battery questions for 18650 vs AAA

[divin'dog]

I just bought my first LED light that can use 3 AAA's or 1 18650 battery. I've tried to find comparisons but EE is not my forté. Can someone explain the benefits to me of using either types of batteries? I'm guessing that AAA's are a bit more expensive in the long run. What about power? Will the power be the same on either set of batteries? I'm really interested in length of burn time vs power on a set of batteries. The longer the burn time, the better I like. I know that 18650's are not cheap which brings me to my next question...

Where can I get some inexpensive but good 18650's and a charger? I have read some threads that recommend Panasonic 18650B batteries. Any opinions? Also, where is a reputable place online to buy?

Thanks in advance. Diving questions, I'm ok at. Batteries, not so much!
dd

 

[rjradical]

Lithium Energizer AAA batteries (from what I could find) have about 1250mAh of discharge (burn time). Eagletac and Panasonic both have 18650 Lithium-ion batteries with 3400mAh ratings (this equates to a longer burn time). You should be able to find the 18650s online but here is a link to the eagletac: https://www.eagletac-usa.com/products/productList.aspx?uid=5-6 With the 18650 you need to buy the recommended charger.

 

[Brian G]

A quality 18650 cell will be 3.7 volts and 2900-3400mAh. I like to buy from lighthound.com or Callie's Kustoms (Callies Kustoms 3400mAh 18650 Panasonic Batteries). From lighthound I recommend the redilast protected cells or AW unprotected cells. Lithium-ion cells can be damaged by over-discharging, either to too low of a voltage or too much current. The protection circuitry prevents this type of failure. The circuitry does add about 3mm to the overall cell length and a bit to the cell diameter, so some lights can't fit them. For a single cell light, the protection circuitry is less important, but I like to have it anyway for peace of mind. A lithium-ion battery that catches on fire is a very bad thing.

The 3 x AAA holder is for those times when your 18650 battery is dead and you need the light to work right now. The light you linked to looks like it would use quite a bit of current on the highest setting though, so you'd need some pretty fancy AAA batteries to power that. Alkalines should do fine on low though, and good NiMH should power it like the 18650, but for a much shorter time. The Eneloop NiMH AAA batteries that I'm familiar with only have 800mAh of capacity, and since 3 of them have the same voltage as the 18650, the mAh ratings are directly comparable.

I personally would ignore the 3 x AAA holder as if you have to use it, it probably won't be bright enough or last long enough for diving. I'd get two 18650 protected cells if the light will fit them and good quality charger. Pila and Xtar are two respected brands of chargers. If the light won't fit a protected cell, then go ahead and use an unprotected cell, but be careful not to discharge it past 2.5 volts (probably not a concern with this light anyway, as I'm guessing that the light won't turn on if the battery drops that low).

Another option for 18650 cells is an IMR cell. This is a different lithium-ion chemistry that is safer (more difficult to set on fire) and has the same voltage as "normal" lithium-ion, but has about 2/3 the capacity. This type of cell doesn't have the protection circuitry of the protected lithium-ion but this is considered safe due to the safer chemistry.

Another safe chemistry is the lithium-phosphate cell. This is only 3.2 volts and even less capacity but has higher charge-discharge numbers. I don't think I'd consider it for this light.

I hope this helps,
Brian

 

[NAM001]

i want to say that the 18650 also needs a aleeve around the battery as its diameter is less than the aaa. Im sure you can make something for it... a little cardboard taped to teh side of the 18650 to keep it centered on the light contacts. brightess wise you could put 3 li on batteries in the light to see what teh 3.7 18650 would look like.

 

[divin'dog]

Thanks for all the suggestions and help. Below is what I ended up with... Very happy with the outcome. My light is extremely bright with the 18650! It is throwing much more light than my 345 lumen SL4 upgrade from SB. Very noticeable.

Bought this charger: Xtar SP1
Bought these batteries: LG 18650 E1 3200mAh 4.35v

The seller, Mountain Electronics, was very helpful and prices were competitive if not lower than other sellers. Reason I bought the LG 3200mAh batteries over the Panasonic 3400mAh is because useable burn time is better with the LG. Panasonic was longer but at a constant decline whereas the LG burns brighter then falls off rapidly.

As for a sleeve for the 18650, a plastic sleeve came with the light. So far so good!

 

[spoolin01]

Wondering how this light has worked out for you, is it reliable? Truly waterproof?

The beam in the eBay ad makes it look pretty tight, is that so?

How do you find the combination of rotary ring, 5 modes, and diving to work out?

Always looking for the better inexpensive dive light...

 

[divin'dog]

Wondering how this light has worked out for you, is it reliable? Truly waterproof?

The beam in the eBay ad makes it look pretty tight, is that so?

How do you find the combination of rotary ring, 5 modes, and diving to work out?

Always looking for the better inexpensive dive light...

The light has been good. I've only been shallow, about 40' max so far. No leaks but I did add a rubber washer at the end of the light so there are 3 seals the water has to get through.

The beam is tight but I prefer the beam from my modded SL4. New light has a tight beam but you can see rings of light and dark from the center out to the edge. Basically not a great reflector design. The SL4 has a nice tight beam that smoothly transitions out to the edge which to me is much more preferable. I still like my modded SL4.

