ROP-High LE Keeps Dimming

[lexina]

I have not been able to run my ROP-high LE in a Mag2C (tail-cap deanodized) continuously for more than 5 mins on 2 of Aw's unprotected 18650s (rated at 2200 mAh). After about 5 mins, the bulb starts to dim rapidly. At this point, I removed the cells and measured the remaining voltage of each cell at around 4.0V. After letting the cells rest for a minute and re-inserting, the bulb lights up again for another 4-5 mins. This happened a couple of rounds until the cells became too weak to sustain the light for more than several seconds. Does anyone else have this experience? Are the cells not able to sustain the 4A current or is it due to something else?

BTW, the ROP-low LE runs perfectly ok.

 

[jdriller]

Are the cells not able to sustain the 4A current or is it due to something else?

I believe that you are correct. 4A is just too much to sustain.

 

[PlayboyJoeShmoe]

I also have a ROP HI LE on 2 of AW's unprotected 18650. I haven't run it for long times, but I get well over 20-30 seconds at a time.

One of our esteemed members runs 2x18650x2 ie: two stacks of 2 in parallel. He gets nearly an hour.

Maybe you have a questionable cell, as most others running this setup haven't complained....

 

[lexina]

I haven't run it for long times, but I get well over 20-30 seconds at a time.

I guess you meant 20-30 min?

One of our esteemed members runs 2x18650x2 ie: two stacks of 2 in parallel. He gets nearly an hour.

Yes, I am begining to think that this would be the ideal setup to run a ROP High. Not sure whether 2 X18650 will fit in an unbored 2D though.

Maybe you have a questionable cell, as most others running this setup haven't complained.

That's why I wanted to check on others' experiences. I did not realize the problem previously because I had always turned it on for only a minute or two at a time. I guess if everyone else has no problem running it continuously for 20-30 mins on 2 X 18650, then it could be my particular cells since other than the deanodizing of the tail-cap and the mini spring, it's a stock 2C.

 

[AW]

lexina,

The 18650s you have are rated for 2C discharge so they should be good for the 4A ROP draw. The dimming you experienced may resulted from a rapid voltage drop or some resistance from your setup. Please check the internal resistance ( especially the stock switch which is not rated for 4A ) and let me know. If it is caused by battery failure, I 'll replace the 18650s.

Regards,
AW

 

[KevinL]

Definitely unexpected - my LG Chem 18650s can withstand full power runs with no dimming until the very last tail end (after ~20 min) which is the sign that the batteries are exhausted and the light should be extinguished immediately.

AW's cells should be able to withstand 4A (2C) if they are at least 2000mAH. Good job on helping lexina get it sorted out :thumbsup:

 

[mattyg]

I've also experienced no dimming until the very end of the charge with AW's cells & the ROP high bulb. I generally get almost 30 minutes of runtime.

 

[PlayboyJoeShmoe]

What I mean is I never run it for more than 30-45 seconds at a time. I don't really USE my bright BRIGHT lights...

But after several runs like that I check my 18650s pretty often and they hold unloaded voltage well!

 

[lexina]

Thanks for all the feedback, everyone.

PJS,
If I run my ROP-high 30-40 seconds at a time, the cells work fine and I can keep repeating it until the cells drain off after around 20 mins of actual use. Only problem is, I can't get a continuous run time of more than 5 mins. Since others can, I guess it's probably a cell issue.

Aw,
Many thanks for offering to sort this out. I presume others have been using the stock Mag2C as well so it may not be a switch problem. Although it looks like these particular cells can't keep up with the ROP-high, they work perfectly fine with the ROP-low and other low current bulbs so I guess I will hold on to them and use them for these applications. Thanks, again.