"Regulated" same as "Protected"?

[Zenster]

I'm not at all concerned about using UNprotected 18650 LithIon rechargeables from the standpoint of charging.
A "smart" charger with a proper charge termination voltage (Pila IBC) coupled with simply taking the batteries off the charger within a reasonable time after they're done is plenty safe.

But what I am concerned about is discharging a battery below it's safe bottom voltage limit.
"Protected" LithIon batteries shut the battery down when that low voltage is reached, but what I want to get a handle on is the role of LED flashlights that are "Regulated" that advertise their voltage range with a high and a low value.
For example, my Tiablo A9s says it has "regulated" circuitry that operates from 2.7v to 10v.

What I'm wondering if anyone knows for sure, if that means that the A9s' circuitry will SHUT DOWN at 2.7v and terminate any further discharge of the battery?... or does that just mean that the flashlight won't be produce much light at that level but it will still continue to drain the battery?

What I'm trying to get at is that if the charger I use properly terminates the charge cycle at a safe and proper high voltage, and the particular flashlight I use terminates the discharge of the battery at a safe and proper low voltage, then it seems to me that I have a situation where I am very literally using a "protected" battery even if it doesn't have it's own built-in protection device.

Of course, if a battery is shorted out or damaged, then all bets are off. But if UNprotected batteries are handled safely in general, and they are used with a charger and a flashlight that both terminate at specific (and safe) voltages, then I don't see any real risk with using the unprotected batteries which offers more choices of more batteries.

Thoughts?

 

[jbierling]

What I'm wondering if anyone knows for sure, if that means that the A9s' circuitry will SHUT DOWN at 2.7v and terminate any further discharge of the battery?... or does that just mean that the flashlight won't be produce much light at that level but it will still continue to drain the battery?

My understanding is that the former is true.

The circuitry will hold constant output inside those two voltages and cease to function outside.

-Joel

P.S. I have no specific knowledge of that flashlight.

 

[DM51]

I don't know the Tiablo at all, but it is possible that what this means is that the light will drop out of regulation, rather than shut down, at <2.7V.

If it just drops out of regulation, you should notice a sudden and fairly marked difference in brightness which will prompt you to stop using that cell straight away and recharge it.

Perhaps someone who owns a Tiablo could let us know about that.

2.7V under load is a reasonable voltage at which to stop using the cell; when resting it will rebound to >3.0V.

If you use protected cells, you will be covered anyway, as the cell's own protection circuit will prevent over-discharging.

It is better to recharge Li-Ions little and often, so you should top them up after each use, rather than waiting for protection/regulation circuits to warn you to do so.

 

[LuxLuthor]

I think it is safe to assume that a flashlight regulated parameter claim should be considered to be overstated until proven otherwise. If you are using unprotected cells, you can try to open quickly and test low cell voltage when regulator is cutting out.

I don't think you can rely on a given brand name light's regulation cutout to save unprotected cells without some way to verify regulation yourself. Obviously one way would be to get at least one set of protected that break circuit at 3V and see what your voltages are on low cut out between protected and unprotected, assuming protected will cut out at 3V, and unprotected will cut out at regulation 2.7V cutout.

 

[FrontRanger]

What I'm wondering if anyone knows for sure, if that means that the A9s' circuitry will SHUT DOWN at 2.7v and terminate any further discharge of the battery?... or does that just mean that the flashlight won't be produce much light at that level but it will still continue to drain the battery?

<snip>

Thoughts?

I strongly doubt that your flashlight's circuitry will shut down entirely when it senses a supply voltage of less than 2.7 V. The circuitry would have to sense that the supply voltage was less than 2.7 V, record this event into a memory element of some type, shut down, and "stay asleep" for as long as the supply voltage remained below 2.7 V, then "wake up" upon some signal. Alternatively, it could be designed to go into a low-power mode whenever the voltage <2.7 V, but that still draws some current because the supply voltage must be sensed. Neither of these scenarios is as likely as the latter part of your post quoted above. The manufacturer of a constant-current driver usually specifies their part by guaranteeing that the current supplied varies less than some tolerance over some range of input voltage (2.7 to 10 V, in your case). When the input voltage goes out of that range, the output current is no longer guaranteed within its tolerance.

To know for sure, it's probably best to contact Tiablo (easiest), or test the circuit yourself by applying different supply voltages (more work, but possibly more fun). As another poster warns, it might not be good to rely on the claimed numbers to protect your batteries.

 

[Dances with Flashlight]

It is better to recharge Li-Ions little and often, so you should top them up after each use, rather than waiting for protection/regulation circuits to warn you to do so.

Thank you for the explanation. I've wondered about that. Does this apply to both protected and unprotected Li-Ions?

 

[DM51]

Thank you for the explanation. I've wondered about that. Does this apply to both protected and unprotected Li-Ions?

Yes. Apart from the protection circuit, there is no difference.

However, there are very wide differences in quality of manufacture. AW's protected Li-Ion cells are highly recommended.

 

[Dances with Flashlight]

DM51. Thank you very much. Appreciate the info.