I think the battery capacity gauge on my Wurkkos CL01 might be inaccurate.
First, when the flashlight shows 0 dots of leftover capcacity, and flashes twice to signal a low battery, I’ve checked the cell in my charger and it reads 0V. This seems dangerously low and is much deeper than I’m comfortable draining my batteries.
Second, when the UI shows 2 dots (half capacity), the battery measures 3.5V. In my experience, 3.5V is closer to “starts to be empty” than “half full.”
Is my specific CL01 measuring the voltage (thus leftover capacity) incorrectly, or is this just how all CL01 lights show leftover capacity?
Well it showed 0V on XTAR VC2 (gauge was showing far left side, where 0V is) - im not sure if it was actually 0V, although surely it was deeply discharged
Would you recommend disposing the battery? It may be unsafe to use.
Btw I already charged it - didn’t go ka boom (yet)
If the above voltage numbers are based on a charger display, first thing I’d advise is to check the cell voltage with a multimeter…
The light has 4 LEDs to indicate charge status, I couldn’t find anything on Google suggesting anyone has determined what voltage (and therefore ~remaining capacity) remains.
Logic would dictate 4 indicators mean 0-25-50-75-100%, but who knows what cell voltages Wurkkos decided to assign these lights…
Also factor in 5% component value tolerance (possibly more); if they’d assigned “50%” indication for cell voltage of 3.7V, in reality, that could be cell voltage from 3.52V - 3.89V.
Correct way to test would be hook up a power supply and sweep the voltage 2.5 - 4.2 and note where the lights come on/go off.
I would caution not to mess with any li-ion cell <2.0V if you don’t know what you’re doing. I know a few guys who do cell recycling and they tell me they mark those cells as “do not charge/use”. It’s not worth the safety hazard to save a few bucks. Just dispose of it and get a new one, good quality cells are relatively cheap.
My CL01 has had very little use and has been sitting on my desk since I bought it 7 months ago. I just turned it on and it indicates 3 lights.
I took it out and on my DMM the Voltage reads 3.82V. When I put the battery back in, the light indicated 4 lights at first.. I turned it up bright and let it run for a few seconds.. then turned it off, and back on a couple of times. The battery lights now illuminate 3 LEDs again.
That sounds like your charger is lying to you..
It is extremely unlikely that the battery was actually at 0 Volts.
The light has LVP and would shut itself off before going below 2.8V.
Suggest you invest in an inexpesive Voltmeter.. I use one from Harborfreight that costs about $8.
Wholeheartedly agree, I have a regular DMM (more expensive than the Harbour Freight one you list) which I’m comfortable using on 240v mains voltages, and a UNI-T UT210e clamp meter, which I’ll use non-contact mains and low voltages. Use them far more than I originally anticipated for example:
Confirming mains power is switched off before commencing DIY
With clamp on a single phase, seeing how much current an appliance is drawing
Polarity measurements of LEDs when emitter swapping
Continuity tests to check for short circuits when re-assembling a light
Voltage/current measurements of various batteries, alternators, chargers, mini solar panels, etc
My DMM came with a thermocouple so also can read temperature
These things are really useful, far more flexible than relying on a charger. That said, I do like the S4+ charger I have, just don’t use the USB output!
That’s quite radical approach . Chargers aren’t meant for measuring/displaying voltage. (Edit: ok, they should be able to measure voltage)
If your charger does the charging right replacement is unnecessary.
With the new charger you will face the very same dilemma “does it show voltage correctly?”.
I would get a multimeter.
Internal resistance could tell you what kind of shape the battery is in. That’s beyond my abilities so someone else would have to tell you about it.
28 mOhms is fine. My Skilhunt 18650 is about a year old and has only been cycled once, and its ir is 46 mOhms
Yes. The IR is tied closely with the cells State o Health (SOH).
But you have to consider other things when evaluating SOH when using IR.
First you need to know your measurement device is consistent and accurate. Second you need to make sure you are measuring under known conditions.
Most of our chargers use DC Internal Resistance (DCIR) methods. Many are not very consistent. Like just removing and putting the cell back into the charger will often change reading significantly. The temperature of the cell also has a significant impact on DCIR readings, so that needs to be taken into consideration. If you are going to track IR over time you need to do it under similar conditions of temperature.
Lastly, the State of Charge impacts DCIR readings quite a bit. It typically goes up at both ends of the scale. Under 10% and over about 80%. So you have to keep track of that when measuring as well.
So yes it is a great tool for determining a cell’s SOH. But there are things you need to consider when using it. I find it is of the best use when tracking health over time. But spot checks can tell you when a cell should not be used. Either extremely high or low readings can tell you whether it is time to retire a cell.
That 28 mOhm reading you got is not alarming. It is what I consider in the normal range for a typical medium discharge cell.
Though stranger things have happened… I wonder if the BPS actually limits parasitic drain.
I know that all of them do not . I have forgotten to physically lock out E-Switch lights and come back several months later to find cells that were under a volt. Even though they should have been stopped at 2.8 to 3 volts.
But yes, if it were me, I would verify the readings with another device. Preferably a reliable DMM.
agree that is theoretically possible, though I dont think that is the case with the OP’s battery.
The consensus in this thread is that the OP’s charger gave an unreliable 0Volt reading.
I appreciate your mention of the benefit of using physical lockout and am implementing that now for my CL01.. since the light is not in use. I turned it on, it showed 3 out of 4 battery ights after sitting unused for about 7 months, and then unscrewed the tailcap until it turned off.
I took your physical lockout suggestion to heart and just went down to the basement where I have an LT1S hanging from the ceiling.. unused for about the past 6 months. I turned it on and it lit 3 out of 4 battery lights.. I loosened the tailcap until the light turned off.
I will keep these unused lanterns physically locked out, as a storage precaution, since they are not in regular use lately.
- didn’t go ka boom (yet)
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