Consumer Li-Ion "cradle" charger roundup...

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> Nano ... remove cell as soon as the light turns green

Oh, yes. I know they're iffy.

I want a smarter charger, before I fall asleep waiting for the light to change.

Thus following this thread.

And I hope the masters of CPF support allowing contributions for this testing effort.
 
csshih said:
this is the exact chip in the charger.
there are 6 of them:
http://www.vitexic.com/data/TP4056Eng.pdf
Click to expand...

Thanks for the link Craig. :thumbsup:

From Xtar:

When the voltage is below 2.9V (±2%), the charger is in trickle charge mode,
When the voltage is 2.9V-4.1V (±1%), the charger is in constant current mode,
When the voltage is 4.1V-4.2V (±1%), the charger is in constant voltage mode.
This charger can monitor the status of each battery in real-time when charging. The batteries are charged intelligently and safely by monitoring the batteries status.
Click to expand...
I'm OK with the first and last parts, but where do they come up with the second and third parts. These are what led me to believe that this charger wasn't really a true CC/CV charger. I don't see how it could be, with those attributes. A true CC/CV charger isn't voltage controlled, as these two parts of the description suggest. And there is no mention of these characteristics in the data sheet you provided. Sounds like the Pila could be using at least a similar chip, but......

Confused. :thinking:

Dave
 
45/70 said:
Thanks for the link Craig. :thumbsup:

From Xtar:

I'm OK with the first and last parts, but where do they come up with the second and third parts. These are what led me to believe that this charger wasn't really a true CC/CV charger. I don't see how it could be, with those attributes. A true CC/CV charger isn't voltage controlled, as these two parts of the description suggest. And there is no mention of these characteristics in the data sheet you provided. Sounds like the Pila could be using at least a similar chip, but......

Confused. :thinking:

Dave
Click to expand...
I'd trust the claims on the datasheet rather than what the Xtar guys say, since plenty of meaning can be lost in translation.
What really is the difference between a perfect charging algorithm and something you see on an Ultrafire? Is there a known, significant gain in capacity, safety, battery lifetime?
 
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higbvuyb said:
I'd trust the claims on the datasheet rather than what the Xtar guys say, since plenty of meaning can be lost in translation.
Click to expand...

Thanks for the tip, could be that's the problem. Still, even those numeric figures do not appear anywhere in the data sheet. I find that odd. It almost sounds as if Xtar has incorporated a voltage checking algorithm in with the CC/CV algorithm, which would be completely unnecessary, and I would think, in no way beneficial to the charger.

What really is the difference between a perfect charging algorithm and something you see on an Ultrafire? Is there a known, significant gain in capacity, safety, battery lifetime?
Click to expand...
Yes.

45/70 said:
......a voltage checking CC algorithm charger, is a charger which attempts to force cells to a predetermined voltage before terminating charge, which damages used, or older cells in the process. This is the reason a CC/CV algorithm is recommended. The CV stage of a proper algorithm prevents damage to the cells by terminating the charge at a point in the declining charge current, thus eliminating excessive oxidation of the electrodes and the heating up of the cells by overcharging. A proper CV stage also avoids the possibility of trickle charging, as well.
Click to expand...

From this post, (one of many) in old4570's thread reviewing the WF-188.

I run up against this "brick wall" every once in a while, and am not going to go into it here, in detail. There is a common belief born of various rumors and hearsay though, that the manufacturers of Li-Ion cells really don't know how they should be charged. With all the vendors that sell inadequate chargers that use a "home-brew" algorithm that very loosely imitates a proper CC/CV algorithm, a lot of users have been brainwashed into thinking that these chargers are OK, when in fact, they are not. In the case of some examples, they are outright dangerous (eg. the original UltraFire WF/UF-139). At the very least, none of these type chargers are good for prolonging cell life.

Dave
 
The TP4056's 1.5% accuracy spec for float voltage looks like a potential weak point. If you get a charger that hits the typical value of 4.20V, then you are good to go. But if you are unlucky and get one that is on the high side (4.263V), that is not so great.
 
The data sheet looks great, if the data sheet for the chip is truthful (it probably is) then I'm really excited to test this charger. The 1.5% tolerance is a little bit wide but that's pretty standard... Hopefully most units will be tighter.

Eric
 
OK, let's let mdocod check it out and not do more second guessing on this charger. Enough is enough.

Bill
 
csshih said:
hey all --

this is the exact chip in the charger.
there are 6 of them:
http://www.vitexic.com/data/TP4056Eng.pdf


now i wonder.... what chip does the PILA use?
Click to expand...


I am suspicious of the graph of the Charge Cycle, because after exact 1 hour the current drops sharply - but the voltage happily goes on rising without any kink. A breakthrough in charging technology?


