18650 and 17670 batterys

If the 18650, or 17670 batterys are fully charged, and then not used, how rapidly will they lose their charge just sitting idle ?

Thanks, Bruce

Howdy RBH and welcome to CPF,
You might get more answers over in the 'Flashlight Electronics-Batteries Included' forum:
http://candlepowerforums.com/vb/forumdisplay.php?f=9

Also, here is a great thread for you to read:
https://www.candlepowerforums.com/threads/201375

depends on the specific battery in question but the self-discharge is remarkably low on rechargeable lithium chemistry cells.

You'll lose 5% in 24 hours, then 2% to 5% per month. Closer to 5 for the smaller, protected batteries, closer to 2 for larger or unprotected batteries.

See the battery university for me details.

As your li-ion cells age, they might begin to drop voltage fairly quickly- if it drops to 4.0V in a month, then it's time to throw it out because the chances of it venting with flame increase notably.

Welcome to CPF, RBH.

I'll move your thread to the Batteries section.

Jarl said:

You'll lose 5% in 24 hours......

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Actually, a new quality (and most not so quality ones as well) Li-Ion cell should charge up to 4.20 Volts (100%) and stay there for days.

There is a commonly believed myth that Li-Ion cells have a "rested" voltage that is lower than "Hot off the charger". This is not precisely true. The only reason a Li-Ion cell will have a lower voltage, say, 1 hour after it comes off the charger, is cell degradation. Once a Li-Ion cell drops to 4.00 Volt after being charged to 4.20 Volts, within 24 hrs, it's time to recycle it. At any rate, if your Li-Ion voltage drops 5% in the first 24 hrs, it's time to recycle.

As to how long Li-Ions will keep their charge, it depends on the cell manufacturer and quality, but generally a Li-Ion should keep 80% of it's charge for 6-12 months. Some protection circuits, have a parasitic drain which causes more rapid self discharge of the cell, but they should still come close to 6-12 months.

Dave

Edit: After reading my post again, it sounded like I was saying Jarl was incorrect. That is not the case. He is quite right. I just wanted point out that 24hrs after charging, a Li-Ion can have lost anywhere from 0-20% capacity.

45/70

What do you consider to be the best charger-battery combo for this type of battery ?

Thanks, again Bruce

AW's protection PCB in his protected cells is claimed to draw 3-6 microamps.

RBH said:

45/70

What do you consider to be the best charger-battery combo for this type of battery ?

Thanks, again Bruce

Click to expand...

Pila IBC charger, IMO.

RBH said:

45/70
What do you consider to be the best charger-battery combo for this type of battery ?

Click to expand...

Well, I'm not much for jumping on "What's best bandwagons". Different strokes for different folks kinda thing.

I will say that the Pilla IBC charger is very well thought of. Also AW's Li-Ion's are equally well respected.

I also edited my previous post for clarity.

Dave

45/70 said:

There is a commonly believed myth that Li-Ion cells have a "rested" voltage that is lower than "Hot off the charger". This is not precisely true. The only reason a Li-Ion cell will have a lower voltage, say, 1 hour after it comes off the charger, is cell degradation....

Dave

Click to expand...

There is also a common misconception that the "no voltage loss" rule associated with Lithium Cobalt chemistry cells carries over to other chemistries... LiFePO4 and LiMnO2 chemistry cells will loose some voltage after resting from the charger even when brand new.

Eric

mdocod said:

There is also a common misconception that the "no voltage loss" rule associated with Lithium Cobalt chemistry cells carries over to other chemistries... LiFePO4 and LiMnO2 chemistry cells will loose some voltage after resting from the charger even when brand new.

Eric

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Ah yes, alternative Li-Ion chemistry. Good point mdocod. I have, of course, been referring to the most common Li-Ion chemistry cells, lithium cobalt.

For my uses, the alternative chemistry Li-Ions either lack voltage, capacity or both. The only Li-Ion cells I have that aren't LiCO's are some LiFePO4 RCR2's. Their true capacity is 200mAh@300mA. Pretty sad. They do work for their intended use though, briefly.

Dave

Just speaking for me, but I have never had a Li-Ion drop to 4.1 volts after being charged to 4.2 volts, within 24 hours. I am talking about 30 or so Li-Ions over a three year period. I have one UltraFire 17670 that will drop to 4.14 volts within 24 hours or so, and that has been the case since I purchased it. I will not run that Li-Ion in series.

Bill

Bullzeyebill said:

Just speaking for me, but I have never had a Li-Ion drop to 4.1 volts after being charged to 4.2 volts, within 24 hours. I am talking about 30 or so Li-Ions over a three year period. I have one UltraFire 17670 that will drop to 4.14 volts within 24 hours or so, and that has been the case since I purchased it. I will not run that Li-Ion in series.

Bill

Click to expand...

All of your cells are in good health then. Enjoy!