Xtar VC4 doesn't know when to quit!

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Timmy1024
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That’ts so! Smile

Any ideas of what might have been going on?

Thanks.

snakebite
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if i were in xtars shoes i would want to know RIGHT FN NOW! if i had a bad batch of chargers that would replicate the samsung note 7 fiasco so i could recall them,pull off the shelves and get them all back.
but thats just me.
on the good side you have to really overcharge a high quality modern cell to get a nasty outcome.like 12v
iirc thats one of the ul tests.
with whateverfire grade cells all bets are off.

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mapache wrote:
Tumbleweed48 wrote:
I don’t know it it has any significance, but I just checked the voltage across the contacts of the VC4 and got 4.64 v. on all four slots.

The Nitecore i4 showed 5.23 v. on all four slots.

I’m still trying to wrap my head around the technical side of charging, but I believe some chargers have a high no load charge voltage.

Yeah, there’s source voltage, there’s the load, and there’s a series resistance in-between to limit the current.

That’s why you can take a 9V battery, 3V LED, and 1kΩ resistor, and get only 6mA through it. The voltage across the LED will read 3V, and the resistor will drop 6V.

Same like float-charging Pb-acid batteries. They’ll soak up (depending on their size) a certain amount of current without increasing their voltage, so you can hit ‘em straight from a 24V bell transformer (and diode, etc.) with only an appropriate-value series resistor, and they’ll safely float away for their full service life without a hitch.

That’s why I like those cheapo 2buk chargers FT sells, because they’re so low a charging current you’d really have to leave them in for days on-end to hurt the cells.

A fast-charger, of course, needs to be WAY more critical in its source voltage.

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Lightbringer
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xtarflashlight wrote:
When the display showing 4.2V means the charging process is going from CC stage to CV stage. In the CV stage, the battery will be charged with a very small current to make sure the batteries will be fully charged but it also takes some time. So if the meter shows 4.2V, it will not read full instantly. And will show “full“when the batteries are real fully charged.

One suggestion, or at least something on my “wish list”, is to have an option to charge a cell to only 90% capacity, for longer life at the expense of runtime.

Charging to only 4.1V (or 4.0V), say, would also leave more “headroom” in case of overcharge.

Just a thought…

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Lightbringer
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snakebite wrote:
if i were in xtars shoes i would want to know RIGHT FN NOW! if i had a bad batch of chargers that would replicate the samsung note 7 fiasco so i could recall them,pull off the shelves and get them all back.

Before all dogpiling on XTAR Big Smile , let’s wait to hear back what their customer-service says.

I got a WK50 with a bit of a wonky switch (only intermittent problems), contacted the vendor to see if they had just a replacement switch to send, vs snailmailing everything back’n‘forth, and was told to keep the light, they’d send me another (it’s on the way!), and even sent instructions with pix as to how to take apart the tailcap and play with it myself to have 2 working lights. I was sufficiently wowed. Big Smile

Absolutely, it’s in XTAR’s best interests to get back the charger and find out what went wrong, even if they have to eat the cost of return postage. A few bad incidents of Li cells going supernova would make XTAR chargers the equivalent of Galaxy phones. Forget recalls (shady sellers would keep selling them anyway). What they’d lose in terms of sales just from BLFers would be probably hundreds of times the cost of the return postage.

I kinda get the feeling that one of their distributors in Canada would realise this and offer to cover return postage. Big Smile

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Eltax1693
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I just signed up for this replay.

Had exactly the same problem with a 0-volt Tronic AA 2500mAh battery.

Removed it from the Xtar VC4 charger after 10-12 hours 1.5v 4400mAh .

snakebite
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yes long term effects are unknown.everything from ruining the cell quickly to a kaboom in the future.

gauss163 wrote:
snakebite wrote:
[…] on the good side you have to really overcharge a high quality modern cell to get a nasty outcome.like 12v
iirc thats one of the ul tests […]

Such isolated UL tests don’t necessarily translate to real-world continuous use, e.g. the cell may not vent with flame for a single UL overcharge test, but if you overcharge it and continue using it then in may develop cumulative damage (e.g. dendrite growth) that may cause venting with flames in normal use conditions.

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Lightbringer wrote:
xtarflashlight wrote:
When the display showing 4.2V means the charging process is going from CC stage to CV stage. In the CV stage, the battery will be charged with a very small current to make sure the batteries will be fully charged but it also takes some time. So if the meter shows 4.2V, it will not read full instantly. And will show “full“when the batteries are real fully charged.

One suggestion, or at least something on my “wish list”, is to have an option to charge a cell to only 90% capacity, for longer life at the expense of runtime.

Charging to only 4.1V (or 4.0V), say, would also leave more “headroom” in case of overcharge.