In my Pila IBC I found two of these chips: Vimicro VA7205 (with better precision.)


mdocod said:
The 1.5% tolerance is a little bit wide but that's pretty standard... Hopefully most units will be tighter.
Click to expand...

Standard to me seems to be 1%. I see a problem here: each of the six chips in the charger - they won't be selected, I'm afraid - has its own tolerance, so the voltage may vary up to 3% between channels!


Wulf
 
Meterman said:
In my Pila IBC I found two of these chips: Vimicro VA7205 (with better precision.)
Click to expand...
Yup, it does look (on paper) as a really good chip.


Meterman said:
Standard to me seems to be 1%. I see a problem here: each of the six chips in the charger - they won't be selected, I'm afraid - has its own tolerance, so the voltage may vary up to 3% between channels!
Click to expand...
I guess something cool would be to buy the chips and assemble/build a charger with high precision parts, and with all matched parts (even 1% resistors will vary +/-1% right?), and do this for each port. This would then minimize differences between caps, resistors, even the chip themselves (there is always "some" variability). Then you would get the very best the particular chip could offer.


Looks like this distributor in ASIA carries both the VM7205 used in the PILA and the new VT4056 used in this new, 6-port charger:
http://www.vitexic.com/chongdianguanli%2811%29.htm
 
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Meterman said:
I am suspicious of the graph of the Charge Cycle, because after exact 1 hour the current drops sharply - but the voltage happily goes on rising without any kink. A breakthrough in charging technology?...

Wulf
Click to expand...

Is suspect that the graph, like many graphs used to describe a product, was created (basically drawn) not generated via an actual test. Human error but it's a minor and typical oversight.

I suspect that when they "drew" this chart to use to describe their product, they simply neglected to include that finer detail of a very minor voltage dip after the current shuts off.

Eric
 
Even if there is some variability between each of the bays, with having 6 bays available, hopefully at least 2 or 3 of them would end up being pretty close to each other.
 
The way I figure is as follows:

Take the Pila IBC. roughly 90% of users report something very close to 4.20V as their termination voltage. About 10% of user report something that is a little further out of bounds that we would normally consider ideal.

If the trend is similar on the Xtar, then that would be perfectly acceptable considering 3X the charging capacity and about half the price. (There wasn't any shipping charge for first class and the CPF disctount did work so it is in fact half the price of an IBC).

--------------------

Bill did make a good point, I need to stop with all the hope and dreams here and just wait to see the results of some thorough analysis...

Funny thing, anyone with a DMM, maybe some spare short pieces of wire, a few cells, and alligator clips can do all of the testing that I do. I'm not using anything special aside from sometimes double checking for accuracy across several different meters.

Eric
 
Here is another very good IC for LiIon, which can also do LiPolimer, and charge at 4.20, 4.35, 4.4, or 4.5 volts (obviously 4.2 for LiIon only!), which is designed to run from either AC or USB ports!. The specs are very decent (again, on paper). About $1.22 each from Digikey:
Microchip MCP73837/8 ...
 
leukos said:
If you want to charge cells one at a time, batteryspace has a few such as this one with CC/CV for $10: http://www.batteryspace.com/smartcharger15afor37vli-ionpolymerrechargeablebatterypack--celisted.aspx
Click to expand...

Still learning...

I thoght it was okay to charge cells one at a time? I'm specifically referring to my Cytac CY-015 charger and AW 18650's and AW 123's (both protected, if that matters). So it is NOT safe to pop in a single 18650 for charging while one bay is empty?

Sidenote: What about charging different cells at once? Specifcally one AW 18650 and one AW 123 in the Cytac at the same time?
 
wquiles said:
Here is another very good IC for LiIon, which can also do LiPolimer, and charge at 4.20, 4.35, 4.4, or 4.5 volts (obviously 4.2 for LiIon only!), which is designed to run from either AC or USB ports!. The specs are very decent (again, on paper). About $1.22 each from Digikey:
Microchip MCP73837/8 ...
Click to expand...

Is it me or is this thread turning more into a charger design thread ? 🙂 not that I am complaining. With a hand full of components and some moderate soldering skills I believe we could build a much better charger than the ones out there now. Sourcing higher quality components, etc. I looked and didn't see a thread, but has that been done here on CPF before ?
 
Sparkss said:
Is it me or is this thread turning more into a charger design thread ? 🙂 not that I am complaining. With a hand full of components and some moderate soldering skills I believe we could build a much better charger than the ones out there now. Sourcing higher quality components, etc. I looked and didn't see a thread, but has that been done here on CPF before ?
Click to expand...

More like comparing the different specs on different chips used for LiIon chargers available (or soon to be available). But yes, with some basic soldering skills one could make a single cell charger with any one of these various IC's, and if one were to be careful with part selection/matching, you could/should end up with an charger with tighter specs than one produced in mass quantity.
 
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