31 PM UTC

freehunter wrote: post #87

lsaferite wrote: post #61

Earlier quoted context omitted.

I wish sites would add automatic abbr tags to think like FWIW or, in this case, TANSTAAFL so those no in the know can easily mouse over and see what the hell you are saying.

PLMATTMETJSOW. People Like to Make Up Abbreviations That Take More Explanation Than Just Spelling it Out Would. SMH.

Hahaha. I love how you end this with another one I had to look up.

Re: Tesla Motors Announces a New Home Battery

#93

Post by jay-saint » Tue, Feb 17, 2015, 2:31 PM UTC

jacquesm wrote: post #73

lsaferite wrote: post #63

Earlier quoted context omitted.

I'd imagine in this case they are looking at the economy of scale they'll be able to gain when producing these out of the gigafactory. I'd be interested to see the $/Wh cost difference once it comes fully online.

Tesla batteries retail for $30K@85KWh, so approximately $350/Wh, Lead-acid deep discharge is about $10000/100KWh, so approximately $100/Wh. That's a pretty large gap.

Keep in mind that $30K for 85KWh is pre-gigafactory and is also for a vehicle. There are many more safety factors involved in making a battery that is going to moving around at 70mph. Much of the cost of the vehicle based batteries, may be able to be skipped, if you are not as concerned with mobile safety and weight.

Re: Tesla Motors Announces a New Home Battery

#94

Post by justinsteele » Tue, Feb 17, 2015, 2:32 PM UTC

skrause wrote: post #38

oloboWd wrote: post #33

Earlier quoted context omitted.

There are many possible reasons. You might enjoy the feeling of independence or self reliance that supplying your own power brings. You might be a weed grower and not want to be found out because of your energy bills. You may feel that it's more responsible to produce your own electricity and have a clear understanding of its environmental costs. Grid power may be unreliable in your area, or expensive. Maybe you thin…

All those are good reasons to also have your own power. You'll get your independence and might even save some money. But even then it's still good to be connected to the grid. It will serve as a backup line and if you produce more enery than you can consume, you might be able to sell something back to the grid.

The "grid" doesn't yet exist in certain plots of land. One may want to build a house in the woods, but not pay the costs to get electric/water/sewage run to the property from whatever main road is closest.

Re: Tesla Motors Announces a New Home Battery

#95

Post by cryptoz » Tue, Feb 17, 2015, 2:32 PM UTC

jacquesm wrote: post #73

lsaferite wrote: post #63

Earlier quoted context omitted.

I'd imagine in this case they are looking at the economy of scale they'll be able to gain when producing these out of the gigafactory. I'd be interested to see the $/Wh cost difference once it comes fully online.

Tesla batteries retail for $30K@85KWh, so approximately $350/Wh, Lead-acid deep discharge is about $10000/100KWh, so approximately $100/Wh. That's a pretty large gap.

The Tesla Model 3 car, due in a few years with a fully online gigafactory, is supposed to retail for $35k I think. This certainly means that Elon is expecting a price drop in the (car) batteries by quite a significant amount - perhaps even down to a price competitive with Lead-acid for the (home) batteries discussed here.

Re: Tesla Motors Announces a New Home Battery

#96

Post by krenoten » Tue, Feb 17, 2015, 2:32 PM UTC

Are orange and red terminals confusing to users? (I'm an electronics noob, maybe this is a convention)

Re: Tesla Motors Announces a New Home Battery

#97

Post by engendered » Tue, Feb 17, 2015, 2:34 PM UTC

headShrinker wrote: post #60

brudgers wrote: post #23

So, where does lithium come from? It comes from the Earth, of course, but it doesn't require strip mining or blowing the tops off mountains like other resources do...most often, lithium is found in briny underground ponds. The liquid is pumped out and left to dry in the sun. TANSTAAFL https://duckduckgo.com/?q=lithium+pond+photos&iax=1&ia=image... Mining is mining. There isn't a "green" form. Tearing holes in the ear…

