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The Battery Solution - Home/Business Supercharger and Battery Backup/Energy Storage!

Discussion in 'Tesla Motors' started by moollar, Jun 11, 2013.

  1. moollar

    moollar Member

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    Hi Everyone,

    I've been mulling over different things that have been announced recently and how some of the main issues with EVs seem to be range anxiety, charging times (particularly at home), replacement cost of the battery and the impact of EVs on the grid. I think I may have a viable solution to all of these issues and think that Tesla could be the company to make it happen. I could be way off with this, but thought I'd put it out there for the collective minds of the intelligent people on this forum to discuss.

    The possible solution (1st draft):

    - Used batteries from Tesla vehicles could be re-sold to home owners (or kept by a current Tesla vehicle owner) and used as a grid connected battery backup. This would offset some of the cost to the Tesla owner of an upgrade to a new battery. As most of us are aware, even though a battery pack gradually loses capacity over time, there is a lot of life that you can get out of battery packs for many years. The price of the re-sold battery could be based on a "minimum rated capacity" at the time it is re-sold. There is an Australian company that is doing a grid connected battery backup / energy storage solution, which is kind of where I got this idea from. Their solution is very expensive though - I think Tesla could do it much cheaper and better!

    - These home-based battery packs can then be connected to a control system designed by Tesla that can be either grid-connected, solar (or other renewable) power system connected, or both. This allows a home owner or business owner to control where and when they source their electricity, the option of selling excess supply back to the grid during peak times to help with load balancing (utilities would love this!) and sourcing electricity during off-peak times if required. This system would obviously be used for charging EVs as well as meeting the energy needs of the home / business. I imagine this is similar to how the superchargers are being set up (you know - surviving the zombie apocalypse and all....).

    - Tesla would design the control system and software to hook up to their battery packs. This control system would include all of the necessary hardware (inverter(s), other hardware and software to control everything, etc.). Tesla know their batteries best and therefore could make a simple interface for an electrician/installer to connect the control system with the battery. Installers would obviously need the appropriate certification(s) to be able to do these installations.

    - Now the best bit - is it possible that these home based energy storage systems could be used as "mini" superchargers?! I could be way off on this and probably don't understand enough about delivering high currents via DC, but this is what hit me hardest when thinking about this idea. IF it is possible to do this, I think that the "mini supercharger" functionality would not necessarily be used to give an EV a full charge, but maybe a half or even third of a charge or less would suffice (to keep you going - i.e. a top up charge or an emergency charge). This smaller amount of charge could obviously be delivered very quickly using the new supercharger tech (5-10 minutes for a top up charge - assuming you will not be charging to more than the 70-80% level? - I don't mean charging 70-80% of the total battery capacity, just up to the 70-80% level of the battery as a maximum so that "tapering off" is not required, if that makes sense). You would need some residual power to be left in the backup battery for meeting the energy needs of the home or business (if required). Even with this limitation, it could dramatically decrease range anxiety for EV owners if they know they can top up quickly if they need to. Then the "Aaaarghhhh, I forgot to plug in when I got home last night!!!" scenarios should become a non-issue.

    - I would imagine that you could customise (Aussie spelling) how EVs connected to these units would be charged. I think it would be best if EVs still charged at "regular" rates for most of the time, with the supercharger rate of charge only being used when necessary (i.e. the default would be to charge at regular rates and you would have to somehow select that you wanted to charge at the supercharger rate in order to preserve battery life). It makes sense to continue to have overnight charging as the norm. It makes sense right now and will continue to make sense as long as humans still need to sleep every day. For regular charging overnight, you could have the EV charging off the backup battery up until it reaches a predefined depletion level on the backup battery (to conserve enough power for other usage), at which point the EV is then automatically switched to charging from the off-peak grid (or stops charging if you are on standalone solar, for example). Or you could have the EV be charging directly off the grid during off-peak, with the battery backup charging after the EV has finished (if required - would depend on how you would use the backup battery / energy storage system - see next point - and whether you are solar connected, etc.). I'm sure there are many more ways you could set things up, depending on your individual needs and circumstances.

    - Assuming that the "mini" supercharger solution is possible, home owners and business owners could opt to have their system as part of an "urban" supercharger system. Options if the mini supercharger is possible:

    * You could have homes and businesses who own the energy storage system opt-in to make their mini superchargers available for the public to use. A Tesla owner could see these mini superchargers on the infotainment system in their cars or on an app on their mobile devices, just like the Tesla owned "long distance travel" superchargers that are being rolled out. The mini supercharger owner could advertise how much they charge per KWh (for example) and how many KWh they have available for public consumption at any given time (the control systems would have to be internet connected to enable this, which is definitely doable). This could generate some income for the home / business owner from their energy storage system. The level of energy available (which would be displayed on the supercharger locator app) would be directly related to how much they are willing to "segregate" from their backup battery for this purpose and how much energy is actually in the battery pack at any given point in time. The driver can then make a decision as to where they would "top up" based on this info. Businesses could even offer their mini superchargers as a free service to customers if they wished. They could limit how much each vehicle can draw (either by KWh, time limit or both). All of this info would be displayed to the driver before they even get there.

