Looking for a high current 21700 cell

Batteries and Chargers Rechargeable Batteries
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Hi guys, I am looking for a high current cell and am currently trying to decide between Molicel INR21700-P45B and Samsung INR21700-50S. What are your opinions? I currently have a few Samsung INR21700-50E, but they can only do slightly under 10A.

Thanks for your help

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Hi there, good question. I think you should either choose the P42A or P45B depending on your current requirements. Vapcell 21700s might be a good choice too

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The P45B will vastly outperform the 50S in everything but low power applications that benefit from higher capacity. The only reason to use a 50S is for the slight advantage in runtime, but it’s only about 5% over the P45B and only for the latter 60% of the usable capacity before voltage cutoff. If your flashlights don’t require more than 20 amps, the 50S is fine, but for more than that, the P45B is better (even a grade A P42A).

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I am currently driving the emitter (Single xhp70) at 8 amps, but I might try more in the Future. I will get the molicel cells to be certainly.

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8A on a XHP70.x is, unless you are using a rare 3V model, up to 16A from the battery - that is quite hefty for a single cell already.

Up to ~10A the 50S outperforms the P45B, from 15A onwards the P45B performs better.

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That is a very important aspect the OP overlooked. When calculating current at the cell, conversion factor of the driver has to be taken into account. 6V 8A boost gives you 48W output. With battery voltage at 4v to 3v it needs to supply up to 16A of current, plus conversation loss (about 5% for a good driver)

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Maybe i should have added, that i use 2 cells in Series, so the current at the battery is roughly the same as the current at the emitter.

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P50b

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P45B. 50S are only mid performance, they’re just the best performing high-capacity cell (until the P50B is available, anyway…)

Do you know where to get some then? :pleading_face:

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Oops

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Is a Magnet between 2 cells still enough at These currents?

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It might be a good temporary solution but you shouldnt rely on it. Try slodering a brass button to the batteries

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Isnt soldering Bad for the batteries, as it heats them too much?

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If available, I would go for the Molicel INR21700-P45B. According to their website, currently in stock at NKON.

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Just placed an order. Thanks for your help.

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There are also these “adaptors” Simon (Convoy) sells in his shop:

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These look great. However they look a lot thicker than the magnets (1mm), I currently use and I dont think they would fit.

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I think soldering is fine if its done right. Im not an expert but this BLF thread might explain what to do and what not to do.Custom Button tops. Very good to Unacceptable.NEED EXPERIENCED SOLDER BLOB EXPERT OPINIONS.

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I have a few of them, so I measured the thickness for you and it’s ~ 2,52mm thick.

In regard to soldering Li-ion batteries:
I have limited experience with soldering onto Li-ion batteries, but I have soldered ‘blobs’ onto 3 flattop 18650’s and with some preperations and a very hot soldering iron/tip, it took me 1 to 2 seconds to solder a nice/round ‘blob’ onto a battery and directly afterwards I touched the battery to feel how much it had heated and there wasn’t almost any extra heat in the battery, due to the very short contact with my soldering iron.

If you solder a copper pill onto the battery as HunterJackson suggested, you might need to heat it up a little longer/more, or maybe pre-heat the copper pill somewhat, because it might otherwise “suck up” part of the heat.

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Naw, they’ll break apart eventually. They don’t like the heat cycles

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