I am looking for some rechargeable batteries to replace my CR123A batteries in a thermal scope which is a real battery eater. One of them is rated for 3.7V “accumulators” but, 16340 batteries are 4.2V off the charger.
This has me looking at RCR123 batteries. The Vapcell T9 looks good and is listed as RCR123A but also shows a charge voltage of 4.2V!
Do I need to look for different batteries with a circuit for charging and current limits to bring the voltage down to 3.0~3.7V?
Can you get clarification from the manufacturer? Seems like you may be OK.
3.7v is the ‘nominal’ voltage which is a description for a ‘standard’ lithium battery that has a voltage range from 3.0v-4.2v.
If it NEEDS to be closer to 3.0v then you need an LiFePO4 battery which has a nominal voltage of 3.2v and a range from 2.5-3.65v. They work on a pretty flat discharge curve around 3.2v.
In the size you want, these are not common. They also don’t have nearly the capacity of 3.7v, (like about half) so may not work well anyway for your use. You need an appropriate charger for them.
that battery you linked has the correct output Voltage to use in devices that call for CR123a. They are rated for 3V output.
However, those special batteries are 2mm longer than a CR123a, so they may or may not fit your device… depends if your device has enough spring travel to accomodate the longer battery.
@sidpost do not use RCR123a, and do not use 16340 (same thing, those are 3.7V cells)
How about CR123A Battery Dummy Cell “fake battery”
+2 “standard” 3.7v R123a rechargeable batteries?
8.4v to start and depending on your device voltage sensitivity might last OK until 6v. They should have a flatter discharge curve.
More capacity and cheaper. No special charger required if you have a stock lithium charger that would take that size.
Two with a “spacer” cell might be worth a try. Thanks for the suggestion. I was wondering if it would be worthwhile to try 2 18500’s if the battery tube would accept that diameter and the extra length (54mm x 2 versus 34mm x 3).
Back in the days when P60 format was popular, there were 17670 cells to replace 2xCR123A for lights battery tube too narrow for 18650s.
Additionally, I’ve old 17500 cells which are unfortunately now challenging to acquire, but might be the format you are looking for? Be aware that the Saft Lithium manganese and lithium thionyl cells are not rechargeable.
In my opinion, if you’re using lithium cobalt in series, they should be protected cells.
The dimensions of a CR123 battery are approximately 34 mm in length and 16.5 mm in diameter
Length: 33.4 mm to 34.5 mm
Diameter: 16.5 mm to 17 mm
CR123A batteries, have very similar dimensions, with slight variations: