How Do I Test a Charger?

I would like to test 18650 chargers to see if they are working properly. How do I do this?

I have a wf-139 that seems to be charging fast, and a 2 cell 18650 charger, wall plug travel charger, that doesn’t seem to work.:

Here is his test of a WF-139 http://lygte-info.dk/review/Review%20Charger%20UltraFire%20WF-139%20UK.html

and here is how he does the test: http://lygte-info.dk/info/How%20do%20I%20test%20a%20charger%20UK.html

If you just want to check that you batteries are charged correctly, use a multimeter to check the voltage of the battery after charging, for most chargers it should be within .05 volts of 4.2 volts.

The WF-139 isn't a good charger, and it charge slowly - what brand and capacity are your batteries?

I wondered if there was an easier way. Just to check and see if it’s safe. Presumably these can vary.

Mine isn’t that slow, and it runs over 4.25 sometimes.

I have Samsung 1800 man (laptop) and Cheap ones.

Perhaps I should have said this before.

I put an 18650 in there, 4.1 V, 15-30 minutes or so later, 4.28 V. Cheap one. So planning on recycling.

Wondering if I can charge a single cell?

It took maybe 2.5 hrs 3.9 V Samsung.

Also, what about 2 cells with say 3.9 and 4.1 V? Different amount left?

I tested voltage on charger with 4.1 V protected cheap one
Got 4.17. Amps were 0.12. ???

The 2 bay eBay travel charger just stays green. Doesn’t seem to charge.

You need a better charger

Good Budget chargers are the Miller ML-101 or ML-102, and the i2

ML-101 @ AU$3.49 - discount: http://www.fasttech.com/products/0/10001919/1158901-miller-ml-101-mini-usb-smart-charger-for-18650Miller

ML-102 @ AU$5.96 - discount: http://www.fasttech.com/products/0/10001919/1158901-miller-ml-101-mini-usb-smart-charger-for-18650

They suit flattops only, such as laptop pulls.

The Nightcore i2 @ AU15.27 - discount http://www.fasttech.com/products/0/10001637/1319800-nitecore-i2-lithium-li-ion-ni-mh-ni-cd-smart

2 up and suits protected batteries as well.

And use the BLF discount code at checkout for a 5% discount on all Flashlight related stuff.

They are shipping the Version 6 of the Miller ML-102 now…I actually taped the 18650 inside of it and use them as “quick booster” packs for my kids tablets…they can push about 20-30% charge into my kids kindles in about an hour…now the kids kindles last a WHOLE lot longer before they are discharged

Just found that leaving the battery in the charger won’t work as a “portable power pack” the ML-102 will go to sleep and not activate if the battery is left in, so have to put in a battery to start the charging, otherwise works INCREDIBLY well as a portable power pack but not as a “fixed battery” portable power pack

http://www.lygte-info.dk/info/Measurement%20UK.html

Lots of good testing how-to here. Charge current way down at the bottom will give you some useful information, not really what you’re looking for though.

I don’t know if there is a way to determine when the charger will terminate without actually charging a cell?

But anyway, like it was said above 4.28v is not good.

Get yourself a rather nice for the price, Nitecore i2 or i4.

Wow yeah I wanted to figure out a way to recharge my phone. Picked up v5 good enough I suppose. Thanks. How many ma do you get with this?

Wf-139 Doesn’t seem to be running alot of current in to the battery, I got 0.28 on the 10 A setting on my DMM. Should work just doesn’t shut off as I’d like. Just babysit it I guess til the other chargers get here. Really tested yesterday was pulling battery off to test every 3 min. or so.

Got 2 cheapie 18650’s + charger with light. The other one went from 4.11 to 4.25 or so in less than 10 min. charger stopped on that one. Probably a bad idea but I ran the 4.28 one down + recharged. Did go a lot slower towards the end. Needed to be broken in? Idk

What sort of USB power adapter do I need for the Ml 102?

Looks like 1 amp, but where can I get one? A lot of stuff is overrated, and as soon as I get a 1 .5 A it will be right on.

Where is a good place to buy?

And most computers and laptops made in the last 4-5 years work fine, and in the real world, supply full power.

If the USB port can't supply full power, then the battery just takes a bit longer to charge.

If you want to buy a wallwart, be careful - see HKJ's review of USB power supplies - most of which had problems.

http://www.lygte-info.dk/info/usbPowerSupplyTest%20UK.html

Fasttech sell the Ioncell that HKJ liked http://www.fasttech.com/products/0/10002574/1336202-universal-2a-ac-power-adapter-4-port-usb-travel-ch

and NO charger should EVER charge standard Li Ion OVER 4.2v (there are chargers and batteries that can do 4.35 but standard Li Ion is 4.2)…EVER there is always a slight deviance…but not 4.28!

I really like my Xtar MC1 after it broke on me…I modded it to one of those small USB charging modules and since it has the slider adjustment I can still charge batteries of different sizes

You can get a power adapter that does 1A or higher, I modded mine (changed the RPROG resistor to 2.2K and limited output current to 500mA~ so I can plug it into any USB and it won’t overdraw it

Good place to buy is fasttech ML-102 (if you purchase over $20 you can select USPS epacket and get stuff in 14~ days CONUS)