I have an onyx 235 balance charger that I used for 3s lipos. Id like to set the charger up to charge RCR123’s for flashlights so I can stop buying expensive batteries for them. My issue is I have no clue as to how to set up a cradle of RC123s to charge. I know where to get a cradle for a few dollars with leads and I haven’t yet purchased the batteries but Im assuming ill end up with Ultrafire lipos or the like. Can someone point me in the right direction? How do I hook up balance board (if I should use it) and the recharge leads to a generic 2 or 4 cradle of RCR123s. Thanks for the help!
Thanks MrsDNF. looking through the links in the search (and getting lost down rabbit hole) I believe I have an understanding of how to wire a cradle and balance plugs. One thing I still don’t understand is why they are using magnets. If the batteries are in a cradle and wired properly, why are some people using magnets?
What light are you going to be using RCR123’s with? Depending on the light and the driver, lico batteries like Nitecores or Ultrafires may not be compatible.
I use magnets which I find to work but not ideal. Magnets attract contaminate which leads to poor connections. One day I will build something better. If you build something post it up. I may just copy it.
Thanks. I have a surefire 6P with a cree drop in head I got from light hound and Im picking up a Primary Arms Ultimate Weapon light V2 that is also LED and runs on 2 or 3 CR123s. Since I have the charger, all it would really cost me is a few bucks for the cradle and my time to wire it up. The battery cost isn’t a concern since I have to buy them anyway.
The reason I was asking is because using lico batteries may provide too much voltage. Depending on the driver inside that light, it could be designed to only accept CR123 batteries, in which case, it would not operate with lico (4.2v) batteries. You may have to go with a LiFePO4 battery like the K2 Energy LFP123, which has a max voltage of 3.7v. The LiFePO4 batteries are pretty low capacity compared to a CR123. You are looking at 600 mAh versus ~1400 mAh.
I would recommend contacting Primary Arms and asking them what the operating voltage range is for the UWL v2 before buying the batteries. Perhaps ask them if it is compatible with lithium ion batteries. If the operating range is 6v to 9v, you can probably get away with using the K2 Energy LFP123, which can be obtained from eBay or www.surefire.com. If it is higher, then you would be ok with 16340’s (RCR123). If you are able to go the 16340 route, the Solarforce blue and white 16340’s have the highest capacity that I have tested. They are a little fat and do not fit in all lights, though.
Thanks orairwolf. The Primary arms light is adjustable from 2 to 3 cells. If I use 3 RCR’s, that could make voltage substantially higher. But I imagine it would handle 2 of them with the light being rated for 3 CR123’s. My charger will charge Life or LiPo batts so I could go with either one. I understand Life batts are a little safer.
You are correct that LiFe batteries are safer. I just think in your particular case, you might want to do some research on that light. A lot of times these “tactical” lights are designed to only accept lithium pile batteries and are not designed with flashlight enthusiasts in mind. The tactical crowd usually prefers CR123’s due to their tolerance to temperatures and long shelf life. Perhaps ask on ar-15.com or another gun related forum if anybody has tried using rechargables with that light.
Honestly, you would probably be safe running LiFePO4 batteries. They are not recommended for incandescent CR123 lights because the high voltage when the light first turns on can burn out the bulb. Since this light is using a “T6” LED, which probably means a Cree XM-L or XM-L2, this high voltage at startup is not much of a concern. Even though you charge LiFePO4’s to 3.7v, when a current is applied, the voltage sag will usually bring them down to about the same voltage as a CR123 (3.2v or so). Worst comes to worst, you can always return the light if it breaks it :p. I have been told by a good friend of mine that is a long established, large distributor of lithium ion cells, that the K2 Energy LFP123 cells are the best LiFePO4’s you can get. I have no evidence to back this up beyond anecdotal, but to me, his word is pretty much from the horse’s mouth.
When I bought my K2 LFP123’s, I got them from www.surefire.com because they were actually the cheapest source when buying 4 of them when factoring in shipping costs. There was a distributor on eBay that was cheaper if buying 2, but more expensive if buying 4. I cannot find them anymore.
I don’t think $12 a pair is necessarily terrible. Especially when you consider that they have hundreds of cycles before they need to be replaced. I like the idea of LiFe batts better. They seem slightly more stable, and slightly more universal over the Lipo versions. Thanks for the link!