Possible Group Buy - Check Interest - Lithium Titanate cells

Discussion in 'Hobby Engineering' started by rainwulf, Jul 15, 2018.

  1. sammy_b0i

    sammy_b0i Laugh it up, fuzzball!

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    I'll buy one.
     
  2. choppa

    choppa Member

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    I will be interested in 100-200 in the next 3 months.

    Does anyone want to join me in making a semi-commercial modular battery backup system?
     
  3. dakiller

    dakiller (Oscillating & Impeding)

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    What would your system look like?

    My plans are for a 48v pack to put on a Selectronics SP PRO offgrid inverter. I would need to make busbar connection system to connect them up and a BMS to manage the cells for balancing and basic protections.
     
  4. OP
    OP
    rainwulf

    rainwulf Member

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    We are running into issues with custom clearance forms and the MSDS - they are classed as hazardous.

    Damnit.

    Still chasing, we want to get at least 20 landed to characterize them.
     
  5. Sunder

    Sunder Member

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    Just a two week poke on this one. Any updates? I am not in a particular rush. Hell, I haven't even finished my own batteries yet from 2 months ago. I'm just curious.
     
  6. Dorz

    Dorz Member

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    keen for a dozen or so!
     
  7. Privatteer

    Privatteer Member

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    Googled LTO batteries to get a bit more info since the above seemed high to me.
    0.5C=7000 cycle life, 1C=4000 cycle life seems the more common spec. More than 4 times that would be a massive jump in tech.

    Watching thread since currently doing sums on a 10kWh pack myself from various sources.
     
  8. mtma

    mtma Member

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    The specs aren't really out of this world for what the brand name LTO battery manufacturers have claimed, e.g: the Toshiba SCIB and Kokam LTO's

    As usual you take any manufacturer data with a grain of salt, whether it's tested, consistent and repeatable is a normal query. A lot of people who do their sourcing in China do in person factory visits to get more information from prospective suppliers; sourcing from China can be a bit of a minefield.
     
  9. hurgh

    hurgh Member

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    If this is still an option, I am interested in 6-12 of them.
     
  10. OP
    OP
    rainwulf

    rainwulf Member

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    Yea we are still chasing this up. Customs and MSDS are the issues here.

    Even though LTOs are safer, people see lithium and go "zomg file"
     
  11. OP
    OP
    rainwulf

    rainwulf Member

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    Ok update, got 20 coming right now for some internal testing for our "peak shift" product me and my boss are working on.

    The primary reason is to check out the issues with getting these batteries here, and cehcking out what distribution channels are available to us, plus management hardware. It looks like supercapacitor control hardware is the same voltage range as LTO's so we are looking at borrowing the tech involved supercap management for LTO management.

    Im super psyched! I have started my peak shift plan for my lead acid pack and its working right now, charging up during the day and putting it back into the house in the evening.
     
  12. dakiller

    dakiller (Oscillating & Impeding)

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    Not to derail, but what exactly is it that you are doing here? Adding batteries to a solar setup?

    Also, anything you're willing to share on this management you are looking into? My 10sec google brings up http://www.ti.com/product/BQ33100
    I thought the LTO's would have similar charging and management characteristics to Li-Ion and LiFePO4's, just with different voltage levels.
     
  13. OP
    OP
    rainwulf

    rainwulf Member

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    Basically... what i want to do is peak shift.

    Use solar during the day to charge batteries, then use them in the evening when the grid is loaded and the house uses more power. What we are looking at is a plug in product to let people use their solar power in their own home instead of exporting it for a few cents. The feed-in tariff has been gutted, and i think thats bullshit. Power companies are getting power for cheap.

    What i want to do is allow people to actually use the panels for themselves, reducing the actual peak load in the afternoons. It will also allow people to have power during blackouts.

    LTOs are much more forgiving and don't need the huge BMS systems that lipos need, they dont care if they even get discharged to zero volts. Obviously we aren't going to allow that to happen, we are looking at using them from 2.7 to 2.1 volts.

    Their massive life though allows treating them more like supercaps, storing excess power during the day, and feeding it back into the house at night.

    This solves 2 issues. One, making power during the day when no one is at home using it, and 2, allowing people to use their own power at night, and during blackouts.

    This is NOT a powerwall thing, we dont want to export the power back out again, mainly because the energy companies buy it so cheap its simply not worth it.

    basically... hybrid off-grid. The actual result would be reduce power demand on the grid in total during peak hours. Powerwalls push that power back out onto the grid during those peak hours, where as our system allows you to use your own damn power dammit haha

    Lots of people have panels, but they are totally useless during evening, and totally useless during blackouts. We want to fix that.
     
    Last edited: Sep 3, 2018
  14. OP
    OP
    rainwulf

    rainwulf Member

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    YES guess what arrived today, and will be in circuit hopefully tomorrow!

    The aluminum can is exactly the same length as my favourite beer. SPOOKY

    [​IMG]
     
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  15. OP
    OP
    rainwulf

    rainwulf Member

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    Found a good BMS for these, and will also integrate a ethernet based monitoring module.

    Need more batteries? just use a 8 port network switch, and you can monitor them all.
     
  16. aXis

    aXis Member

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    Just watch out for Ethernet based modules, they chew quite a bit of power and will dig into your overall efficiency. Serial / 1-wire is much more energy efficient.
     
  17. OP
    OP
    rainwulf

    rainwulf Member

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    Mm thanks for that. I was eyeing of the 1000volt isolation.
     
  18. mAJORD

    mAJORD Member

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    How would these go as a boot mounted car battery replacement? 400A max discharge seems sufficient. Quite light (~7.2kg of cells)
     
  19. OP
    OP
    rainwulf

    rainwulf Member

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    They would go amazingly well with a BMS. They care much less about temperature variations.
     
  20. mAJORD

    mAJORD Member

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    Many small bms available for these though (off the shelf)

    Not much info out there on them in general!
     

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