Zebralight 18650 batteries

Hello,

I decided to try Zebralight 18650 batteries and bought the following ones:

a) the red battery, Sanyo NCR18650GA 3500mAh 10A 18650 Li-ion Flat Top, paid 6 USD (on sale);

b) the green battery, Sony US18650VTC6 3000mAh 30A High Discharge Flat Top, paid 6 USD (on sale);

c) Zebralight branded battery, ZL635 3500mAh 18650 Protected Li-ion Battery, paid 12 USD (on sale);







I have a lot of pictures but since I cannot post them on the forum I will mostly provide the info in the text form.

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First thing to check is the check of capacity. I used IQ338 XL and measured discharge capacities of each battery:




1) Sanyo NCR18650GA - 3260 mAh, internal resistance 32 mR;
2) Sony US18650VTC6 - 2899 mAh, internal resistance 44 mR;
3) ZL635 - 3361 mAh, internal resistance 33 mR;

I am pretty confident that my IQ338 XL measures the capacity correctly, I have another charger (MAHA C9000) and in the past I measured the capacity of other batteries on both charges - they matched.
Another thing I was interested in is the voltage drop under the load (the current is 1A). I made a small rig to measure the voltage correctly, there is the picture:



1) Sanyo NCR18650GA, Voltage without the load: 4.173V Voltage under the load: 4.013, current: 0.965A;
2) Sony US18650VTC6, Voltage without the load: 4.182V Voltage under the load: 4.072, current: 0.946A;
3) ZL635, Voltage without the load: 4.174V Voltage under the load: 4.044, current: 0.972A;

to be continued;

Realistically, I doubt you would notice any visible difference in output between those readings.

stephenk said:

Realistically, I doubt you would notice any visible difference in output between those readings.

Click to expand...

Sorry, I did not respond earlier, a recent snow storm made a lot of damage and the Internet was not available for several days.

Actually the only reason I bought these batteries is because I was reading the forum and saw a lot of people saying how bad are the old batteries from old/used notebook battery packs.
I did not have any previous experience with 18650 batteries so I had to start from something. I had 2 notebook battery packs, one (8 SONY US17670GR FUKUSHIMA) I bought with a SONY FX501 laptop in 2000 and another is a ThinkPad (6 US18650GR) battery pack from 2006.

SONY 18650 (yes, 19 years old) batteries were laying fully discharged for 5 or 6 years, when I looked at them, the voltage was close to 0 and I had to boost it with the some external power to make the voltage be about 2.5V - from this moment IQ338 XL started charging them without any problems. Average discharge capacity is between 0.9A -1A, the resistance is between 45-90 mR, voltage drop about 2.5 volts under the 0.9A load and drains fast.
When the load is removed the voltage slowly climbs up i.e. the voltage drop is a serious issue for high current drain usage. But other than that the batteries are pretty usable, I will use them to power low current electronic devices.

US18650GR (13 years old) batteries are much better, the discharge capacity is between 2.1A - 2.3A, the resistance is between 45-80 mR, voltage drop about 1.5 volts under the 0.9A load. I used those batteries in the H600c Mk IV 18650 XHP50.2 4000K, they worked OK in low current drain modes.

So, the people on forum were saying that they would charge their 18650 and check every week the batteries voltage and if it would drop like 10-100 millivolts over a week they would consider that battery to be bad and stop using it. This makes sense to me only in case if one uses those batteries in life critical situations (speleology / caving / tec). Thus I decided to get the best Zebra branded batteries and compare them with those what I already have. Obviously, the new batteries are better, I got them for cheap (since they were on sale) but I did not see an astonishing difference and that is my point.

May be if admin is reading this post he can move the topic to "Flashlight Electronics - Batteries Included" since looks like, initially I have chosen wrong section.

Moved.

Also, you can post pics via a photo hosting site and the insert image buttons in the post editing window.

h17 said:

1) Sanyo NCR18650GA - 3260 mAh, internal resistance 32 mR;
2) Sony US18650VTC6 - 2899 mAh, internal resistance 44 mR;
3) ZL635 - 3361 mAh, internal resistance 33 mR;

Click to expand...

The capacity numbers are probably in the right ballpark, but don't rely on those internal resistance numbers at all. Most chargers give wildly inaccurate values for internal resistance. For example, the VTC6 should have less IR than the GA cell, and your voltage sag values confirm that.