Recent content by gauss163

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    18650 best soldering technique part2

    Again, not a good analogy. Yes, you're effectively playing Russian roulette with a large number of chambers. IircNASA claims the odds of internal shorts is in the range of 1 in a million to 1 in 10 million for cells from reputable manufacturers, but it can be as high as 1 in 10000 for some...
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    18650 best soldering technique part2

    ^^^ There's no need to again debunk the errors of that logic since it has already been done before here. If you choose to blatantly ignore the science and safety warnings of reputable manufacturers then best of luck to you. You're playing Russian roulette - where, alas, good luck won't last...
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    18650 best soldering technique part2

    ^^ You shouldn't expect to be able to see damage by naked eye (e.g. dendrites that can cause (micro) internal shorts may be much too small to be visible by eye). The great difference in heat from soldering vs. spot welding has already beenclearly demonstratedin this post in the originalthread...
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    Making your battery cycle properly despite useage pattern

    Whether or not float charging Li-ion is worse for heath than some (shallow) cycling cannot be answered without much further context, since the answer depends on many parameters, such as the cycling window location, float voltage, temperature, chemistry, rate, etc.
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    testing the batteries/cells out of an LG Chem RESU- 10H system

    Beware: if those pouchcells are similar tothe LG cells used in the 2019 McMicken substation BESS explosion in Surprise, AZ then you should be very careful with them since the linked report claims that they found lithium plating in many of the cells (one of the main causes of internal shorts and...
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    Battery Capacity Math Question

    No, as I explained above, you are talking about battery"energy" (or "energy capacity") (Wh), not "power capacity" (W). Of course it comes as no surprise that there are some (hobby) pages on the web where authors misuse standard terminology (whether by oversight or inexperience). Below is an...
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    Battery Capacity Math Question

    No, standard English terminology is that battery "capacity" refers to its charge capacity (Ah). Instead, what you refer to is calledenergy (Wh). Sometimes "energy" is called "energy capacity" but it should not be called "capacity" since that easily leads to confusion between charge (Ah) and...
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    Bus bar wire gauge

    A problem with aluminum (vs. copper) busbars is it has a much lower melting point: 660C (1220F) vs. 1084C (1983F). If a thermal event causes an aluminum busbar to melt it mayflow into areas that maycause (further) shorts - increasing the chance of thermal runawaychain-reactions. For example...
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    Battery Capacity Math Question

    Batteries in parallel will always be at the same voltage (so same SOC if they have the same chemistry and temp, and the voltage is measured at rest). Let's consider a simpler (ideal) example. Suppose we parallel a 4Ah and 2Ah cell of same chemistry, and the 4Ah cell has half the IR of the 2Ah...
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    SoC% false accuracy? State of Charge

    In fuel gauge terminology an SOC recalibration usually means that when you are at some known SOC you reset that gauge to this known value. In the simplest casethe SOC is "known" by mapping a (near)resting voltage to SOC (based on known V to SOC tables). This serves to eliminate any errors that...
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    SoC% false accuracy? State of Charge

    Yes, it appears you need bottom vs. top recalibration. Are you sure Batrium does not offer such? Usually both are available in most fuel gauges - even the simplest ones. I'd suggest contacting their tech support to inquire about that.
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    SoC% false accuracy? State of Charge

    You do, because here "100% SOC" refers to the SOC of your virtual battery defined by the limited range you use in your physical battery. E.g. if you charge only to 4.0V/cell and wish to use at most 123Ah from a 200Ah physical battery then your virtual battery consists of the 123Ah range below...
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    Battery capacity ?

    ^^^ Some chargers support parallel discharging, so you can hook a single battery to all 4 slots to get 4x the max discharge rate (e.g. the Opus CT-3100 supports this - see here and here). If the Liitokala also supports thisthen you could get 2A max on one cell. But be careful testing for support...
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    SoC% false accuracy? State of Charge

    So you're getting about 1% drift each day from Batrium's coulomb counting fuel gauge (due to charge inefficiency, self-discharge and current integration errors). That amount of drift is not unusual for a simple coulomb counting algorithm. To counter it you can recalibrate daily by forcing the...
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    Wolf's PowIRwall

    ^^^ Hmm,2705mAh is 9.5% higher than HKJ's testat 1A (2470). What rate did you discharge them at? Perhaps Opus is to blame for that (maybe older version units)? But 2593mAh looks more accurate if it was at low rate (best HKJ got was 2551 at 0.2A) Congrat's on the build.
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