Shoddily assembled button top, 100% sure. I would remove it.
Some chargers (like the Lii-500) just cannot measure internal resistance with fully charged batteries or close to. In case of the Lii-500 the charger needs to inject a current pulse to the cell rail for it to work. Since it cannot go above absolute maximum cell voltage (≈4.2V), if a cell has high enough internal resistance and its voltage is close enough to rail maximum the measurement fails.
If you aim to obtain anything worthwhile out of the Lii-500's li-ion IR measurement set cells to be measured preferably below 3.9V as a general rule.
+1 Yeah, it’s not accurate, but it’s good enough to tell crappy cells from good cells. And cheap, too! Just use a brightness app on your smartphone, if you have nothing else.
I have 4 30qs that all perform worse than an MJ1 in direct drive. Lii-500 shows 125 ir. It’s lower when they’re fully charged but still higher than the MJ1. The button is off center so yh it might have something to do with that. Purchased the MJ1 1 year after the 30qs from the same store and the button is centered properly.
You are doing it wrong. See #24 above. When insert and properly seat a fully charged cell in my Lii-500, it shows 10mΩ (it's the minimum and means failure).
The Lii-500 does not display anything higher than 125mΩ. Your cells are probably or surely fakes. If they feature 4 lobe or 4 legged top they're fakes. It could also be that you bought cells with botchily assembled button tops. And it can also be that your cells feature botchily assembled button tops over fake high IR cells. Did I guess the winning combination? O:)
If that is the case then the button tops were botchily assembled with really bad welds or absence of. My advice is to remove them. Should be pretty easy.
Wow, yeah, someone sure welded the s**t out of those when they put on the button tops. Never seen them like that. I guess they’re okay like that, but seems overkill.
You ordered button tops. All standard 18650 are flat tops, to get button top it is required to weld a button top on the cell. Yours looks like a good type with the button top welded directly to the flat top. It is often done with a strip where the battery and top is welded on and the the strip is folded, this is not as good as directly welding the top on.
In any case, those living on the edge flashlight setups are not my cup of tea. Not because I cannot take care of them, in fact I take a lot of care. But I'aint got time to bleed. ;-)
Read the FT03 thread. They changed the bond wires to copper from gold so it can handle more current. We don’t know exactly how much though. Nobodys has blown out yet so 9 amps should be fine it seems but yh I get what you’re saying. 30T would be pointless anyway.
You can’t test IR on cheap consumer grade testers and expect to get results that match datasheet specs. First off, there is a big difference between DC and AC IR. Standard datasheets generally report IR based on a 1Khz AC pulse. You need a dedicated IR meter to get accurate results. One that has 2 contact points on the positive and 2 points on the negative.
My 30Q’s measure about 14-15 mili ohms on my extech IR tester.