The tester probably uses AC impedance test, that gives a considerable lower value than DC impedance/resistance test (Like I do in my battery test).
Yes it uses an AC algorithm to measure impedances, the way our systems are tested this is the only reliable method without disruption, it is also quick and convenient. It matchs the results of our BitBox testers also which iirc use a simple 50hz waveform but at much higher currents, not suitable for these small cells tho as the minimum AC current is approx 10a
Wow thanks for doing this!! I was suspecting the volt meter on my hobby charger was all off-whack. Its reading about .15V low. I never really thought to meter the thing while discharging.
These readings are much lower than the rest of the testers.
Yes IR & mAh
Please only use these results to compare within themselves. My capacity readings are inline with others but I terminate the discharge early. The impedance readings are measured with dedicated, calibrated machine, this gives lower results than hobby charger calculations etc. the AC current will also interact differently to the protection circuits I suspect.
OK a quick look at the protected Panasonics avalible from DX, ok lets compare with a unprotected version bought from HKE last year:
So that was the most recent discharge, they have done about 4 cycles now and have increased slightly, most noticably on the second discharge. The cells were charged on a WPII v2
Protected #1 started at 4.24v and gave 2414mAh (i think the high DC is because i topped the cell off from a very high state of charge already)
Protected #2 started at 4.19v and gave 2561mAh
Compare those results with the unprotected, charged on the same charger and discharged on the same Imax at the same settings, the difference is between 205mAh and 48mAh. I realise two cells is a very limited comparision but its 2 better than none ;)
If anyone has protected Panasonics from the other suppliers please feel free to post pics for comparision, as always please dont compare my results to others but only with my other results, thanks.
I tested these a lot in another thread and got higher mAh, to get the most out of them they need to be discharged to 2.5v i like 3 volt cut off as thats about the lowest most of my torches can go, but at 3 volt there is mot much of a gain over cheaper batteries. These have come a long way down on price and are more common now. Ive been noticing a little less mAh with protected batteries while discharging & higher internal resistance as the pcb uses power from the cell to run, but it looks like yours where the other way round. Very good batteries. But the protected ones i got preformed so bad i had to remove the protection, the batteries work really well now and the seller has corrected the pcb issue. Other wise ill post my results.
Hi Benckie, no that's the same as mine, slightly reduced power from protected version, as you say almost certainly down to protection PCB increasing impedance/consuming power. I was concerned they may be fake cells but they certainly appear and perform as originals. Where did you source yours?
It,s the same with all cheap protected cells Ive tested once Ive removed the protection they read lower internal resistance and a slight gain in mAh.
I brought them from IO the early protected ones and got poor results, I'm told the new ones with better PCB,s are good but i have not brought any more.
Here is the link to the old thread.
https://budgetlightforum.com/t/-/4557
My testing did not start till post #64 and you can see how much a bad or poor PCB protection circuit will affect performance. In case you don't want to read through it all ill post some of my results.
My tests before i removed the protection PCB,s
Cell A internal resistance 127 milliohms
Cell B internal resistance 129 milliohms
For the internal resistance test's you need to take into account the magnets i used on my charge leads and my soldering.
Cell A 3 amp discharge from 4.18 volt to 3.013 volt i got 1229 mAh.
Cell B discharged from 4.18v to 3.194 volt at 3 amps I was not even able to extract more the 1000 mAh.
With the bad PCB protection units removed i got
Cell A Internal resistance 103 milliohms
Cell B Internal resistance 98 milliohms
For the internal resistance test's you need to take into account the magnets i used on my charge leads and my soldering.
discharged from 4.18 volt to 3 volt @ 3amp 2485 mAh (averaged out over the two cells)
discharged at (1C) 3.1 amp to 2.5 volt 2876 mAh (averaged out over the two cells)
discharged at (2C) 6.2 amp discharge from 4.16 to 2.5 volt i got 2876 mAh
discharged from 4.15 volt to 2.5 volt at 0.5 amps 3020 mAh
discharged from 4.163 volt to 3 volt at 0.2 amps 3033 mAh
So in light current draw like 0.2, 0.5 amps there is not much difference from a discharging cut off between 3 volt and 2.5 volt, but at higher draw like 3 amp there is a difference thats is noticeable. Good cells if you get the genuine ones and or with good pcb's with at lest 2 mosfets.