semi-annual battery test

Once or twice a year I take all my batteries in use and run them through a discharge test on the hobby charger. I must be hard on them since some of them are half of their original capacities.

I won't bore you with a spreadsheet but here are some of my observations based on the numbers for 18650 batteries only:

  • The cheap brands like Trustfire (flame) 3000mAh (originally tested at ~2600mAh) now all have really high resistance with just 18 months of use. Some of them will pop right away on the hobby charger within a minute at 1A discharge set to 2.9V from 4.2v. 6 cells tested with varing but similiar results. Even though their performance was up to par when first purchased, they definately don't last. Needless to say that it'll be the last time I buy these budget batteries.

  • Panasonic 3100s/3400s and Sanyo 2600s (6 batteries) that are dedicated to high current torches (>4A) tend to wear alot faster than batteries used in 3A or less torches (7 batteries). 13 batteries in total.

  • The high current batteries (IMRs - 4 tested) tend to fair better in terms of wear and tear. They have all kept at least 80% of their original capacities compared to ICR batteries (ICR - 13 batteries tested) that are now 50-75% of their original capacities.

Even though the # of batteries tested isn't enough to paint an accurate picture, these numbers are consistent with what we know of them. The numbers itself, especially the remaining capacities are a little alarming. At this rate, I'll have to junk 1/2 of my batteries every 12 to 18 months if my cut list is 60% of the original capacity.

What are your findings? Like to share?

EDIT - spelling

How much use/cycles do you think those batteries have gone through?

Even if you have to junk them every year it’s still far cheaper than Alkaline. Though 12-18 months seems a bit crazy. I’ve had the stock nitecore 2300mAh 18650’s that came with the mh40 thor for around 3 years iirc. They still hold more than enough to last an entire 6-10 hour night fishing trip (which is all I need).

If I were to guess...after 18 months, average 20-30min use per cycle...

  • 6 Panasonic 3100s/3400s and Sanyo 2600s (used in high current >4A) - 10 cycles
  • 7 Panasonic 3100s/3400s and Sanyo 2600s (used in high current =<3A) - 20 cycles
  • 2 Panasonic IMR batteries - 20 cycles
  • 2 Moli IMR batteries (pulled from 2 year old cordless drill) - 20 cycles
  • Trustfire (flame) 3000mAh - 20 cycles

LOL - sorry don't mean to alarm you!

The numbers are exagerated due to the poor Trustfire 18650's results. If we take those 6 failed Trustfire's out of the equation then we get 20% of the premium batteries failing the 60% capacity cut list and not 50% of the batteries.

I also have one bad battery, trustfire flames 2600 from 2009.
One has still 19xxmAh(that’s about the same as new) and the other one has 1300mAh on 1A discharge and gets warm while this…high resistance

Not sure why one is so much worse…
I used one in a tr801 with low load and the other one in a p60 with a P7(LOL a p7), so maybe the p60 one got warmer and had more drain…

similar goes to my batteries for bullet point 1. 3 out of 6 TF flame batteries already can’t retain the high voltage in storage.
as for point 2, I also use for that particular condition. however the cycle is still less than 10 and usage about 6 months. haven’t notice any significant drop yet.

Thanks for posting.

What kind of currents do you run your IMRs at? And whats their capacity so we can figure the C rate.

The last trustfire flames I bought about 2 years ago from a very reputable dealer, would not even supply 3 amps without going under 3v. Couldn’t even run a discharge test with them set as a lipo under a 3amp load. The charger kicked the batteries as soon as the voltage dropped below 3v which was all of a second or two. Could have run a Nimh discharge test on them, but figured what was the point, they had already proven to me they where crap batteries to me. The older flames (4 to 5 years ago) to me where a very good budget battery with decent performance. But the newer ones I bought where crap. With the price drop of quality batteries in the last year or two, I only buy quality batteries and have never looked back.
Not bashing trustfire, to each there own. Just stating my past experience with them.

I like having this kind of data, which hobby charger do you use?

How do you store em bigwood? temps and charge?

Which TF flame, the 3000 or 2400?

I agree with OP on the TF 3000, it drops performance very quickly within a year. I’ve been mentioning this on several posts before as well. I only have 2 and no longer bought any more after a few months run, not worth it.

But I’m not seeing this trend on my TF 2400s, they seem to perform quite well, even newer ones. Well, except the Dino Rechaigealle Balleiys version, of course. :wink:

Thanks for posting your findings, it’s very interesting to see that the discharge rate has an effect on lifetime as well. Do the ones used in >4A torches with about 10 cycles now have lower capacity than the ones used in =<3A torches with 20 cycles? I would be interested to see some more detailed numbers.

I’ve also been wondering whether the charging rate has any effect on lifetime. Any ideas or data on that?

2400mah flames from KD.