Recent content by thegoogler

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    Which is worse, discharging to empty or charging to full?

    CATL recommends keeping my battery in the 10-90% SoC range. I think most of the LiFePO4 batteries are similar. However below is my actual battery voltage during a discharge with a <0.01C load applied (which is super low, I know). I started the discharge 24 hours after charging, so the battery...
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    Which is worse, discharging to empty or charging to full?

    It's a lot harder in my experience (practically speaking) to prevent charging to 100% than it is to prevent discharging to 0%. For the latter you can always just set your BMS cut-off higher. For the former though using voltage is a poor way to judge SoC, it's difficult to find a charging...
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    Containing a battery pack meltdown.

    Sort of. Water is your friend if you have a lot of it available to drown the pack and dilute the lithium-to-water ratio. To the OPs original question I wouldn't try to drown a lithium battery fire with a (melting plastic) gallon of water. Water will cool the pack but will react to lithium so...
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    Containing a battery pack meltdown.

    Oh gawd please don't use water. Lithium + water = chemical reaction + hydrogen gas. You don't really want to mix the two...
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    AliExpress LiitokalaVariCoreFlagship Store 280AH LiFePO4 Fraud

    yeah. for my purpose they're ok. I have a RV, and I was using a 100Ah lead battery. So ~250Ah of LiFePO4 is far better capacity at the same weight. And in fairness I bought 280Ah cells instead of 200Ah cells because I was afraid all cells wouldn't test out at the spec rate. I knew it was a...
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    AliExpress LiitokalaVariCoreFlagship Store 280AH LiFePO4 Fraud

    Meh, it depends on your definition of "luck". My "280 Ah" Liitokala cells had 271Ah CATL QR codes right on them. They tested to 262Ah at 0.01C (2 Amp load), which is 1/100th the rated load. I'm sure if I could test at 1C I'd find these were even less capacity... probably ~240Ah-ish. Given...
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    420Ah Cells on Aliexpress!?

    1. Definitely could be. $50 out of $675 is probably an easy chargeback to deal with. I do agree I'm surprised they put up with the amount of fraud that seems to happen, but then I just assume my surprise is because I'm a westerner and I get all righteous when someone tries to scam me whereas...
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    Clawing back money for miss-sold "420ah" cells

    If you modified the vehicle title to say "1948" then the buyer gets their $ back in full. If you want the Corvette back you need to pay to retrieve it. At least that's how the law generally works in the developed western world. It might be one thing if the seller mistyped 420 instead of 240...
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    420Ah Cells on Aliexpress!?

    I have a very US-centric view of the world, even having been to a few other countries in Europe and Asia. But I suspect AliExpress survives because there's a very large part of the world, especially developing countries, that doesn't expect honesty and very much follows a "buyer beware"...
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    liitokala Official Store

    I paid for express shipping on mine back in ~May, but even still they took close to the full time listed. Given mine had what looks like an official CATL QR code, and had an official Liitokala sticker for even high Ah, but tested lower than both, I highly suspect the stuff Liitokala is selling...
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    liitokala Official Store

    tl;dr - My Liitokala cells (from the official AliExpress store) came with only 90% of advertised capacity. Possibly less if I were to put a real load on them. I highly suspect these were used cells. I pulled my Liitokala battery from my trailer for the winter (probably unnecessary but we do...
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    XiaoXiang BMS Spontaneously resets Remaining Capacity display

    Other than replacing the BMS, has anyone found a fix for this? Is there a firmware update, or a different phone (or desktop) app which will allow tweaking of how the SOC calc works? I'm doing a multi-day, low draw capacity test on my ~271Ah pack and I got down to 30% last night. Voltage was...
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    DIY batteries a lot cheaper?

    I built a 12V, 270-280Ah battery for about $650 once all the parts were accounted for. If I'd tried to build ~200Ah it probably would've been $550, give or take. So about half the cost of the SOK (though IIRC the BattleBorn batteries I was originally comparing pricing to were around $900 for...
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    The secret to compression

    If you want a rigid plate instead of a flexible bladder, just put a plate between the cell and the bladder(s) to distribute the force. i.e. bladder -> plate -> 3.2V cells -> plate -> bladder I personally wouldn't want a flexible rubber/poly-something/etc bladder against a sharp corner of a...
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    The secret to compression

    Nice clean build there I prefer the German method of "gutentight"
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