Battery university

[scrubadub]

Not sure if this has been posted before, did a quick search and couldn't find it anywhere:

Welcome to Battery University

Looks like a nice resource for those of us who would like to understand all the battery talk a bit more.

 

[Pleased2BHere]

Good post and essential to understanding an important aspect of these devices.
I have been consistently curious at the initial use advice given by the manufaturers. The charge routine they advise would be very appropriate for NiCad's which have a "memory" but don't apply to Lithium Ion batteries??? I have also been doing some voltage testing during the charge cycle on my Janty KB batteries, When my light goes green, the battery is at 4.16- 4.17 VDC, This usually takes about an hour. If I leave it on the charger another 2 hours it may be up to 4.19 or 4.2 VDC. This difference in charge is functionally negligible and doe not warrant the extra charge time. Yet all our advice is to charge for 3-4 hours? I also see no basis at all for Janty's initial charge time of 12 hours!!! Can anyone out there justify that?

 

[Cage]

That's a great resource.
There's a "How to charge - when to charge table" inside:
How to charge - when to charge table

Answered a lot of my questions.

Thanks!!

 

[Tetsab]

Hey, that's useful and informative. Any point in asking a moderator if that link could be added in FAQ's or stickied in the New Members area?

 

[Myk]

After reading about Lithium Ion I'm getting convinced that the reason these Lithium batteries are not living (other than switch failure) is over charging.

 

[Sun Vaporer]

After reading about Lithium Ion I'm getting convinced that the reason these Lithium batteries are not living (other than switch failure) is over charging.

Looking at Battery University, Lithium Ion's love a top off and can not be overcharged when left on the charger and repeatedly discharging all the way down is what kills the battery. See How to charge - when to charge table for Lithium Ion. So it appears to not wait till the battery is dead before you place it on the charge.

 

[equazcion]

Looking at Battery University, Lithium Ion's love a top off and can not be overcharged when left on the charger and repeatedly discharging all the way down is what kills the battery. See How to charge - when to charge table for Lithium Ion. So it appears to not wait till the battery is dead before you place it on the charge.

Yup - It says it's better to charge li-ion batteries more often and not let them completely die first. Didn't know that, and I doubt most people here do either. Thanks for this post

 

[Myk]

Looking at Battery University, Lithium Ion's love a top off and can not be overcharged when left on the charger and repeatedly discharging all the way down is what kills the battery. See How to charge - when to charge table for Lithium Ion. So it appears to not wait till the battery is dead before you place it on the charge.

See, Charging lithium-ion batteries

[FONT=Verdana, Arial, Helvetica, sans-serif] No trickle charge is applied because lithium-ion is unable to absorb overcharge. A continuous trickle charge above 4.05V/cell would causes plating of metallic lithium that could lead to instabilities and compromise safety. Instead, a brief topping charge is provided to compensate for the small self-discharge the battery and its protective circuit consume.[/FONT]

and

[FONT=Verdana, Arial, Helvetica, sans-serif]Hints to long battery life [/FONT]

• [FONT=Verdana, Arial, Helvetica, sans-serif]
  [*] Limit the time at which the battery stays at 4.20/cell. Prolonged high voltage promotes corrosion, especially at elevated temperatures. (Spinel is less sensitive to high voltage than cobalt-based systems).[/FONT]

Topping up is not the same as overcharging.
If these chargers or batteries can keep from over charging then it's meaningless to leave them on after they go green and it's harmful to the charger because it builds needless heat.
If the chargers can't be trusted and they do trickle once they go green then it is harmful to the battery.

 

[leaford]

I think the problem is that the light goes green after one hour, or at apx 70%, according to this, even though it takes the full 3-4 hours to reach 100%. That fits with my experience, repeatedly tested, that you get 20-30% fewer puffs if you remove the battery as soon as the light turns green. So the light is changing at the wrong point in the charging cycle.

 

[Myk]

I think the problem is that the light goes green after one hour, or at apx 70%, according to this, even though it takes the full 3-4 hours to reach 100%. That fits with my experience, repeatedly tested, that you get 20-30% fewer puffs if you remove the battery as soon as the light turns green. So the light is changing at the wrong point in the charging cycle.

If that's the case then it's possible to over charge because the charger is continuing to charge the batteries after they are telling themselves to turn off.

My chargers don't act like that. They go off anywhere from instantly to four hours depending on how run down the battery was.

 

[TheEmperorOfIceCream]

My batteries rotate endlessly on the chargers. I doubt if I ever use more than half the charge of any given batt, even when out and about (I carry eight batteries in a cigarette case, plus one on the device). I haven't, therefore, noticed any falling off in performance. My dead 'uns go out spectacularly, usually from switch failure.

