Wipe the charger terminals with a little isopropyl and a cloth, warm the battery in your hands a bit, or just keep disconnecting and reconnecting it. It’s not a perfect measurement. Eventually it’ll mess up and let you fast charge anything if you try it 25 times. You probably shouldn’t, but eventually it’ll let you
1 Thank
Why, the VC4SL was a waste of time and money. I have other chargers which do what I want 
I only want to say that the behavior of the VC4SL at current selection is maybe not what a user would expect if he had chargers from other brands which do what he selects.
I thought you were asking.
It’s good for beginners. Better too slow than too fast. It’s not a perfect system. I think yours might just be dirty though. Or it could be it doesn’t like your phone charger. They are really finicky about the QC3.0 thing.
The only time it ever gives me an issue is with protected cells, because they suck, or if a cell is inserted crooked or something like that. Otherwise I can always charge at the current I want. The vapcell does the same thing just with a higher cutoff, even in manual mode.
I can sympathize. I have an XTAR charger, advertised as being 2A, that has steadfastly refused to charge high current cells like 30Qs, new or old, at anything more than 1A, despite trying a variety of cables, and power adapters.
For whatever reason, intended or not, it simply doesn’t do what it claims to, so I use it rarely. Not to mention its voltage display is wildly inaccurate. But at least it does terminate properly, and the capacity test function does seem to work. It has soured me on fancy chargers in general. I’d rather just have a basic charger that does what it’s told to do, in a competent fashion, without any fancy bells and whistles.
If safety is a concern, or a desire to safeguard novice users, then they should simply remove the current selection feature, and stop advertising it, since it is practically non-functional anyway.
Make the VC line a fully “safe” line for everyman, and resurrect the VP line, for more experienced users, which will have fully functional, actual current selection for those who are more advanced, understand the risks, and don’t need training wheels.
Trying to straddle both worlds, unsuccessfully, will only serve to frustrate at least one of them.
Imagine if Ferrari sold cars that were capable of 300kph+, but delivered limited to 130kph, for “safety,” since that’s the legal limit in Italy. It would be a great way to lose credibility, and alienate the potential buyers who do have the requisite skill and venues to fully exploit their potential performance.
I know this is just an aside and has nothing to do with anything, but I gotta be ‘that guy’ and point out that Ferrari already does this.
The California, for example, is delivered with a 120mph limiter, and has been for years. You can raise the limit by pressing some buttons on the dash… But technically it’s delivered limited.
They also have had several hardcore models throughout the years that they literally will not let you buy unless you’ve demonstrated you have the requisite skill and venue to fully exploit their performance potential, and even then only under their supervision.
Like the whole FXX program started in the early 2000s with the original FXX, and continues today, where hand-picked buyers are given the privilege of paying Ferrari several million $ for a car they are never allowed to take possession of. They are only allowed to drive the car on special track days, on specific tracks, as approved by Ferrari, only after the car had been inspected by Ferrari techs and the owner briefed by Ferrari drivers. Then at the end of the day Ferrari puts your car in their truck and drive it away for safe keeping so you don’t get tempted and misbehave before your next approved track day.
Also, not Ferrari, but German performance cars, BMW, Audi, Mercedes (not Porsche) have had a hard 255km/h speed limiter on their cars that can’t be turned off without special software, and have for a decade or two.
And all new Ferrari’s (and every other car) sold in Italy are required to have Intelligent Speed Assistance going forward, by EU law. But that’s not a real limiter it’s more like a seatbelt warning.
2 Thanks
Because people often do dumb things without any concern for other people around them. They’ll not just kill themselves, but also hurt a bunch of people around.
It actually translates very well into batteries/chargers too. Someone sets 3A charging current on half dead low quality cell because they want it charged fast, bumps voltage to 4.3v just for good measure (who does not need some free extra capacity?), it catches fire, sets whole apartment complex on fire and ruins whole bunch of other people’s stuff if not kills someone.
No, it is better to limit off the shelf charges to safe values. For those who know what they are doing - it is possible to charge cells however they want with either more advanced/“professional” equipment or a simple CC/CV power supply…
Sorry, that was a misunderstanding. I tested many things. Different cables, some PSUs and found out it´s impossible to make this charger work like my other chargers.
