Tesla unveils solar-batteries for homes

This is a little lite on details, but exciting none the less:


A little more detail here.

Here's an article on Gizmag about it:
http://www.gizmag.com/tesla-battery-powerwall/37283/

Presuming that you had a solar array that produced at least 10kWh more than you used during a day, and that you were in a standard "sleep at night" sort of household, the chances of using up 10kWh over night for most homes is pretty slim. Of course, YMMV.

The real key for Permies here is that it's not just solar panels that this system will store energy for. If you have a Lister diesel engine burning vegetable oil, pressed from rape you grew on your own farm, connected to a generator that cranks out 7kW, you can run the thing for an hour and a half, completely fill your batteries, then shut it down. If 10kW will get you through an entire 24-hour period (or 22.5 hrs in this case), you're set.

J.D. Ray wrote: If you have a Lister diesel engine burning vegetable oil .... you're set.

these are rare and expensive if are you able to find them, in my experience.

i would like to look more into these batteries, as we plan to start building our solar array in the next year or so.

You can buy a Lister in good working order for under $1500. In my experience, solar panels cost a lot more, at least per kW of energy output. But then there's the matter of the fuel...

I think it is quite exciting that we are looking at other technologies for batteries as lead acid batteries have really held back the off grid world for too long. I'm not sure how "permies" these Tesla batteries are but it is just a first step. I like the way Elon Musk has made the design open source so other companies can push the advancement of the field.
I would prefer to see Nickel Iron batteries being more mainstream instead of lithium but new battery designs will come now someone has made the first move I hope.
The problem with mainstream off grid is average people want a system that can provide all the energy they now enjoy and will use it as a excuse to wantonly use power because it is "green". A permie would first find ways to reduce energy consumption to a minimum and then design a manageable system with enough capacity to not tax the system too much.

Also, coming to a country near you. Spain -the sunniest country in europe- is considering taxing people who are off grid based on there generating capacity because the main energy providers are loosing money due to the increase in off grid installations.

We really do live in a fucked up world

paul

I would prefer to see Nickel Iron batteries being more mainstream instead of lithium

Why?

I think this is the industry's answer to the games the grids are now playing. I know ours in KS is getting furious as people move to solar and wind. Our's is meeting it's 20% fed mandated renewable quota by 2020 mainly by wind not solar per the RPS. You can find your states RPS and incentives here: http://www.dsireusa.org/

Our new net-metering program is deteriorating. After July 1 2014 they are allowed to monthly wipe any credits or storage, it use to be annually before that. They only credit retail rates through a buy back meter they will swap out for free (here ~.10kwh), any overages gets paid at what they pay for it in that month (~.03 KWH) again if not used lost. I makes no sense to be grid tired what are they doing for the consumer? Back up power in an outage, generators do that and it rarely happens.

There is still a 30% tax credit on equipment cost and it can be depreciated over 5 years. No state property tax on equipment here. Helps a little not much, especially as prices drop.

You can buy panels at $.80/watt: http://www.ecobusinesslinks.com/surveys/free-solar-panel-price-survey/ I would not think they drop much further.

Before you do that might want to run a simulation and financial model with SAM or PVwatts, 2015 software is excellent: https://sam.nrel.gov/

They challange I'm facing is running mainly DC to avoid the losses in the inverters and transformers. I'd be interested in what they are doing with MPPT? or the bast way to manage storage? It appears as if Powerwall is the MPPT and you need an inverter? Wonder why they did not integrate the two for new designs? http://www.teslamotors.com/presskit/teslaenergy

This is worthy of nothing more than a resounding 'meh'.

Some upsides, yes; integration is a plus for some folks, and presumably Tesla has learned about keeping batteries alive and healthyish in suboptimal conditions. Liquid thermal control and indoor/outdoor installable sound promising. Good press for solar in general I suppose.


Downsides, per their currently sparse specs page @ http://www.teslamotors.com/powerwall

It's a 350-450V DC power pack. Yikes. 'Requires installation by a trained electrician' indeed. No doubt the warranty is void otherwise.

I don't want to play with voltages that high, and for this size of bank it seems unnecessary; it's only like that because they need that high voltage for their vehicle applications.

Like Terry, I'd like to run as much as possible off DC directly. I'm not aware of a lot of 350V DC appliances! Stepping the voltage down from, say, 48V to 12V is pretty simple/cheap, if you choose to go with a larger system that benefits from a bank voltage above 12V. Stepping down from '350-450V', not quite as cheap/easy. Even more so when it's all sealed up to keep you from killing yourself, and playing around voids the warranty.