Also many municipalities don't allow battery 'grid-tie' with the option of 'off the grid' living. For example, Connecticut has laws which don't allow houses to have batteries that would allow a house to be self sustaining and have a connection to the grid. This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. The…

>you can't even live 'off the grid' in a grid tied system

I can't find any references for your stated claim about Connecticut, however it seems deeply illogical given that a generator (which surely aren't banned), solar panels, wind, etc, all have the potential of feeding energy back to the grid in an outage. Which is why there are regulations and home inspections and all of that, to ensure that the appropriate safeties and switches are in place. Simply banning one of many possible mechanisms of generating power would be very short sighted.

Many regions that offer feed-in time-of-day tariffs are rightly trying to figure out how to accommodate battery systems, where some users are trying to game the system by charging a big battery array during low cost hours, and then "selling" it back to the grid during peak hours (at inflated, subsidized prices).

EDIT: As a reply to msandford, given that I can't reply lower -- the reason they have this limit is that the tariff price paid to home solar/wind generators is way above the bulk, "wholesale" price of power. It was created as an incentive to encourage green energy. So when you feed back their own power to them, it does them no favor given that now they're paying 2x+ what they would pay on the normal power market for power, and simply undermines the entire incentive program.

Re: Tesla Motors Announces a New Home Battery

#98

Post by boris » Tue, Feb 17, 2015, 2:34 PM UTC

Today I went to pick up two 100AH lead-crystal batteries for a long-run UPS (we now have regular load-shedding here in South Africa). If I believe all what I have read about them online, they are amazing, compared to lead-acid. Crazy heavy though (33kg each).

Re: Tesla Motors Announces a New Home Battery

#99

Post by davegardner » Tue, Feb 17, 2015, 2:34 PM UTC

headShrinker wrote: post #60

brudgers wrote: post #23

So, where does lithium come from? It comes from the Earth, of course, but it doesn't require strip mining or blowing the tops off mountains like other resources do...most often, lithium is found in briny underground ponds. The liquid is pumped out and left to dry in the sun. TANSTAAFL https://duckduckgo.com/?q=lithium+pond+photos&iax=1&ia=image... Mining is mining. There isn't a "green" form. Tearing holes in the ear…

Also many municipalities don't allow battery 'grid-tie' with the option of 'off the grid' living. For example, Connecticut has laws which don't allow houses to have batteries that would allow a house to be self sustaining and have a connection to the grid. This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. The…

The same issue exists with grid connected solar panels. My solar panels are designed to stop working whenever there is a power outage. This is a legally mandated requirement here and is very annoying when it happens on a beautiful sunny day.

A solar panel installer told me that if I add a battery backup to my installation, then at least it'll still charge the batteries during a power outage.

Re: Tesla Motors Announces a New Home Battery

#100

Post by vidarh » Tue, Feb 17, 2015, 2:35 PM UTC

lsaferite wrote: post #65

higherpurpose wrote: post #53

Earlier quoted context omitted.

You charge your laptop everyday. So it depends on how often you recharge them, which means it will depend on how big of a battery you'll buy. If you buy a 100 KWh battery (probably around $10,000-$15,000), I think that should last most Americans at least several nights to a week? So it might approach 10 years before it starts degrading, and then probably a few more years of charging it every day. I assume's Tesla's b…

Isn't the idea that you keep it topped of and use it when grid power is expensive or missing? That usage pattern would involve multiple charge cycles, perhaps even 365 in a year. I guess it would actually follow the Tesla charging patterns fairly close as well. What is the estimated lifetime of a Tesla's battery?

If the battery has sufficient excess capacity, you can split it into multiple banks of smaller batteries, and cycle which ones you charge and which ones you use. Add a small computer and you can use whatever logic gives you optimal charging/discharge patterns to optimise for lifetime.