Vappower Green 35A 2500mAh 18650 Bench Test Results...a 20A battery, no higher

[Mooch]

Tested at 10A-25A constant current. This cell was purchased by a friend from IMRBatteries and donated for testing. To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18650, 26650, etc.


Disclaimer
The conclusions and recommendations I make based on these tests are only my personal opinion. Carefully research any battery you are considering using before purchasing.

Testing batteries at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them. My safety precautions are the ones I have selected to take and you should not assume they will protect you if you attempt to do any testing. Do the research and create your own testing methods and safety precautions.




Bottom Line
In my opinion, this is an average 20A continuous discharge current (CDR) cell that almost exceeds my temperature safety limit at 25A. I recommend not using it above 20A.


Test Results



Comments

• At 10A it reached about 2400mAh. This is pretty good performance for a 2500mAh-rated cell.
• At 20A the maximum temperature reached 83°C. This is the highest temperature I'll accept for a cell operating at its CDR. It is several degrees above the 25R but the same as the HG2 and 30Q.
• At 25A the temperature rose to 96°C. That almost reached my 100°C safety limit and is way too hot to operate a cell at.
• Five additional cycles at 20A showed only the normal loss in capacity resulting from operating a cell at its CDR.
• Discharges at 30A and 35A were not done because the temperature would exceed my 100°C safety limit, dangerously high.
• I am setting a CDR of 20A for this cell. While operating any cell near its rated maximum current causes damage to the cell, I would expect good cycle life from this cell at 20A. I would not recommend operating this cell above 20A due to the very high temperature.
• To see how other cells have tested and how hard you can safely push them, check out the links in my signature.

 

[State O' Flux]

Know what I find interesting brother Moochy...

That every cell on your chart (save for the ones that are rated below 15A), will safely make 15A. Nine will make 20A safely, and with the exception of the HB6, none will go beyond 25A without getting a caution or fail.

Another item worth noting, all the batteries that have a mfg. advertised rating above 30A (the first 6 and 2 in the bottom)... none safely reach the 30A or higher mark. So much for truth in advertising, eh?

I wonder, considering that only 1 out of 32 cells makes 25/30A safely... is the HB6 you tested a freak of manufacturing tolerance? Any chance of obtaining a few more, preferably from different lots (if one can tell such a thing), and doing a retest, to see if the values obtained were/are consistent... or a fluke?

Cheers,
CAH

 

[Mooch]

Know what I find interesting brother Moochy...

That every cell on your chart (save for the ones that are rated below 15A), will safely make 15A. Nine will make 20A safely, and with the exception of the HB6, none will go beyond 25A without getting a caution or fail.

Another item worth noting, all the batteries that have a mfg. advertised rating above 30A (the first 6 and 2 in the bottom)... none safely reach the 30A or higher mark. So much for truth in advertising, eh?

I wonder, considering that only 1 out of 32 cells makes 25/30A safely... is the HB6 you tested a freak of manufacturing tolerance? Any chance of obtaining a few more, preferably from different lots (if one can tell such a thing), and doing a retest, to see if the values obtained were/are consistent... or a fluke?

Cheers,
CAH

Yea, so far the rewraps are not doing well, ratings-wise, in my tests.
I think the SX22 is the only one that met its rating.

Of all the cells I've tested so far, the HB6 is the only one definitely rated at 30A by the original manufacturer of the cell. For me, the test results to date fit in well with this. While it's certainly possible that the HB6 I tested was a fluke, I tend to think not. Quality control and consistency are very tight on the cells from Panasonic, LG, Sony, and Samsung. And the HB6 does test out to its rating no better than a 25R tests out to its rating. Or any or other battery from one of those four manufacturers.

The HB6 is also only one of a couple of cells that has a low capacity, allowing LG to design it for low internal resistance and high current delivery. The Sony VTC3 also has a low capacity rating and does come close to being a 30A cell.

But, I do have another HB6 I can do a quick test at 30A with. Probably the same batch though as they were purchased at the same time. If someone wanted to buy an HB6 and donate it to the cause, I'd be happy to test it. I'll post the 2nd HB6 test results when I do them.

