Problem with C2H and AW IMR

[gchronis]

Hi guys,

I need some advice. I had the C2H running on level 3 on an AW IMR. I've been using the same battery for about 3 weeks without a charge. At some point the light shut off (after about 3 minutes). I figured that the battery ran out eventually and that I was just going to recharge it in the morning. I left the light clicked on throughout the night though! Does that ruin it?
I put the battery on the WF-139 the next day and it's not charging (light stays green). Switched charging circuit, same thing. My other IMR charges just fine and the light runs fine on my other IMR as well. Did I fry the battery? If so, what can I do next time to avoid it? I thought the C2H had a protection circuit (I haven't cut it off). Is it that I left it on? Would a Pila revive the battery?

Thanks!

 

[mdocod]

Why are you using an unprotected li-ion cell in a boost regulated LED light?

I realize that some dereelights are claiming to have over-discharge protection, but we've had a few reports of incidences now where that did not kick in and prevent over-discharge. I'm not sure what's up with that at this time.

Please follow manufacture recommendations for li-ion cells. Discharge below 2.5V is not advised. Most chargers are designed to reject over-discharge li-ion cells as they can be a safety hazard if recharged. In your case, since it's an IMR cell, there isn't a major safety issue, but leaving the light on over-night has probably done permanent damage to the cell. You are going to need to use something "stupider" to charge it above ~2.5V before a li-ion charger is going to accept it. Easiest way to do this would be to connect it in parallel with another li-ion cell, but ideally, put a resistor in-between them to control some current flow during recovery. A bench power supply would be even better, you might also consider stripping the wires of an old wall-wart transformer that belongs to a device you no longer use, anything ~20-200mA rated ~3-9V would work fine. You'll need a multi-meter to determine when the cell is over 2.5V again.

Eric

 

[gchronis]

Hi Eric,

Thanks for the advice. I'll try the wallwart. IMR's were actually recommended by the manufacturer. I didn't realize the light was drawing current after it shut down. I haven't even checked the battery voltage yet (not home right now). I may just switch to protected, even though the consensous is that IMR's work better on the C2H.

 

[mdocod]

Hi Eric,

Thanks for the advice. I'll try the wallwart. IMR's were actually recommended by the manufacturer. I didn't realize the light was drawing current after it shut down. I haven't even checked the battery voltage yet (not home right now). I may just switch to protected, even though the consensous is that IMR's work better on the C2H.

Someone needs to contact DereeLight and let them know that these "low-voltage" cutoffs are not working in their lights- OR...

Double check you have the "setting" correct for it to be enabled, I was under the impression originally that from the factory they come set for use with CR123 primary cells. (could be wrong on this)

Until the low-volt cutoff thing is straightened out, I'm afraid I have to lump DereeLight in with my recommendations for pretty much all regulated LED lights, and that is to avoid unprotected cells in them.

Eric

 

[gchronis]

I know for a fact that you have to physically cut off a trace in the light to disable the "protection" circuitry for it to work with CR123. Says so very clearly in the manual and on a lot of threads here. I had no idea these circuits are not to be trusted much. I'll also measure the voltage across the batt when I get home just out of curiosity before I try reviving it. And I'll make sure I recharge my batteries more often, never again forget the light on (was in the middle of the night and I were half asleep), IF I ever use unprotected again.

 

[gsegelk]

I've used IMR's in my C2H and it has always cut off. Whenever this happens I usually take it out right away and replace it with a fresh one so I've never had the situation as the OP describes.

I wasn't aware that it is a known issue about the overdischarge protection sometimes not kicking in. I'll lookup more info tomorrow about it but this is very good to be aware of b/c I think there are a good many people using IMR's in the C2H.

 

[mdocod]

It was mentioned as being an issue in a DBS (IIRC) in another thread recently...

