Test/Review of Charger Xtar VC4

[HKJ]

So since it shows the charge delivered to the cells - i wonder if there was any way I can use this charger to weed out dodgy batteries which do not provide the advertised mAh.

Yes, as long as you can discharge the batteries in a controlled way, i.e. you need something that uses one battery and automatic turn off when the battery is empty.
Then you can charge the batteries and compare the mAh.

I understand that having one poor battery in a group can significantly degrade performance overall.

Correct, when you uses batteries in series.

On car batteries (Lead-Acid) I used to run a drop test where a known load is applied and if the voltage drops below 9V then the battery is not good enough for use.
Is there such a test on these Li-Ion batteries?

You can something equivalent on LiIon with a voltmeter and a resistor (1ohm power resistor is fine). The actual drop will depend on the battery, but all batteries used together must have about the same drop.
Checking tailcap current on a single cell high power flashlight can also be used, all batteries must again show about the same value.

 

[HKJ]

Having had a while now i am full of discontent ,tried different apple chargers which cover the required 5v 2.1a ,even bought extra plugs and same issue. Then paid almost £15 from a UK shop for a "good" travel charger ,again rated at 5.0VDC/2100mah. Again 2 cells in 1+4 with 1a charge only lasted minutes before dropping to 0.75 or 0.5 later...........i can not get a 1a charge rate for 2 cells for the charge duration.

Are you are using more cable than the cable supplied with VC4?

One cell i can manage........useless .

You obvious need your cells charged fast, for many people it is not a huge problem if it takes a few hours extra to charge.

My guess is that either you have been very unlucky with the usb power supplies (i.e. they are all max. 5.0 volt) or your copy of the VC4 is extra critical with the charge voltage.

 

[jc9121]

Yes, as long as you can discharge the batteries in a controlled way, i.e. you need something that uses one battery and automatic turn off when the battery is empty.
Then you can charge the batteries and compare the mAh.



Correct, when you uses batteries in series.



You can something equivalent on LiIon with a voltmeter and a resistor (1ohm power resistor is fine). The actual drop will depend on the battery, but all batteries used together must have about the same drop.
Checking tailcap current on a single cell high power flashlight can also be used, all batteries must again show about the same value.

Thank you for your response once again.

I can try to compare the tailcap voltages of the batteries in my light when they finish charging.

 

[ven]

Hi HKJ,yes i use the original cable supplied with the vc4,tried a good few plugs now,ordered a 5v 3a as a last port of call.

I dont mind a slightly slower charge but it can drop at times down to 0.25 or bellow the mid way 0.5a on display. I would expect to see 1a on bay 1+4 and using all bays a drop to 0.5a. In effect its like using all 4 bays for charging yet only 1+4 are occupied by 18650 cells. It does the same on AA eneloops too,so its either the cable/plug.......or charger itself! Unfortunately i dont have another usb cable to fit the charger.........this i am working on

 

[Timothybil]

Get yourself one of the ZTS battery testers. I know at least one model will test 3.7v Li-Ion cells. It only provides a five step readout, but if you test the set on a regular basis as you use it, any cell that is not pulling its weight will show up with the ZTS tester. If one cell consistently tests lower than the others, it is a pretty good indicator that it isn't holding its charge as well as it should.

 

[ven]

Hi there,thanks for suggestion,can get readings off the opus(resistance/capacity) but cells i have tried have been from older to new/ish and tried many. No issues on other chargers at all. So i cant even say its a specific cell/s............defo charger/cable/plug or maybe all....

 

[HKJ]

Get yourself one of the ZTS battery testers. I know at least one model will test 3.7v Li-Ion cells. It only provides a five step readout, but if you test the set on a regular basis as you use it, any cell that is not pulling its weight will show up with the ZTS tester. If one cell consistently tests lower than the others, it is a pretty good indicator that it isn't holding its charge as well as it should.

With a LiIon cell a voltmeter/DMM is better, for most other battery types the ZTS is best.

 

[HKJ]

I can try to compare the tailcap voltages of the batteries in my light when they finish charging.

Not voltage, current.

Hi HKJ,yes i use the original cable supplied with the vc4,tried a good few plugs now,ordered a 5v 3a as a last port of call.

It is not really the ampere that is important (As long as it can deliver enough), but the voltage. The VC4 uses the voltage to adjust the charge current and it only needs to drop a bit below 5.0 before it will reduce the current.

 

[ven]

Not voltage, current.



It is not really the ampere that is important (As long as it can deliver enough), but the voltage. The VC4 uses the voltage to adjust the charge current and it only needs to drop a bit below 5.0 before it will reduce the current.

Having tried apple air2 chargers(bought another to use separate to my ipad),even tried older ipad chargers which should be fine on paper,i am a little stuck now

 

[zipplet]

Hi ven,

Do you have any deoxit or contact cleaner? I have had dirty USB sockets transfer dirt to plugs causing a voltage drop. I'd recommend cleaning the USB cable for your VC4 (both ends), the power input socket on the VC4 and the USB socket on your apple charger.