    * Tesla could sell the battery pack and control system cheaper to customers who are willing to commit a "portion" of their battery pack capacity to this "urban" supercharger network. In fact, utilities could do the same thing (for load balancing purposes) and provide some incentive to the property owner to do so. In the case of Tesla, they could then make these mini superchargers part of a HUGE "free" distributed supercharger network very quickly. I would imagine Tesla would prefer this option as it would keep it in line with the "free" philosophy of the supercharger network. Info (such as charge available, etc.) about each mini supercharger location would be displayed in the supercharger app. Tesla could also partner with other companies (like Solar City) for installation and other deals for customers (particularly for those who have or would like to install a solar system).

    Any other thoughts/options/opinions? Is any of this even possible? Perhaps something like this is what's being announced on the 20th?
     
  2. yobigd20

    yobigd20 Well-Known Member

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    I like this idea of having mini-superchargers all over. A electrical engineer will need to comment on this on whether or not this is possible. My understanding is that the energy is stored as DC in these batteries, so I don't see why they can't be used as a mini-supercharger. It may have to do something with voltage, and whether or not these batteries can discharge at a high rate to charge up the Model S fast enough. I would guess they can, considering if you hit the pedal to the medal you can discharge your Model S at 320kWh ;)

    recycled batteries = awesome.
     
  3. moollar

    moollar Member

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    Yeah, me too. Having one at your home or dotted around the place at businesses would be super convenient.

    I think that this would be a key enabling factor as far as long term infrastructure for not just EVs, but property owners as well. It would render the argument against solar (and possibly other renewables) a moot point. I think that these systems should still be grid-connected as it gives the owner the opportunity of both being energy independent, as well as the ability to become an energy distributor (and earn an income from it at the same time). At the moment, grid-connected solar without something like this means that a property owner still has to rely on the grid for their charging and other "non-sunshine" hours energy usage (even if their net energy production from solar is greater than their consumption).

    Elon has always talked about both sustainable energy production and consumption. With current "intermittent" renewables such as solar and wind systems (ones without battery backup), critics can still argue (if somewhat weakly) that EVs rely on hydrocarbon energy production. These systems destroy that argument.
     
  4. aronth5

    aronth5 Long Time Follower

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    Elon with Solar City is already going down this road. Will be interesting to watch where this goes.

    http://www.solarcity.com/residential/energy-storage.aspx
    "SolarCity is making the latest advancements in battery technologies available to you through our partnership with Tesla Motors. Only SolarCity's home backup system uses technology engineered by Tesla, leveraging their expertise in developing battery technologies for premium electric vehicles.
    Tesla's long history of research and development has enabled a cost-effective, wall-mounted storage appliance that is small, powerful and covered by a long lasting full 10 year warranty"

    solar city batteries.JPG
     
  5. RandyS

    RandyS Fan of Elon

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    The Solar City home batteries were 5 kWh last time I checked...
     
  6. Frankrb

    Frankrb Member

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    I have a 10 kwh PV system on my house and discovered the other day when the grid went down, THAT I COULD NOT GET AT MY PV POWER WITHOUT GOING THRU THE GRID. I understand that the only way to have access to your PV power and bypassing the grid, would be to have a bypass switch, batteries and a regulator/inverter to insure you get good regulated power in a "grid down" emergency.

    This Solar City solution looks like a good way to solve that problem also. Comments?
     
  7. Lloyd

    Lloyd Active Member

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    You want a "Sunny Island" by SMA

    http://www.civicsolar.com/product/sma-sunny-island-6048-us-inverter?utm_source=google_shopping&utm_medium=google_shopping&utm_campaign=google_shopping&gclid=COKF5YWo3bcCFWbhQgodkW8AKA
     
  8. moollar

    moollar Member

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    Not anywhere near enough for a meaningful charge of an EV, but fantastic as an emergency backup power system or for household energy usage at night, etc. It would be great if Tesla could come up with something that could also provide a meaningful charge for an EV.
     
  9. johnnydop

    johnnydop Member

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    The issue with using recycled Model S batt packs is that most people might now want a Lithium-Ion battery pack in their house. If there was a fire those could be explosive. The Tesla Backup being designed for SolarCity are sand and water based which makes them safe for in home installations.
     
  10. moollar

    moollar Member

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    I've thought about this too. Although, my next thought was shouldn't they have to take fires into account when designing the battery pack in case of car accidents (i.e. an impact with an ICE car that may catch on fire)? The Aussie company I mentioned in my first post uses Lithium Iron Phosphate (LiFePo) batteries in their solution. Would this make a difference?
     

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