18650 Current draw test

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357mag1

Enlightened
Joined
Nov 21, 2009
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677
Location
Chesapeake, VA
I have an MKN SST-90 flashlight that draws right around 3 amps of current at the tailcap with IMR 26650 batteries. I decided to see how my 18650 batteries would act under this fairly high current draw.

Here are the tailcap amperage readings from multiple tests (about 5-7 per battery). All numbers were recorded where the batteries seem to settle out after a few seconds.

IMR 26650 4000mah (2 tested) - 3A (4.04v)
IMR 18650 1600mah (2 tested) - 3A (4.0v)
AW 18650 2600mah protected (2 tested) - One at 2.7A and one at 2.8A
Ultrafire 18650 2600mah red protected (6 tested) - 5 between 2.58 and 2.62A one at 2.3A
Ultrafire 18650 3000mah protected (2 tested) - 2.35A (2.12A and 3.7v)
Tenergy 18650 2600mah protected (2 tested) - 2.62A (3.8V)
AW (DLG) 17650 1400mah unprotected (1 tested) - 2.7A
AW 17650 1600mah protected (1 tested) - 2.7A
AW 18500 1600mah protected (2 tested) - One at 2.55A the other 2.65A
IMR 18500 1100mah (2tested) - 2.9A
Ultrafire 18350 1200mah unprotected (6 tested) - 2.3A to 2.44A (3.7 to 3.8v) higher volts delivered more current.
IMR 16340 550 mah (6 tested) - 2.65A - 2.72A (4.0v)
AW 16340 Lifepo4 500mah - High mode of light drew about 20ma and was very dim but worked fine in med .88A and Low .27A modes.
AW (DLG) 14500 700mah unprotected (2 tested) - 2.2A (3.78v)
AW 16340 750mah protected (5 tested) - 2.2A (3.78v)
Ultrafire 16340 880mah (3 tested) - 1.85A (3.6v)
Battery Station 900mah (3 tested) - 1.44A, 1.48A and 1.64A (3.5v)

All batteries were almost new with very few hours on them.

Hope people find this half as interesting as I did taking the readings.
 
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Hello 357mag1,

In general, the lower the current draw the higher the voltage of the cell under load.

In this case the Ultrafire 3000 mAh is being loaded at about 1C and seems to be holding the highest voltage under this load.

At the other end of the scale the IMR 1600 mAh cells are being loaded to almost 2C and have the lowest voltage under this load.

Tom
 
But isn't this MKN SST-90 light direct drive? Thus, if a cell delivers higher current, it means its voltage under load sagged less and was thus higher than some other cell that delivered less drive current to the SST-90.
 
Looks like SilverFox is not knowing that the MKN SST-90 is a direct driven device.

Bill
 
Silverfox,

While I know electronics pretty well (been doing it for 30 years) I do not know flashlights that well. They are a fairly new hobby for me. I do think you need to look at the fact the IMR 26650 rated at 4000mah managed 3A and the only other cell to do so was the IMR 18650. Next closest was the IMR 18500 so I think this test is proving which cells are better at high current draw.

I am out to sea right now or I would repeat the test and borrow another top quality DVM to measure voltage at the same time I'm measuring current. You have me curious so I will add voltage readings in a week or so when I get back.

I will say I have tried the IMR cells in several higher current draw lights (M1X, M21, and TK30) and noticed the current was always lower with the IMR cells. I came to the conclusion then the regular AW cells were able to provide all the current needed for regulation and the IMRs must be sagging less under load explaining the lower current draw.

While testing batteries in the MKN light it was bezel down on the table so I can't comment on relative brightness between batteries. I could just see light peaking around the crenelations making it hard to compare brightness except in the case of the LifePo4 cell which barely gave an output on high.
 
Hello 357mag1,

Float safely out there... :)

I think when you add voltage measurements things will sort themselves out.

The IRM cells are very good. The voltage under load is a function of cell design. Cells designed for high currents tend to hold higher voltages under load.

On the other hand, the harder you drive a cell, the lower its voltage under load will be. Also, in a direct drive light, the higher the voltage the brighter the light should be.

I look forward to your further testing.

Tom
 
Thanks for the clarification. I got a bit confused as KD doesn't say those 18350s were protected, whereas some sellers on ebay claim that those same cells were protected. thus I thought there were more than one variation of the 18350s.

I'm still skeptical about those 18350s, is it really a different type of cell to the 16340, or is it just a 16340 "dressed up" to look bigger while offering no increased capacity?

Anyhow, even if its just cosmetic and offers no increased capacity to 16340s, I need them to better fill up a Solarforce L2P body, believe it or not but a protected AW18650 2200mah looks kinda undernourished in there...:duh2:

357mag1 said:
Yes, as those are the only 18350s that I'm aware exist. Battery Junction has them for a decent price.
Click to expand...
 
