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MASSIVE restock of EV Batteries at 5% coupon "POWERWALLS"
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    where to get high cycles cells?

    You don't, because this kind of cycle life is pretty much exclusive to LiFePO / LFP chemistries. LiTiO / LTO is even more extreme with cycle life in the 5-digit ranges. To a certain extent you can squeeze out more cycles out of the other 3.7V lithium chemistries by limiting the end of charge...
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    Bank of laptop batteries for powerwall

    Because it's proprietary, simple as that. Like mike said, proprietary means you don't know the specs, you don't know what it does and how it does it, it's difficult to follow its operation, you don't know about its data connections, if there are some, and so on...
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    Is it safe to draw 12v from a 36pack?

    Sure, this will be working slowly towards an unbalanced battery. The cells powering the LEDs will be drained quicker than all the others. It's better to put a 36V to 12V buck converter across the entire battery and run the LEDs from it. As a side effect you will also have a relatively nice and...
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    Inconsistent testing results

    Sorting in 100mAh ranges is actually the right way to do it BECAUSE the accuracy of the whole process isn't good enough. At least for how most people do it. If you could then you should work with even smaller ranges.
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    Inconsistent testing results

    300mAh difference between tests in one thing, generally way too high results is another. The inconsistency is a problem, the unrealistically high results not so much if you can find a baseline that you can work with. If this is connected however, i.e. inconsistent results because the offset...
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    Hi Everyone

    Within certain limits it has to be expected that the results are inconsistent, especially with these cheap testers. If the differences aren't too big then it's not a big deal.
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    Li-ion from cell phones

    The pack is the battery, in it there are just cells.
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    li ion and NiMh

    What's the capacities we're talking about here and how much solar power do you have? Maybe a ratio other than 50:50 might be a solution. Or maybe you can go 100% lithium and repurpose the lead acid batteries. It's not really the most sophisticated advice, you probably don't need me to tell you...
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    li ion and NiMh

    You probably want to split your solar in half with dedicated chargers and inverters for each chemistry and then switch the load between them.
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    Li-ion from cell phones

    Proprietary batteries can be useful if you have a lot of them. Several thousand is a lot. You could make something up with only these batteries as they are difficult to combine with standard format lithium cells. They usually come with their own BMS, which can be useful. It is just a matter of...
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    B or C grade cell ideas ... test & use

    Well, if they have so little capacity left then I wouldn't use them for anything.
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    Pouch Cells -- LiIon or LiPo?

    The right pouch cells are especially suited for very high loads. However you never know what quality and spec was fitted here as high power wasn't needed in the first place. As with any used cells, test their behaviour for the given current you want to draw.
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    22kwh battery pack

    Just get a multimeter and check the voltage of the battery. Or have the seller do that for you and make sure to include this number in the deal. If it's at reasonable voltage it will most likely be perfectly usable. Lithium cells aren't really affected by calendar life / shelf life as long as...
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    B or C grade cell ideas ... test & use

    I have run into Panasonic cells with the same behaviour as the well known Sanyo cells. Panasonic bought Sanyo back in 2009 and maybe some of the reasons why Sanyo cells do that were transferred over to Panasonic cells. Potential usage for them, yes, sure, for any below 4.2V situations, just...
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    li ion and NiMh

    In theory the answer is yes, you can use them together. However you shouldn't connect them in parallel because of all the reasons that have already been given. So in practice that is a No for your use case. However you could connect them in series though if you like to create a higher voltage...
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    Samsung 33J - a 21700 Li-ion battery designed for Tesla

    chamele0n, I think there was no doubt that Tesla uses 21700 cells in general. That's well known. It was rather about this cell in particular since they also have (or had?) a partnership with Panasonic and also manufacture their own cells.
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    Draw on each cell stupid question

    The reason for any specific amount of cells in parallel is either the maximum current or the required capacity. This depends on the application. A powerwall in generally are relatively low power application. You need a lot of cells to get the desired capacity and by doing that you automatically...
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    18650 temperature

    You always need reference values. Is it only a few Panasonic cells (out of a larger amount of Panasonics) or is it all Panasonic cells and/or only Panasonic cells? 43C is generally nothing to worry about.
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    Hard to open Bosch pack

    It's a single piece of plastic and this can't be opened further without destruction. The cells can be pushed out lengthwise after all the connections have been removed. It might require a bit of force, always push them from their negative side. Probably not worth it though as the cells are rusting.
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    Fixing the AEG CX8-50EB, battery powered vacuum cleaner

    It doesn't work like that. If that was possible then you would be generating power out of thin air and we wouldn't need specs on devices anymore :) A 12V PSU with a maximum output of 10A will never put out more than 120W because that is 10A at 12V. You're feeding a maximum of 120W to the DC-DC...