17670 Batteries?

[DHart]

A "3.7v" nominal Li-Ion is 4.2v right off the charger. Mine spend most of their lives between 4.2v - 3.8v, in my usage pattern. You get a longer useful life from Li-Ions if you top them off regularly rather than run them down to cut-off or (even worse) dead, especially on a regular basis.

If a long runtime is necessary, by all means, drive the M60 with a single 18650 and run it down until it dims significantly or is shut down by the PC. But no need nor benefit from doing that as a matter of course.

That's the nice thing with the M60... it's really versatile! You can drive it with 1 to 3 primaries, 2 rechargeables, or a single rechargeable (16340, 17500, 18500, 17670, 18650) and get good output from all. And you can get especially long runtimes with a single 18650. With the M30, you get an imperceptibly brighter output when compared to the M60 in single cell mode, but for a much shorter runtime. And you lose the ability to use more than a single cell. Both the M60 and the M30 are great lamp modules, but the M60 gives you a lot more options.

 

[realitycheck]

Alright guys I have another problem here. Please tell me what im missing here. I'm looking at these two batteries right here. I have the 17670 at 1800mah, and I have the rcr123 at 900mah x2=1800mah. The 17670 is only 3.7 volts, but the rcr123 would be 6 volts, the 17670 protection is 2.75 volts and the rcr123 is 2.5 volts. Wouldn't the RCR123 hold the light in regulation for longer and also have a longer drop off time in direct drive??
Thats the way the numbers seem to me but im new so im sure im confused?
Link to two batteries,
http://www.batteryjunction.com/protected-17670.html
http://www.batteryjunction.com/rc390reliba.html

 

[DHart]

Remember that Li-Ions are about 4.2v when fully charged.

Voltage is additive (3v cell + 3v cell in series = 6v) but capacity (I believe) is not additive in series, but perhaps in parallel? Someone correct me if I'm wrong here... battery science can get complicated very quickly when you consider voltage, current, capacity, forward voltage, chemistry, series, parallel, etc. (And I'm no expert by any means here.) (Of course, parallel is not applicable to this situation.)

Here's some good info:

https://www.candlepowerforums.com/threads/217683

 

[realitycheck]

Oh yeah your right. I knew something wasn't right.
So I think either way the 17670 is going to be my best bet.
Thanks for pointing out coming off the charger it is 4.2 volts.

 

[Kestrel]

An RCR123 which claims to be 900 mAh is horribly inflated, it's probably ~600 or so, especially at the relatively high drain rates that we are asking of it. The best way to look at stored energy is watt-hours, and a single 17670 has something like ~50% more watt-hours than two rcr123's.

Regarding voltage levels:
CR123: 3.0v nominal -> 2.5v under load
RCR123, 17670, etc: 4.2v nominal -> 3.7v under load.

Also, 17670's are just basically awesome.:thumbsup:

 

[realitycheck]

hehehe, Kestral you guys have convinced me. I'm going to roll with the 17670 and the ultrafire charger.
Thanks so much for helping a newb out guys.

 

[Kestrel]

hehehe, Kestral you guys have convinced me. I'm going to roll with the 17670 and the ultrafire charger.
Thanks so much for helping a newb out guys.

Are you sure you want the ultrafire charger? Pila IBC's are the way to go IMO, ~$50 but well worth the extra money. My two lumens.

edit: Earlier today I gave a quick scan to CPF/Marketplace - Batteries / electronics to check an idea. I saw NINE cheapo 3.7v chargers in various states of selling or being withdrawn on the first page alone. I don't even recall when I last saw a Pila IBC for sale, even though they are extremely popular on CPF. That should tell you something right there. Why is everyone selling their cheapo 3.7v chargers, but nobody is selling their Pila IBC's?

(FYI, I gather that there are better chargers than the Pila IBC, but the Pila is relatively inexpensive, a simple one to use, and shouldn't get you into trouble, from what I've read)

 

[realitycheck]

Well I've heard good and bad now that im reading stuff.
I dont want to burn my house down over a few bucks thats for sure. I didnt know if the Pila IBC charged 17670's or not?

 

[Kestrel]

Well I've heard good and bad now that im reading stuff.
I dont want to burn my house down over a few bucks thats for sure. I didnt know if the Pila IBC charged 17670's or not?

With various spacers (included and improvised) you can charge pretty much any 3.7v cell reliably with the Pila (except for the really tiny ones like 10180 or whatever).

Think about it this way: Any ____fire besides SureFire is sure to you give you a fire, eventually.
(I'm only kidding here ..... for the most part. There's a thread around here somewhere where a guy lost half his garage in a charging incident, and that hasn't been the only one.)

 

[DHart]

The most important thing to attend to for safe charging, with ANY charger, is make SURE you don't leave cells charging unattended. Don't put them on the charger if there's a chance you might forget about them or leave the house for any prolonged period of time. Be there to pull them off the charger... ANY charger, when the light indicates done. And is doesn't hurt to put the charger on a metal tray in the event of an, event! The Pila charger is well respected and a good choice. But many of us use the WF-139 with excellent results as well. Just remember the safety procedures and you'll be fine.

 

[realitycheck]

Well I think im going to get a FM 18650 body and then get a Pila charger and AW18650.
My question is how long does it take to charge the 18650 battery on a PILA charger???

 

[Yoda4561]

Between 3 and 4 hours for a full charge. That's probably off by a bit because the pila isn't a CC charger, it has a CV stage that may invalidate a simple capacity/charge rate calculation.

 

[realitycheck]

That's probably off by a bit because the pila isn't a CC charger, it has a CV stage that may invalidate a simple capacity/charge rate calculation.

I have no clue what this means. Can anyone please help me with this?
Thanks so much for your help yoda, and all.

 

[Yoda4561]

Most NIMH and cheaper Lithium ion chargers use CC, or Constant Current. This means the charger uses the same charging rate from beginning to end of charge. All you need to do then is divide the battery capacity (in milliamp hours) by the charge rate (in milliamps) to get the charge time. This is fine with nimh/nicad batteries as the chemistries are fairly robust in regards to mild overcharge. Lithium ions however are extremely sensitive to any time spent above 4.2 volts, and CC chargers may bring the cell to over 4.5 volts near the end of the charge for a brief period. The Pila and better lithium ion chargers use a CC/CV charge, where it uses Constant Current, then near the end of the charge it will switch to Constant Voltage. This means the charge rate will get slower as the battery nears the end of the charge, and should keep the battery within proper voltage at all times. Whether that will affect charge times in any meaningful way, I'm not sure.

 

[SilverFox]

Hello Realitycheck,

Figure 1 in this article demonstrates CC/CV charging.

That article is 11 years old, but the only change is that most of the cells we are using are now charged to 4.2 volts.

Tom