Is that @ 24 hrs resting or right off the charger 
Is there an equivalent to the value or pi: 3.141592653589793238462643383279502884197
What does that work out to in Roman digits?
Thanks for the reply!
I have the batteries in the light and cases. I didn’t know if I should remove the batteries and stored them in the cases.
You can store your cells in your lights. Lights with a mechanical clicky switch do not have any parasitic drain, but lights with E-switches, and especially those with aux LEDs, do. The rate of drain is dependent on the light, but it can be very low, taking years to drain a full cell. Some lights with aux LEDs can drain a cell rather quickly, in a matter of weeks. To know for certain you’d need to measure the current draw if the aux LEDs are to be left on continuously. (see this thread) If it draws 200uA, this would use 1mA every 5 hours, which is >1 year to drain an 18650 with 2,000mAh left in it. If it has an e-switch but no aux LEDs, it could draw ~50uA or less, taking several years to drain the cell.
I check the voltage before storing the flashlight. Then I check a few weeks later. It was the same voltage.
I read on the forum some members are storing the light with the round, ground cardboard tab to stop the battery making contact with the ground.
Well said.
I should purchase digital volt meter with longer digits then… :person_facepalming:
X2
FWIW, I store mine in a plastic case fully charged. Have a pair from a decade ago that I use maybe once a year. Last I checked they appear to work pretty much as well as they ever did. Have a few more from around that time and they are as bad as they were then. If I had a much larger collection I probably would store them at a lower voltage. Have yet to degrade a decent cell so I just don’t see the need or point to not having a fully charged cell ready to swap as needed.
Every light has a cell in it. Even my e switch lights get the battery swapped / checked at least once a quarter. Has not been a problem for me. Never have a cell drop below 3 V in normal use. Just swap with a fully charged cell from the case whenever and don’t worry about it.
Just happened to check my backup 21700 yesterday. It is sitting at 4.13 V about 6 - 8 weeks off the charger. (4.15 V at about 24 hrs IIRC.) Only have 2 21700 so far. EDC one and when it gets down around 3.5 it goes on the charger and the one from the case goes in the light.
My most used light is an AAA and I have a special set of 4 AAA just for that light. Three of them are always fully charged and one is in the light. Have replaced the entire set a couple of times over the years as once the IR starts going up they just are no longer up to the task and get relegated to other uses.
I wouldn’t use the cardboard tab to prevent battery contact. That just makes the light more difficult to use. I’d just unscrew the tail cap a bit to accomplish the same thing if the light is going to be stored for a while.
It came with the light when I first purchase it. I just figure it will be perfect when the light is not in use. It’s so easy to remove the tailcap and remove the tab. I’m not sure what the tab is called but if the manufacturer uses it to stop the battery ground from contacting the spring then it has to be good for storing the light.
I’m not sure what the tab is made out of.
Does not matter really where you store it, as long it is not very hot, not freezing, and they are not under load. If you store it in a device with e switch, just unscrew the cap, so it wont discharge it too low. or remove them if it is not possible to open the circuit
All new cells I get, I run ’em through a cap test to see how they rate vs what’s on the tin. Then I leave ’em (ie, 4.2V) and store ’em in those plastic cases.
Lights which are in active use, ie, my “nightstand lights”, they’re in the lights and connected.
Those that I rotate through, I might have a cell in ’em, but they’re physically locked out. As in clicky off, unscrewed, optionally an insulating disc just in case.
I had one a pair of ’123s go China Syndrome in my MH20. Melted the shrinkwrap and everything was HOT.
Also had an 14500 similarly start fizzing in my GTmicro.
So figure even cells that were NOT abused nor run down (both lights were in active rotation and probably at least half-charged) could still have catastrophic failure and I’d have a pipeboemb go off right next to me.
So best to have the cells stored separately.
Mine are in those plastic snap-type cases but also in padded camera-cases to hold the stacks of plastic cases.
Wanna be thorough, stick ’em in vented ammo cases or the like.
By using the tab to stop the ground spring making contact with the battery. Do I still need to unscrew the tailcap?
How would I know if the light has a E-switch?
I’ve been storing my batteries at full charge, I figure it will lasy longer until I need to charge them again. I don’t know if this is the correct way of storing the batteries.
Any ideas as to what cause the batteries meltdown?
Short Circuit — Over Charging — Maybe in some lights the long term Spring Tension causes problems — I started unscrewing tail caps to keep from compressing deforming springs and to open the circuit
You’re “supposed to” store them at 3.6V or such, but once I cap-test them, I come back and they’re topped up to 4.2V, so I just leave ’em and not run them down. In an emergency situation (blackout, etc.), I might just need to grab some cells for lighting or whatever else, and it doesn’t make sense to have them half-dead.
No idea.
Same reason why I keep 15 18650’s fully charged in my earthquake supplies. If there’s a major event solar charging is going to be slow, if it’s even possible. The cost of batteries compared to everything else in the supplies is minor and well worth the expense.