I have a streamlight protac rail mount 2 which runs on two 3v cr123 batteries. How should I go on about rechargeable batteries? If I have to get a niche size battery that’s the size of two cr123s, what size and voltage should I get if at all possible?
I suppose I could order cr123 batteries online but the mail carriers have been very inconsistent with my packages for over a year and I like the idea of rechargeables.
Most lights that use 2 x CR123 batteries stacked end-to-end can use one rechargeable 18650 lithium-ion battery in their place.
When you combine two batteries with 3V @ (like the CR123), you're creating a 6V max power source. Most 18650s are about 3.6-3.7V. In a flashlight, there's no issue there. If you're trying to use a 18650 in a photo accessory (flash), you might never get the flash to fully charge, because the voltage is too low.
However, the CR123 has a CAPACITY of only about 1300 mAh (milliampere hours). 18650s can be in the 2600-3600 mAh range on average. That means in a flashlight, a rechargeable 18650 @ 2600mAh will last about twice as long as 2 x CR123s before it needs recharging.
There are a few things to consider when buying 18650 rechargeable batteries:
-- They are not cheap.
-- They come in 2 main flavors: protected and unprotected. The protection circuitry prevents fires when charging/discharging, regulates voltage when charging, and makes the battery casing slightly thicker.
-- The size of the battery varies. If you have a light that is tight around CR123 batteries, make sure to check the physical size of the 18650 you choose, or it might not fit.
-- The life of a rechargeable is about 300-500 charges, depending on the quality and device used.
-- There are LOTS of counterfeit 18650s out there, even on Amazon. It's easy to take a cheap knockoff and relabel it as a better brand.
Make sure to buy from a reputable source. It might not be as cheap as Amazon, and you might have to pay for shipping, but many sellers on Amazon won't ship batteries to Hawaii anyway. So, PRIME may not be a factor.
You can save money sometimes by getting a bundle with a couple of batteries and a charger. Make sure the charger is better than the cheapest ones. A crappy charger can destroy the battery circuitry or simply stop working. The batteries are useless if you can't recharge them. It's good if the charger has lights/display to indicate the level of remaining charge when you insert batteries, so you can gauge how long to fully charge. That makes the charger also a tester -- to see how much charge remains in a battery so you know if it needs charging before use.
I just bought some new Fenix flashlight rechargeable batteries last week. They have a new version out with a built-in charger port. Just attach a micro-USB cable to it, plug it into a power source (AC, car outlet, PC USB port, etc.), and it'll charge. No need for a separate charger. They are slightly thicker than the original Fenix batteries I have, but fit my Fenix flashlights fine -- slide easily when inserting or removing.
If interested in those, I bought from
Fenix-Store.com. They were 22.95 EACH, and I bought 4, for a total of $91.80. Shipping to Hawaii was free. I ordered on 1/29, and they arrived 2/2.
ARBL-L18-3500UCapacity: 3500 mAh
Voltage: 3.6V
Protection Circuitry
Micro-USB port
If you're on a budget, the 2600 mAh batteries without the charging port is about $14, but you need a charger.
I also just bought this charger that gets good reviews for $15.54 and free Prime shipping on Amazon, since my old charger bit the dust recently.
I charged all of my 18650s I've owned for years with the new Nitecore charger 2 batteries at a time, and they all charged to 100%.
https://www.amazon.com/gp/product/B0096U26QQ/ref=ppx_yo_dt_b_asin_title_o04__o00_s00?ie=UTF8&psc=1