Testing Li Ion NP-F970 batteries

[tonygamble]

I added this later.

EDIT. I have just looked at the Imax manual. It says the maximum discharge cannot exceed 1C. Can I up my setting to 7.2 if it goes that high?

??

Tony

 

[apagogeas]

You can surely set it to pump in the maximum iMax can offer which is 6A I think, this will automatically get lower by the charger if the pack cannot accept that high amount of current. You'll notice that by observing iMax showing 8.2V in the LCD and try to adjust to Amps so not to raise the voltage - if the pack can accept that amount of A, the voltage will be lower to this 8.2 limit. No reason to go that harsh really. 2-3A is plenty anyway. I hope you have set it to charge Li-Ion, not the default LiPo!

 

[tonygamble]

You can surely set it to pump in the maximum iMax can offer which is 6A I think, this will automatically get lower by the charger if the pack cannot accept that high amount of current. You'll notice that by observing iMax showing 8.2V in the LCD and try to adjust to Amps so not to raise the voltage - if the pack can accept that amount of A, the voltage will be lower to this 8.2 limit. No reason to go that harsh really. 2-3A is plenty anyway. I hope you have set it to charge Li-Ion, not the default LiPo!

Are you talking about discharging? That was my question.

Yes I am on Li Ion.

My concern is to get a discharge rate that I can monitor. Seven/eight/nine hours is useless if I am not supposed to leave the cell unattended.

Of my ten cells two register less than 8 volts when charged. On what you say above these must be suspect. I now want the Imax to tell me what they hold in terms of mah. The settings I need are what I'd love to hear from you.

Tony

 

[apagogeas]

You can't discharge more than 1A (iMax B6) or 2A (iMax B6 mini). These ratings would be easily handed by NP-F. My answer was for charging (6A). I do all my tests only at 1A (the maximum) to be comparable among the batteries I test and the fastest possible. Those lower than 8V are indeed suspects, definitely they are past their prime time. They may serve well for now but I expect you'll start noticing reduced running times.

 

[CuriousOne]

Built-in overcurrent protection in F970 will trip approx at 3-4A discharge current.

 

[tonygamble]

Just a note to say I am making good progress testing all my 11 packs and I will report when I finish.

In the meantime a comment about the B6AC Pro. It is programmed to stop charging after 7,000 mah. I have one pack rated at 8,900 mah and it only discharged it by 7,000 mah. I should have reset the discharger to see what else it took from the pack. I didn't because I was not thinking clearly but I will do next time.

Watch this space. Fascinating to see how these packs vary.

Tony

 

[apagogeas]

Post your findings when you have them. On my end, I have removed all the cells from this pack to test them individually. 3 cells were at 0-1V, didn't bother to even attempt to charge/discharge for safety reasons and they are ready to recycle. Two cells can deliver around 1.8Ah and the other around 1Ah as tested by Liitokala. Both sets of cells had at least one dud cell in parallel. Unfortunately, there is absolutely no indication/code of the type of cells.

 

[tonygamble]

I'm posting a spreadsheet below that shows the results of my test of 15 NP-F*** batteries

Column 1 is a three digit number that I have given to each pack.

The letter that follows shows "D" for the DSTE batteries that come through Amazon UK. I started with six of them but was uncertain that two were working properly. This stimulated this whole testing. It turned out that two had failed. In fairness to the vendor I do report that he immediately replaced them foc. The vendor is QiaoJL - a fair trader!!

Batteries marked "G" came with two of the Godox 500 LEDs that I bought on eBay from China. They seem quite reasonable and I cannot put a price on them as they were part of the deal.

Those marked "X" come from Ex Pro. The one priced at £33.37 is larger than all the others in dimension. And it is far an away the one with
the biggest capacity. In terms of value for money their NP-F960 comes out top. That is pack 248. Why 247 costs £7 more and has a lower mah
rating I cannot tell. I will test the two again and come back if I find my figures need transposing.

The next column along is the voltage reading of each fully charged pack. This was done with a voltmeter that applies load whilst making the reading.

The next column is the mah rating on the bottom of the battery.

The next column is the mah reading obtained by discharging the batteries with my Imax B6AC Pro charger/discharger. What this proves is what people were saying when this thread was running and that is that any battery showing less than 8.0 volts fully charged is probably faulty or failing. Why 243 shows its figures I cannot say at the moment.

The final column is the price in UKP.

If anyone has any comments or observations please let me know.

