AW IMR difference in Pila vs UF-139

[Joe Talmadge]

Hi, I have a Pila IBC and UF-139 charger. I just got two AW IMR 16340s. I put them in the Pila first, and since they're too small even with the screwed-in spacers, I took the two aluminum spacers I usually use in my UF-139 and used them too. So it was battery, then aluminum spacer, then Pila screwed-in spacer. The Pila thought both batteries were already fully charged. Then I put the batteries in the UF-139 with just the aluminum spacers, and the 139 charged them up for a while (not too long, but it obviously thought it needed to top them off).

Alas, I don't have a multimeter, do plan to get one, but am wondering if there's an obvious explanation for this. Could it be that in the Pila, two sets of spacers add so much resistance that it cuts of at a lower voltage, versus in the UF-139 with only one spacer the batteries charge up correctly. Alternatively, could it be that the Pila is correcting stopping the charge at the right time, and the UF is getting fooled by the IMR's lower resistance and topping the battery off to the detriment of the battery?

I realize that until I get my multimeter I won't know the correct explanation. I'm hoping that I understand the basic concepts well enough that I came up with two reasonable explanations. Anyone have personal experience that leads them to believe one over the other?

edit- just thought of another explanation, which is that I misread the meaning of the lights on my (brand new) Pila. Will need to go over the manual again.

Thanks,

Joe

 

[45/70]

I don't really know Joe, but I expect the difference you're experiencing is, at least in part, due to the two chargers using different algorithms. The Pila uses close to an ideal algorithm, and the UltraFire, one that is full of compromises, but seems to work, sorta.

The resistance difference, using the spacers, may come into play, but I've always thought that resistance doesn't have as much of an effect when charging cells, as discharging. Still, that may be part of it.

CPF member #20. I'm duly impressed! :thumbsup:

Dave

 

[LitFuse]

I don't know what the answer is, but did you try pushing the reset button on the charger while the batteries were installed?


Peter

 

[Joe Talmadge]

Dave: here's the funny part, I may indeed be CPF member #20, but I have no idea how you know that

LitFuse: I did not. Will give it a try next time I see this happen.

Thanks!

Joe

 

[rookiedaddy]

Dave: here's the funny part, I may indeed be CPF member #20, but I have no idea how you know that

by pointing to your user name? http://www.candlepowerforums.com/vb/member.php?u=20

 

[Joe Talmadge]

Heh, thanks. Years ago member number used to be displayed right under your name. I don't recall being quite so low in the membership, I would've thought I'd be in the 50s at least, since I lurked for quite a while before joining. Maybe if stale member numbers get flushed people shift downwards, or maybe I just am misremembering

 

[45/70]

Your "Join Date: Aug 2000" is what tipped me off.

Did you try the reset button on the Pila? I don't have a Pila, as I've had a YOHO-122 for about 5 years, but I am curious.

Dave

 

[Joe Talmadge]

I didn't try that yet, because I charged both batteries up in the 139 and now they're in use, so both are depleted somewhat. Next time I charge them up, I might deplete them slightly and then see how both chargers behave. Hopefully by then I'll have a cheap multimeter too so I can check the voltage on the cells