Technically speaking, if the C2H runs basically direct drive off the line, (many 1x3.7V lights out there do), then it would make sense to recommend an IMR16340 for best overall performance. Some of these little lights could really push a regular RCR123 to the limit of safety, but if the flashlight isn't going to actually shut off the circuit when ~2.5V is reached, then I don't think they should recommend unprotected cells....

Sounds like the issue is that, while the light turns off, the power consumption does not.. curious..

Eric

 

[gchronis]

Yeah, Eric is most probably right. It didn't stop draining the batt and I shouldn't have left it on. Just to satisfy my curiosity, I'll measure the voltage now, then try to revive it and recharge. Since I've most probably compromised the life of the batt and since it's only $7, I'll run it down again and measure voltage immediately after it shuts off. Then I'll do it again and hook up a meter to check the draw after it shuts off. This should "shed some light" on this whole issue.

And yes, I bet a lot of people are using IMR's, since the C2H draws a lot of current on high and everyone has reported better results with the IMR's. My money is on me screwing up by leaving the light on, though, and not so much on a faulty protection circuit.

 

[HKJ]

It was mentioned as being an issue in a DBS (IIRC) in another thread recently...

The DBS does not have any protection circuit, only the C2H pill have that circuit.

And the protection circuit in C2H does not turn the light off, only disables high.

 

[andi555]

The DBS does not have any protection circuit, only the C2H pill have that circuit.

And the protection circuit in C2H does not turn the light off, only disables high.

Just the 3SM pills don't cut off. The 3SD do!!!

Also the C2H does cut off in any stage when the voltage is under about 2,7V!!


The only thing is this: It seems if the protection of the Dereelights kicks in, there is still current flow - so the batterie will be overdischarged.

So when it cuts off you still must switch off the light!!

See here: http://www.candlepowerforums.com/vb/showthread.php?t=218254

 

[gchronis]

My C2H definately switched off from level 3, not 4, which is high. And yes, it most likely didn't stop current, that's why it drained the batt. Live and learn...

 

[WadeF]

Sounds like user error. :) These set ups aren't toys and must be used properly and with caution. If your light shuts off from the protection circuit kicking in, take the battery OUT of the light to be safe. Then charge it ASAP when you are able to monitor the charging process. I don't like to leave my lithium ions charging unattended (if I'm out of the house).

Reading the Dereelight website, and the instructions included with the C2H, it states the light will no longer work on high when the voltage reaches 2.75v (high should be the 3rd mode, 4th is burst). The light will work in medium and low for a bit (probably because when the battery is under less load it will be above 2.75v). The instructions then state when the protection kicks in you should charge the battery "Remember to charge soon when this happens."

I do my best to recharge my IMR's before they drop low enough for the protection circuit to kick in. I feel if the protection circuit kicks in it should be an "UH OH" moment and prompt action should be taken to get the cell out and on the charger. Why do I feel this way? Because I read the warnings posted by AW who I purchased the IMR batteries from, which states: "Recharge empty batteries ( resting voltage below ~3.6V ) as soon as possible. Leaving LiIon batteries in discharged state will incur irreversible damage ( capacity / cycle loss );"

 

[HKJ]

Just the 3SM pills don't cut off. The 3SD do!!!

3SM is a buck converter and is not supposed to give any output below 3 volt, i.e. it looks like it turns off, but is not designed as a low voltage protection.
3SD is a boast converter and works until the voltage is to low to support the circuit.

 

[mdocod]

"1S(1-stage) cree XR-E Q5 Pill

Input Range: 2.8~4.2V
Output Range: 1.2A
Battery Type: 1x18650,1x17670
Features:
*constant output at it's fully input range
*over discharge protection"


"3SD(3-stage digital) Cree XR-E Pill

Input Range: 2.8~4.2V
Output Range: 1.2A
Battery Type: 1x18650, 1x17670
Features:
constant output at it's fully input range
*three stage output,100%-50%-5%
*over discharge protection
*memory functon
*change level by push switch"

 

[HKJ]

"3SD(3-stage digital) Cree XR-E Pill

Input Range: 2.8~4.2V
Output Range: 1.2A
Battery Type: 1x18650, 1x17670
Features:
constant output at it's fully input range
*three stage output,100%-50%-5%
*over discharge protection
*memory functon
*change level by push switch"

It looks they have something in the 3SD, but it does only turn the light off, not the circuit.
I just tried measuring it, when just below the threshold it uses 17 mA, if the voltage goes further down, the current goes up for a max of about 70 mA at 1 volt.