Tony

236	D	8.31	7900	6394		19.66
237	D	7.87	7900	1570		19.66
238	D	8.31	7900	6315		19.66
239	G	8.38	6000	5964
240	G	8.01	6000	6031
241	D	7.78	7900	799		19.66
242	D	8.26	7900	5165		19.66
243	D	8.15	7900	4841		19.66
244	G	8.33	6000	6134
245	G	8.3	6000	6121
246	X	8.26	8800	9367		33.37
247	X	8.33	8800	7410		27.97
248	X	8.31	6500	7474		20.97
249	D	8.29	7900	6345		19.66
250	D	8.27	7900	6241		19.66

 

[CuriousOne]

Excellent results, but to properly evaluate them, it would be better if you'd give us also a number, how many times approximately each pack was charged-discharged, before doing the tests.

 

[tonygamble]

Up to 245 about six times.

The others are new. Out of box effectively.

Tony

 

[tonygamble]

Another observation.

If you use a charger like this Ex Pro one with the LED display you will usually find that failing batteries never complete the 100% cycle. Good batteries fill to 100% and the LED continues to show it. Weaker batteries fill to 90% and the LED turns off.

http://tinyurl.com/y98u2m26

Tony

 

[apagogeas]

Indeed very good results overall Tony. For a starter I have learned that ExPro makes very good and cheap batteries, never heard of that brand before, now I know where to go to get such batteries!
Your table also generally shows that mAh exaggeration as illustrated by DSTE batteries. The outstanding exception here is your ExPro, especially #246, did it really return 9+Ah?? or is this a typo! Also G brand (if you can find out what it is) is also very good and consistent.
Now, I am a bit surprised by pack #240 which actually returns full capacity even starting at 8V instead of 8.3+. I can't make this out, doesn't make sense since all other G brand packs return about the same capacity and start from 8.3+V. Even worse than your #243 observation is the comparison of #242 & #250, for virtually no difference to the starting voltage there is 1 Ah capacity difference. I believe the situation here is some capacity loss overall in all the cells of packs #242 & #243 with a slight imbalance. It does look like DSTE is not that good as I used to believe, it has both exaggerated mAh and inconsistency among the packs. One of my failing packs here is also a DSTE.

 

[tonygamble]

Indeed very good results overall Tony. For a starter I have learned that ExPro makes very good and cheap batteries, never heard of that brand before, now I know where to go to get such batteries!
Your table also generally shows that mAh exaggeration as illustrated by DSTE batteries. The outstanding exception here is your ExPro, especially #246, did it really return 9+Ah?? or is this a typo! Also G brand (if you can find out what it is) is also very good and consistent.
Now, I am a bit surprised by pack #240 which actually returns full capacity even starting at 8V instead of 8.3+. I can't make this out, doesn't make sense since all other G brand packs return about the same capacity and start from 8.3+V. Even worse than your #243 observation is the comparison of #242 & #250, for virtually no difference to the starting voltage there is 1 Ah capacity difference. I believe the situation here is some capacity loss overall in all the cells of packs #242 & #243 with a slight imbalance. It does look like DSTE is not that good as I used to believe, it has both exaggerated mAh and inconsistency among the packs. One of my failing packs here is also a DSTE.

Ex Pro are a Brit company based in the north of England. They sell direct and thru Amazon. I have retested batteries 247 and 248 and still the cheaper one produces a slightly better result. 7417 mah this time.

The Ex Pro that produced 9,367 is 50% larger than all the other batteries. Maybe it contains more cells. I would not buy it again as the others are plenty good enough for me and the extra weight may be a bit too much for the fitting that holds these batteries into the lights.

The G brand came from Eachshot (again via Amazon). This is similar to the battery in looks but mine do say 6,000.
http://tinyurl.com/ydebu9t5

242 I am testing again. 243 has just been re-tested and was 4,841.

250 I will test again.

Ex Pro clearly gets my vote and for those who don't want to go through this detail of testing I repeat the comment that their top level charger spots the ones that will not read 100% - and those are the weaker batteries when tested.

DSTE I will not be buying again.

I am glad you found the stats interesting.

Tony

 

[tonygamble]

Just a note to say that I tested 246 again and it came in at 9326.

My discharger says it is two cells and not three as I suggested.

I have now tested all the batteries for my Oly E-M5 and am starting to look at the ones I have for my Godox flash units which are in the 11 v range.

Tony

 

[Gauss163]

Beware that generic / fake camera battery packs can be extremely sketchy, e.g. behold the Frankenbattery below excerpted from a Youtube video teardown of a fake Sony NP-F970 videocam battery. What a piece of work, eh? Caveat emptor!

 

[Gauss163]

I agree with earlier remarks that the cells that don't fully (dis)charge are likely due to highly unbalanced cells. Since your packs are "new" either they were not balanced well at the factory, or they were assembled with mismatched recycled cells (as in the above Frankenbattery). Most likely it is the latter. But if it's the former then you can open them and manually balance them and they may perform well after that (as reported with some unbalanced 9V PP3 2S Li-ion batteries).