Fusion_m8 said:
Thanks for the clarification. I got a bit confused as KD doesn't say those 18350s were protected, whereas some sellers on ebay claim that those same cells were protected. thus I thought there were more than one variation of the 18350s.

I'm still skeptical about those 18350s, is it really a different type of cell to the 16340, or is it just a 16340 "dressed up" to look bigger while offering no increased capacity?

Anyhow, even if its just cosmetic and offers no increased capacity to 16340s, I need them to better fill up a Solarforce L2P body, believe it or not but a protected AW18650 2200mah looks kinda undernourished in there...:duh2:
Click to expand...

These 18350s are unprotected and they do have roughly 250mah more capacity than an AW 16340. Filling up the extra space is the main reason I bought these 18350s in the first place. They do that well but are a little longer which makes them a tight fit in some flashlights. I have dimpled the negative end of the battery in slightly on some due to how tight they fit length wise. Now if AW would produce this size in IMR I would be vary happy.
 
Updated the original post with more batteries and some voltage readings. I was surprised the IMR 16340 was able to hold 4 volts for the 30 seconds or so of the test with no problem. The IMRs have proved without a doubt they sag less under voltage to me.

If you notice the lower amperage readings with the Ultrafire 3000mah cells they were not able to match their current readings from the initial test. These cells are less than 6 months old (bought from Battery Junction) and have never been discharged below 4 volts when removed from the load. In fact they have been used only intermittently to show off some lights to friends and family. The first test must have stressed them out as now they will not charge above 3.165 volts. They were only in circuit for approximately 30 seconds at a time and tested 7-10 times so may have a total of 5 minutes use. In both test series I kept putting them in the charger to make sure they were provided the best chance to perform. In the first test they were charging to 4.20 volts.

I included the two worst batteries in my inventory the Ultrafire and Battery Station 16340s. Two samples of Ultrafire and six of Battery Station all quickly drop to or below 4.10 volts after being removed from the charger. As you can see they produce the least current and sag the most under load both here and in tests done which required much lower current draws. I would avoid these batteries.
 
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I must have a good batch of UF 3000mAh 18650's then.

Charged and tested six UltraFire 3000mAh, 18650's yesterday afternoon. Resting an hour after charge, voltage readings were:

4.24V, 4.23V, 4.20V, 4.22V, 4.22V, 4.22V.

:thinking:

Just tested:

This morning, I took a tailcap reading while 1X18650 was installed in a JetBeam Jet-III M: 1.01A @ 4.19V. Resting voltage after yesterday's charge: 4.22. Resting voltage after today's test, 4.22V.

:confused:

Checked the tailcap reading of a JetBeam M1X, with UltraFire, 3000mAh, 2X18650's installed: 1.66A @ 8.26V.

The resting voltage yesterday, after one hour charging rest: 4.24V and 4.23V. The resting voltage after test, 4.17V and 4.17V.

Just checked the tailcap reading of a JetBeam RRT-1 with UltraFire, 3000mAh, 1X18650 installed:

The resting voltage yesterday, after one hour charging rest: 4.20V. The resting voltage this morning, before test, 4.20V.

Tailcap reading: 1.01A @ 4.12V. Resting voltage after test, 4.19V

Life really sucks when it seems that you're the only one at the party, skewing the averages.

:naughty:

And for the sake of argument, I have two Pila IBC chargers ordered up from Bug Out Gear, sixteen TrustFire, True 2400mAh, 18650's on order from DealExtreme and sixteen more UltraFire 3000mAh, 18650's and another cheap charger on order from DinoDirect. All batteries will be logged in with a charging number so I can easily keep track of this herd of batteries. I wonder how much Cadex wants for a Cadex C5000 battery analyzer?

:confused:

Just putting my money where my questions are.

:cool:
 
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I would like to see that 4.19v under a load. I do not believe it and it brings into questions all the rest of your data.

Enjoy your ****fire batteries. Hope they work better for you than they have for me. I'm not brand loyal, everything is based on test and experience.
 
BeeMan458, I do not know how you are testing for voltage under a load but these voltage readings should be much lower than you posted. What is your method for testing voltage under a load?

Bill
 
I would like to see that 4.19v under a load. I do not believe it and it brings into questions all the rest of your data.

There's no need to call me a liar. I posted the load data and the V's while under a load. The data is good, even if it doesn't meet your bias'd expectations.

:thumbsup:
 
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BeeMan458 said:
I would like to see that 4.19v under a load. I do not believe it and it brings into questions all the rest of your data.

There's no need to call me a liar. I posted the load data and the V's while under a load. The data is good, even if it doesn't meet your bias'd expectations.

:thumbsup:
Click to expand...

He is not calling you a liar, he does not believe the data. Big difference.

Bill
 
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