Just a side note...
There is another 30A-rated cell by one of the Big 4 manufacturers available...the HB2. I'll be testing it soon. And the AW 1600mAh that's in testing now is definitely in the 25A range.

One last note...
The safety grade chart is great for quickly sorting out cells but assigning a grade to each cell does have a down side. A cell might only be 1°C hotter than another cell that has a Pass grade. But that additional 1°C could force it to be graded with a Caution. The two cells could be essentially the same. But charting them forces cells to be split into categories that can make them seem further apart in performance that they might be. Unfortunately, I can't see any way around that unless I have additional grades and/or test at additional current levels. Frustrating...

 

[State O' Flux]

One last note...
The safety grade chart is great for quickly sorting out cells but assigning a grade to each cell does have a down side. A cell might only be 1°C hotter than another cell that has a Pass grade. But that additional 1°C could force it to be graded with a Caution. The two cells could be essentially the same. But charting them forces cells to be split into categories that can make them seem further apart in performance that they might be. Unfortunately, I can't see any way around that unless I have additional grades and/or test at additional current levels. Frustrating...

This last is interesting. I agree that those looking only at the chart... may not take the time to read the full test report on a specific battery, but simply trust "The Chart" to tell them all they might need to know.
.
Perhaps on those cells that are on the ragged edge of making a higher (or lower) grade, you could add another asterisk or notation below the chart (as you have now), indicating it as such... so that a cell just 1°c away from making a grade would be put into consideration for an acceptable discharge slightly below that higher grade.

 

[Mooch]

This last is interesting. I agree that those looking only at the chart... may not take the time to read the full test report on a specific battery, but simply trust "The Chart" to tell them all they might need to know.
.
Perhaps on those cells that are on the ragged edge of making a higher (or lower) grade, you could add another asterisk or notation below the chart (as you have now), indicating it as such... so that a cell just 1°c away from making a grade would be put into consideration for an acceptable discharge slightly below that higher grade.

That could work...
It's worth taking another look at. I've been avoiding it up to now so I could see if it was going to be a problem or not. It would be nice to have some way to "fuzz up" the safety grading limits. Don't want to make it make it a more complex table though. Just having more than Pass/Fail already has made it pretty complicated for some folks new to vaping and battery safety. Thanks!

I'll be able to squeeze in that HB6 test on Friday.

 

[State O' Flux]

I know how you feel. You've done so much already, and the majority are as thrilled as a bathtub full of otters to have all this objective data available (finally), but... there's always a "but", isn't there?

You can leave it totally as is, and I can't imagine anyone dumb enough to complain, but (there it is again)... when you can see yourself, the "little issues" that you'd like to clarify, and knowing that you are as much a detail freak as I am (at least that)... then you just can't leave it as is, for long.

Anyway... do what you do. The only one that could possibly expect more, is you.

Hugs n' kisses

 

[Mooch]

Awww...shucks.

Know what I find interesting brother Moochy...

That every cell on your chart (save for the ones that are rated below 15A), will safely make 15A. Nine will make 20A safely, and with the exception of the HB6, none will go beyond 25A without getting a caution or fail.

Another item worth noting, all the batteries that have a mfg. advertised rating above 30A (the first 6 and 2 in the bottom)... none safely reach the 30A or higher mark. So much for truth in advertising, eh?

I wonder, considering that only 1 out of 32 cells makes 25/30A safely... is the HB6 you tested a freak of manufacturing tolerance? Any chance of obtaining a few more, preferably from different lots (if one can tell such a thing), and doing a retest, to see if the values obtained were/are consistent... or a fluke?

Cheers,
CAH

Here's a shootout between the two HB6 cells I have...

They're essentially identical except for their capacity. Cell2 (the one I just tested) has a capacity about 4% lower than Cell1.

Every cell has a different capacity but a 4% difference seems a bit high. Cell1 had undergone several more cycles before its 30A discharge than Cell2. Cell2 was cycled twice at 10A to check its basic functionality and then discharged at 30A. This might account for the extra couple percent difference in the measured capacity for Cell1.