It could be the VC4SL is over-sensitive with the PSUs but QC or not, the sometimes extreme early terminations on NiMH are reality. These are even more annoying than the decisios about the charge current of the charger
Using the V C4SL rarely, it seems to work better with LiIon, but I would expect more than that because other brands do overall better
That’s true. Ive noticed that too on both my vc4sl’s. It’s definitely better with li-ion
…no, it isn’t. If I put one P45B in, it will charge at 3A if I let it, but I don’t want to do that. If I put two in, it will try to do 2A each - that’s fine for an emergency, but still too high for regular day to day use. That’s why it’s a limit and not a forced current.
I have a dedicated eneloop charger for NiMH and actually sometimes forget the charger can do NiMH too, but yeah, I have read that from other people and ultimately I guess again, would use in an emergency, but I have a chemistry-specific charger for each already for normal use.
1 Thank
Because it´s my worst charger in this case I can´t recommend it as universal charger. Dunno if Xtar is able to make a good charger for NiMH, my VC4 is better in this but still not good enough.
But in general I would avoid charger which are not able to set different charge current for single slot, I think no Xtar can do that
Ya that would be really annoying if you only had one charger. But I don’t think that’s unreasonable for the price point.
It’s still ol’ reliable for me. It’s the charger that’s never given me an issue. Never charged past 4.2v, never got so hot it melted the adhesive that was holding the temperature sensor in place, (making the whole thermal safety cutoff thing kind of useless), never burnt a hole through an IC or made a resistor look like a golden brown marshmellow or made my house smell like burnt electronics. And it’s the only charger I’ve had that’s never done any of those.
1 Thank
I think prices depends also on the countries.
The price of the VC4SL here is similar to the Nitecore UMS4. The UMS4 had also weak points like Slot-sharing and termination problems wih NiMH which are don´t reach 1,5V but is overall a better charger IMHO.
The VC4SL is very special, it´s a chain of bad design, at least for NiMH. I have/had sometimes problems to charge 200mAh in cells with over 800mAh capacity. Otherwise it don´t terminate some cells, inserted a fully charged AA and the VC4SL charged over 2 hours with 500mA (charger don´t allow more with 3 cells inserted) then I stop it. I tried again, insert only this cell and then I was able to charge with 1A, some minutes later it terminates the full cell.
So a problematic cell which can only charged with 500mA will maybe never terminated (or much to early).
I would expect more than this from a brand like Xtar which have so many chargers.
Besides, I saw that 5 problematic Xtar-chargers (VC4SL, VC4, MC4S, VC8, VC2 Plus) are all models without a built-in or supplied PSU. Is this the problem? While my UMS4/UM2 works
good with all PSUs I tried, the ISDT C4 EVO is also a bit problematic with some PSUs and terminate NiMH sometimes to early.
I have UMS2. Got it specifically for one feature - lifepo4 support. And my opinion is - this is bad, inherently unsafe charger.
Why? You plug in a lifepo4 cell and it immediately starts trying to charge it to 4.2v with like 2A. Then you need to navigate through menus to switch it to 3.7v (which is still higher than normal, but it actually charges to normal ~3.65v despite what’s shown on the screen). If you plug in fully charged cell it would probably overcharge/hurt the cell before you have enough time to change the settings.
Less critically - It also shows set charge voltage (so 4.2v or 3.7v) once charging is complete, instead of actual cell voltage.
2 Thanks
I don´t use LiFePO4 but the Nitecore have also problems with some NiMHs. It maybe stops after 20h, but I´m not sure what happens if you charge a AA with 1A for 20 hours
Dont get an Xtar VC4 blah blah, it doesnt charge my nimh a d doesnt fully charge my lith ions
I thought at least it works with LiIon?
It has a relatively high cutoff current in the CV stage, 150mah. I consider this a feature, it means when you take an 18650 or a 21700 out of the charger the OCV is right on or just below 4.2v, but never over 4.2v. 4.195v is where mine usually stop. I prefer it that way. Better cycle life.
But if you’re charging a 16340 that 150mah is significant. Those might come off the charger at 4.16v.
1 Thank