I discovered that my li-ion battery charger’s minimum charging current is 0.5A. Apparently for 10440 that’s too much. It should be 0.35A. I don’t want to invest in a whole other multi-bay charger for just one battery type. So is there a relatively inexpensive li-ion battery charger around that delivers just 0.35A?
EDIT:
Well, Nitecore doesn’t do a good job of providing this information on their product page, but I found out by watching their video on the UMS2… that it can go as low as 0.3A.
> information on their product page
the product page for the UMS2 lists 10440 as one of the battery options it can charge
also true for the olight-uc-magnetic-usb-charger
charge level is variable
more info
link includes photos of the charge rate tapering down below 0.30, but I have not used 10440, only 14500, 16340…
XTAR XP1 —— These work great .25 and .5 Li-ion and NiMh — but the ones I’m finding are expensive now
Yes, the UMS2 not only lists the 10440, but states in their manual that the current range can go from 0.3A to 2A. On the Fenix ARE-D2 and ARE-A2, the 10440 is listed as supported, but indicates selectable current from either 0.5A to 1A or 2A. My hope would be that Fenix is smart enough to drop down to 0.3 or 0.35A when a 10440 is installed, but they don’t make any mention of it. That Olight Universal Charger is a great idea, nice to have as a backup, being super convenient to carry. Only .750A charge rate, and weird how the specs don’t mention minimums. If it will drop down to 0.3A, that’s great!
Took a look at lygte-info.dk’s review. He does indicate “Between 1.7V and 3V it assumes LiIon and it will slow charge (0.3A).” So it has the capacity to drop to 0.3A. However, in his battery chart, he has 10440 marked in red. In his review of other chargers, his conclusion would note something like “10440 is charged at a higher rate that recommended.” He didn’t make this note on the Olight UC. I also don’t know when he did his test… Maybe Olight made adjustments since?
Something about the design of some XTAR models doesn’t ring with me, except those that are out of my price range.
I’m just the opposite — I’m starting to not like any Automatic chargers — I find they either over charge small cells are under charge large cells — I like picking my own charge rate
I wonder if a breakout box with a 7135 on the ground end might work. It’d starve the charger with lower voltage ’til it could only put out 350mA max.
Got a disposable usb cable?
I had liked the UM2 because I found it wasn’t overcharging cells. My Fluke DMM would verify. But the shoddy build quality… I won’t buy another UM2. But the UMS2 looks better, could be they’ve solved the weak Micro USB mount. Both the UM2 and UMS2 have manual override on current, from 0.3A to 1A or 2A. The Fenix ARE-D2 has it too, though it won’t go below 0.5A (email with CS verified that…), despite their claiming 10440 support.
I don’t think that would work. For example, my UM2 runs off of USB. When I was using a cord that wasn’t delivering full power, the charger behaved erratically. The display would have many stutters, or the cell wouldn’t charge.
I have a Nitecore UMS2 and it goes down to 100mA charge rate (or at least claims to). It seems to work well for my 10440s
If your charging a Vapcell 10440 then 500ma should be fine.
you can set it to 100mA? I thought the lowest was 300mA?
If so, this is a clear winner.
There’s lots of chargers out there which you can set manually to 0.25A. Just pick how many bays you need. 2, 4, or 8. I haven’t looked but there’s probably a 6 bay charger which you can set manually to 0.25A
Interesting, as their product page cites 300mA for selectable charge. I wonder if it’s 100mA when the UMS2 is doing trickle charge only.
Yes, on Vapcell’s site they indicate 500mA capable for quick charge. Likely most quality 10440’s can take 500mA as a quick charge. I’m more interested in 350mA current for a safe charge that won’t diminish the 10440 lifespan.
I heard back from Olight and the response I got wasn’t very technical. Just, “it won’t be a problem, friend!” :person_facepalming: 
Not a satisfying answer. The Olight UC charger doesn’t have any kind of visual interface on charge levels. I wonder if inserting DMM probes in between the charge plates and battery would show the current amperage being delivered to the battery?
The Vapcell 10440 is in my opinion a high current 10440 for its size any way. When a cell is made for lots of current going out it usually coincides with the charge current going in.
I think Vapcell was probably being conservative for battery life. From my eperiences and research its the voltage its charged to plus the end voltage of discharge that influences the cell the most with life span. You can gain a lot of cycles just by cutting the charge short before hitting 4.2v.
I think you would be fine at 500ma but thats just my opinion.
You can measure the charge current by putting a DMM set for current in the path of the current. One lead on a charger terminal and the other on the battery terminal that usually touches it.
Unless I’m confused .25A equals 250mA. If so, the xtar rocket sv2, Vapcell s4 plus, xtar vc8 plus will meet your requirements.
Anything less and this seems to be the best option. SkyRC MC3000.
Nitecore UM2 can also be set at 0.1A according to lygte while UMS2 only goes to 0.3A. Not sure of the difference between the two
I’ve got 4 Xtar XP1 Hummingbirds and they’re awesome for what they are.
Chris
The UMS2 is a slightly more robust build, and replaces the UM2 (now apparently discontinued). But in looking at the Micro-USB port design, it’s identical to the UM2… so I don’t expect they improved the port soldering to the PCB.
The XP1 cell support stops at 18500… so no 18650 or 21700. That would be a bust for me, as I’m often charging 18650 and now 21700 cells.
The slow vs. fast charge was something I’d checked into with regard to cell phone batteries. The common theme I ran into looking across a number of sources was that fast charging is OK once in a while, but that for most charging it should be the slower rate. Quick Charge apparently stresses the battery and cuts down on lifespan. I don’t know if that’s just exclusive to the particular chemistry of these proprietary cell designs that aren’t high drain. Perhaps based on your experience, the well established liion cells, 10440 ~ 21700, don’t have that kind of vulnerability?
I’d also read about with cell phone batteries, it’s best not to frequently charge to 100% or drain down past 10%.
It really depends on the battery and what is considered a fast or quick charge but you are right, slow charging will extend the life especially when compared to what would be a max charge. Phones have been pushing the limits in hopes of winning the fastest charging phone award. I think the Galaxy S7 fire issues made them think a little more conservative, even though it wasn’t charging related the burden of all the lawsuits and recalls weighed in on design safety.
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Most any li-ion will charge fine and is considered safe at 1C, which in this case with the 10440 is 350ma. This being what I consider a high drain cell for it size should be capable of charging at a slightly higher rate which Vapcell has stated a fast charge at 500ma. I would say if your looking for ever possible cycle you can get out of the cell before having to replace it then charge at 1C. I wouldn’t imagine that charging at 500ma would decrease the expected life cycles to drastic though. With flashlight batteries, at least mine, they hardly ever see over a hundred cycles. Ever couple of years someone comes out with a better cell so mine get replaced. I still have the older cells but they just set on a shelf. It does seem like the improvements are slowing down though.
A little more reading if your are interested in getting the most life possible out of a cell.
In the OP you asked for a Inexpensive charger to charge your 10440 cells —- ???
You could also buy some of these and load 2 batteries in parallel.
With two batteries in parallel the charging current divides in half or 3 in thirds or 4 in quarters.
They also make AAA holders such as these but it would require a little work to make the holder into a parallel holder.
I have a 4 18650 holder rigged up for charging multiple 18650’s quickly from a hobby charger.
Works great with batteries that come out of a multi cell light such as a Q8.