This kind of protection is very simple to implement with a micro controller (At least if it has a ADC input), but it requires that the light is turned off, when the protection activates.

 

[WadeF]

Maybe instead of listing "over discharge protection" it should state "low voltage warning" and when the light turns off that is your warning the battery is low and you should take the appropriate action.

 

[gchronis]

Ok, good news. Just got back home (wife had an emergency appendicitis surgery yesterday) and my IMR is back to life! The "float" voltage applied by the WF-139 charger brought it up to charging standards again and now it's at 4.13. Works fine in the C2H again. Yay!

I did learn my lesson though, and whatever you want to call the warning or protection, I'm not going to let my batteries reach it. I ordered an additional 2 IMR's just in case the one that went south gives up the spirit and I'll take better care of the batteries from now on.

Thanks all for the advice and just for the record, I never said there was anything wrong with either the light or the batteries. I love AW products just as much as I love all my Dereelights (and keep buying them). I merely wanted to get some advice from experienced CPFers on what exactly I did wrong, so that I wouldn't do it again. I'm new to this flashlight "thing" and although I have a PhD in Robotics and AI, I cannot say I am completely aware of the inner workings of modern flashlight circuits.

Again, thanks all for your time.

George.

 

[HKJ]

I did learn my lesson though, and whatever you want to call the warning or protection, I'm not going to let my batteries reach it.

You hope!
I just had an accident, a DBS turned on in my bag and I did not notice it. Two IMR cells down :mecry:

I used a bench supply to bring them up and then used my WF139 to charge them, but I do not have anything to check the remaining capacity of the cells. I hope they work ok.

We need somebody to make something with the analyze capabilities of the MAHA MH-C9000 charger and a even greater flexibilty for cell size than the WF139 charger, for LiIon, if it was below $100 I would probably buy it immediately.

 

[gchronis]

Ok, let's just say I will try to not let this happen again to my batteries :thumbsup: I'm not so sure how much I've damaged my IMR, but what the heck, it's $7. I'm glad the light is ok.

About your accident with the DBS: When I transport a light like this, I usually take the batteries out, or for convenience I may just unscrew it. Unscrewing it is cheap insurance. It doesn't take that long and it's the same space (rather than having batteries in a case, cause you can't have them floating around either).

You hope!
I just had an accident, a DBS turned on in my bag and I did not notice it. Two IMR cells down :mecry:

I used a bench supply to bring them up and then used my WF139 to charge them, but I do not have anything to check the remaining capacity of the cells. I hope they work ok.

We need somebody to make something with the analyze capabilities of the MAHA MH-C9000 charger and a even greater flexibilty for cell size than the WF139 charger, for LiIon, if it was below $100 I would probably buy it immediately.

 

[HKJ]

About your accident with the DBS: When I transport a light like this, I usually take the batteries out, or for convenience I may just unscrew it. Unscrewing it is cheap insurance. It doesn't take that long and it's the same space (rather than having batteries in a case, cause you can't have them floating around either).

After the accident I have decided to always loosen the tail cap, before I put a LiIon (with IMR cells) flashlight in my bag!

I have also found out that the Zebralight H30 need to have a loose tail cap, but that only cost me a CR123 battery :(.

I know this kind of accidents will always happen, but I still hate it when I blow a perfectly good battery on it. At least I have spares and can get up and running again very fast (I usual caries spares batteries for the flashlight I have in my bag).