Basic Basic Rechargable Battery Questions

[NightBandit]

I know that this information is out here somewhere, but I have done several searches and read hundreds of threads, but I can't seem to find the information I'm looking for (maybe it's so basic that everyone assumes that everyone else already knows this).

I'm looking at getting a LumaPower M1 and since I don't want to burn through a pile of CR123As, I wanted to get some rechargeable 18650s. There are so many choices, that it's getting confusing. I've seen 3.6v and 3.7v 18650s. Within each voltage, there are many mAh ratings (is this amp hours?), 1800, 2000, 2200, 2400, etc. Are the volts the actual power put into a light? Is the mAh the runtime (in amp hours) of the batteries? If this is true, do I just want the highest voltage (brighter light) and highest mAh (longest running) batteries that I can find? I'm assuming that this isn't the case or there wouldn't be so many choices out there.

Also, I have a Fenix P1D-CE that I have been using standard (Surefire) 3v CR123As in. I'd like rechargeable batteries for this light as well, but once again, all the choices confuse me. There are 3.0v RCR123As (with 600, 750 or 900 mAh), 3.6v RCR123As (with 800 or 900 mAh) and 3.7v RCR123As with 750 mAh (plus probably a whole lot more). Are 3.6 and 3.7v batteries interchangeable with 3.0v batteries? I suppose that it depends upon what light I'm putting them in? As a general rule, am I safe with a higher voltage in most LED lights but be careful with incandescent lights?

The more I read, the more confused I get. Any help would be GREATLY appreciated.

Thank you,

NightBandit

 

[mdocod]

as far as the 18650s go, here on CPF we recommend 3 types.
1. Wolf-Eyes
2. Pila
3. protected AW

AW calls them 18650s, I think Wolf-Eyes and Pila call em 168A cells...

these are the best cells for flashlights because they have good built in protection circuits that prevent you from over-discharging cells, also they will cut off power in the event of a high unsafe load, (accidental short circuit).

As for the P1D, I have no idea what the electronics are capable of dealing with. I think some people are running 3.7V cells, but I think the manufacture suggests against it. maybe someone else can make a suggestion here. if you can use 3.7V cells, AWs protected RCR123s are about the best out there.

 

[VidPro]

The more I read, the more confused I get

oh great, not like i am gonna help that any.

3.6-3.7 all the same, its called the "nominal" voltage of the cell, and if you ask me it means little to nothing.
the total possible voltage RANGE of the cell is more important. for li-ion and li-poly its about the same ~4.25v maximum spec charge, and mostly discharged at ~3.0v

there ARE other li-?? type of cells that are comming out that have different max-min voltage specs, but they rarely call them li-ion. like the li-fe-po4 things. the total max voltage on any of them would be the "critical" factor on the survival of the light. many lights that cant handle 4V would be able to handle the 3.8v and down.

miliamp is (1/1000 amp) the total possible capacity of the cell, that is your 1800-2400 etc things. that is how much energy it can hold in miliamps. that is the "capacity" of the battery, and is often overrated. the higher REAL capacity, the longer the "runtime" WHEN the rate of discharge is the same.

there can be other specs, for miliamps or amps, that indicate the RATE that you can discharge and charge the cell

Then with li-ion you should not buy or use "unprotected" cells unless you totally know what your doing. the "protection" curcuit can be rated for the RATE that you can discharge the battery at.
the protection curcuit, is added to the Cell, and keeps the cell within "spec" for the chemisty. so the protection will keep the battery from discharging to far (often 2.4v), charging to far (often 4.25v) and from being shorted, or discharging to fast (often 2amps also at 4amps).

the "change" the protection makes to the cell, doesnt noticably alter the capacity, or voltage of the cell, so that is all good, although it can alter the RATE of discharge the battery can undergo. so protection is usually a very good thing that does not mess up anything.

Hotwires and multi leds, and incans, can attempt to discharge the protected battery beyond the protection Amp Rate, which gives that type of light different issues.

 

[VidPro]

WHEN the light is Designed for 2x3v lithium primary:
2 x 3V type lithium batteries are 6V total. wheras a single li-ion is 3.6v , so often when people use a 18650 to replace 2 primary 3v lithiums the light runs a bit Lower, and slower.
so when people change from TWO 3v cells, to a single li-ion the light runs a bit lower, and for really really long.

then reverse that
when the light was designed for a SINGLE lithium 3V primary, and they put a 3.6V cell in (that can be at 4.2V) they often drive the curcuit and led Harder, and is often out of spec for the lights design.

Because, MANY of the curcuits used to drive the led lights, are not totally 100% regulated, if the voltage goes up, the consumptiom/brightness does too.
MANY of the curcuits in flashlights are not designed for more than the 3V intended, will fall OUT of regulation , slightly overdrive the led, and run a shorter ammount of time.