I usually buy cells directly from Convoy’s official store.
Simon has a lot of options, and free flashlights per cell hahaha.
Greetings.
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…i -have- been thinking about upping my UV flashlight game…
To continue the cell discussion, I can’t find anything that definitively describes whether the 100w is bi-directional? I.e does this thing hammer 5A of charge into each cell during charging?
I don’t have access to a 100W PD charger to confirm and it’ll take me a while to discharge mine to test charging speed with the 65W one i do have- will report.
I will try to do a short test at 100w charging it.
I don’t know what the charging protocol is in such a (balanced) series charger, but assuming it’s CC/CV type of charging, 100w divided by 4.2V is 23.8A, so just under 4A each. When you take into consideration conversion losses/efficiency of the charger, that actual number might even be a tiny bit lower.
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Here some proof the power bank can indeed be charged up to 100 watt.
I used an Allpowers R600 power station, which outputs 100w over USB-C, as can also be seen on it’s screen:
I had a USB meter in between, that also confirmed the roughly 20V/5A and 100w:
And the power bank itself also showed that it is beeing charged with 19V (Only displays full voltage numbers) and 5A, so basicly also confirming the 100w charging:
I used an Anker 100w rated cable for it, so that shouldn’t had any influence.
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And just as a bonus, also did a quick discharge test on my electronic load just now, to proof it puts out 100w.
First photo shows the 20V/5A output on the power bank:
Second photo is from my electronic load, proving that it (almost) puts out 100w:
I hope this information is useful to you @gravelmonkey !
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Wow great info, thanks!
My calculations used nominal 3.7V/cell so I was getting 4.5A/cell
When they are empty (3V) one would assume this could be as high as 5.5A/cell.
At 1C charge rate, I think most 21700 cells on the market should be able to manage this.
I’ve been looking at the Samsung INR21700-50S because I’ve found a reputable retailer offering it for £3.35/cell.
Post coffee edit: I’ve realised, obviously, if I’m worried about charge rate, the solution is to use a 65W capable power supply. Duh!
That’s the same thing I also did previously, for the same reasons:
The fact that it can charge at 100w, doesn’t mean it has to be charged at that. 65w charging is still fast, compared to a lot of cheap battery packs, which a lot of them max out at 22,5w. It’s just good to know that you have the option!
By the way: I just checked the voltage each cell was charged at, at 100w. Before connecting it to the charger, each cell was at roughly 3,73V. Charging them at 100w, I measured ~3,96V at each cells terminals.
I’m also planning to test the current each cell recieves, but I have to make a small tool for it that I have in mind. It’s a pretty simple design, but since I lack time and have way too many things on my mind, it take a while before I get round to that!
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I appear to have a thermistor measuring air temperature, does anyone know what this is supposed to be measuring?
I expect that normally to be taped to one of the cells with a small piece of kapton tape. (Powerbanks that I’ve disassembeled in the past also always had the thermistor taped to the battery.)
So far I’ve noticed that the battery closest to the USB ports, so call it cell #1, tends to get slightly hotter than the other ones, which makes it the perfect candidate to tape the thermistor onto.
By the way: I haven’t measured the exact temperature difference between cell #1 and the rest, just noticed it by touch while checking a couple of times. Will try to take exact measurements next time I (dis)charge it. (I expect ‘a couple of degrees’ (celcius) difference; it didn’t feel extremely different.)
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Anyone have any long(er) term use updates?
I used mine in November to keep my laptop charged up while the power was off for electrical work.
Also had a bit of use with the storms, I keep it topped up then when the weather clears, I’ll charge my phone a few times to drop the cells voltage.
Would you still recommend getting this one, or are have you found a nicer option?
@Wingman I am wondering if you ever got around to doing this??
BTW, I bought one of these. It seems to work as it is supposed to. I have had no problems with it. Not sure if there is anything better out there.
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In the end I ordered 10 of these cells (for € 1,69 each, ex. shipping) and took the 6 best matching cells for this power bank. They certainly remain cooler than the (lower drain) Samsung 48G I had previously in it, when charging the power bank at 100W.
Since then, I’ve only used it a few times. It did work fine those times, but haven’t got around of doing some actual measurements/tests on it. (For general use, i.e. lower power charging situations like a phone or tablet, I tend to grab my Lumintop Auroras (with 46950 batteries) when I need a power bank.)
No, unfortunately not; life has really gotten in the way in the meantime and taken up almost all of my energy (and time) over the past couple of months.
I haven’t found nicer options, but to be honest, I haven’t been looking for them either, so I’m not sure what the current options are out there.
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