4.5V from an RCR123? Really?

[fyrstormer]

I just tested one of my AW protected RCR123s, which has been sitting on a shelf for a few days since last being charged, and the voltage reading was 4.5V! That doesn't seem right. Anyone know where the extra voltage might be coming from?

 

[gswitter]

Maybe an inaccurate meter?

 

[fyrstormer]

Maybe an inaccurate meter?

It's reading my unprotected RCR123s at 4.2V, give or take a couple hundredths. I don't think it's the meter.

 

[kramer5150]

I have had old meter probe cables play tricks on me and cause all kinds of strange readings.
What charger are you using? Some versions of the the WF-139 (for example) overcharge and do some very strange things with protected cells.

 

[Ray_of_Light]

To me, it seems the combined effect of a defective protection PCB and the use of a pulsed charger.

Some defective protection PCB resets without the application of a load, when the charging voltage falls below 4.3 V. The defect is not apparent in normal usage of the battery.
When this defect combines with a pulsed charger, the result is what you got.

Anthony

 

[AW]

Try with another meter to see what you get. Most likely you have a depleted battery in your meter.

 

[45/70]

Try with another meter to see what you get. Most likely you have a depleted battery in your meter.

I would try another meter, as AW suggested, but I'm more inclined to go along with Ray's scenario. When a meter's battery goes south, it's true they can be way off, but they are usually fairly consistently so. If fyrstormer is getting consistent ~4.20 Volt readings of the rest of his charged cells, I'd say the one reading 4.50 Volts is overcharged. Either that, or his cells that are reading 4.20 Volts, are in really bad shape and are actually ~3.90 Volts when fully charged. I think he'd notice if the other cells were that bad, as their overall performance would be noticeably poor.

fyrstormer, if your cell really is charging to 4.50 Volts, you need to invest in another charger. The one you have has the ability to kill cells in short order, particularly unprotected cells, and it's a potential safety hazard anyway. :shakehead

Dave