I’ve got a few flashlights with built-in chargers. I conducted a test with three of them that I have on hand. None of them topped off the battery to a full charge. One was perhaps at 90% capacity, while the other was a little less than that… but the other, was maybe at only 75% (A Sofirn D25L). And these are all relatively new batteries. When removed, then reinstalled and plugged in, the built-in chargers would take a few minutes and then indicate a full charge was reached. But, inserting into a portable external charger would show otherwise.
So I’m wondering if this is typical, or if the built-in chargers in some flashlights will complete a full charge?
Good observation, I taught it was just with me. I have a few new lights from Nitecore, (MH12S, MH11, MH25S) and after charged I checked the batteries at 4,15V. Usually the external charger go to 4,2V. Now thinking perhaps this was by design, to increase the life span of the batteries and I don’t think the difference in real world use would be that much, perhaps a few minutes, but if you really need to get the most out of the battery external charger is a must.
Its typical. They seem to either use crummy components or someone forgot to calibrate the damn things.
The annoying problem is that they are often not consistent, i have seen the same charger charge from 4.05-4.2V “fully charged”. No consistency
That said i want your 75% one, i try to charge to 80% for longer battery lifetime.
When I see the charging rate drop to 0.2a I typically stop charging. I don’t always catch it but I’m happy to stop at 4.1v or even slightly less. Most of the time I don’t drop below 3.5v either.
Thanks. Yeah, I was wondering about calibration… would be interesting to hear if anyone bought multiples of the same light with built-in charging and tested to see if they all charged to the same level.
I had heard that it’s good to only charge fully once in a while, not on a regular basis, to extend battery life. There’s also the matter of rate… even cell phone makers with built-in batteries (not user serviceable) are starting to incorporate adaptive charging (disabling quick-charge and using a much slower rate to “exercise” the battery chemistry differently).
Its not necessary to fully charge at all. The less time spent over 80% the better. That said if you need more power and your going to drain it below 80% quickly then its probably not a big deal.
As for quick charging thats another kettle of fish and charging at 1/4 C (capacity) per hour is probably best for longevity.
My SP36 goes over too. Most of mine stop in the 4.1X range consistently which is fine with me. I use a USB meter to monitor the charge cycles. I find that the charge indicator light on my Convoy M3-C is all out of whack. but it does charge correctly. My FT03 goes down to a trickle and will stay there for what seems like forever before terminating. I am glad to see 0 milliamps after termination so I don’t have to watch it that closely.
I love internal charging and stopped buying lights without it. Removing the batteries seems archaic to me now and very rarely use lights without it unless I don’t have a similar form factor light with it to use. I won’t gift a light without it. All my car lights and travel lights have it. I don’t own any series cell lights and the meter gives me enough snap shot of what’s going on to feel safe.
I dont have a % device… what are you using, and how reliable is it for LiIon cells?
a while ago someone was using a device that reported %, it was for alkaline batteries… which is not useful for LiIon…
I rely on a DMM to read Voltage. If the charger achieves 4.1v or above, I consider the battery fully charged. All my chargers achieve that.
I mostly use the Olight Universal Charger. I dont rely on built in charging, because that means I cannot use the light until it is done acting like a charger. I prefer to remove the spent cell, and install a fresh one, so I can keep using the light.
I’d rather have a built-in undercharge to 4.1v than lean towards full-charge 4.2v or over-charge.
Since flashes are potentially exposed to varying levels of moisture I don’t blame built-in charge designers for limiting their ceiling.
When built-in charging yer obviously minus the charge port cover so now normally isolated electrified components are exposed. About the last thing ya need is raindrops or worse infiltrating internals, right? And the perfect moisture channeling conduit is the USB cable in of itself.
External chargers don’t typically have potential looming moisture ingress issues so there’s inherent latitude.
’Course if magnetic charging someday becomes di rigueur then who’ll need USB-Micros or even USB-C’s anyway? Then moisture issues are essentially eliminated. I would bet then built-ins would trend to full charge just like externals.
I think magnetic charging is the wave of the future for higher-end flashes. So all this USB-C hoofarah benefits over USB-Micro is likely relatively short-lived anyway to begin with.
The percentage is obviously used in place of measured data. I don’t have a specialized device that’s Micro-USB or USB-C to plug-in inline to check on power flow and mAh accumulation. And of course, my stated percentages were an off-handed estimation—I did not conduct a laboratory test starting measured cells at nearly depleted levels, timing of the charge duration, and taking voltage tests of the batteries at regular intervals. So my inquiry was a generalized one.
Essentially I’m actually glad to know that the built-in chargers I have don’t charge cells to their full potential, so as to help reduce wear on the batteries. That satisfies my inquiry.
You really should have at least a cheap multimeter to be able to measure battery voltage. Various lights do different things at various voltages and it’ll help you identify and understand what’s going on. Measuring the voltage of any new batteries you get or those that have been sitting for a while or even your car battery issues. Even a cheap harbor freight one for under $10 is useful.
I have at least 2 that overcharge. One finished at 4.28v measured on the battery after pulling the battery after the charge completed.
The other was higher still, but I don’t remember what the value was.
I would think manufactures might like to aim low. That way any variance will be, hopefully, in a safe range.
I’m way happier with a conservative value.
Take a look at some of HKJs battery draw graphs. Notice how little time is spent above the 4.1v potential.
I have a Fluke multi-meter, one of the older rugged ones used by electricians with the super thick semi-soft rubber encasing. Trouble is, I don’t have the connector for getting access to the current for measurements on a USB-C or Micro-USB socket.
Yeah, much better to fail in the safe direction (less, just to avoid a mess). I imagine light makers must be cognizant of that, simply for legal reasons.
Really important point, about overcharging. I’m going to test the other light I’ve got with built-in charger to be sure it at least doesn’t overcharge.
Testing amperage going into the cell through the USB cable is useful but that’s not your primary concern right now. Just being able to test the battery voltage on a loose cell out of the flashlight is a good starting point.
