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]

Originally Posted by 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.

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]

Originally Posted by Sun Vaporer

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]

Originally Posted by Sun Vaporer

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

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.

and

Hints to long battery life

• 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).

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]

Originally Posted by 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.

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.