I've purchased a few Romisen flashlights from Shiningbeam and like them a lot. I'd been using rechargeable AA batteries to power them up until now, but received a free CR123A battery with my last shipment and was very pleased with the light output. Two questions, however, have popped up during my research on the Internet.

1. Is there a preferred vendor for rechargeable CR123A batteries (I believed their often called RCR123A, and are sometimes up to 1mm longer than their non-rechargeable brethren)?
2. Why is the stored power of the rechargeable CR123A batteries approximately half of the non-rechargeable batteries (~750-900 mAh vice ~1400-1500 mAh)?

Thanks.

Bill

If money is no object, a respected vendor of Li-ion cells is AW (can be purchased in CPF Marketplace or from Lighthound.com). Personally, I'd probably buy something cheaper, but I'm not sure what is recommended. Check CPF.

I think using 18650 cells seems a lot more practical. DealExtreme SKU 20392 is generally considered to be a good low-cost 18650; a couple (much) pricier options would be AW and Redilast.

which light are you using, many flashlights can use cr123's but cannot take the extra voltage that the rcr123's put out.. You can fry your light using rechargeables..

Using 18650's is a better option but you will save a lot of time getting them from a us seller like lighthound.com

or ebay has some decent options.. the soshine cells and charger are very nice: https://cgi.ebay.com/18650-SOSHINE-Ch...item4cf2fd1bc4

less expensive alternative is dsd charger + UF cells: https://cgi.ebay.com/new-18650-charge...item2c5941e0d9

Thanks MechanicalMan.

socalrider, I have two different Romisen models now. A single RC-N3 Q5 and two, newer RC-N3-II-NWs. The former no longer appears on Shining Beam's website, but the writeup on the latter indicates it runs fine with some RCR123A batteries, but is not recommended by manufacturer.

Looks like I'll be using rechargeable AAs for now, with a switch to 18650s down the road. I already have a Pila 4-stage charger on order from Bug Out

The 123 family has several characteristics, many of which do not make them so good for bike use IMO.

The non rechargeable CR123 has good current delivery for its size, low weight, good cold temperature performance, and long shelf life - unless you get inferior ones, which are generally Chinese imports. However, they can catastrophically ignite and vent with flame and toxic smoke, especially when used in multiples (series) when cells can get unbalanced. Many feel this is much more likely with the poorer quality control product. I stick only to US made CR123s now myself. I never had flames, but I had a lot of import cells lose most of their capacity after a few years on the shelf, instead of the 10+ years for good cells. Nominal voltage is about 3.1 volts. Good cells can be had for about $1.25 each in modest quantities on the internet.

The rechargeable RCR123 cells usually have a protection circuit built in to prevent overcharge or over discharge; this means the room for chemicals is reduced on top of the reduced energy from lithium ion over the non rechargeable. Unprotected cells are available, but you have to be very careful to prevent overcharging or discharging below about 3 volts. Off the charger, RCR123s are about 4.2 volts, enough to blow some lights or make them run in their unregulated zone until the voltage sags. The current draw is also less than nonrechargeables, IIRC.

Single 123 lights have limited runtime for bikes, and IMO double 123's are not much better and have many headaches and dangers. 18650 packs seem to have become pretty standard, but the Magicshine recall probably illustrates that all batteries have dangers, even more so in packs. There's a lot of energy in these things.

I personally use AW RCR123 cells and have been very satisfied for several years, but I use them for pocket lights, knowing I can get at most 1 hour of 100 lumens or so. Lighthound and 4Sevens have them, about $8-9 each.
My NiMH AAs and AAAs are Sanyo Eneloops.

Thanks Litespeedlouie for the explanation....it makes sense that the presence of protection circuits lessens the space for chemicals.

As I said above, I'll think I'll stick with AAs for now and switch (if needed) to 18650s down the road. My new Pila 4-stage charger should be able to handle them both. And thanks for the recommendation on the Sanyo Eneloops, I'll give them a try.

The protection circuits are very small (~2mm) and are simply added at the end of unprotected cells. Li-ion batteries are just different from lithium primaries; different compositions. You can buy 18650s (protected or unprotected) that are ~2900mAh.

Ah, I've never used unprotected cells. Are they 2mm shorter, or do they put a 2mm dummy button in? It was my understanding that unprotected cells pass more current without the protection circuit.

Protected cells end up being a little longer and very slightly wider in diameter because a protection circuit is added on the end and then the cell is wrapped to keep it in place. So for example, the 2900mAh AW and Redilast 18650s are both Panasonic NCR18650 batteries with an added protection circuit. Here is a picture of one that has been disassembled.



An unprotected NCR18650 is approximately 65 mm in length, and the re-branded, protected versions are around 68 - 69 mm.

Thanks everyone for their advice. Instead of going down the CR123A/RCR123A route, I went with a pair of TrustFire LiOn 18650 (2400mAh) batteries and a new ShiningBeam-S-mini-XP-G flashlight to match with my Pila charger. So far I love the amount of light the flashlight throws and its small size, although the switch could be improved.