It requires a inverter able to handle that voltage in order to be any use. Looks like Tesla is partnering with SolarEdge to make this, and it will either include a solar charge controller, or tie in with dedicated SolarEdge charge controllers. Either way, $$$$. http://www.jpost.com/Business-and-Innovation/Environment/SolarEdge-to-provide-inverter-technology-for-Teslas-solar-powered-Powerwall-battery-402045

This implies that as shipped it will be chargable only from AC power via an integrated AC powered charger.

It's Lithium Ion instead of Lithium Iron Phosphate; ie, it can blow the fuck up.

A ten year warranty hopefully does not indicate a 10 year lifespan... and I don't see details on the terms of that warranty.

It weighs 220lbs. Not bad for the amount of energy storage, but I sure can't carry it piece by piece like a modular system.

The fact that I can install it outside is good, because it's really unhealthy to be around a lithium ion cell if it blows up or vents. OTOH, if it was a less volatile battery, I wouldn't consider this such a plus... and keeping it inside would eliminate the need for weatherproofing, and perhaps for that fancy 'Liquid thermal control' system.

Even for those who are grid tied this has potential... as prices come down for these units you introduce the option of effectively trading cheap off peak power for expensive on peak. Charge up your pack at 3am when the power is cheap and use it in the day when it is expensive.

In the book "Sustainable Energy - Without the Hot Air" link to pdf

They examine the roll that modern home battery and car systems can play in stabilising the grid as a larger and larger proportion of variable power generation is used. Smart batteries can smooth the baseload out, feeding energy back to the grid in times of peak demand and drawing down surplus at times of low demand. Enough of these installed will reduce the need for base load power (coal, gas, nuclear) and allow more windfarms and solar setups to be grid tied. Encouraging consumers to install these is going to be a cheaper approach ultimately than building new, large, centralised power supply setups.

EDIT - a sensible model will pay homeowners for energy they store and supply back to the grid, helping fund installations.

This is a step forward IMO. If I had a choice between the Tesla and any other battery bank with cost being equal, Tesla would win hands down. My Rolls Surrettes are only a couple years old, but once they go - I will happily replace with the Power Wall.

have been getting quotes on solar .. finding panels that are 250- 260 watt for $0.55 per watt and micro inverters between $80 -$200 for these panels. Complete 5KW systems for 3500 but have to add shipping and a array frame.

As to the Tesla battery they also have 7kw smaller unit but it is not much less than the 10KW

Steve where are you finding .55/watt? and the inverters? I'll call Telsa see what I can find out, especially the issues Dillon raised - thanks for that!

an alternative to the tesla alternative

http://www.techswarm.com/2015/02/dont-want-to-wait-for-teslas-home.html

Don't Want to Wait for Tesla's Home Battery? Try This Off-Grid Battery Pack -

"Aquion Energy manufactures its proprietary Aqueous Hybrid Ion batteries to provide affordable off-grid power storage. These eco-friendly batteries are made with saltwater, cost less and last up to ten times longer than traditional batteries currently used in solar home systems, and are already linked together in a bank for optimum charging speeds and easy installation."

https://www.youtube.com/watch?v=aANBtotnsLI
http://www.aquionenergy.com/

put in a request for quote on batteries micro inverter and solar panel on alibaba .. that is where I got these quotes

At this point most of this equipment is coming from there ..


The panels ranged from 250 -300 watt the micro inverters are interesting as they range from 300 to 1500 watt which allows one to use on single panel or mini array of 4 panels per inverter.. quite a nice savings

Pffft. Telsa's already sold out of the home batteries thru 2016!
http://inhabitat.com/teslas-powerwall-home-battery-is-already-sold-out-through-2016/

Glad they are sold out. I want lots of rich people to fund the building of version 2.0. That one should be good enough and cheap enough to actually make a difference in a big way.

Duane; Thanks for sharing Aquion battery information. I find them more interesting at this time than the tesla battery.(who wants high voltage & only electrician installed !) I have been off grid with lead acid batteries for 30+ years and am really tired of replacing them every 10 years or less. I am going to research these a lot closer.

As far as I know, electricity is the same price here no natter when it is used. My meter doesn't know when I use a kWh.

I have a 3.185 kW system. I have a net meter. After one full year the meter was at 1300, meaning I used 1300 kWh more than I produced for the year.

Here in MA, the power company buys your excess power at retail, just taking the amount off your bill and giving you a credit balance. I burn through that credit during the shorter days and when there are several feet of snow covering the panels. If I were to produce more than I used in a year, the power company would consider me a producer and would buy my excess power at wholesale.

I have thought about some battery storage, but it doesn't seem worth it at all. They way I look at it, my neighbors use my excess power during the day.

In order for battery storage to have any advantage for me, I would have to go totally off grid. That would save me the $10 a month that the power company charges me just for having an account, and it would allow me to use my own power during power failures. As it stands now, my system shuts off when there is a power failure in the grid. They say that is so that linemen don't have to deal with power feeding into the lines from the wrong direction. It makes sense. They test the lines, find them dead, but then the sun comes up, the clouds part, or my clothes dryer shuts off and all of a sudden I am feeding power into a line they think is de-energized.