Re-test after doing that, keep using the apple ipad charger as they are known to work well with the VC4.

If you want to just verify this theory, try pulling the USB plug slightly out of the power supply and see if things improve. Usually they will as a different contact point will be in use. If things are really dirty that might not help though.

(Do you have a USB voltmeter? They are great for situations like this)

 

[ven]

Hi zipplet,yes i have an xtar usb for checking the voltage so will double check(cant remember results now) will try that too,is odd as everything new.

Will try and get back:thumbsup:

 

[ven]

Two plugs i am testing now

Apple

Both same results





Xtar usb showed 5.1v or 5.3v at one short time.........

Everything usb wise is spotless,tried to clean but nothing to clean,Q tip spotless.

 

[zipplet]

Hmm, I'm not sure what to suggest. Your charger or cable might be faulty.

To be honest, I would contact XTAR and get them to try sending you a replacement cable. I don't think they would quibble over that.

 

[ven]

Hi Zipplet,the mail was sent yesterday suggesting cable or also if they had a USB plug thats known to work. Just to add,the cable is not tied up,its fully undone from the tie.

Will see how i get on

Cheers...........least my "noisy" bt-c3100 works as it should,luckily i have a good few Xtar chargers,if it was the only one and i depended on it,i would not be happy.................

 

[KenSrf]

I am a bit confused reading the test and the thread and would appreciate some clarifications.

Is the reason why the charging was so slow when charging four 18650s batteries (1100 seconds, twice as long as NiteCore D4) because of the resistance from the additional cables you had to use to perform the tests? Should one expect faster charging with high quality 5V adapter, without needing to increase the voltage above 5V?

And if so, what would qualify as a high quality adapter? I don't have a high current 5V power supply (ignoring old PC PSUs, which I find to be too bulky for this purpose). Previously mentioned 12W apple costs nearly as much as the charger, and it seems that even then some people are not getting specified charging currents.

I initially thought that this charger would be better and faster than D4 but now I am no longer sure.

 

[HKJ]

Is the reason why the charging was so slow when charging four 18650s batteries (1100 seconds, twice as long as NiteCore D4) because of the resistance from the additional cables you had to use to perform the tests? Should one expect faster charging with high quality 5V adapter, without needing to increase the voltage above 5V?

Yes, but both charger and usb power can have tolerances on voltage, making it difficult to predict the exact result (I.e. if you get full charging speed).

And if so, what would qualify as a high quality adapter? I don't have a high current 5V power supply (ignoring old PC PSUs, which I find to be too bulky for this purpose). Previously mentioned 12W apple costs nearly as much as the charger, and it seems that even then some people are not getting specified charging currents.

A good adapter is something that keeps a high output voltage, even at 2A. You can check my tests for candidates: http://lygte-info.dk/info/ChargerIndex UK.html (Xtar has one that looks promising).

 

[voodoogreg]

Been lurking on this thread since I own one of these, been a while since I posted on CPF, Ven I think your unit is screwed. albeit a little slow I find mine to charge Li-ion's and Ni-mh's full and accurate, without blasting them too hard. I just ordered another to take on the road (union musician, and I can't have wireless unit's or flashlight's, pedalboard light's etc failing, ever...)
I did invest in a couple of Anker 40W 5-port (71AN7105) HKJ reviewed very well, but even on an std issue apple 1ma it seem's about the same. Just my experience. VG

ps, De-oxit is a must for my road gear, but alcohol and a tooth brush should be enough to clear any kinda home dirt off even old USB's...

 

[KenSrf]

Increasing the usb voltage to 5.2V to compensate for wire losses improves the charge speed.
The display shows 2781mAh 2764mAh 2884mAh 2857mAh.

In your opinion why is charging rate dropping from 500mA to about 350mA after two hours of charging?

 

[ChrisGarrett]

I have a new Apple 12w 2.4A wall wart, but right now, I'm using my Ruinovo 4x18650 power bank and my VC4 now, having just discharged two Sanyo 2600mAh FMs down to 3.62v and I'm getting 1.07A/1.08A into the Xtar via my Xtar current/voltmeter at 4.91v after 90 minutes. Charge current is 600mA, but started out at 1A.

I'm about 900mAh into the charge. Display is off.

Chris

 

[KenSrf]

Yes, but both charger and usb power can have tolerances on voltage, making it difficult to predict the exact result (I.e. if you get full charging speed).



A good adapter is something that keeps a high output voltage, even at 2A. You can check my tests for candidates: http://lygte-info.dk/info/ChargerIndex UK.html (Xtar has one that looks promising).

I missed this message, thanks.

Did you ever test this charger with Xtar adapter, that seems to be a nice match for their charger given the higher voltage?