Still no dice. I touched the leads and it read zero across the board then I hooked it up to the battery and it still all zeros when I have it on ohms.
I don’t think this feature works. I recall trying to use it a few years ago and got the same results.
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The middle one is common, meaning the black lead goes there. The red lead goes into the right port (for voltage, resistance, etc.) Also, the red lead can go into the left port if measuring current (obviously don’t measure across a battery in this mode because you will blow the internal fuse of your DMM). Note: the holes are color-coded 
The reason it works (voltage measurement) in your incorrect configuration is because the left current hole and the middle common hole are actually shorted (using a shunt resistor). The DMM measures the voltage drop over this resistor to measure current. However, using this port (instead of COM) for voltage/resistance is introducing some error into your measurements because you have a resistor (a low value one) in series.
Back to internal resistance measurements: you cannot do this (using resistance mode) with a regular DMM. You can do it using the method linked by @TARTARA (which is essentially what your battery charger is doing to measure IR). A easier, more repeatable method is to get an AC IR tester like this one: YR1030+
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^^^
Thanks for the good explanation/ information. Now I know why I can’t measure resistance.
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I’m not clear on this. So there’s no way I can do this with my DMM?
Why would they have that symbol on there if I was unable to check for internal resistance?
I am lost as to how to implement Tartaras method with my DMM?
Thx.
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I would imagine the Voltage Sag is higher(lower voltage under load) on the older cells and the ability to hold the amperage that is needed for your light to stay in Turbo
Basically the same thing that happens with a lower drain cell
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Did you watch the Youtube video? You also need to have a resistor like he does in the video (he has a 1Ω 20W resistor).
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Yes I watched the video. I don’t have those accessories.
I’ll just buy a new batteries as I planned to prior to this thread! I was hoping my DMM was capable of doing it on its own ,the way that it was sent to me.
Can anyone answer question #3?
Here it is again.
Does capacity loss in a battery and it’s inability to push amps decline at the same rate?
Thanks for all the input.
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Question number 4 LOL.
When using a battery charger to get internal resistance, does it matter what the voltage is? I think I heard years ago it should be fully charged but I’m not sure?
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I don’t really know i you can find 100% accurate answers… and of course we are not experts… !
Simply we trying to help around with the few - random things that it happens to know around… !?
If you consider that a battery has 10ys self life… ! Then you can estimate that you taking something out of it’s life every time that you use it… !? Plus all the loads and the pressure that you are putting on battery… !? Just some thoughts in general… !
Yeah, it seems to me that some specifications that I have read mention “full charge” or 4.2 volts in the IR specs.
Just using the various chargers that I have (yeah I know none of them are great at it. But the Xtar Dragon + has a separate function and leads, supposedly 4 wire so maybe better?), the IR does seem to vary some by state of charge. So, when I am recording IR for cells, I always check it when they are fully charged. If nothing else, it gives me a baseline for comparison.
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From video above in Tartara’s post, at 8 min 13 sec: yes it does, if I understand him correctly.
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[Does capacity loss in a battery and it’s inability to push amps decline at the same rate?]
These are WAG (wild ass guesses) but based on using them for over a decade.
Do both decline with use? Yes.
Same rate? No, but in the same general direction. As resistance increases, current support will decline and so will capacity.
Can it be quantified? Doubt there is a general factor that applies to all batteries. You might be able to determine a variable that would apply to A battery.
Can resistance vs current support be quantified? May be somewhat more able to do that, but doubt that is at the same rate either. Probably the answer above is more in the ballpark.
Ultimately, outside of interest do you really care? All you can do is try to match the battery to the task, use it until it doesn’t meet your requirements, and move on.
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I’ve always been inquisitive that’s why I posted the question.
Thx
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there is not going to be a formula
just a huge fuzzy wide line
CL = PA x X
where X is probably a big fuzzy fat line about +/- 50% of its center width
I did a quick test this morning.
Light S2+ Triple XPL with a Fet driver
Cell: Sony VTC6 ( The only ones I had on hand that have minimal cycles vs no telling how many cycles)
both have same exact date code 2019 — week of production off by 5 weeks
#1 2910mah / amp output Turbo 10.20
#2 2510mah/ amp output Turbo 9.0
Although not exact percentages, there seems to be correlation between the two
The only way to really know is to take cells from new, check them – then after said cycles check again
I sometimes believe resistance increases in certain lights . On more than one occasion I have tested a new build, register a certain amount of lumens. Then later on, I can’t reach those numbers again.
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Hi,
I’m not asking for a formula. Not surprised that there is not one.
… just asking does capacity loss in a battery and it’s inability to push amps decline at the SAME rate?
Flydiver answered No. That’s probably the best answer I will get.
There are probably too many variables to determine which rate is faster and by how much?
Considering emailing HJK… Even though he’s semi retired, he will probably respond back.
Also emailed an engineering friend of mine who’s in the battery business.
I always like to hear a number of experiences, views and opinions. Never basing it on just one.
My experiences with my aging hydrain batteries when they’re unable to sustain Max output has prompted my brain to come up with this question.
Particularly the 27 month old 30Q’s that are in my TN42 CFT90. When they were new Max run time was 27 minutes. Now it’s 18. Totally understandable. Again the baffling part to me is as soon as I turn it on it steps down five to seven times. Then it locks in to Turbo most times until it’s too hot or battery depletion.
Maybe that’s the driver? I am guessing no because brand new VTC5D and 25S do not do that Only aging batteries or ones that can only Supply 10 amps which is obviously not enough for that led.
One other important thing to me.
This is not about… when should I get new batteries? I know when to get new batteries. And The Time Is Now for those 30Q.
It’s about trying to learn more about the batteries chemistry and why they act in particular ways.
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I have read- learned and bought multiple test devices to satisfy my needs ---- Just sticking a set of cells in a light, then saying they work and then saying that they don’t work after time isn’t much to go on-- basically like saying with a naked eye you can tell the difference between 1400 and 1600 lumens
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The above relates to a question I was going to ask… “Can the flashlight itself build up resistance over time & use???”
Your experience (quoted above) would ** seem ** to indicate that might be possible. ? ? ?
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