I'm confused about the hype around this.

You can already buy lead acid or Li-ion batteries for around 20-25% of the per KWh price of this tesla pack.

I've been trying to find out the warranty details. Both are warranted for ten yrs. The 7KWh pack for "daily use" the 10KWh pack for weekly use.
If Tesla has made a Li-ion pack that really can go thru 3650+ recharge cycles then I am impressed.

I wonder, and it's only a guess in lieu of them publishing much detail on their warranty, if they expect to be replacing batteries in the pack under warranty well before ten yrs are up but the 4-5x overpricing is going to cover this, especially assuming that many/most customers won't cycle the pack every day and that costs to tesla will fall over the ten years.

So here's the major differences between Lead-Acid and LIPO.

Depth of Discharge. LIPO can discharge to 20% without harm, lead-acid 50%, meaning for a desired capacity, it would take 30% more lead-acid for the same use.

Weight: On average, including Battery management, LIPO weigh 75% less than lead-acid

Charge cycles: LIPO will endure at least 4 times the number of charge/discharge cycles of lead-acid.

Note that LIPO batteries are rated in USABLE capacity, not total capacity. Lead-acid are rated at total capacity. To maintain the appropriate level of discharge (50%), you need twice the capacity of lead-acid to equal LIPO.

So, let's do some math:

Lead Acid: approx. $0.11/watt (this is what I paid for 4-6v crown lead-acids for my 24v bank). A bank capable of cycling 7 kw (meaning a 14kw bank) would cost $1,540. If properly maintained and cycled daily, this bank would provide about 2 years of service before needing replacement (or losing significant capacity). Over 10 year this bank would need to be replaced 5 times for a total cost of $7,700. Let's say you can nurse it and get twice the life (4 years), the cost would still be $3,850.

Tesla's 7kw pack has a $3,000 price for the same 10 years.

Regarding the higher voltages, we've become conditioned to use DC at low voltages but the benefits for higher voltage are smaller conductors, less line and conversion loss.

Please give me a link to where you can buy Li-ion for 20-25% the per kwh price of the tesla. I'm looking at converting my camper from lead-acid to lithium and would love to find a price lower than $0.42/watt

Steve Farmer wrote:I'm confused about the hype around this.

You can already buy lead acid or Li-ion batteries for around 20-25% of the per KWh price of this tesla pack.

I've been trying to find out the warranty details. Both are warranted for ten yrs. The 7KWh pack for "daily use" the 10KWh pack for weekly use.
If Tesla has made a Li-ion pack that really can go thru 3650+ recharge cycles then I am impressed.

I wonder, and it's only a guess in lieu of them publishing much detail on their warranty, if they expect to be replacing batteries in the pack under warranty well before ten yrs are up but the 4-5x overpricing is going to cover this, especially assuming that many/most customers won't cycle the pack every day and that costs to tesla will fall over the ten years.

At 1:38:56 of episode 1571 of TSP, Steve Harris explains why the Telsa batteries are a huge game changer.
http://www.thesurvivalpodcast.com/calls-5-8-15

Blah! My town is not leading in this technology, nor the first. Salt water batteries are extremely efficient and close to non toxic. I worked with these people in the start up phase, and we were using kitchen equipment to build batteries. Take a gander. The prices come (if the system is well designed) at 25 us cents per watt. With a 5000+ cycle, with a 100% discharge. The batteries are not great at appliance start surges, if installed into a direct low voltage system. This is a fault for one whom wants all the bells and whistles of a consumeristic home. This is not a beta company, they produce and sell. Beat that.
http://www.aquionenergy.com

If you decide to research the company, make sure the comments are relevant, they have come a long way in the past 9 years.

Lead acid battery dischargeability depends on the thickness of the internal plates. Leisure/consumer/boat/golf cart batteries are made to be discharged to near zero hundreds of times but are not capable of providing the amps your starter motor needs. Typical car batteries are optimised to give several hundred amps for a second or two to fire your starter motor but if you discharge it beyond 80% full 2 or 3 times you've killed it.

Usually a lead acid batteries AH rating is based on how much power it can provide without its voltage dropping below 90% of it's rated voltage.

Li Ion batteries off ebay (search "18650 battery") available to consumers in tiny quantities come out at less than 25% of tesla's per KWh price. Ask a Li Ion pack builder to build you a 7KWh pack and they will laugh in the face of Tesla's offering. But as I noted in my first post, the 3650+ recharge cycles IS impressive (if true).