Emp

 

[tribalmasters]

If you listen closely to the sound your charger is making you can tell when its charged. Mine buzzes whilst charging and then makes a high pitched whine when done, luckily for the DSE-901, the green light comes on so chances are the green light on these chargers is accurate enough, you will also notice the charger cooling down when charged as its power supply idles away

 

[leaford]

If that's the case then it's possible to over charge because the charger is continuing to charge the batteries after they are telling themselves to turn off.

I don't think the light actually tells the charger to turn off. Just because the indicator is working wrong doesn't mean the charging cycle is working wrong, too. Does a faulty fuel guage mean the fuel tank doesn't work?

I'm not sure how authoratative "Battery University" is, but the charging cycle it describes (70% charge in first hour, 2-3 hours for the remaining 30%) is exactly in line with what I find, and none of my chargers seem to get hot. Nothings caught on fire. So the charge cycle seems to work just fine. It's only the indicator that seems to be off.

And, again, I'm not talking about one or two particular chargers either. This is my experience with virtually all of them. ANd I'm not the only one, many MANY others have reported the same thing.

 

[Pleased2BHere]

I think the problem is that the light goes green after one hour, or at apx 70%, according to this, even though it takes the full 3-4 hours to reach 100%. That fits with my experience, repeatedly tested, that you get 20-30% fewer puffs if you remove the battery as soon as the light turns green. So the light is changing at the wrong point in the charging cycle.

I have no doubt that this is the average experience. However, these are very inexpensive chargers and there is likely going to be some variation (10-20%) in the point where the led changes. I have a background in electronics but am not an engineer.
I did some investigation into Lithium Ion battery chargers and the reason for needing the additional time to reach full charge is because as the battery reaches that "70%", it tapers off the charging current fairly quickly. It continues to taper off the charging current as it approaches 4.2 volts (which is the maximun safe charge). This is due to the circuit design required to keep from overcharging which could damage the battery. In all likelihood the symptoms you are seeing are a good thing since it tends to show that even these cheap chargers aren't likely to overcharge.
My speculation is, that it is likely that it is cheaper to tie the LED to same component which handles current limiting at that 70% point, (a voltage comparator). Which is why it changes before full charge is reached. Otherwise they would need seperate voltage comparators to handle current limiting (that 70% point) and to handle the LED change. This would not be technically difficult but it would add another 50 cents or 1$ of parts. Much easier and cheaper to tell us to keep charging.

 

[rsngfrce]

This thread SERIOUSLY needs to be BUMPED UP! Amazing info! No point in the initial 8 hour charge? I hate battery voodoo! Can anyone dispute the info in this thread?

 

[a2dcovert]

I'll bump this up as I want to hear more from others. The issues with Li-ion batteries are really out of our control. The batteries contain a protection circuit built in. Li-ion batteries are very fragile when it comes to charging and discharging. Without this protection circuit you would very easily destroy the battery from discharging it too far or overcharging.

The circuit cuts off the battery when the voltage gets too low. You cannot fully discharge a Li-ion battery. The protection circuit cuts off the battery at around 3.5 volts. If you put a volt meter on a "fully discharged" battery in its case you will get no voltage. If you were able to get into the case and test the battery directly you would see that the battery isn't really fully discharged. It will still have about 3.5 volts.

When charging the battery the protection circuit will cut off the battery from the charging circuit at about 4.0 or 4.1 volts, not sure if all brands use the same voltage. You can't over charge the battery. Li-ion batteries also do not trickle charge. When the charge light turns green the charging cycle is complete.

These batteries will fade slightly over time and at some point will no longer take a charge. They do not develop the "memory effect" like the older style batteries. They do have a limit to the number of times they can be charged and discharged.

 

[SerialVapistPR]

Peter, on the VaporsDelight website (Intellicig) posted the following:

"If you repeatedly crank down too hard on the battery as you screw it into the USB charger you can actually push the small, metallic ring with the gasket around it in the battery's end down into the well that it sits in. If this happens the battery will not properly contact with the atomizer and the EVO will not work. You can permanently break your battery this way."

I've had two batts that, while they appear to be fully charged, totally stopped powering the EVO. Anybody else seen this?

 

[~bruce~]

I have! The center contact is the problem...they seem to move around quite a bit. Solution is to very carefully and slowly pull them back out using a small paperclip or something... it's not a whole lot, mind you...just enough so the little silicon insulator is no longer deformed.

 

[greenie]

That's a great resource.
There's a "How to charge - when to charge table" inside:
How to charge - when to charge table

Answered a lot of my questions.

Thanks!!

I like this grid.

If I understand this right. These are Lithium-ion

Leaving the battery in the charger won't hurt it.

Allow for a full discharge and charge once in a while but partial charges don't hurt it.

....but battery life will still remain the same. They will lost their charge completely after x amount of uses.