I don't like the rotary ring. Thought I would but you kinda need 2 hands to turn it on/off. Also the ring is good for getting debris stuck in it. It's feeling a little gritty right now. Tried to wash it out without too much luck. I also don't need all the different options for blinking, sos, etc. Nice to have high, medium and low power though.

The new light is nice and bright for me and my needs but might look for something with a simple switch and better/smoother beam. Might have to spend a little more money.

 

[eelnoraa]

i want to say that the 18650 also needs a aleeve around the battery as its diameter is less than the aaa. Im sure you can make something for it... a little cardboard taped to teh side of the 18650 to keep it centered on the light contacts. brightess wise you could put 3 li on batteries in the light to see what teh 3.7 18650 would look like.

Incorrect, 18650 battery means the battery cell is 18mm in diamter and 650mm in length. It is quite a bit bigger than AAA. In fact, its is quite a bit bigger than AA as well.

---------- Post added August 7th, 2014 at 01:13 AM ----------

Lithium Energizer AAA batteries (from what I could find) have about 1250mAh of discharge (burn time). Eagletac and Panasonic both have 18650 Lithium-ion batteries with 3400mAh ratings (this equates to a longer burn time). You should be able to find the 18650s online but here is a link to the eagletac: https://www.eagletac-usa.com/products/productList.aspx?uid=5-6 With the 18650 you need to buy the recommended charger.

Also incorrect. The unit mAh is NOT burn time, it is a unit for energy content at given voltage. A 3400mAh means if you are to draw 3400mA, the battery will last 1 hour. But if you draw half the current, 1700mAh, the battery will last 2 hours.

---------- Post added August 7th, 2014 at 01:30 AM ----------

I just bought my first LED light that can use 3 AAA's or 1 18650 battery. I've tried to find comparisons but EE is not my forté. Can someone explain the benefits to me of using either types of batteries? I'm guessing that AAA's are a bit more expensive in the long run. What about power? Will the power be the same on either set of batteries? I'm really interested in length of burn time vs power on a set of batteries. The longer the burn time, the better I like. I know that 18650's are not cheap which brings me to my next question...

Where can I get some inexpensive but good 18650's and a charger? I have read some threads that recommend Panasonic 18650B batteries. Any opinions? Also, where is a reputable place online to buy?

Thanks in advance. Diving questions, I'm ok at. Batteries, not so much!
dd

Currently, 18650 battery has much higher energy content than AAA battery. Not only 18650 has higher mAh number, it also operate at a much higher voltage, 3.7V vs 1.5V. When compare the total engery contained in a battery(ies), take the operating voltage x mAh.

A 18650 with 3400mAh has total engery of 3.7V x 3400mAh = 12580mWh (mill watt hour or mill Joules) of energy. Now this is energy, it basically tell you at a given brightness, how long the light will last.

The second part of it is power. It has to do with how much current the battery can delivery at sustained load. Take the same 18650 3400mAh for example. Again 3400mAh mean if you draw 3400mA, it will last 1 hour. mathematically, it also means if you draw 34000mA, it will last 0.1 hours. But 18650 battery is NOT capabile of delivery 34000mA. So there is a spec'ed number for this: max sustain load current.

Having that the above said, 18650 is overall a much better battery platform. It is capable of delivering much high load current than AAA (brighter lights), operate at a higher voltage (so you don't need so many in series), and contain much more energy. 18650 does cost more, but has become very affordable these days.

 

[spoolin01]

The light has been good. I've only been shallow, about 40' max so far. No leaks but I did add a rubber washer at the end of the light so there are 3 seals the water has to get through.

The beam is tight but I prefer the beam from my modded SL4. New light has a tight beam but you can see rings of light and dark from the center out to the edge. Basically not a great reflector design. The SL4 has a nice tight beam that smoothly transitions out to the edge which to me is much more preferable. I still like my modded SL4.

I don't like the rotary ring. Thought I would but you kinda need 2 hands to turn it on/off. Also the ring is good for getting debris stuck in it. It's feeling a little gritty right now. Tried to wash it out without too much luck. I also don't need all the different options for blinking, sos, etc. Nice to have high, medium and low power though.

The new light is nice and bright for me and my needs but might look for something with a simple switch and better/smoother beam. Might have to spend a little more money.

I find the inexpensive multi-mode LED lights I've tried to be a PITA. They often have an unreliable switching sequence and quickly become fiddly to use.

I agree the modded SL4 is pretty much in the sweet spot for an inexpensive but quite decent dive light using standard batteries. It's a bit bulky but the next option down is AA which gives up a lot. The high-efficiency LEDs and drivers seem to have rescued alkaline batteries somewhat from the second-class status they came to suffer as NiMH became affordable - at least to my liking - so I wish some form in between AA and C would become commonplace. A shorter C would be a nice addition if the main battery brands would take it up. 18650 is nice technology, just not as convenient.

Incorrect, 18650 battery means the battery cell is 18mm in diamter and 650mm in length. It is quite a bit bigger than AAA. In fact, its is quite a bit bigger than AA as well.

That caught my eye too at first, but the light uses a carrier to hold 3 AAAs, which itself is slightly bigger in diameter than the 18650.