Things I liked:
Good value for money.
High quality construction.
Fits the vast majority of cylindrical NiMH and Li-ion batteries, including protected 21700.
Analysing functionality (though with limited information in the manual).
Recognises over discharged NiMH batteries.
Things I didn’t like:
Voltage display is only steps - I would prefer voltage to be displayed accurate to 2 decimal places (e.g. 4.19V).
No percentage full indication.
I had connectivity issues with a flat top 30Q battery.
As with all XTAR chargers, the VC4SL is high quality, well constructed, and good value for money. It is an excellent update to the VC series, with good battery compatibility and basic analysing functions. It is thus one of the best USB powered and consumer chargers available. It could be improved with more accurate voltage display, and % full indication.
Just wondering, when you dim the display screen on the VC4SL (holding down the Mode button will dim/turn Off the display), does the display become totally Off (nothing visible) or it just becomes very dim?
On the previous Xtar VC4S, holding down the Disp button will dim the display = the display becomes very very dim, but the display is still barely visible when used in a dark room.
When you press the Curr button the charging current is displayed on the digital display as well. And of course the actual charging current is shown as well when you cycle through the displays with the Mode button.
I saw your review some days ago. I was a doubt about the mode that should “revive” 0V NiMH and I contacted with XTAR directly by mail. Here is my question and the answer they sent to me.
Me - Normally, all chargers that can “revive” over-discharge batteries, only can do this with li-ion ones, but XTAR does not specify. Could this chargers revive over-discharge NiMH batteries too?
Answer - propably not, as in most cases, “revive” is for Li-ion batteries only.
After receiving this mail from XTAR I can´t be more confused. I was looking for a charger that could revive some AA NiMH batteries (that even works with actual charge in some gadged that require a few current but my Varta charger marked them as “null”). I speak about an intelligent charger, not and old one. The question now is: Is there any charger with this funtionality? I could not find any quality information for now…
NiMH doesn’t need anything special to attempt to get them going if they’re over discharged. If you want to be gentle about it, give them a C/10 charge (~200-250mA for an AA) for a few hours, but there’s really no need.
Over discharged LiIon can have two issues. One, below a certain voltage, the charge current needs to be low. Two, it’s possible it’s 0V because a protection circuit has tripped. The charger is capable of resetting that circuit.
Using a “dumb” charger should revive the NiMh (if it is revivable).
Or just do a temporary “parallel” with another good NiMh battery (connect + to +, - to - of the good battery and the battery to be revived) for several seconds until the zero-volt NiMh has a bit of voltage, enough to allow the charger to restart charging.
I know the older Xtar VC4 starts charging very low-voltage batteries at a very low current, regardless if it is NiMh or Li-Ion.
The newer smarter Xtar chargers seem to report error or doesn’t seem to charge very low-voltage batteries as well as the earlier Xtar VC4 (at least in my few experiences).
Thus, aside from “dumb” NiCd/NiMh chargers, I find the older Xtar VC4 to be pretty good for reviving very-low voltage batteries (note: always monitor the battery when charging an overdischarged battery, check temperature)
That’s actually the only issue with 0V (or even maybe 0.4V) NiMH : they don’t need to be “revived,” but the charger does have to be willing to recognize a battery is even inserted in the slot.
I have an old 2 AA NiCd charger that will work, but usually just do the paralleled AA thing. Really easy with the MC3000 - you don’t even have to remove the battery to do that. Might be possible with other spring-slider chargers, depending on the positive contact shape.