Just a thought…

With a hobby charger like the I charger not sure the model and the clone versions of it. You can set it to cut off at a exact voltage like that. And during the discharge test you can set the exact cut off voltage you want to terminate at

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Mike fahner
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Idk if this helps but I just received my xtar vc4 charger yesterday and straight out of the box before I even plugged it in it has that almost burnt like electronic smell so strong that it can smell it while laying in bed, sitting on my night stand right next to me. It’s strong but isnt the exact smell from burnt electronics but its close. Alot of electronics when new have strong smell to them till them break in kinda heating off the smells with regular use. Alot of glues used in the transformer wrappings and certain materials used create an odd smell. I’m an certified automotive technician and know what burnt electronics smell like and even though this is close it isn’t and at least with mine everything is fine. So far mine seems to work as advertised. Hope this helps

Mike fahner
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Also all printed circuit boards have a like glazed coating on them to protect the current paths from arcing out on foreign objects which wold create shorts, this coating has a smell that may be associated with “burnt” or “bad” electronics. After time once the coating fully cures the smell will dissapate. Sometimes “heat” from normal usage will agitate the smell for a certian period of time

Tinderbox UK
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Any fakes of the Xtar VC4 being sold.??

 

John.

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flydiver
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Eltax1693 wrote:
I just signed up for this replay.

Had exactly the same problem with a 0-volt Tronic AA 2500mAh battery.

Removed it from the Xtar VC4 charger after 10-12 hours 1.5v 4400mAh .

Those look like pretty dubious batteries: http://www.candlepowerforums.com/vb/showthread.php?297893-Lidl-red-Troni...

Take a poor quality battery, run it dead > it may end up even worse.
NiMh termination is MUCH harder than Li-on CC/CV. Missing termination, or early termination, can indicate a problem with the battery, the charger, or both with a kind of compatibility issue. In this case I would strongly suspect the battery, not the charger. The VC4 is one of the more reliable chargers I’ve had.

I’ve got a few NiMh that don’t terminate properly. Generally they are old and abused, but not always. I’ve had it happen to new AAA Eneloops. I mark them, watch them, and if they continue to do so are trashed.

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Tinderbox UK
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I read that the Tronic ECO 2400mah were very poor quality, I have 24 of the Tronic AA ECO 2300mah and they are very good (maybe a different manufacturer)

 

Are the Tronic 2500mah he has the old non LSD professional or the new Tronic ECO LSD 2500mah version.

 

John.

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flydiver
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I wouldn’t be surprised if Tronic was just a shrink wrap of whatever they can get their hands on. I can’t imagine a 2500mA AA is LSD, or at least decent LSD.

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I just got a VC4 today and I tossed some HE4’s in it to charge and when I checked it they were at 4.22V and still charging with no signs of stopping.

I have an old junk cell in it now charging to see what happens.

Needless to day I am not too happy about this utterly worthless charger, makes me glad I went with a hobby charger up to now, at least with it the voltage is dead on and never overshoots.

flydiver
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I either use a junk cell or a 4.35v cell to test new chargers. I’ve had a couple of the red light/green light cheapies not work so well.

FWIW you are seeing the CV phase of the VC4 charge. It has to ‘over charge’ just a tad to get to the final charge correctly. 0.02v is not a big deal even if it was actually an overcharge, which you’ll have to allow to complete to actually find out.
I’m sure someone else here would be disappointed if it only got to 4.18v. Wink

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flydiver wrote:
I either use a junk cell or a 4.35v cell to test new chargers. I’ve had a couple of the red light/green light cheapies not work so well.

FWIW you are seeing the CV phase of the VC4 charge. It has to ‘over charge’ just a tad to get to the final charge correctly. 0.02v is not a big deal even if it was actually an overcharge, which you’ll have to allow to complete to actually find out.
I’m sure someone else here would be disappointed if it only got to 4.18v. Wink

It was at 4.22V off the charger and held there for 10 mins before I discharged it and it was not even done charging yet.

Also I find it very odd that the cells get warm on the VC4 when charging yet when I use the imax B6 at even higher charge rates they stay cool?

I guess it is just a confirmation that I made the right choice when I decided to go with the hobby charger.

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flydiver wrote:
I wouldn’t be surprised if Tronic was just a shrink wrap of whatever they can get their hands on. I can’t imagine a 2500mA AA is LSD, or at least decent LSD.

Just apropos of nothing, I have a couple dozen Amazon Basics LSD High Capacity AA cells that are rated at 2550mAh, and consistently charge to close to that level every time I charge them on my VC4. And yes, they are LSD, as some have been sitting around doing nothing for over a year and still have all their electrons.

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