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Winston LFP life?? Real world usage

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  • #16
    Ampster today the easiest analogy to define a LiPo is a battery in a Foil like Pouch aka Coffee Bag vs say a cylindrical or prismatic solid structures. It allows manufactures to make the just about any shape they need to fit the application. Example cell phones, netbooks, and tablets. In other words mold it into any shape required. There is no specific chemistry used and can be any of the ones already mentioned including LFP.

    A true LiPo of yesteryear did not find many applications because they exhibit a high resistance which really limits what they can be used for. They are as you said used a polymer solid electrolyte. Today that has been replaced with a gelled electrolyte. So today what is called LiPo can be any of the chemistries, but it boils down to the case it is made out of or rather a lack of a shell or case. That makes them dangerous because they can be easily punctured. What it does is improve Energy Density which is expressed as wh/Kg. Without a metal case can make the battery 20% lighter in weight.

    Hope that helps.
    MSEE, PE

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    • #17
      Sooooo. Getting back on topic of Winston life, you won't find anyone that has had 7000 real world cycles of their Winstons as the cells haven't existed that long.

      In practice, you will find many 2010 and onwards battery packs still performing as new. (ie cycling anywhere from 80 - 20% daily)

      The common factor of longevity is well known - keep SOC between 20 and 80, don't charge cells above 35deg c or below freezing.

      If you are in Australia and are getting your system professionally installed, you are better of using the BYD system. Not much more expensive, warranted for 10 years, integrates with SMA and Victron.

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      • #18
        As I mentioned earlier, I had good luck with the Winston's I used in an EV. They were also used in some small yard trucks used in Los Angeles Harbor to move containers. The local distributor, Balqon did that implementation in 2012. I haven't heard anything negative about that project.
        Originally posted by tom rickard View Post
        If you are in Australia and are getting your system professionally installed, you are better of using the BYD system. Not much more expensive, warranted for 10 years, integrates with SMA and Victron.

        Speaking of BYD, it looks like they are trying to have a presence in the US:
        http://www.byd.com/cn/en/BYD_ENProdu...817!-900746506

        They have been manufacturing buses for the public transportation sector for a while. Several years ago I toured an assembly plant in Lancaster, California.
        Last edited by Ampster; 03-04-2019, 10:07 AM.

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        • #19
          The battery test centre in Canberra Australia has been setup with manufacturer's batteries that under go accelerated x3 discharge/charge cycles per day. https://batterytestcentre.com.au/
          The discharge end point is aggressive at about 10% SOC for most brands. In test report 5 they have measured capacity fade. Not looking good for a Calb (Winston equivalent) that have faded to 80% after 1000 of these aggressive cycles. BYD and Alpha ESS (both self contained LiFePO4 with integrated BMS) down to 90%

          The Calb had an early battery failure and there has been some poor reliability of SOC from its REC Bms (hard to get exact details on what happened from website and reports- no mention of balancing or how the 32x100Ahr cells were setup and monitored). All this testing was in a controlled temperature setting. I would suggest that in the real world Australian environment (especially if remote and unattended and a coastal location) relying on precision electronics to control the battery charge and discharge to a 80-90% levels that the manufacturer's are pushing is pie in the sky stuff. As I think tom rickard said somewhere - glad that the battery test center is not installing off grid systems (my understanding is that they were all installed and adjusted by the suppliers or to manufacturer's specs).

          But I understand your pain, we are being ripped off here in Australia with cost of batteries, the best I have seen from a local supplier is 180AHr Calb batteries is $288 each. If you want to get to A123 quality then I believe there is an Australian manufacturer that supplies military/industry -lithbattoz.com.au (?previously lifetech out of Taiwan) but at x3-4 the price.

          So if you are going to go down the cheaper import from chinese suppliers and prepared to take the risks I would base calculations on a 50% discharge cycle if you want to come anywhere near a 10 year lifespan. If you want to look at chinese suppliers here is a list that you can check out at your own risk (not affiliated with or used any of their products)
          https://www.rj-lithium.com/
          https://evlithium.com
          https://www.aukpower.com/index.asp

          and as some have said in an attended off grid LiFePO4 storage system that is initially well balanced and operated away from the knees of the voltage curve a complicated BMS may not be necessary.



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          • #20
            Originally posted by ocular View Post
            ..........
            So if you are going to go down the cheaper import from chinese suppliers and prepared to take the risks I would base calculations on a 50% discharge cycle if you want to come anywhere near a 10 year lifespan. If you want to look at chinese suppliers here is a list that you can check out at your own risk (not affiliated with or used any of their products)
            https://www.rj-lithium.com/
            https://evlithium.com
            https://www.aukpower.com/index.asp

            and as some have said in an attended off grid LiFePO4 storage system that is initially well balanced and operated away from the knees of the voltage curve a complicated BMS may not be necessary.
            That is good input. There is no doubt that there are quality cells being manufactured in China. The hardest part is finding a reputable seller that will sell you the ones that come out on top from their binning process. Among the DIY electric car community there were positive reports in the USA about Calbs coming with as much as 10% greater capacity than what the cell said. That was years ago and the US distributor may have had some influence over quality.

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