Chad, I was interested enough to click through to the Aquion website, but... No tech specs or pricing readily accessible, just fluff. To me, a company that does not have this info readily available to the end consumer, probably doesn't want to sell to me. For my purpose(RV) it's a moot point anyhow, since a 19.2kWh unit weighs 1285KG! This is about 1/4th the energy density by weight of a LiFePO4 solution. Not a dealbreaker if you're in a fixed location, but shipping is going to sting!

All that said, a far less toxic option would be fantastic, and if they can actually get the prices down to near their projected $200/kWh in 5 years, that will be another matter entirely.

Gerard Foret wrote:Depth of Discharge. LIPO can discharge to 20% without harm, lead-acid 50%, meaning for a desired capacity, it would take 30% more lead-acid for the same use.

Worse, really... if you're sticking with 20% and 50% DoD, you need about 60% higher capacity in Lead-Acid to get the same usable capacity. 100AH*0.8DoD=80AH usable from a 100AH LiFePO4 cell, so you'd need 160AH*0.5DoD to get the same 80AH from a Lead-Acid cell...

Gerard Foret wrote:
Regarding the higher voltages, we've become conditioned to use DC at low voltages but the benefits for higher voltage are smaller conductors, less line and conversion loss.

As a general statement, totally true, but this doesn't seem terribly applicable as a plus for the Tesla system, because, really, how many things are you going to be feeding 350V DC to? The inverter should be right next to the battery bank, and then it's AC from there.

For lower voltage systems, line loss usually isn't much of a problem in a well designed system, because the major draw (inverter) is easy to locate near the batteries. Sure, you need a bit of serious cabling for a high powered inverter, but we're talking a few feet, not a few hundred feet. The other DC loads that come to mind are lighting, possibly pumps, fans, lowish power electronics like tablets and phones via a 5V regulator, and *maybe* a fridge/freezer... Mostly fairly low amperage with correspondingly reasonable gauge requirements and line loss, and you basically can't get these things in 350V versions, so it's hardly useful that they would have lower line loss if you could...

The supply side voltage from a solar or wind array is completely separate anyhow, so since you can stick your controller near the battery and run at source voltage up to that point, you can take advantage of higher voltages and cheaper wiring on that side of the system without needing to screw with it for the batteries.

Gerard Foret wrote:
Please give me a link to where you can buy Li-ion for 20-25% the per kwh price of the tesla. I'm looking at converting my camper from lead-acid to lithium and would love to find a price lower than $0.42/watt

I was planning to use Balqon LiFePO4(http://www.balqon.com/online-store/#!/All-Batteries/c/2736691/offset=0&sort=priceAsc) cells in my campervan, which were selling for less than a dollar per AH in the bigger sizes(3.2V individual cells, up to 1000AH), but are currently at about $1.2 per AH, not much below your $.42 per watt figure. Won't have my BMS til fall, so I'll keep considering options until then... Either way, not the cheapest option, but I have no great liking for the cheaper Lithium Ions. I've taken apart enough old laptop batteries to be leery of that route for serious energy storage.

The sodium battery is definitely much larger and heavier, but with its benifits. I now see your dilemma with size and weight issues being a rv. I was mostly just throwing it on the table, as a comparison to tesla's "break through" developments. I personally think we need to get away from these heavy metal batteries, and start looking towards some of these other promising alternatives. I agree it needs some work before it is practical. For anyone who is interested, do contact them, the warehouse is small, and has troubles meeting demands, but they do sell to home owners. Thanks for taking a look at the company dillon!

Ps, sorry duane! I didn't notice you already made a post about aquion

Ali-express shows some very low prices for Li 18650 batteries. (Straight from China)

Note of advice: ALWAYS read the buyer feedbacks on Ali express. There are even companies on there to incorrectly claim 8800mAh 18650 Li batteries. (As far as I have seen, 3400mAh is about the maximum there is now)

Buyer Feedback will mention the actual capacity of the cell having tested them on an IMAX device

An example would be:

http://m.aliexpress.com/item/1198812901.html

Around 36 usd for 25Ah worth of 3.6V storage.

Around .4 usd/W

Luke

I did check out the Aquion option.

I even found an online reseller:

http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Saltwater-Technology/Aquion-Energy-S20P-Pre-wired-Battery-Stack-48V/p11629/

However there is a back log until July at least.

Shipment for me to Thailand would be an issue too...

Luke

$0.07 / Wh here
http://www.ebay.co.uk/itm/4pcs-UltraFire-5800mAh-18650-Batteries-3-7V-Li-ion-Rechargeable-Battery-NK-Blue-/141447946619

I've bought from this seller and all ok.

Less than one SIXTH the price of Tesla's offering

You should check the actual capacity on those. Ultrafire is infamous for overstating capacities.

I saw in the feedback on some Ultrafire 5800 mAh on Aliexpress that they tested as only 1500 mah.

If they overstate capacity by 400%. How much do they overstate longevity?