Is my AW RCR123 ok?

[ky70]

Hello folks I was running my Lumapower Incendio V3 on a protected black label AW RCR123 on high yetserday to test run time and as expectsed the light ran for about 45 minutes and then light dimmed. I let it run about another 5 minutes in the reduced output state and then I cut it off.

When I check th battery on the multimeter it read 3.18v. I was suprised to the voltage that low and I have a few questions:
1. Is it ok that voltage got that low? I know I've seen in a few places that a 3.7v rechargeable Lithium battery with a reading of 3.6v or lower is without power. Do I have this correct? I also seem to recall that discharge protection kicks in around 2.75v - 3v...so I'm not sure how to reconcile these competing thoughts.
2. Is it ok for me to let this battery run completely out during usage or do I need to monitor this (because of the protection I assumed no)? If so, what level should I not let the battery fall below?

Thanks.

 

[andrewnewman]

The minimum safe discharge voltage for LiIon chemistry is a bit of a sliding scale with increased risk the lower you go. So the first point is to try not to do this again. You tripped the protection circuit. As AW cells have pretty good circuits, the circuit reset itself. The protection circuit tripped because you were pulling enough current on the depleted battery to cause the voltage to dip below 3V. After the cell was isolated from the load it bounced back above 3V. That said, 3.18V with no load is really really low.

Assuming that the cell is relatively new and that you are fairly sure hasn't been regularly abused this way, I would put it on a charger and watch it like a hawk.

Periodically measure the voltage as it charges and test the temperature of the cell. If it begins to get hot or takes a protracted amount of time to charge, throw in the recycle bin and order another. It's probably OK but there are no guarantees.

In the future, try to engage in shallower discharges and more frequent recharges. I would not regularly drain the cell below 3.6 volts (no load). Also if the light flickers or dims then shut it off right away. If you are worried this might happen in the field, keep a spare charged cell with you to swap in.

 

[NutSAK]

You tripped the protection circuit. As AW cells have pretty good circuits, the circuit reset itself. The protection circuit tripped because you were pulling enough current on the depleted battery to cause the voltage to dip below 3V.

Why do you think he tripped the protection circuit?

I let it run about another 5 minutes in the reduced output state and then I cut it off.

He didn't say the light shut off by itself.

 

[ky70]

Why do you think he tripped the protection circuit?



He didn't say the light shut off by itself.

That's correct. The light did not shut off, I cut the light off on my own. There was still useable light coming from the flashlight when I shut it off.

Assuming that the cell is relatively new and that you are fairly sure hasn't been regularly abused this way, I would put it on a charger and watch it like a hawk.

Periodically measure the voltage as it charges and test the temperature of the cell. If it begins to get hot or takes a protracted amount of time to charge, throw in the recycle bin and order another. It's probably OK but there are no guarantees.

In the future, try to engage in shallower discharges and more frequent recharges. I would not regularly drain the cell below 3.6 volts (no load). Also if the light flickers or dims then shut it off right away. If you are worried this might happen in the field, keep a spare charged cell with you to swap in.

This is a relatively new rechargeable (2 weeks old) and this is the first time I've let it drain this low. I did successfully charge it and it charged cool with no apparent issues. Thanks for the advice.

 

[NutSAK]

In that case, you didn't trip the protection circuit, but you did run it to a low enough voltage to possibly reduce the capacity of the cell. When you let the voltage go low, you should be sure to charge the battery as soon as possible, as the affect on the capacity will be greater the longer you leave the cell depleted.

At a high current, the voltage can pull down fairly low, but the open voltage should "rebound" somewhat after the current is ceased. Did you read the 3.18V immediately after shutting of the light, or a few minutes later?

 

[45/70]

......the light ran for about 45 minutes and then light dimmed. I let it run about another 5 minutes in the reduced output state and then I cut it off.

Regardless of which chemistry of Li-Ion cells you use, or other conditions, shut the light down immediately when a drop in output occurs. This is a sign that the cell(s) is being over discharged, and should be avoided in the future. Always try to remove and recharge/replace cells before this occurs. Repeated over discharging will kill your cells. Don't run cells down untill the protection circuit trips either. Doing so shortens cell life considerably.

Dave

 

[ky70]

In that case, you didn't trip the protection circuit, but you did run it to a low enough voltage to possibly reduce the capacity of the cell. When you let the voltage go low, you should be sure to charge the battery as soon as possible, as the affect on the capacity will be greater the longer you leave the cell depleted.

At a high current, the voltage can pull down fairly low, but the open voltage should "rebound" somewhat after the current is ceased. Did you read the 3.18V immediately after shutting of the light, or a few minutes later?

It was probably 10 minutes after being shut off when I measured the voltage. Thank you for your help.

Regardless of which chemistry of Li-Ion cells you use, or other conditions, shut the light down immediately when a drop in output occurs. This is a sign that the cell(s) is being over discharged, and should be avoided in the future. Always try to remove and recharge/replace cells before this occurs. Repeated over discharging will kill your cells. Don't run cells down untill the protection circuit trips either. Doing so shortens cell life considerably.

Dave

Will do. Thank you for the direction.