USB AA charger

I have been looking for a portable USB AA charger similar to this one being sold at FT:

https://www.fasttech.com/p/1333001

Appreciate if you can recommend one that is a little “smarter” than the one above. I would prefer if it can charge 2 AA/AAAs simultaneously and terminates properly if the batteries are full already. The charger above is OK except user has to monitor manually if the battery is full already.

TIA.

I’d suggest the reason that with the relatively low power output of usb 2.0, has deterred many manufacturers from bothering to create these devices, and utilising usb 3.0 for the higher output is too expensive. I’m not sure there are many options out there, above the chargers that will just do the job

USB 2.0 500 mA[a] 5 V 2.5 W
USB 3.0 900 mA[b] 5 V 4.5 W

With that kind of output you are highly unlikely to find any ‘smart’ NiXX charger.
OTOH, the one you link to has 0.16A output so is pretty safe for AA though a bit high for AAA.

0.16A is way to low for both AA and AAA, it is very doubtful a -dv/dt algorithm will work at that current.

5W is enough to charge 2 AA at 1A. Virtually all USB ports can deliver 5W in reality.
2.5W would be enough to provide about 0.7A to 2 AA. That’s assuming 80% efficiency which might be a bit optimistic…

sanyo mdu01 or panasonic equivalent bq-cc14

delta-v termination. individual channels

I have one of the soshine SC-F3, but it is only 1 channel but does 800 mAh for Nimh cells. Chloe and HKJ have reviewed it here.

And this project looks cool too:
http://www.ultrasmartcharger.com/

I bought 2 of those for 79 cents apiece on sale and really like them, I can’t rate chargers, but they sure seem gentle charging, small, and convenient to me, I keep one in the car. It would be easy to keep one with your laptop if you carry one around.

Just a couple thoughts about these Chinese USB chargers. I keep one of those cheap chargers in my disaster bag to go with the solar panel, power pack and Eneloop AA and AAA batteries. I also keep one in my electronics bag and on the road I often charge AA batteries from a power pack. With the compact solar power bank and the other ones I carry, it’s usually close to a week before I even need to plug in. Most of my gadgets are USB but I obviously have flashlights and other gear like computer mice and a little Canon point-and-shoot camera which takes AA.

Most of the time I’m using AA or AAA batteries as matched pairs as measured with an analyzing charger, so it doesn’t bother me that this cheap charger doesn’t use separate channels. One good thing about this charger is that it’s very light. Since I usually travel heavy, I’m always looking to shave off weight without losing functionality.

So I guess what I am saying is that I highly recommend those cheap fasttech / dx.com chargers as long as long as they are used responsibly.

When I use mine, when the red light dims on a battery I put my voltmeter leads to the charger to read the voltage, and when one of the batteries gets to what I think is correct, I pull out that battery.

Is that the correct thing to do, or am I missing something?

Thanks a lot for all the responses.
I apologise if I wasn’t able to include in the original post that I intend to use it as part of my emergency bag or when travelling light like what RaceR mentioned in his reply. I don’t mind if it takes 1-2 whole days to significantly charge my eneloops, better that not being able to charge them at all. If I am home or have access to regular wall power, I use my Sanyo AA/AAA charger and sometimes my Opus charger. For home use, the 2 mentioned are more than enough for my needs. But when I am mobile or when power failures happen, I want to have the option of charging my eneloops from my vehicles CLA or through my USB power banks.

I really like those Sanyo/Panasonic USB chargers posted by Overclocker but they are hard to find in my place. I bet they will also be relatively more expensive.

If you buy the cheap spices at Walmart or other stores, that little plastic container is perfect for holding that charger, I drilled a few holes to in it to not trap moisture, wrapped the charger in a piece of thin bubble wrap, and put it in the container, that keeps it completely crush proof.

FYI lots of chargers like the i4 and the Opus can be used in a vehicle with a 12V cord.

Thanks Racer.
You are right. I am actually looking for a 12V lighter adaptor (don’t have one) that can do min of 3A so I can use my Opus in my car. Only drawback I see is the size of the Opus vs something as small as the sample I posted in the OP. I am also not sure if the Opus can still charge properly 2xAA batteries even at the lowest 200mA level if connected to a 12V 2A DC source.

Thanks Overclocker for the very precise info. :bigsmile: Hmm, expensive at the posted price of approx $26. Clear example of Law of supply and demand.

used to be P480 at cdrking

I remember now seeing them at CDR-King when I bought 2 packs of Gen 2 Eneloops some years ago for my camera flash. Thanks.

I am currently looking at the Soshine SC-F3 from FT. Might also get a Miller ML-102 and make it a pair.