Cut off point for AW protected 17670

[kenL]

Please help. What is the cut-off point for an AW 17670 protected battery? My AW reached below 2.9v and my light still work perfectly. I am wondering if I got a bad battery or the protected shut off level is below 2.9V? I am using a eagletac P100C2 by the way. Thanks in advance.

 

[Black Rose]

In general I think protected cells cut off around 2.75v.

EDIT: AW's 16340 cells cut off at 2.45V

 

[AW]

The eagletac P100C2 should be run with 2 x CR123A or 2 x R123. It won't run in full regulation on a single 3.7V 17670. The protected 17670 will cut off at around 3.0V under a load of 300mA or above. However, if it is run in direct drive with an LED, the diminishing current draw will only trigger the low voltage cut off at 2.45V which is the default value of the protector IC. The 2.45V design parameter is to get most of the capacity of the battery out to work but will rebound to a healthy resting voltage of 3.0V or above when the battery is working under a reasonable load - not a diminishing draw situation like direct driving a LED which go as low as a few mA. The higher the load, the higher the rebounced voltage when cut off.

 

[csshih]

heh. nice to hear from the dealer himself!
now that's customer service! :twothumbs

 

[kenL]

Thanks for all your reply. So I guess it is safe if I let it run until it shut off right?

 

[mdocod]

Thanks for all your reply. So I guess it is safe if I let it run until it shut off right?

Please re-read AWs response. While doing so, please apply this thought:

"The P100C2 is a buck regulated LED light that does not operate in regulation on a single li-ion cell."

 

[1dash1]

Thanks for all your reply. So I guess it is safe if I let it run until it shut off right?

On an occasional basis, you may get away with it. However, I wouldn't suggest doing so as a general practice.

IMO, the downside of routinely running your cells down to shutoff isn't the risk of damaging the cells. My thoughts are that we need to guard against an attitude of complacency.

If cells are handled, stored, used, charged, periodically checked for voltage (both before and after recharging) properly; then we can avoid situations that put us at risk. We are the primary failsafe device, the built-in electronics are our backup.

 

[Al Combs]

You didn't notice your P100C2 dimming when you pulled the battery to check the voltage?

Thanks for all your reply. So I guess it is safe if I let it run until it shut off right?

 

[kenL]

Please re-read AWs response. While doing so, please apply this thought:

"The P100C2 is a buck regulated LED light that does not operate in regulation on a single li-ion cell."

Thanks, sorry for the newbie question. My knowledge and terminology about li-ion rechargeable batteries is very limited. But what is under a load, mean?

 

[kenL]

You didn't notice your P100C2 dimming when you pulled the battery to check the voltage?

No, not really, that’s why I was curious to find out if is okay to let it run until shut off, ‘cause there is no way for me to know when the battery is below the recommended recharge level without measuring it with my multimeter. Now that I re-read AW respond I got a better understanding. Thanks.

 

[Lone Eagle]

I have experienced that AW will always share his advice and knowledge relating to his batteries in a prompt manner when asked. I have learned plenty just reading his responses in CPF. Great resource!

 

[SilverFox]

Hello KenL,

Under load means with the light turned on. Resting means with the cell removed from the light (and any load) sitting on the table by itself.

Since there is no problem frequently recharging Li-Ion cells, why not just charge your cell up weekly? Or, if you don't use the light frequently, monthly...

Tom

 

[Oddjob]

On an occasional basis, you may get away with it. However, I wouldn't suggest doing so as a general practice.

IMO, the downside of routinely running your cells down to shutoff isn't the risk of damaging the cells. My thoughts are that we need to guard against an attitude of complacency.

If cells are handled, stored, used, charged, periodically checked for voltage (both before and after recharging) properly; then we can avoid situations that put us at risk. We are the primary failsafe device, the built-in electronics are our backup.

Big +1 and as Silverfox suggested, charge them frequently. You'll get longer battery life doing so rather than letting them discharge fully. No harm in charging a cell that has been discharged to 70% or 80%