I bought the VC4SL and used my 5V/2A power supply from my Smartphone and it looks like it work, but I have a strange experience with this combination. It seems the two inner slots work fine but the outer slots stop the charging too early. I used 4 AAA cells with 950mAh, 500mA charge current. The inner slots load over 700mAh, which i OK I guess, but the outer slots stop charging <400mAh.
I also use the Grading function and the right slot shows with an older AAA a capacity of 260mAh which is to low, my S4 showed 685mAh. If I use the inner slots the results from S4 and VC4SL are more similar, the VC4SL shows always a higher capacity than the S4.
I dont have a QC3.0 power supply to test, but I´m not sure whether it´s the reason for this behavior.
@Johnny_Bravo
Try it with li-ion batteries. These multi chargers have only rudimentary support for NiMH, sadly. Also I’ve noticed that the capacity measurement during charging seems to take the internal resistance into account which causes different displayed capacity for two batteries with the same current and charging time.
@puglife2
Not officially, it’s just slightly too short. You can remove some of the plastic at the bottom and they can fit.
I won this charger in the XTAR Christmas GAW on Facebook and Instagram.
No, as an avid non-social-media person, I have not fallen off the wagon.
XTAR very friendly allowed me to deliver my input via their company website.
And now I’m looking at it. It comes with a lot of “bling” on the display.
My personal choice would have been to make that display a bit less abundant.
But when you look past that it is a very nice straight forward 4-slot charger.
If I need a charger with more elaborate tricks, I’ll still have my OPUS.
But this is a charger you can almost operate with your eyes closed.
Which can come in handy since lights with 3, or 4, or more batteries are on the rise.
My personal opinion is that everybody should at least have one charger like this.
If you discharge a Li-ION battery too far, it gets “out of reach” of most chargers.
Because at 2.X V it is considered to be a loaded Ni-MH and it stops charging it.
Where other chargers often fail, a charger like this probably can revive it.
I don’t recommend to do this with batteries you dig up from an old drawer.
But if you need that last bit of energy and have no spare on you, it can be saved.
I know that because my XTAR VC2Plus Master and I go back a looong time
I have only a few Li-ION, maybe I tets it some day
The Grad-function measures at discharge, or am I´m wrong?
It confused me that the results in the inner slots looks realistic, a bit more than my S4 shows but less than my C3100 shows. But I guess not all chargers load exactly the same mAh in the cells.
Testet a bit again, the 4th Slot don´t charged so far one cell to full and shows at Grad.Function also to less values.
The 1st slot worked at this try, I wonder whether it depend on the number of used cells or selected current. Mayb I get soon a QC3.0-PSU and test it again.
I don’t want to hijack this thread since I think SammysHP’s review should be the focus. I’ve started a new thread here to continue the discussion: https://budgetlightforum.com/t/-/70506
Today I bought Xtar vc4 plus which is considered to be the retail version of xtar vc4sl with same specifications.
I just placed a Chinese AA Eneloop which is probably in a bad condition, aged and has been over discharged before. Cell is rated 1900 mah and prior to charging it dropped to 0.9V while being used in a wireless mouse which draws very low current so you can consider it totally depleted. Charger measured 60 miliohm and started with 2A. It terminated early at 130 mAh. I pulled it out just after termination and measured voltage, it was 1.45 V and was dropping so fast so it probably reached 1.55V and that’s why it was terminated. When I reinserted it, internal resistance was measured 170 miliohms. So probably charger didn’t terminate early in vain. This time it decreased charge current to 500mA and it’s still charging while I’m writing this message.
So I guess the reason why vc4sl and vc4 plus terminates early is because temporarily internal resistance increases and this also increases total cell voltage. Since charger cares for instantaneous internal resistance but not a moving average of resistance nor an average value, it terminates early.
This can probably be avoided by choosing a lower charge current.
I wish Xtar brought more customization options to its chargers.
I would like to add something more after using the grade function for the first time. I have a very old, many times depleted, over discharged 2700 mah cell. Its internal resistance was measured 760 miliohms. Its capacity was measured 370 mAh. And it stayed at 1V almost from the beginning of discharge so these results were expected. When charging it also terminated fast so I guess charger was able to terminate very old, high resistance cell properly.
Grading is slow, it discharges like 250 MA current. That would be much better if it discharged with hight current first and then drop discharge current as voltage approached to 1 V. However there’s already Skyrc mc3000 doing all these and unfortunately it doesn’t have a competitor with lower price. So I cannot criticize at that point. I wish Xtar had a competitor with reasonable price like 50ish USD.
I’ll test the charger with new cells too. And I’ll check if it terminates early. But I still feel like the problem is probably fluctuating cell resistance. My old cells which aren’t charged for 4-5 years have fluctuating voltage during discharge with Xtar. This means their internal rezistance is fluctuating during constant current discharge. I fell like it will stabilize with some charge / discharge cycles.
I’ll inform you if same thing happens with newer cells and if they terminate early. I really wonder what causes this. I don’t feel like it’s a buggy software, it should be more like a component inside. I’ll try to observe it if I can find PC connector if my multimeter. Sadly I don’t have an oscilloscope at home.
By the way what’s your charge rate for nimh while using xtar vc4sl?
